← The Saudi aviation reference, in one place.
NTSB Safety Study - Public and GA Aircraft Accidents (SS0101)
Reproduced for study. Always verify against the official GACAR at gaca.gov.sa.
NATIONAL
TRANSPORTATION
SAFETY BOARD
WASHINGTON, D.C. 20594
SAFETY STUDYPB2001-917004
NTSB/SS-01/01
Public Aircraft Safety
Safety Study
Public Aircraft Safety
NTSB/SS-0101
PB2001-917004 National Transp ortation Safety Board
Notation 7393 490 LEnfant Plaza, S.W.Adopted October 23, 2001 Washington, D.C. 20594
National Transportati on Safety Board. Public Aircraft Safety . Safety Study NTSB/SS-01/01.
Washington, DC: NTSB, 2001.
Abstract: Public aircraft are aircraft operated for th e purpose of fulfilling a government function that
meet certain conditions specified under Title 49 United States Code , Section 40102(a)(37). The Safety
Board identified 341 public aircraft accidents that occurred during the years 19932000. Using activity
data from the Federal Aviation Administration (FAA) (fo r the period 19961999), the Board calculated an
accident rate of 3.66 accidents per 100,000 flight hours fo r nonmilitary, nonintelligence public aircraft.
Using activity data from the General Services Administration (also for the period 19961999), the Board
calculated an accident rate of 4.58 per 100,000 flight hours for nonmilitary, nonintelligence Federal
aircraft. Both rates were lower than the general av iation accident rate (7.2 accidents per 100,000 flight
hours), but higher than the accident rate for air taxis (3.47), scheduled Part 14 CFR 135 operations (1.06),
or 14 CFR Part 121 operations (0.30). Comparis ons between public and general aviation accidents
revealed similar proportions of broad causal factors. However, accidents in these two sectors differed in
other ways. A higher proportion of public aircraft crashed during local flights, at off-airport locations, and
during maneuvering phases of flight. Also, accident-involved public airc raft pilots were more likely than
accident-involved general aviation p ilots to hold advanced ratings. Li mitations and flaws associated with
the FAAs nonairline activity estimates made it imposs ible for the Board to make carefully controlled
comparisons of the safety of public versus civil aircraft . The data were not sufficie ntly detailed to support
the calculation of public and civil aircraft accident ra tes for specific purposes of flight (for example, aerial
observation, aerial application, and so on). Furthermore, FAA flight hour estimates are potentially biased
because they are based on a survey th at is administered to a sample of aircraft owners listed in the FAAs
Civil Aircraft Registry, which is know n to contain many outdated or inaccu rate records. As a result of these
findings, the Board made safety recommendations to the Federal Aviation Admini stration and the General
Services Administration.
The National Transportation Safety Board is an independent Federa l agency dedicated to promotin g aviation, railroad, highway, m arine,
pipeline, and hazardous ma terials safety. Estab lished in 1967, the agency is mandated by Congress through the Independent Safet y Board
Act of 1974 to investigate transportation acci dents, determine the probable causes of the accidents, issue safety recommendatio ns, study
transportation safety issues, and evaluate the safety effectiven ess of government agencies invol ved in transportation. The Safe ty Board
makes public its actions a nd decisions through accide nt reports, safety studie s, special investigation reports, safety recommen dations, and
statistical reviews.
Recent publications are av ailable in their entirety on the Web at <http:// www.ntsb.gov>. Other inform ation about available pub lications also
may be obtained from the Web site or by contacting:
National Transportation Safety Board
Public Inquiries Section, RE-51
490 LEnfant Plaza, S.W.
Washington, D.C. 20594(800) 877-6799 or (202) 314-6551
Safety Board publications may be purchased , by individual copy or by subscription, fro m the National Techni cal Information Serv ice. To
purchase this publication, order report number PB2001-917004 from:
National Technical Information Service
5285 Port Royal Road
Springfield, Virginia 22161
(800) 553-6847 or (703) 605-6000
The Independent Safety Board Act, as codified at 49 U. S.C. Section 1154(b), precludes the admi ssion into evidence or use of Boa rd reports
related to an incident or accident in a civil action for damages resulting from a matter mentioned in the report.
iii Safety Study
Contents
Acronyms and Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Chapter 1: Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Oversight of Public Aircraft Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
FAA Analysis of Public Aircraft Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Chapter 2: Accident and Exposure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Accident Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Exposure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
All Public Aircraft Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Federal Public Use Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6
Chapter 3: Accident Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Chapter 4: Accident Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Accident Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Trends and Seasonal Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Aircraft Category. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Local Versus Point-to-Point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
First Occurrence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Phase of Flight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Causes or Contributing Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Pilot Certification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Chapter 5: Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Appendixes
A: Partial List of Federal Aviation Safety Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
B: Statutory Definition of “Public Aircraft”. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
C: Effect On the Public Aircraft Accident Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
D: Selected Portions of 14 CFR Part 47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
iv Safety Study
Acronyms and Abbreviations
Abbreviated Terms
Air-21 Wendell H. Ford Aviation Investment and Reform Act
for the 21st Century
CAP Civil Air Patrol
CFR Code of Federal Regulations
FAA Federal Aviation Administration
FAIRS Federal Aviation Interactive Reporting System
FAMIS Federal Aviation Management Information System
GA general aviation
GADIT General Aviation Data Improvement Team
GA survey General Aviation and Air Taxi Activity Survey
GSA General Services Administration
ICAP Interagency Committee for Aviation Policy
OMB Office of Management and Budget
PCIE Presidents Council on In tegrity and Efficiency
USPS United States Postal Service
VIS Vital Information Statistics
v Safety Study
Executive Summary
Section 702 of Public Law 106181, the Wendell H. Ford Aviation Investment and
Reform Act for the 21st Centur y, directed the National Tr ansportation Safety Board to
conduct a study to compare the safety of public aircraft and civil aircraft, and to review
safety statistics on ai rcraft operations since 1993. Publ ic aircraft refers to certain
government aircraft operations. Public aircraft status mean s, among other things, that an
aircraft will not be subject to some of the regulatory requirements applicab le to civil (or
civilian) aircraft. Although the precise statutory definiti on has changed over the years,
public aircraft operations gene rally include law enforcement, low-level observation, aerial
application, firefighting, search and resc ue, biological or geological resource
management, and aeronautical research.
For this study, the Safety Board identi fied 341 public aircraft accidents that
occurred during the years 19932000. Using act ivity data from th e Federal Aviation
Administration (FAA) (for the period 19961999), the Board calculated an accident rate
of 3.66 accidents per 100,000 flight hours for nonm ilitary, nonintelligence public aircraft.
Using activity data from th e General Services Administ ration (also for the period 1996
1999), the Board calculated an accident rate of 4.58 per 100,000 flight hours for
nonmilitary, nonintelligence Federa l aircraft. Both rates we re lower than the general
aviation accident rate (7.2 ac cidents per 100,000 flight hours), but higher than the accident
rate for air taxis (3.47), scheduled 14 CFR Pa rt 135 operations (1.06) , or 14 CFR Part 121
operations (0.30). Comparisons between public and genera l aviation accidents revealed
similar proportions of broad causal factors. However, accidents in these two sectors
differed in other ways. A hi gher proportion of public aircraft crashed during local flights,
at off-airport locations, and during maneuvering phases of fli ght. Also, accident-involved
public aircraft pilots were mo re likely than accident-invol ved general aviation pilots to
hold advanced ratings.
Limitations and flaws associated with the FAAs nonairline activity estimates
made it impossible for the Safety Board to make carefully controlled comparisons of the
safety of public versus civil ai rcraft. The data were not suff iciently detailed to support the
calculation of public and civil aircraft accident rates for spec ific purposes of flight (for
example, aerial observation, aeri al application, and so on). Furthermore, FAA flight hour
estimates are potentially biased because they are based on a su rvey that is administered to
a sample of aircraft owners listed in the FAAs Civil Airc raft Registry, which is known to
contain many outdated or inaccurate records.
As a result of this study , the Safety Board issued eight safety recommendations to
the Federal Aviation Administration and two safety recommendations to the GeneralServices Administration.
1 Safety Study
Chapter 1
Background
Section 702 of Public Law 106181, the Wendell H. Ford Aviation Investment and
Reform Act for the 21st Cent ury (Air-21), directed the National Transportation Safety
Board to conduct a study to compare the safety of public aircraft and civil aircraft, and
to review safety statistics on aircraft operations since 1993. Public aircraft refers to
certain government aircraft ope rations. Public aircraft stat us means, among other things,
that an aircraft will not be subject to some of the regulatory requirements applicable to
civil (or civilian) aircraft. (A ppendix A provides a partial listing.)1 Although the precise
statutory definition has chan ged over the years, public ai rcraft operations generally
include law enforcement, low- level observation, aerial a pplication, firefighting, search
and rescue, biological or ge ological resource management, and aeronautical research.2
The Independent Safety Board Act Amen dments of 1994 narro wed the definition
of public aircraft, expanding the number of nonpublic government aircraft operations
(considered civil by the Federal Aviation Ad ministration (FAA)). Th e act specified that,
among other things, public aircra ft status did not attach to government-owned aircraft
transporting passengers (other than those pe rsons required to be on board the aircraft to
accomplish the governme nt function for which the aircraft is operated, such as search and
rescue or in-flight research), unless the ai rcraft was operated by the Armed Forces or a
United States intelligence agency.3 Air-21 further redrafted the definition of public
aircraft, modifying the statut ory language to more clearly specify requirements for public
aircraft status.
1Although all aircraft must follow certain sections of 14 CFR Part 91, public aircraft operators do not
have to comply with safety regulations, including maintenance rules under 14 CFR Part 43 or pilot
certification standards under 14 CFR Part 61.
2Aircraft used by the Department of Defense are al so public aircraft, but this study considered only
nonmilitary, nonintelligence aircraft.
3P.L. 103411. The 1994 amendments also bestowed upon NTSB, for the first time, specific
jurisdiction to investigate all accident s involving public aircraft, except thos e public aircraft operated by the
Armed Forces or by a United Stat es intelligence agency. Prior to th e 1994 amendments, however, the NTSB
had in place memoranda of understanding with ma ny government operat ors that enabled NTSB
investigation of a number of public aircraft accidents.
2 Safety Study
The term public aircraft is actually somewhat mi sleading because the phrase
refers not to a specific popul ation of aircraft, but to govern ment-sponsored flights meeting
specific criteria laid out in the Code of Federal Regulations (CFR). Essentially, public
aircraft operations are a subset of governmen t-sponsored aircraft operations (figure 1).
The regulations determining wh ether a particular flight qualifies for public aircraft
status are complicated. Appendi x B presents the current st atutory definition of public
aircraft. In this report, the te rm public aircraft operations wi ll be used to describe flight
operations meeting the statutor y definition of public aircra ft detailed in appendix B.
Public aircraft will describe aircraft pe rforming these operations . Government aircraft
operations will descri be the larger set of flight operations conducte d to perform a
government function (of which public aircraft operations are a part).
Oversight of Public Aircraft Operations
Because public aircraft operators are exempted from certa in aviation safety
regulations, government organi zations conducting public airc raft operations supervise
their own flight operations wi thout oversight from the FAA. Oversight policies are most
clearly specified at th e Federal level. A circ ular issued by the U.S. Office of Management
and Budget (OMB) has guided airc raft management at executiv e agencies of the Federal
government since 1983.4 A 1989 revision of the circular directed the U.S. GeneralFigure 1. Government aircraft operations
versus public aircraft operations.
4OMB Circular A-126 Improving the Management and Use of Government Aircraft.Government Aircraft
Operations
"Public Aircraft"
OperationsBackground
3 Safety Study
Services Administration (GSA) to create and maintain a si ngle office responsible for
oversight of Federal aircraft management a nd to establish a single interagency committee
for assisting the GSA in this role. This led to the creation of the Interagency Committee
for Aviation Policy (ICAP).5 A 1992 revision of the circ ular specified, among other
things, requirements for aviation safety pr ograms within Federal agencies, adding the
responsibility for collecting accident and incident data. In addition, the revision
recommended that Federal agencies a dhere voluntarily to portions of the Federal Aviation
Regulations from which they were exempted.
The United States Senate Committee on Governmental Affair s, Subcommittee on
General Services, Federalism, and the District of Columbia , chaired by Senator Jim Sasser
(DTN), began a study of the Fe deral governments management of its civilian aircraft
fleet in August 19 91. In its report, Management of Federal Civi lian Aircraft: Findings and
Recommendations , presented to President Willia m J. Clinton in April 1993, the
subcommittee reported that in formation concerning inventory and usage of aircraft was
inaccurate or incomplete, that many aircraft were underutilized, a nd that there were no
binding safety standards in ef fect. In addition, the subcommi ttee concluded that the GSA
had been hampered in dealing with other executive agencies by a perception that the GSA
lacked adequate authority and aviation-related expert ise. In response to these findings, the
subcommittee proposed a blueprint for reform ing the management of government aircraft.
Executive agencies responsible for governme nt aircraft operations were directed to
cooperate with an audit conducted by the GSA inspector general. In addition, the
subcommittee recommended that Congress consider eliminati ng the exemption of
Federal civilian aircraft from commercial aviation safety requirements, providing for
specific exemptions only after the demonstration of unusual or extraordinary government
needs.6
Three well-publicized public aircraft accidents in a 14-month period in 1992 and
1993 also brought scrutiny on government aircraft operations, and public aircraft
operations in particular. On August 7, 1992, a State-owned Sikor ski S-76A helicopter
crash-landed near Grae fenburg, Kentucky, seriously in juring five of the six persons
aboard, including the Governor of Kentucky.7 The Safety Board reported that the probable
cause of this accident was an inadequate preflight inspecti on by the flight crew who failed
to ensure that all four of the engine cowli ng latches were properly secured, which resulted
in subsequent failure of secti on II of the tail rotor drive sh aft after the cowling contacted
the main rotor blades and tail rotor drive shaft.
On April 19, 1993, a State-owned Mitsubi shi MU-2B-60 crashed near Zwingle,
Iowa, following the in-flight loss of a pr opeller blade at 24,000 feet , killing South Dakota
5The GSA established the ICAP in 1989 at the dir ection of the OMB. The GS A chairs the committee.
About 17 Federal agencies are member s, although this number varies from year to year. With advice from
ICAP, GSA makes policy for Federal aviation management.
6United States Senate Committee on Government al Affairs, Subcommittee on General Services,
Federalism, and the District of Co lumbia [Jim Sasser, Chairman], Management of Federal Civilian Aircraft:
Findings and Recommendations (Washington, DC: U.S. Senate, April 2, 1993).
7NTSB Accident No. NYC92GA147.Background
4 Safety Study
Governor George Mickel son and eight others.8 The Safety Board reported that the
probable cause of this accident was fatigue cracking and fracture of the propeller hub arm.
The resulting separation of the hub arm and the propeller blade damaged the engine,
nacelle, wing, and fuselage, thereby causi ng significant degradation of aircraft
performance and control that made a successful landing pr oblematic. The cause of the
propeller hub arm fractur e was a reduction in the fatigue strength of the material because
of manufacturing and time-relat ed factors, that reduced th e fatigue resistance of the
material, probably combined with exposure to higher-than-normal cyclic loads during
operation of the propeller at a critical vibration frequenc y which was not appropriately
considered during the airplane/p ropeller certification process.
On October 26, 1993, a Beechcraft 300-F ow ned and operated by the FAA crashed
into a mountain near Front Royal, Virginia , while on an airport inspection trip, killing
three persons.9 In its accident report, the Safety Bo ard faulted the FAA flying program for
inadequate management over sight, stating that the proba ble cause of this accident
encompassed not only the failure of the pilo t-in-command to ensure that the airplane
remained in visual meteorological conditi ons over mountainous terrain, but also the
failure of the FAA executives and managers responsible for the FAA flying program to:
(1) establish effective and a ccountable leadership and overs ight of flying operations; (2)
establish minimum mission a nd operational performance sta ndards; (3) recognize and
address performance-related problems among the organizati ons pilots; and (4) remove
from flight operations duty pilots who were not performing to standards.
In December 1996, the Presidents Council on Integrity and Efficiency (PCIE)
issued a report on the Federal civilian agencies aircraft management programs.10 A series
of audit reports (20 reports covering 11 diff erent agencies) prepared by the GSA inspector
general were included in the PCIE report. These audits confirmed the safety-related,
operational, and administrative shortcomings described in the Sasser report. The GSA
found frequent and significant in stances where agency safety standards (generally less
stringent than FAA safety regul ations) were not being met. Th e authors of the PCIE report
lauded the provision of the I ndependent Safety Board Act Amendments of 1994 requiring
government aircraft operations involving carriage of passengers or cargo to comply with
FAA standards. The report also acknowledged the provision giving the Safety Board the
responsibility and authority to investigate al l nonmilitary, nonintelli gence public aircraft
accidents, commenting, these actions go a long way towards a ddressing the concerns
relating to aircraft safety.
In 1997, the Associate Admi nistrator, Office of Governmentwide Policy, GSA,
established an independent Ai rcraft Management Policy A dvisory Board to examine all
aspects of the manage ment of federally sponsored av iation programs, including safety
aspects. In June 1998, the advisory board reported that, although pr ogress had been made
8NTSB Accident No. DCA93GA042.
9NTSB Accident No. DCA94GA010.
10Presidents Council on Integrity and Efficiency, Combined Report on the Federal Civilian Agencies
Aircraft Management Programs , Report No. A43006/O/W/F97011 (Washington, DC: PCIE, December 16,
1996).Background
5 Safety Study
on the issues raised in the Sasser and PCIE reports, fundamental problems remained, and
these problems stemmed from a lack of indepe ndent safety oversight of Federal aircraft
operations. In addition, the advi sory board referred to a c ontinuing questioning of GSAs
role in Federal public aircra ft management, stating, the re is widespread uncertainty
about who is in charge, and th ere is no clear enforcement aut hority. As a result of these
findings, the advisory board recommended: (a) the revisi on of OMB Circular A-126 to
better define GSAs authority to set aircraft management po licy and safety guidelines, (b)
the proposal of statutory langua ge to Congress that would place the responsibility for
regulation, oversight, and enfo rcement of all Federal govern ment aircraft operations on
the FAA, and (c) the allocation of resources to the FAA comm ensurate with this increase
in responsibilities.11 The advisory board also reco mmended that the GSA associate
administrator be designated ch air of the ICAP, and that IC AP member agencies appoint
representatives of equivalent stature to ease GSAs dealings with the member agencies on
matters involving aircraft management.
Since the release of the advisory boards recommendations, GSA has assisted the
OMB in drafting a revision of Circular A-126. GSA also dr afted a revision of its own
regulations, to be contained in 41 CFR 102-33, to better defi ne its authority for aircraft
management. Both revisions are being reviewed by OMB an d have yet to be formally
approved. The GSA deputy associate administra tor met with representatives of the FAA
and congressional staff me mbers in mid-1998 to discuss the advisory boards
recommendation that GSA propose statutory language to Congress placing the
responsibility for regulati on, oversight, and enforcemen t of all Federal government
aircraft operations on the FAA. According to a representative of the GSAs Aircraft
Management Policy Division, neither the FAA nor congressional staff members present at
that meeting were receptive to the recomm endation. No further ac tion has been taken. In
other developments, the GSA ha s designated its associate administrator as the chair of
ICAP, and some of ICAPs memb er agencies have appointed representatives of equivalent
stature to ease GSAs deali ngs with those agencies.
FAA Analysis of Publ ic Aircraft Safety
The FAA performed an analysis of public aircraft safety in 1997.12 This study,
which explored the legislativ e history and the characteris tics of government-owned or
government-operated aircraft and examined av ailable safety data, was never published. It
was, however, used as the basis for a brie fing of the U.S. Gene ral Accounting Office,
which was examining the issue of public aircraft safety in re sponse to the conclusions and
recommendations published in the report of the GSAs Ai rcraft Management Policy
Advisory Board. The number of aircraft engaged in governme nt aircraft operations was
estimated in the FAA study using preliminar y data from the ICAP, which had begun to
11U.S. General Services Administration, Report of the Aircraft Management Policy Advisory Board
(Washington, DC: GSA, 1998).
12Federal Aviation Administration Office of Accident Investigation, Safety Analysis Branch, An
Analysis of Public Aircraft Safety (Washi ngton, DC: FAA, 1997, unpublished document).Background
6 Safety Study
build a list of aircraft owned or operated at all levels of government,13 and data from the
FAAs National Vital Information Statistics (VIS) database.14 The FAA compared
accident characteristics for government ve rsus general aviation (GA) operations, and
across levels of government. The resulting FAA analyses were of limited value because
the FAA lacked activity statistics for government aircraft operations.
Since that time, the FAA has begun publ ishing public airc raft flight hour
estimates. The FAA first released estimate s in 1997 for the 1996 cal endar year. In its
study, the Safety Board used these data to co mpare the safety of publ ic and civil aircraft
operations.15 The Board calculated accident rates for the period 19961999 rather than
1993present because FAA estimate s of public aircraft activi ty were available only for
these years. Furthermore, th e Board was not responsible for investigating most public
aircraft accidents prior to mid-1995. Before 1996, the Boar ds public aircraft accident
record is less complete. In short, th e period 19961999 was the time frame for which
complete data were availabl e. The remainder of the repor t discusses the calculation of
these rates, comparison of accident character istics, and data limitations encountered by
Safety Board staff during the cour se of this effort to compare the safety of p ublic and civil
aircraft.
13This data collection effort, performed primarily by the Department of Energy, an ICAP member, has
since been discontinued because of difficulties in maintaining the currency of the data set.
14The FAA uses the VIS database to track commercial and government certificates.
15Accident rates are calculated by dividing accidents by some measure of transportation activity, such
as trips taken, miles traveled, or hou rs spent in transit. This adjustment is sometimes called normalization.
The rationale for normalization is as follows: traveler s and system operators run the risk of experiencing a
transportation accident primar ily when they travel. The more people travel, the more they are exposed to
risk, and the more likely they are to be involved in a tr ansportation accident.Background
7 Safety Study
Chapter 2
Accident and Exposure Data
Accident Data
The Safety Board maintains the official government census of civil aviation
accidents and, as of Ap ril 23, 1995, certain public ai rcraft accidents as well.16 The
Independent Safety Board Act Amendments of 1994 required most public aircraft
operators to report accidents to the Safety Board. The Board relies on its investigators to
identify incoming reports of public aircraft a ccidents, and to distinguish these from civil
aircraft accidents. I nvestigators code accident-involved public aircraft public use or
investigation of a government agency as they enter acci dent data in the Boards
Aviation Accident/Incident Database. Base d on these codings, Safety Board staff
identified over 300 accidents that occurr ed between January 1993 and December 2000.
Staff reviewed a brief report of each accident in the sample. The case-by-case
review of the public aircraft accident sample could not ensu re that every accident flight
was operated in a manner consistent with th e statutory definition of public aircraft in
effect at the time the accide nt occurred. The statutory defi nition of public aircraft status
takes many factors into account that are not documented in a typical ai rcraft accident
record (for example, length of the lease agreement for St ate governments, presence of
nonessential crewmembers, and so on). The purpose of the review was merely to look for
cases where the information in the accident record wa s clearly inconsistent with
classification of an airc raft operation as public.
Staff inspected each case to determine whether the owner or the operator of the
accident aircraft was a nonmilitary, nondefe nse government organiza tion. If so, the case
was retained. If not, the long narrative and the accident doc ket for that accident were
examined for other information suggesti ng that the aircraft was on a government-
sponsored mission. If such evidence was found, the case was retained. If no such
information was found, the case was discarde d. Eleven accidents (3 percent of the
accident set) were eliminated from the sample based on th ese criteria. Three additional
accidents were discarded dur ing the review process beca use they involved aircraft
operated by non-U.S. governments that crashed outside U.S. territory.17 Although they
were on a mission sponsored by a military organization, tw o privately owned aircraft
operating under contract to th e U.S. Coast Guard and seve n privately owned aircraft
operating under contract to the Department of Defense were included in the accident
sample because the operators were civilian. Th ese aircraft are excluded from the accident
sample used for calculating the Federal ai rcraft accident rate later in this report.
16The Safety Board does no t maintain official reco rds of military or inte lligence aircraft accidents.
17NTSB Accident Nos. FTW97RA314, IAD00RA033, and SEA00WA163.
8 Safety Study
During the review, staff noticed one system atic error made by the Safety Boards
investigators: Civil Air Patrol (CAP) accidents were coded publ ic use, despite the fact that
CAP flights are not technically considered public aircraft. CAP aircraft were left in the
accident sample because the FAA includes CAP flight hours in its estimate of public use
flight activity. (Appendix C give s a more detailed explanation.)
The final sample consisted of 343 public aircra ft involved in 341 accident events
(table 1). These accide nts resulted in 167 deat hs and 220 injuries. Each record contained
information on a variety of event-, aircraft -, and occupant-related variables. Staff
classified the accidents in terms of severi ty using a four-categor y classification system
developed by the Board for classifyi ng air carrier accide nts (table 2).18 Staff also classified
accident-involved public aircraft according to the level of gove rnment served (table 3).
The majority of the missions (51 percent) were Federal. The rest were divided evenly
between State and local governments. Five pre-1996 accident airc raft could not be
categorized by level of government because their accident records lacked sufficient
detail.19
18This classification system was developed by the Safety Board in response to congressional direction
under the Federal Aviation Reauthorization Act of 1996 to develop a system that was more informative than
the traditional fatal/nonfatal dichotomy.
19NTSB Accident Nos. ATL93T#A01, MIA 93T#A02, FTW94T#A03, SEA94T#A05, and
ANC95T#A01.Accident and Exposure Data
9 Safety Study
Table 1. Accident-involved public aircraft and associated injuries, 19932000.a
Accident severity Injuries
Type of operation YearAccident
aircraft Fatal NonfatalPersons
killedPersons
injuredPersons
uninjured
Public Aircraft 1993 36 8 28 23 25 50
1994 46 10 36 24 48 42
1995 45 9 36 19 18 491996 42 6 36 12 20 42
1997 41 9 32 15 34 43
1998 46 15 31 25 23 461999 41 6 35 22 31 54
2000 46 15 31 27 21 36
Total 343 78 265 167 220 362
General Aviation
b 1993 2,059 405 1,654 740 1,020 2,227
1994 2,014 410 1,604 730 1,052 2,188
1995 2,077 420 1,657 734 964 2,2421996 1,939 368 1,571 634 898 1,944
1997 1,873 362 1,511 641 914 1,928
1998 1,930 377 1,553 628 892 1,9371999 1,938 349 1,589 630 925 2,032
2000 1,870 356 1,514 630 844 1,990
Total 15,700 3,047 12,653 5,367 7,509 16,488
Air Taxi 1993 87 23 64 42 24 41
1994 96 29 67 63 32 36
1995 88 26 62 52 14 231996 102 30 72 63 22 23
1997 100 20 80 39 23 31
1998 86 17 69 45 10 401999 87 17 70 38 14 31
2000 92 23 69 71 10 43
Total 738 185 553 413 417 1,296
aStatistics for general aviation and air taxi operations are provided as contex t for the public aircraft accident statistics.
Accident-involved public, general aviation, and air taxi aircraft were identifi ed by Safety Board staff using the Boards
Aviation Accident/Incident Database.
bThe Boards policy has been to include public aircraft acci dents that are investigated by the Board in the category
general aviation for press releases cont aining aviation safety statistics and for the Annual Review of Aircraft Accident
Data. This practice was continued here to maintain consis tency with aviation safety st atistics previously published by
the Board. As a result, 285 public acci dent aircraft and related injuries were included in the general aviation statistics
presented in this table. Most of thes e accidents occurred during 1995 and later years.Accident and Exposure Data
10 Safety Study
Exposure Data
The Safety Board gathered government airc raft flight hour data from two sources:
the FAA Office of Aviation Policy and Plans, and the GSA Aircraft Management Policy
Division. The FAA publishes ac tivity estimates for public use aircraft operations, a
category that is similar to but less restrictive than th e statutory definition for public
aircraft.20 The GSA collects flight hour data from executive agencies of the Federal
government that operate aircra ft. The two sets of exposure data cover overlapping sets of
operations, but they are collected independent ly. The FAA estimates activity for all levelsTable 2. Classification of public, general aviation, and air taxi accidents by severity.a
Public General aviation Air taxi
Severity Accidents Percent Accidents Percent Accidents Percent
Major 109 32 4,247 27 205 33
Serious 29 9 1,148 7 39 6Injury 1 0 126 1 6 1Damage 202 59 9,957 64 379 60Unknown 31 0 1 0
Total 341 100 15,509 100 630 100
aStatistics for general aviation and air taxi operations are provided as contex t for the public aircraft accident statistics.
Accident-involved public, general aviation, and air taxi aircraft were identifi ed by Safety Board staff using the Boards
Aviation Accident/Incident Database. Multip le-aircraft accidents were counted as a single event for this table. Accident
severity was defined as follows: major accident an aircraft was destroyed, more than one person was killed, or an
aircraft was substantially damaged and one person was killed; serious accident no airplanes were substantially
damaged but one person was killed, or an ai rcraft was substantially damaged and at least one person was seriously
injured; injury accident no airplane was substantially damaged but at least one person was seriously injured; damage
accident an aircraft was substantially damaged and no one was killed or seriously injured.
Table 3. Level of government served by acci dent-involved public aircraft, 19932000.a
Year of accident Federal State Local Unknown Total
1993 18 7 9 2 36
1994 22 10 12 2 46
1995 22 11 11 1 45
1996 27 9 6 421997 19 12 10 41
1998 27 9 10 46
1999 14 13 14 412000 25 10 11 46
Total 174 81 83 5 343
aAccident-involved public, general aviation, and air taxi aircraft were identif ied by Safety Board staff using the Safety
Boards Aviation Accident/Incident Database. Level of gover nment mission was determined by examining the aircraft
operator and the narrative information contained in Board acci dent records. Five accident aircraft (cases ATL93T#A01,
MIA93T#A02, FTW94T#A03, SEA94T#A05, and ANC95T#A01) could not be categorized. All five of these aircraft
crashed prior to 1996, and these accidents were not investigated by Safety Board personnel.
20The FAA defines public use aircraft operations on its flight hour survey qu estionnaire as Federal,
state, or local government owner or leased aircraft used for the purpose of fulfilling a governmental
function.Accident and Exposure Data
11 Safety Study
of government; the GSA reports activi ty only for the Federal government.21 Both sets of
activity statistics describe populations of government aircraft operations that are broader
than the population of operations qualifying for public aircraft status. However, they are
the best data currently available.
The Safety Board could not find independe nt estimates of State or local public
aircraft activity. The PCIE report in 1996 acknowledged the difficulty in finding such
information, as did the FAAs unpublished anal ysis of public aircraft safety in 1997.
During the search for da ta on State and local public airc raft operators, the Safety Board
could not locate even a comprehe nsive list of State or local government aircraft operators.
The National Association of State Aviation Officials provided a list of 165 aircraft
involved in State executive transportation. Since the stat utory change in 1994, however,
executive travel has not been categorized as a public aircraft operation. The U.S.
Department of Agriculture provide d a list of State forestry c ontacts. However, this list of
contacts included county agencies, local ag encies, Federal empl oyees, and private
citizens, with no clear means to distinguish among the opera tors in terms of level of
government. The Airborne Law Enforcement As sociation indicated that the organization
did not maintain a comprehens ive list of operators or ope rational data. After repeated
efforts yielded no useful information, the Sa fety Board proceeded with the study using the
best approximations of public aircraft activity available: flight hour estimates from the
FAA and the GSA.
All Public Aircraft Operations
The FAA Office of Aviation Policy a nd Plans obtains its public use aircraft
activity estimates from the FAA-sponsored General Aviation and Air Taxi Activity
Survey (GA survey). The firs t GA survey took place in 1978,22 collecting data on flight
activity during the 1977 cale ndar year. Since 1978, the name of the survey has changed,
but the FAAs overall approach to estimating nonairline flight activity has remained the
same, with some minor change s in the design of the sampli ng process. Ques tionnaires for
the 1999 survey were mailed to the register ed owners of over 30,000 nonairline aircraft
(about 12 percent of the fleet).23 The FAA selected these aircra ft from all aircraft records
in the FAAs Civil Aviation Registry, using a stratification procedure based on 19 aircraft
categories and 9 geogr aphic regions. Combining thes e two dimensions yielded 172
different aircraft groups from which samples were drawn at random. In statistical terms,
these groups are referred to as cells of the samp le frame matrix. Wi thin each cell, a
predetermined number of aircraft were selected for inclusi on in the survey. The number of
21These activities do not include military or intelligence aircraft operations.
22Prior to 1978, the FAA used the Aircraft Registration Eligibility, Identification, and Activity Report,
AC Form 8050, to collect data on GA activity and avionics. The form was sent to all owners of civil aircraftin the United States and served two purposes: Part 1 was a mandatory aircraft registration revalidation form,
and Part 2 was voluntary and applied to GA aircraft only, asking questions on the owner-discretionary
characteristics of the aircraft such as flight hours, avionics equipm ent, base location, and use. This
information was used by the FAA to estimate aircraft activity.
23The FAA surveys aircraft owners, not pilots, b ecause the GA survey is also used to acquire
information on aftermarke t avionics equipage and because pilo ts commonly fly mu ltiple aircraft. Accident and Exposure Data
12 Safety Study
aircraft selected were chosen to minimize sampling error a nd to ensure that individual
aircraft owners were surveyed as infrequently as possible.
Each aircraft owner selected for in clusion in the 1999 survey received a
standardized 19-question GA su rvey form. This form request ed the following information:
hours flown by the aircraft duri ng the calendar year, lifetime airframe hours, percentage of
flight hours that the aircraft operated while rented or leased, and proportion of flight hours
under different flight plans and weather c onditions. In addition, ow ners were asked to
estimate the percentage of hour s flown for each of 15 differ ent purposes (table 4). Public
use was included as a resp onse category for 1996 and subse quent years. Beginning with
the 1996 survey data, the FAA estimated public aircraft flight hou rs by multiplying an
aircrafts total flight hours by the percentage of hours flow n for public use, weighting
each product by an appropriate constant rela ted to the sample de sign, and summing the
results across aircraft.
While studying the FAAs public aircraft flight hour esti mation process, the Safety
Board identified important weaknesses that shoul d be discussed in this report, because the
comparison of public and civil aircraft safety contained in this report depended on the
reliability and validity of flight hour estimates.
First, as mentioned earli er, the definition of public use provided on the GA
survey form is broader than the statutory definition for public airc raft. The definition onTable 4. Purpose-of-flight categories for the 1999 GA survey.a
1. Personal/Recreational: Flying for personal reasons (excludes business transportation)
2. Instructional: Flying under the supervision of a flight instructor (includes student pilot solo; excludes proficiency
flight)
3. Business Transportation: Individual use for business transportation without a paid, professional crew
4. Corporate/Executive Transportation: Business transportation with a paid, professional crew
5. Regional/Commuter: 14 CFR Part 135 scheduled passenger service only
6. Air Taxi: 14 CFR Part 135 on-demand passenger and all cargo operations (not scheduled passenger service
or air tours)
7. Air Tours: Commercial sight-seeing conducted under 14 CFR Part 135
8. Sightseeing: Commercial sight-seeing conducted under 14 CFR Part 91
9. Public Use: Federal, state, or local government owner or leas ed aircraft used for the purpose of fulfilling a
governmental function
10. Aerial Observation: Aerial mapping/photography, patrol, search and rescue, hunting, traffic advisory,
ranching, surveillance, oil and mineral exploration, etc.
11. Aerial Application in Agriculture and Forestry: Crop and timber production and protection
12. Other Aerial Application: Public health sprayings, cloud seeding, firefighting, including forest fires, etc.
13. External Load: Operation under 14 CFR Part 133, rotorcraft external load operations, examples include;
helicopter hoist, hauling logs, etc.
14. Air Medical Services: Air ambulance services, rescue, human organ transportation
15. Other Work Use: Construction work (not 14 CFR Part 135 operat ion), parachuting, aerial advertising, towing
gliders, etc.
aThese categories and associated definitions were provided on the 1999 General Aviation and Ai r Taxi Activity survey
form.Accident and Exposure Data
13 Safety Study
the survey form actually refers to all govern ment aircraft operations . Therefore, the flight
hour estimate is an inflated substitute for actual public aircraft flying activity.
Second, the estimation of airc raft flight hours by purpose of flight depends, to a
great extent, on the record-keepi ng policies and memories of aircraft owners, and, in some
cases, the willingness and ability of aircraft owners to obtain needed information from the
pilots who fly their aircraft. When the owner is not the sole operator of an aircraft, the
owner may have difficulty estimating flight hours by purpose of flight. It is difficult to
know the extent to which these difficulties might distort fl ight hour estimates, but the
potential for erro r clearly exists.
Third, the FAAs Civil Aviation Registry r ecords are used to estimate the size and
characteristics of the GA fleet and as a sour ce of contact information for mailing surveys
to aircraft owners. After surveys are return ed, registry data are used to extrapolate
reported activity to the entire GA fleet. The quality of the ac tivity estimates derived from
the GA survey depends greatly on the accu racy and completeness of records in the
registry. However, the FAA c ontractor responsible for conduc ting the GA survey recently
estimated that the proportion of incorrect GA aircraft records in the regi stry lies between
19 and 40 percent.24
In order to explain how this could be possible, it is important to understand the
FAAs aircraft registration policies (as sp ecified in 14 CFR Part 47). When someone
purchases an aircraft they intend to opera te, they must submit an application for
registration to the Civil Aviati on Registry. This application contains certain information
about the aircraft as well as contact inform ation for the aircraft owner. After initial
registration, 14 CFR 47.45 requires the aircraft owner to notify the FAA aircraft registry
within 30 days of any permanent change of a ddress. After 3 years ha s elapsed since receipt
of registration information from an aircraft owner, the FAA sends a Triennial Aircraft
Registration Report form. The ai rcraft owner is required to return this form within 60
days, verifying basic aircraft information as well as cont act information for the owner.
Although 14 CFR 47.51 specifies that Refusal or failure to s ubmit the Triennial Aircraft
Registration Report with the information required by this secti on may be cause for
suspension or revocation of th e Certificate of Aircraft Registration, the FAA has not
enforced this requirement for at least 20 years. Neither has the FAA enforced the
requirement to submit notific ation to the FAA within 30 da ys of a permanent change of
address. (Appendix D provides selected porti ons of 14 CFR Part 47 describing aircraft
registration requirements.)
Owner contact information and other parts of an aircraft record are outdated for
many aircraft. Evidence also suggests that th e currency of the registry continues to
deteriorate. Each year, the co ntractor conducting the GA surv ey excludes aircraft owners
24Based on analyses by the FAAs principal contractor for the GA survey, PA Consulting, as described
in a memo from Nicholas Ni tka and Lark Lee to the FAA on April 6, 2001. Incorrect records were described
as GA aircraft records that did not have correct address information and GA aircraft records in the registry
that were not actually part of the active GA fleet, that is, air carriers, destroyed aircraft, museum aircraft,
military-owned aircraft, and so on.Accident and Exposure Data
14 Safety Study
from consideration in the survey because the re gistry database indica tes that their contact
information is outdated. The c ontractor also excludes aircra ft owners with postmaster
returns on record from prior GA surveys th ey have conducted. Af ter these known outdated
records are excluded, a sizable percentage of GA surveys ( 10 percent in 1999) are returned
by the U.S. Postal Service (U SPS) with information indica ting that the address is no
longer valid and that the U SPS has no forwarding address on file. The FAA contractor
responsible for analyzing GA survey returns has estimated that the number of records in
the Civil Aviation Registry th at were valid for inclusion in future GA surveys (after
known outdated records were excluded) decrea sed from 79 percent in 1999 to 74.8 percent
in 2000.25
In a meeting with Safety Board staff, managers at the Civil Aviation Registry
stated that a fairly consta nt proportion of owner addresse s (currently about 10 percent)
have at least two USPS returns on record in response to trienni al registration form
mailings.26 Registry staff reported that they have taken steps to prevent further
deterioration in the accuracy of aircraft records in rece nt years. On May 4, 1999, the
registry began biannual comparisons between the FAAs database of registered aircraft
owners and the USPSs database of change-of-address forms submitted by U.S. residents.
In cases where a match has been made, the re gistered aircraft ow ner was sent a letter
asking whether they wanted th eir contact information updated to reflect the new address.
About 2,000 of the 20,000 letters sent to aircraft owners under this new program were
mailed back. Some owners re quested that the registry ch ange their principal contact
information, and some requested that their pr incipal contact information remain the same.
The reasons why the remaining 18,000 aircraft ow ners contacted in these mailings did not
respond to the FAA are not documented.
Another way the FAA hopes to improve the currency of its Ci vil Aviation Registry
is through online verification of aircraft registration inform ation by aircraft owners. The
FAA began offering aircraft owners the capability to query and inspect aircraft
registration information online on April 4, 2001. It is now possible for aircraft owners to
look up their own aircraft on the Internet and examine the accuracy of the aircraft record.
The FAA provides a downloadable form that can be mailed to the registry for correction
of any inaccuracies. Interest in the Web site appears to be high. According to registry
managers, the site had over 300,000 hits with in 2 months of its debut. The managers
hope that this new capability will lead many aircra ft owners to submit updated registration
information, thereby improving th e currency of the registry . They plan to run ads in
industry magazines encouraging pilots to take advantage of this new method of verifying
the accuracy of their aircra ft registration information.
In an interview with Safety Board staff, registry managers st ated that they were
opposed to the imposition of civil penaltie s for violation of ai rcraft registration
regulations. They felt it would damage the c ooperative relationship th ey have attempted to
25Memo from Nicholas Nitka and Lark Lee, PA C onsulting, to Arthur Salomon, Federal Aviation
Administration, April 6, 2001.
26Meeting conducted with Mark Lash, Manager, Civil Aviation Registry, and Julie Stanford, Manager,
Aircraft Registration Branch, Civil Aviation Registry, on May 30, 2001.Accident and Exposure Data
15 Safety Study
cultivate with aircraft owners. They ci ted an attempt in 1978 to enforce aircraft
registration requirements which resulted in the de letion of 15,323 aircraft records from the
registry before the effort was halted. According to regi stry personnel, many of these
aircraft were never re-registered. The numbe r of these aircraft that remained active is
unknown. The only real result of this attempt at enforcement, the managers argued, was a
reduction in the number of aircraft records contained in the registry.
Fourth, the GA survey produces imprecis e public use flight hour estimates because
of a relatively high level of sampling error. Sampling error es timates provide an indication
of the degree to whic h random errors associated with th e sampling process influence flight
hour estimates. The level of sa mpling error is partly a func tion of the number of aircraft
included in the survey sample. As sample size increases, sampling error decreases.
Estimates of sampling error can be used to calculate confidence in tervals for flight hour
estimates within a particular category of flight operations . Estimated sampling error for
1999 public use flight activity (e xpressed in terms of a perc ent standard error) was 9.7,
compared with much lower standard errors for personal (1.7), business (4.3), instructional
(3.1), or corporate flight hours (5.5).27 As a result, public use activity is being monitored
with less accuracy than other major categor ies of aviation, reduci ng the accuracy with
which trends in public aircraft accident rates can be examined.
Fifth, because of the way in which aircra ft owners are asked to break down flight
hours according to purpose of fl ight, the purpose of flight categories provided on the GA
survey form are a mixture of flying tasks and administrative purposes of flight. Therefore,
the categories are not mutually exclusive. Fo r example, a private contractor performing
aerial application work mu st choose between aerial applicatio n and business
transportation. Similarly, a government aircraft operator pe rforming public health
sprayings for mosquito control faces a choice between other aerial application (which
includes public health sp raying) and public use. No instru ctions are provided to help the
respondent choose between categories. It is doubt ful that all aircraft owners faced with the
same choice would make the same classification.
The limitations of the GA survey are recognized by t hose close to the sampling
and activity estimation process but are less apparent to othe r users of the data, such as
researchers acquiring accident rate stat istics through the U.S. Department of
Transportations Bureau of Transportation Statis tics. In an effort to improve the quality of
GA data, a joint government/indus try committee, the Genera l Aviation Data Improvement
Team (GADIT) was organized in April 2000. GADIT was organized into several breakout
groups, one of which (the Activity Data Ta sk Group) was directed to examine current
FAA procedures for es timating GA activity da ta and to look for wa ys to improve the
quality and timeliness of these estimates.28 The Activity Data Task Group presented
recommendations to the FAA Safer Skies Joint Steering Committee (a
government/industry working group) in Ma y 2001. However, due to differences in
opinion among members of the committee, cons ideration of these recommendations was
27Federal Aviation Administration Office of Aviation Policy and Plans, General Aviation and Air Taxi
Activity Survey (Washington, DC: FAA, 1999).
28There have been previous effort s by industry to improve the data. The General Aviation Coalition
submitted recommendations to the FAA in 1997.Accident and Exposure Data
16 Safety Study
deferred. No action was taken and no date was set for furt her consideration of these
recommendations.
Most of the GADIT Activity Data Task Groups recommendations focused on the
improvement of existi ng survey process (clarifying pur pose-of-flight de finitions, adding
questions, increasing sample size). There were, however, three recommendations to
enhance the Civil Aviation Registry. Thes e included asking each owner to periodically
respond to address verification requests, even if the address had not changed; making
registration mandatory every 3 years (one-third of the owne rs each year) and requiring
completion of the GA survey when registration is filed; or having the registry provide
voluntary revalidation of airc raft registration. The task group did not favorably assess
alternate data collect ion methods. These included a su ggestion supported by a minority
opinion filed with the groups report that woul d require FAA airworthiness inspectors to
submit a record of flight hours on an airc raft when it receives an annual inspection.
Federal Public Use Operations
The Safety Board obtained Federal aircra ft activity data from the GSA Aircraft
Management Policy Division. The GSA has b een responsible for collecting information
on Federal aircraft ownership, utilization, and cost accounti ng since 1989, as directed by
OMB Circular A-126. Rather than surveying by mail, the GSA collects complete records
of activity from Federa l agencies. Seventeen Federal agen cies currently report these data
to the GSA (table 5).29 In recent years, these agencies have submitted total annual flight
hours statistics, broken dow n according to whether the aircra ft used were federally owned,
leased, or chartered. However, the GSA bega n collecting more deta iled Federal aircraft
activity data using a new Internet-based reporting system called the Federal Aviation
Interactive Reporting System (FAIRS) in April 2000. FAIRS will provide easily
accessible quarterly reports of cost and utilizati on data, as well as flight hours coded
according to aircraft class a nd mission characteristics. The fi rst complete year of FAIRS
activity data will be available after the end of calendar year 2001. The FAIRS system will
also contain a complete cen sus of Federal aircraft by the end of 2001. Eleven mission
category codes are being used to categorize flight hours in the FAIRS system (table 6),
with more detailed subcategories available within these categories.
29The number of reporting agencies can change from year to year depending on aircraft utilization.Accident and Exposure Data
17 Safety Study
Table 5. Federal agencies reporting aircraft activity data to the U.S. General Services
Administration for the year 1999.a
Agency or DepartmentNumber of
government-
owned aircraftHours flown:
government
aircraftHours flown:
contract,
charter, rentalHours
flown: total
1. Department of Agriculture 365 19,920 78,348 98,268
2. Department of Commerce 14 3,708 3,708
3. Department of Energy 29 8,980 1,047 10,0274. Department of Health and Human
Services 1,371 1,371
5. Department of Housing and Urban
Development
6. Department of Justice 321 102,094 10,449 112,543
7. Department of State 98 19,933 19,933
8. Department of the Interior 107 21,574 52,852 74,4269. Department of the Treasury 145 36,009 36,009
10. Department of Transportation 46 21,398 22,347 43,745
11. Department of Veterans Affairs 7 712. Environmental Protection Agency 678 678
13. Federal Emergency
Management Agency
b
14. National Aeronautics and Space
Administration 104 2,310 2,310
15. National Transportation Safety
Board 21 21
16. National Science Foundation 14 4,002 1,858 5,860
17. Tennessee Valley Authority 11 2,486 81 2,567
Total 1,254 242,414 169,059 411,473
aThese data are preliminary. They were obtained from the U. S. General Services Admini stration, Aircraft Management
Policy Division. These flight hour data were collected prior to the implementation of GSAs Federal Aviation Interactive
Reporting System (FAIRS) in April 2000, making it impossible to subdivide hours ac cording to the type of aircraft flown
or purpose of flight.
bFlight hours for the Federal Emergency Management Agency were unavailable for calendar year 1999.
Table 6. Purpose-of-flight codes used to categorize Federal aircraft flight activity in
U.S. General Services Administrations Fed eral Aviation Interactive Reporting System
(FAIRS).a
Category
1. Fire fighting and disaster response
2. Flight inspection / calibration3. Law enforcement4. Mission support5. Research and development, including scientific experimentation6. Resource management7. Search and rescue8. Surveillance9. Training10. Transportation of cargo11. Transportation of passengers
aThis list of mission categories was obtained from the U.S. General Services Administration (GSA), Aircraft
Management Policy Division. The GSA began us ing these categories for collection of aircraft activity data during the
2000 calendar year. The first complete ca lendar year of FAIRS data will be 2001.Accident and Exposure Data
18 Safety Study
Prior to the implementation of FAIRS, Federal agencies submitted brief annual
activity reports to the GSA for the years 1998 and 1999. These reports categorized flight
hours according to the type of financial arrangement (governme nt-owned aircraft,
contract, charter, or rental). However, these reports provi ded no categorization of flying
activity by aircraft class or mission type. Prior to 1998, Fe deral agencies reported flight
hours to the GSA using the Federal Aviation Management Informat ion System (FAMIS).
FAMIS records provided much of the same in formation that will now be reported through
FAIRS, but the FAMIS information was stored in a way that made it very difficult to
access and analyze. In additi on, FAMIS data were generally inaccurate, incomplete, and
late.30
Federal government aircraft activity figur es are shown in table 7. For the purposes
of this study, the Safety Boar d collected Federal public aircraft activity data for the years
19961997 from agency FAMIS submission s and for 19981999 from the annual flight
hour summaries submitted to the GSA by Fe deral agencies after the FAMIS was shut
down. The GSA collects activity data on all aircraft operations sponsored by Federal
executive agencies without di stinguishing which fl ight hours were ac crued as part of
qualifying public aircraft missions. Theref ore, flight hours for Federal government
aviation operations are an inflat ed substitute for the Federa l public aircraft flight hours
they include. The GSA flight hour data, how ever, are currently the closest available
estimate of Federal publ ic aircraft activity.
30Presidents Council on Integrity and Efficiency, Combined Report on the Federal Civilian Agencies
Aircraft Management Programs , Report Number A43006/O/W/F97011 (Washington, DC: PCIE, December
16, 1996).Table 7. Public aircraft flight hours, 19961999.a
YearPublic use flight hours
(all levels of government)Federal aircraft flight hours
(Federal aircraft only)
1996 1,047,000 341,000
1997 1,096,000 383,000
1998 1,373,000 417,000
1999 1,107,000 411,000
Total 4,623,000 1,552,000
aActivity estimates for all levels of government were obtained from the Federal Aviation Administration Office of
Aviation Policy and Plans. Activity esti mates for Federal aircraft were obtained from the General Services
Administration Office of Aircraft Management Policy. F ederal aircraft hours were adjusted for the years 19961998 by
subtracting hours flown by the U.S. Coast Guard, which were included in GSA estimates dur ing this period. U.S. Coast
Guard flight hours were obtained from the U.S. Departme nt of Transportation Office of Surface Transportation.Accident and Exposure Data
19 Safety Study
Chapter 3
Accident Rates
Safety Board staff calculated an accide nt rate of 3.66 per 100,000 flight hours for
all public aircraft opera tions, and 4.58 per 100,000 flight hours for Federal aircraft
operations, for the period 19961999 (tables 8 and 9). Although th e 4-year acci dent rate is
higher for all public ai rcraft than for Federal aircraft , it is difficult to draw firm
conclusions about the difference between th e rates. The activity estimates used to
calculate each accident rate contain unknown propor tions of nonpublic government
aircraft flight hours. In addition, as described in chapter 2, there are several aspects of the
FAAs processes for estimating public use flight hours that ar e likely to introduce
nonsampling error to the FAA s public use activity estimates. Furthermore, during the
most recent year for which da ta were available (1999), the Fe deral public aircraft accident
rate (2.92) was lower than the overall public aircraft accident rate (3.70).
Table 8. Public aircraft accident rates (all levels of government), 19961999.a
YearFlight
hours AccidentsFatal
accidentsNonfatal
accidentsAccidents
per 100K
hoursFatal
accidents per
100K hoursNonfatal
accidents per
100K hours
1996 1,047,000 42 6 36 4.01 0.57 3.44
1997 1,096,000 41 9 32 3.74 0.82 2.921998 1,373,000 45 14 31 3.28 1.02 2.26
1999 1,107,000 41 6 35 3.70 0.54 3.16
Total 4,623,000 169 35 134 3.66 0.76 2.90
aPublic and general aviation aircraft accide nts were identified by the Safety Boar d using the Safety Boards aviation
accident/ incident database. Multiple-aircraft accidents were c ounted as a single event. Public aircraft flight hours were
obtained from the U.S. Federal Aviation Administ ration Office of Aviation Policy and Plans.
Table 9. Federal aircraft accident rates, 19961999.a
YearFlight
hours AccidentsFatal
accidentsNonfatal
accidentsAccidents
per 100K
hoursFatal
accidents per
100K hoursNonfatal
accidents per
100K hours
1996 341,000 22 1 21 6.46 0.29 6.16
1997 383,000 14 5 9 3.65 1.31 2.351998 417,000 23 8 15 5.52 1.92 3.601999 411,000 12 1 11 2.92 0.24 2.68
19961999 1,550,000 71 15 56 4.58 0.97 3.61
aFederal and aircraft accidents were identified by the Safety Board using the Safety Boar ds aviation accident/incident
database. Multiple-aircraft accidents we re counted as a single event. Accident s involving the Civil Air Patrol and
privately owned aircraft contracted to the Department of Defense were excluded from this table, because the flight
activity of these operators was not included in Federal flight ac tivity estimates. Federal airc raft flight hours were obtained
from the U.S. General Services Administration, Office of Governmentwide Policy. Federal aircraft hours were adjusted
for the years 19961998 by subtracting hours flown by the U. S. Coast Guard, which were included in GSA estimates
during this period. U.S. Coast Guard flight hours were obtai ned from the U.S. Department of Transportation Office of
Surface Transportation.
20 Safety Study
Safety Board staff calculated 19961999 acci dent rates for several categories of
civil aviation (GA, air taxi operations, scheduled 14 CF R Part 135 operations, and
scheduled 14 CFR Part 121 operations) to pr ovide context for interpreting the public
aircraft accident rates. Subrates were also calculated with in some of these sectors for four
combinations of aircraft category (rotorcr aft versus fixed-wing) and accident severity
(fatal vs. nonfatal) (table 10 ). Subrates were not calcul ated by aircraft category for
scheduled Part 135 or schedul ed Part 121 operations becau se activity data were not
available at this level of detail from the FAA.
At the broadest level of analysis, the acci dent rate for all public aircraft for the
years 19961999 (3.66 accidents pe r 100,000 flight hours) lies between the rate for GA
(7.20 accidents per 100,000 flight hours) and the rates for sche duled Part 135 and Part 121
operations (1.06 and 0.27, respectively). The accident rate for public aircraft (3.66) was
almost identical to the rate for air taxi s (nonscheduled Part 135 operations, 3.47 accidents
per 100,000 flight hours) (tab le 10 and figure 2). Again, any conclusions about the
differences between these accident rates mu st be considered tentative because it isTable 10. Accident rates by aviation sector, aircraft category, and accident severity,
19961999.a
Aviation sector
Aircraft category, accident severity AccidentsbFlight hoursbAccidents per
100,000 flight hours
General aviation: 7,578 105,190,000 7.20
Rotorcraft, fatal accidents 115 4,991,000 2.30Rotorcraft, nonfatal accidents 561 4,991,000 11.24
Fixed-wing, fatal accidents 1,268 89,442,000 1.42
Fixed-wing, nonfatal accidents 5,376 89,442,000 6.01
Public aircraft: 169 4,623,000 3.66
Rotorcraft, fatal accidents 16 1,929,000 0.83
Rotorcraft, nonfatal accidents 77 1,929,000 3.99Fixed-wing, fatal accidents 18 2,536,000 0.71
Fixed-wing, nonfatal accidents 54 2,536,000 2.13
Air taxi: 322 9,290,000 3.47
Rotorcraft, fatal accidents 14 2,201,000 0.64
Rotorcraft, nonfatal accidents 33 2,201,000 1.50
Fixed-wing, fatal accidents 59 6,690,000 0.88Fixed-wing, nonfatal accidents 217 6,690,000 3.24
Scheduled Part 135:
cd 48 4,545,000 1.06
Fatal accidents 11 4,545,000 0.24Nonfatal accidents 37 4,545,000 0.81
Scheduled Part 121:
c 166 60,513,000 0.27
Fatal accidents 9 60,513,000 0.01
Nonfatal accidents 157 60,513,000 0.26
aAircraft accidents were identified by the Safety Board usi ng the Safety Boards aviation accident/incident database.
Multiple-aircraft accidents were counted as a single event. Aircraft flight hours were obtained from the U.S. Federal
Aviation Administration, Office of Aviati on Policy and Plans, Planni ng Analysis Division.
bGliders, lighter-than-air craft, and ultr alights were not included in fixed-wing accident totals. Autogyros were not
included in rotorcraft accident totals. In addition, multiple aircraft accidents within a sector sometimes involved both a
rotorcraft and a fixed-wing aircraft. In these cases, the ac cident was counted once in each aircraft category. For these
reasons, the sum of fixed-wing and rotorcraft accidents does not add to the total number of accidents within each sector.
cFlight hours were not available by ai rcraft category for scheduled 14 CFR Part 135 and scheduled 14 CFR Part 121
operations.
dMany scheduled 14 CFR Part 135 operators transitioned to operation under 14 CFR Part 121 in 1997 because of a
change in the Federal Aviation Regul ations governing passenger service.Accident Rates
21 Safety Study
difficult to estimate the combined effects of sampling and nonsampling error that affect
FAA flight hour estimates within these categories.
To examine how much the public aircra ft flight hours might be affected by
sampling error alone, Safety Board staff calcula ted a 90-percent confid ence interval using
sampling error statistics from the FAAs 1999 flight activity estimates.31 The confidence
interval for public us e flight hours ranges ± 16 percent (between 930,000 and 1,284,000).
This means that the confidence interval fo r the 1999 public aircraft accident rate (3.70)
actually ranges from 3.19 to 4.41. Staff lacked adequate data to calculate confidence
intervals for the GA or air ta xi accident rates because sa mpling error figures published by
the FAA were not available at the desired level of analysis.32 Even if the Board had been
able to calculate confidence in tervals for all of these accide nt rates, it would still be
difficult to draw conclusions about the di fferences between public and civil aircraft
accident rates because of the numerous sour ces of nonsampling error the Board believes
may be influencing the FAA hou r estimates (as discussed in chapter 2). Nevertheless, the
effects of nonsampling error w ould have to be quite large to change the ranked order of
the broad accident rates in each sector (as shown in figure 2) , with the exception of the
public and air taxi accident ra tes, which are quite similar.
The more detailed public, GA, and air taxi accident rates shown in table 10
generally show the same ordering as the overall rates, with public aircraft and air taxi rates
both being substantially lowe r than GA. There is one ex ception, however. Although the
rates for nonfatal public and GA rotorcraft ac cidents are both substantially lower than the
rate for nonfatal GA rotorcra ft accidents (2.12 for public and 4.93 for air taxi, compared
with 13.55 for GA), the rate for nonfatal public rotorcraft accidents is more than double
the rate for nonfatal air taxi rotorcraft acci dents. Again, it is di fficult to assess the
significance of this difference due to the l ack of data availabl e for the calculation of
confidence intervals for the rates involved.Figure 2. Accident rates by aviation sector, 19961999
31A 90-percent confidence interval re presents the range within which one can be 90 percent confident
that a statistic would lie if sampling could be performed without error.
32For example, three separate ac tivity figures are routinely comb ined by the FAA and the NTSB to
estimate air taxi flight activity: air taxi, air tours, and sightseeing. The FAA publishes an estimate of
sampling error for each of these ca tegories individually, but not for all three comb ined. The Board faced a
similar dilemma when seek ing to calculate confidence intervals for GA activity.0.001.002.003.004.005.006.007.008.00
General Aviation Public Aircraft Air Taxi Scheduled Part
135Scheduled Part
121Accidents per 100,000 flight hoursAccident Rates
23 Safety Study
Chapter 4
Accident Characteristics
This chapter describes characteristics of public aircraft accidents. The reader is
cautioned that the statistics presented in this chapter are not representati ve of all public
aircraft flight operations, only a ccident flights. Accident flight characteristics likely differ
from the nonaccident flight characteristics.
Statistics describing GA accident flight s are presented alongside public aircraft
accident statistics in some of the tables that follow. In addition, some ta bles provide more
detailed breakdowns within each sector fo r rotorcraft versus fixed-wing aircraft.
The time frame for most of the analyses covers the period 19951998 rather than
the period 19961999, because many of the variab les analyzed in this chapter are not
entered in the Safety Board da tabase until an accident i nvestigation is completed and
many of the accident investigations begun in 1999 had not yet been completed at the time
this report was prepared.
Accident Location
Safety Board staff ranked States accord ing to the number of public aircraft
accidents reported during the 19932000 period. This ranking indicated that California,
Alaska, Florida, and Texas were in the t op four. These four States accounted for 46
percent of all public aircraft accidents. These were also the top four States for GA
accidents during the 19932000 period.
The concentration of nearly half of all public aircraft accidents in four States
probably reflects the magnitude of flying activity within t hose States. Since the FAA does
not estimate aircraft activity by State, it woul d be very difficult to analyze the extent to
which the concentration of acci dents is merely a function of flight activity . The percentage
of public aircraft accidents by Stat e is shown graphically in figure 3.
24 Safety Study
Trends and Seasonal Components
Staff analyzed trends and seasonal patt erns affecting public aircraft accidents
during the study period as well . These analyses indicated th at the annual number of public
aircraft accidents has remained stable over the last 8 year s. No significant upward or
downward trend was evident (f igure 4). The analyses reve aled substantial seasonal
influences that affected public aircraft accident totals from month to month, with accidents
peaking in June and reaching their seasonal low in Decemb er. The seasonal pattern looks
very similar to that of GA (figure 5).Figure 3. Percent of all U.S. public aircraft accidents occurring within each State.
10% Plus 5-9% 2-4% 1% 0%Accident Characteristics
25 Safety Study
Figure 4. Public aircraft accident trend, July 1993June 2000. Trend line based on a
13-month moving average, which removes seasonal effects. The first and last data
points were not plotted, due to distortion from the averaging process.
Figure 5. Public versus general aviation accide ntsseaonal factors. Data shown are
the number of accidents occurring within each calendar month from January 1993
through December 2000. Accidents involving multiple aircraft were counted as a single event.11.522.533.544.555.56
Jan-93 Jul-93 Jan-94 Jul-94 Jan-95 Jul-95 Jan-96 Jul-96 Jan-97 Jul-97 Jan-98 Jul-98 Jan-99 Jul-99 Jan-00 Jul-00
Month13 Month Moving Average
05101520253035404550
JanFebMar AprMayJun JulAugSepOctNovDecPublic Use Accidents
05001000150020002500
General Aviation Acci dents
P ublic Aircraft General Aviation AircraftAccident Characteristics
26 Safety Study
Aircraft Category
Accident aircraft are tota led by category (for exampl e, airplane with single
reciprocating engine, airplane with multiple reciprocating e ngines, etc.) in table 11. A
higher proportion of public acciden t aircraft were rotorcraft (47 percent for public aircraft
versus 7 percent for GA, respectively). This likely reflects th e higher proportion of
helicopters performing public use flights, which, according to the 1999 GA survey,
generated 49 percent of all public use flight hours, but only 1.6 percent of GA flight hours.
Local Versus Point-to-Point
Accident aircraft totals ar e presented in table 12 accord ing to whether the accident
flight was local versus poi nt-to-point. Approximately 64 percent of public accident
aircraft were engaged in local flying, compared to only 48 percent of GA accident aircraft.
Furthermore, local public aircra ft accident flights were more likely than local GA accident
flights to have crashed at an off-airport locat ion. Neither of these fi ndings is particularly
surprising, considering the kinds of mi ssions flown by public aircraft operators.Table 11. Public versus general aviation accident aircraft by category.a
Public aircraft General aviation aircraft
Aircraft categoryAircraft Percent Aircraft Percent
Airplanes:
Single reciprocating 69 40 5,903 77
Multiple reciprocating 10 6 537 7Turboprop 6 3 209 3Turbojet 1 1 73 1Unknown airplane 4 2 84 1
Total 90 52 6,806 89
Rotorcraft:
Reciprocating 21 12 324 4
Turboshaft 58 33 238 3Unknown rotorcraft 2 1 5 0
Total 81 47 567 7
Other aircraft 3 2 270 4All Aircraft 174 100 7,643 100
a Accident aircraft were identified us ing the Safety Boards aviation acciden t/incident database. Data for the period
19951998 were included in this analysis. Some perc ent columns may not add to 100 because of rounding.Accident Characteristics
27 Safety Study
First Occurrence
When accidents investigated by the Safety Board are entered into the database,
occurrences (categories of events leading to the damage or in jury) are coded. Staff
sorted occurrence codes into broad categor ies and counted the num ber of public versus
GA accident aircraft associated with each category. These ai rcraft were further grouped in
terms of their involvement in fatal vers us nonfatal accidents (table 13). The only
noteworthy difference between the two sect ors involved in-flight collisions. A higher
proportion of fatal public aircraft accidents began with an in -flight collision (46 percent
for public aircraft versus 29 pe rcent for GA aircraft (table 13). Followup analyses did not
reveal any obvious difference between the two s ectors in terms of the type of collision (for
example, collision with terrai n, tree, power line, utility pole, and so on). However, when
broken down to this level of detail, the numbe r of accidents in each category was too small
to make valid comparisons.Table 12. Type of flight.a
Public aircraft Genera l aviation aircraft
Type of flight Aircraft Percent Aircraft Percent
Local
At airport 28 16 1,642 21
Off airport 83 48 2,113 27
Total 111 64 3,755 48
Point-to-point
Destination 39 22 1,930 25
Origin 13 7 870 11
En route 11 6 1,271 16
Total 63 36 4,071 52
Total 174 100 7,826 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis.Accident Characteristics
28 Safety Study
Because public use aircraft accidents invol ve a higher proportion of rotorcraft than
accidents in other sect ors of aviation, staff conducted the same analysis using two subsets
of the accident data presented in table 12 (rotorcraft onl y (table 14) and fixed-wing aircraft
only (table 15).Table 13. Public versus general aviation accid ent aircraft by first occurrence, all
aircraft categories.a
Public aircraft Genera l aviation aircraft
First occurrence FatalPercent
totalNon-
fatalPercent
total FatalPercent
totalNon-
fatalPercent
total
Collision:
In-flight 18 47 18 14 425 29 801 13On ground/water 7 5 4 0 431 7
Noncollision:
In-flight 15 39 27 21 711 49 1,140 18Power-related 5 13 37 29 247 17 1,949 32On ground/water 34 27 32 2 1,596 26
Miscellaneous 4 3 22 2 118 2
Gear-related 1 1 1 0 145 2
Unknown 14 1 2 0Total 38 100 128 100 1,456 100 6,182 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Some perc ent columns may not add to 100 because of rounding.
Table 14. Public versus general aviation accident aircraft by first occurrence, rotorcraft only.a
Public rotorcraft General aviation rotorcraft
First occurrence FatalPercent
totalNon-
fatalPercent
total FatalPercent
totalNon-
fatalPercent
total
Collision:
In-flight 3 21 10 16 30 30 94 18On ground/water 5 8 12 2
Noncollision:
In-flight 8 57 17 27 47 47 169 32Power-related 3 21 22 34 18 18 160 30
On ground/water 7 11 3 3 80 15
Miscellaneous 2 3 1 1 15 3
Gear-related 1 2 2 0
Unknown
Total 14 100 64 100 99 100 532 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Some percent columns may not add to 100 as a result of rounding error.Accident Characteristics
29 Safety Study
Phase of Flight
Staff also examined the frequency with which public aircraft accident sequences
began in different phases of flight (see ta ble 16). Staff observed th e following significant
differences between the two sectors. Both fata l and nonfatal public ai rcraft accidents were
more likely than GA accidents to have occu rred during a maneuvering phase of flight (42
percent of public aircraft vers us 26 percent for GA aircraft in volved in fatal accidents, 20
percent for public aircraft versus 10 percen t for GA aircraft fo r nonfatal accidents).Table 15. Public versus general aviation accident aircraft by first occurrence, fixed-
wing aircraft only.a
Public fixed-wing aircraft General aviation fixed-wing aircraft
First occurrence FatalPercent
totalNon-
fatalPercent
total FatalPercent
totalNon-
fatalPercent
total
Collision:
In-flight 15 63 6 10 390 30 641 12
On ground/water 2 3 4 0 398 7
Noncollision:
In-flight 7 29 9 15 633 48 901 17
Power-related 2 8 15 25 227 17 1,783 33
On ground/water 27 44 28 2 1,471 27
Miscellaneous 2 3 19 1 78 1
Gear-related 1 0 142 3
Unknown 14 1 2 0Total 24 100 61 100 1,316 100 5,416 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Some perc ent columns may not add to 100 because of rounding.Accident Characteristics
30 Safety Study
Again, staff performed the same analys is after limiting the sample first to
rotorcraft, then to fixed-wing aircraft. Ag ain, sample size and statistical power were
limited. Analyses failed to confirm the same result in these more restricted samples,
although the proportions lay in the same direction (tables 17 and 18).Table 16. Public versus general aviation accident aircraft by phase of flight for first
occurrence, all aircraft categories.a
Public aircraft Gene ral aviation aircraft
Phase of flight Fatal PercentNon-
fatal Percent Fatal PercentNon-
fatal Percent
Cruise 12 32 15 12 385 26 869 14
Maneuvering 16 42 26 20 384 26 607 10
Approach 4 11 9 7 228 16 762 12
Takeoff 3 8 22 17 212 15 1,346 22Climb 1 3 1 1 84 6 160 3
Descent 45 3 148 2
Landing 37 29 34 2 1,892 31Hover 1 3 9 7 11 1 78 1
Standing 5 4 9 1 71 1
Other 1 1 8 1 6 0Taxi 4 3 3 0 205 3
Uncontrolled descent 2 0 9 0
Emergency landing 1 0 16 0Holding 1 0
Unknown 1 3 50 3 12 0
Total 38 100 129 100 1,456 100 6,182 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Some perc ent columns may not add to 100 because of rounding.Accident Characteristics
31 Safety Study
Table 17. Public versus general aviation accident aircraft by phase of flight for first
occurrence, rotorcraft only.a
Public rotorcraft General aviation rotorcraft
Phase of flight Fatal PercentNon-
fatal Percent Fatal PercentNon-
fatal Percent
Cruise 2 14 10 16 27 27 87 16
Maneuvering 7 50 19 30 34 34 126 24Approach 1 7 2 3 5 5 44 8
Takeoff 2 14 9 14 9 9 66 12
Climb 1 7 3 3 9 2Descent 4 4 7 1
Landing 10 16 1 1 91 17
Hover 1 7 9 14 11 11 77 14Standing 5 8 1 1 14 3
Other 1 0
Taxi 5 1
Uncontrolled descent 4 1
Emergency landing 1 0
HoldingUnknown 4 4
Total 14 100 64 100 99 100 532 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Some perc ent columns may not add to 100 because of rounding.
Table 18. Public versus general aviation accident aircraft by phase of flight for first
occurrence, fixed-wing aircraft only.a
Public fixed-wing aircraft General aviation fixed-wing aircraft
Phase of flight Fatal PercentNon-
fatal Percent Fatal PercentNon-
fatal Percent
Cruise 10 42 5 8 353 27 760 14
Maneuvering 9 38 7 11 339 26 458 8Approach 3 13 7 11 215 16 676 12
Takeoff 1 4 11 18 197 15 1,233 23
Climb 1 2 76 6 150 3Descent 40 3 132 2
Landing 26 42 31 2 1,717 32
Hover 1 0
Standing 8 1 53 1
Other 1 2 8 1 5 0
Taxi 4 6 3 0 198 4Uncontrolled descent 2 0 5 0
Emergency landing 15 0
Holding 1 0
Unknown 1 4 46 3 12 0
Total 24 100 62 100 1,318 100 5,416 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Some perc ent columns may not add to 100 because of rounding.Accident Characteristics
32 Safety Study
Causes or Contributing Factors
The proportions of accidents due to the broadest categor ies of aircraft-related,
environment-related, and pilot-related factor s were virtually identical for public and GA
accident aircraft. Accident aircraft counts, grouped by cate gories of causal factors are
shown in table 19. The most common causes or related factors reported by accident
investigators for both public and GA accident ai rcraft were pilot-related (83 percent for
fatal public aircraft accidents versus 88 percent for fa tal GA accidents), followed by
environment-related and aircraft-related factors.
Table 19. Public versus general aviation cause and contributing factor categories by
accident severity, al l aircraft types.a
Public aircraft General aviation aircraft
Cause/contributing
factor FatalPercent
total NonfatalPercent
total FatalPercent
total NonfatalPercent
total
All aircraft factors: 9 24 39 31 331 23 2,053 34
Propulsion controls 4 11 27 22 199 14 1,463 24
Flight controls 27 2 100 2Airframe 1 3 1 1 51 4 72 1
Landing gear 7 6 4 0 253 4
Systems 4 11 6 5 65 5 251 4
All environment factors: 17 46 67 54 591 42 2,771 46
Weather 9 24 30 24 404 29 1,223 20
Light conditions 4 11 7 6 170 12 232 4Object 1 3 12 10 84 6 457 8
Airport facilities 1 3 2 2 12 1 48 1
Terrain or
runway conditions 7 19 35 28 150 11 1,410 23
All personnel factors: 35 95 106 85 1,353 96 5,150 85
Pilot 31 84 96 77 1,276 90 4,740 78
Others aboard 1 3 4 3 24 2 47 1
Others not aboard 14 38 13 10 179 13 543 9
Accidents with at least
one known cause/factor37 100 124 100 1,413 100 6,055 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Percent columns do not add to 100 because more than one category of
causes or related factors could be count ed for a single accident. However, multiple causal factors in a single category
for a single accident were only counted once.Accident Characteristics
33 Safety Study
The same analyses were repeated for rotorcraft (table 20) and fixed-wing aircraft
(table 21), with similar results.
Table 20. Public versus general aviation cause and contributing factor categories by
accident severity, rotorcraft only.a
Public rotorcraft General aviation rotorcraft
Cause/contributing factor FatalPercent
total NonfatalPercent
total FatalPercent
total NonfatalPercent
total
All aircraft factors: 6 46 22 35 37 38 207 39
Propulsion controls 3 23 16 25 23 23 155 30Flight controls 5 5 20 4
Airframe 1 8 3 3 9 2
Landing gear 2 3 7 1Systems 2 15 6 10 7 7 35 7
All environment factors: 8 62 31 49 36 37 181 34
Weather 3 23 10 16 19 19 64 12Light conditions 3 23 5 8 11 11 21 4
Object 6 10 8 8 35 7
Airport facilities 1 8 1 2 1 1 2 0Terrain or
runway conditions 3 23 17 27 11 11 94 18
All personnel factors: 11 85 49 78 89 91 440 84
Pilot 8 62 41 65 74 76 375 71
Others aboard 4 6 1 1 10 2Others not aboard 6 46 9 14 27 28 81 15
Accidents with at least one
known cause/factor13 100 63 100 98 100 525 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Percent columns do not add to 100 because more than one category of
causes or related factors could be count ed for a single accident. However, multiple causal factors in a single category
for a single accident were only counted once.Accident Characteristics
34 Safety Study
Pilot Certification
Accident-involved public airc raft pilots were very different from accident-
involved GA pilots in terms of pilot certification (table 22). Accident-involved public
aircraft pilots were mo re highly qualified than accident-i nvolved GA aircraft pilots in that
they were more likely to hold a commercial pilot rating (64 percent for public versus 36
percent for GA) and they were more likely to hold an airline transport pilot rating (24
percent for public versus 12 percent for GA).Table 21. Public versus general aviation cause and contributing factor categories by
accident severity, fixe d-wing aircraft only.a
Public fixed-wing aircraft General aviation fixed-wing aircraft
Cause/contributing
factor FatalPercent
total NonfatalPercent
total FatalPercent
total NonfatalPercent
total
All aircraft factors: 3 13 16 26 282 22 1,810 34
Propulsion controls 1 4 11 18 173 13 1,301 24
Flight controls 18 1 73 1
Airframe 45 3 56 1Landing gear 5 8 4 0 246 5
Systems 2 8 56 4 202 4
All environment factors: 9 38 34 56 550 42 2,478 46
Weather 6 25 20 33 380 29 1,083 20
Light conditions 1 4 2 3 159 12 207 4
Object 1 4 5 8 75 6 398 7Airport facilities 1 2 11 1 46 1
Terrain or
runway conditions 4 17 17 28 137 10 1,284 24
All personnel factors: 24 100 54 89 1,228 94 4,495 84
Pilot 23 96 52 85 1,168 89 4,167 78Others aboard 1 4 22 2 27 1
Others not aboard 8 33 4 7 146 11 445 8
Accidents with at least
one known cause/factor24 100 61 100 1,310 100 5,359 100
aAccident aircraft were identified using the Safety Boar ds aviation accident/incident database. Data for the period
19951998 were included in this analysis. Percent columns do not add to 100 because more than one category of causes or related factors could be count ed for a single accident. However, multiple causal factors in a single category
for a single accident were only counted once.Accident Characteristics
35 Safety Study
In addition, accident-involve d public aircraft pilots were more likely than
accident-involved GA pilots to hold an instru ment rating (78 percen t for public versus 50
percent for GA) (table 23).Table 22. Highest rating for accident-involved pilots-in-command.a
Public aircraft
Pilots-in-commandGeneral aviation aircraft
Pilots-in-command
Highest rating Pilots Percent of pilots Pilots Percent of pilots
Airline transport pilot 41 24 877 12
Commercial 109 64 2,740 36Private 18 11 3,419 45
Student 1 1 576 8
aAccident aircraft pilots were identified using the Safety Boards aviation accident/incident database. Figures in this
table were based on accident data for the period 19951998.
Table 23. Type of instrument rating for accident involved pilots-in-command.a
Public aircraft
Pilots-in-commandGeneral aviation aircraft
Pilots-in-command
Instrument rating held Pilots Percent of pilots Pilots Percent of pilots
Any instrument rating 135 78 3,918 50
Airplane 114 66 3,628 46Helicopter 49 28 338 4
No instrument rating 39 22 3,908 50
aAccident-involved pilots were identified using the Safety Boards aviation accident/inc ident database. Ratings shown
for pilots-in-command only. Figures in this table were based on accident data for the period 19951998.Accident Characteristics
37 Safety Study
Chapter 5
Analysis
The Safety Board compared the safety of public and civil ai rcraft by reviewing
safety statistics on aircraft operations since 1993. The Boar d was hampered by a lack of
available public aircraft activ ity estimates for years prior to 1996 and by the unreliability
and lack of detail characterizing activity es timates published since that time. As a result,
the Board can only offer tentative conclusions a bout the relative safety of public and civil
aircraft. A comparison of public and GA aircraft accident ra tes, based on imprecise FAA
activity estimates, revealed that during the period 19961999, public aircraft experienced
fewer accidents per flight hour than GA aircraft, but more than aircraft performing
scheduled operations under 14 CFR Part 135 or Part 121.
The Safety Boards concerns about the re liability and validity of the FAAs public
aircraft activity estimates used to calculate the accident rates in this report are fivefold:
1. The definition of public use provided on GA survey forms used to collect the
data for estimating public aircraft fli ght hours is broader than the statutory
definition for public aircraft.
2. Accurate reporting of publ ic use flight hours and pur pose-of-flight information
depends on the ability of aircraft ow ners, who may be one or more steps
removed from the actual flying of the ai rcraft, to obtain detailed information
about the aircrafts flying activ ities during the previous year.
3. Accurate public and civil aircraft fl ight hour estimates depend on the currency
and accuracy of the FAA Civil Avia tion Registry. However, it can be
conservatively estimated th at about 19 percent of regi stry records are outdated
or incorrect, impeding flight activ ity sampling and estimation processes.
4. Too few public aircraft are sampled as part of the GA survey; as a result,
sampling error is much higher for estimat es of public aircraft flight hours than
estimates for GA flying conducted for personal or business reasons.
5. The GA survey questionnai re is designed in a way th at prevents the reporting
or estimation of public airc raft flight hours accordi ng to purpose of flight.
The records and processes used to genera te the FAAs annual flight hour estimates
for public and civil aircraft are in need of several improvements.
First, because FAA estimates of public ai rcraft flight hours are based on a set of
aircraft operations broader than those meeti ng the statutory defini tion of public aircraft
operations, the FAA should revise the GA survey data collec tion system to more clearly
distinguish between government aircraft ope rations that qualify for statutory public
aircraft status and those th at do not. This will allow the Safety Board and other
government organizations to calculate more accurate public airc raft accident rates.
38 Safety Study
Second, the FAA should identify and impl ement methods of ch ecking the accuracy
of the information collected using the GA surv ey. The FAAs inability to sample as much
as a quarter of the active GA fleet raises se rious questions about the organizations ability
to accurately estimate GA or public aircraft flight act ivity using a sample survey
approach.33 The reliance on aircraft ow ners to provide the desire d information is subject to
a number of weaknesses discussed in chap ter 2. Although surveying owners may be the
most practical means availabl e for collecting nonairline fli ght activity data, the FAA
should identify and implement methods independ ent of the GA survey that can be used to
check the accuracy of nonairli ne flight hour estimates.
Third, the FAA should improve the accuracy and currency of the Civil Aviation
Registry. The GADIT committe e recently recommended th at the FAA obtain address
verification every 3 year s by requiring a response to the tr iennial aircraft registration form,
regardless of any change in an owners registration informati on. Although this would
represent a positive step, the Sa fety Board believes that it is insufficient to ensure the
currency of the registry. It would do nothi ng to improve the 28,000 ai rcraft records that
are known to contain outdate d owner contact information. These individuals no longer
receive triennial registration report form s because the FAA cannot contact them. The
registrys effort to contact aircraft owners who have submitted a cha nge of address form to
the USPS and request updated contact informati on also represents a positive step, but the
vast majority of owners so contacted fail to respond to the FAA. For these reasons, the
Board is concerned that owner contact info rmation in the registry will continue to
deteriorate, further hampering the FAAs ab ility to estimate a nnual nonairline flight
activity. The FAA should implement a progr am that will (a) m easure and track the
currency of aircraft owner contact information in the re gistry and (b) systematically
improve the currency of this in formation in a measurable way.
Fourth, the FAA should reduce the sampli ng error associated with estimates of
public use flying activity. Estimates for public use flying acti vity are currently less precise
than estimates for major categories of GA activity (for example, business, personal,
instructional, and so on). This results from differences in the number of aircraft sampled.
This situation can be improve d by sampling an increased numbe r of aircraft that perform
public aircraft operations. The FAA should revi se the sampling strategy of the GA survey
to achieve a precision of public use flight hour estimates (in terms of sampli ng error) that
is equivalent to the precision of estimat es for personal, busin ess, or corporate
subcategories of GA.
Finally, the FAA should revise the GA su rvey form so that operators can report
public aircraft flight hours by purpose of flight. Purpose- of-flight categories should be
mutually exclusive. Current ca tegories mix administrative pur poses of flight with flying
activities. The FAA should develop a new re porting matrix on the GA survey form that
separates the administrative pur pose of flight (for example, personal, business, corporate,
regional, air taxi, air tours, si ghtseeing, public use, air medica l services, search and rescue,
33This figureone quarter of th e active fleetincludes known ou tdated or inaccurate records
combined with the number of estimated outdated or inaccurate records yet to be verified. The figure is given
in a memo written by the FAAs contractor for survey data analysis, PA Consulting, dated March 26, 2001.Analysis
39 Safety Study
and so on) from the actual flyi ng activity performed (for exampl e, transport of passengers,
flight instruction, aerial obs ervation, aerial application, ex ternal load, and so on). The
FAA should incorporate these changes in published flight hour estimates as well.
In addition, the FAA should re vise the GA survey so th at aircraft owners can
report public aircraft flight hours according to the level of government served (Federal,
State, or local) within each purpose-of-fli ght category. This will make it possible to
compare the safety of public aircraft ope rations sponsored by different levels of
government.
An additional issue of interest involves the FAAs inclusion of CAP flight hours in
annual public use flight activi ty estimates. CAP flight h ours made up about 7 percent of
the FAAs 1999 estimate of public use flight hours despite the fact that CAP flights are not
considered public aircraft operations under current law. The inclusion of these hours
inflates the FAAs annual est imate of public use flight act ivity. The CAP returned 14
surveys to the FAA for the 1999 GA survey. On these surveys, CAP personnel classified a
total of 1,263 aircraft flight hours as public use. Based on the FAAs sample weighting
factors for these aircraft, these surveys cont ributed 75,324 flight hours (7 percent) to the
FAAs overall 1999 estim ate of public use flight hours. The FAA should remove CAP
flight hours from future estima tes of public aircraft activi ty so that the figures are
consistent with the current statut ory definition of public aircraft.
With respect to Federal public aircraft act ivity data, the Safety Board applauds the
steps the GSA has taken to improve collecti on of Federal aircraft activity data. Although
Federal government operators have been re porting aircraft flight hours to the GSA in
recent years, these data were reported by each agency only in an aggregate fashion. The
GSAs new automated data entry and analys is system, FAIRS, should provide easily
accessible activity and co st data at the level of specific ai rcraft with added ability to total
flight hours according to mission characteris tics and other factor s. This system will
provide a complete set of data describing Federal airc raft operations for 2001 and
subsequent years. The FAIRS system, curr ently being deployed by the GSA, should
enhance the GSAs ability to monitor Fede ral government aircraft activity and should
allow the GSA to provide better informati on to other Federal agencies, including the
Safety Board. The Safety Board encourages th e GSA to finish the implementation of this
system and take steps to ensure that it will function as inte nded. The Safety Board believes
that the GSA should collect and maintain aircraft flight hour data from Federal agencies in
such a way that it is possibl e to distinguish Federal public aircraft flight operations from
other Federal government-spons ored flight operations.
A final concern involves the parallel de velopment of activity data collection
systems at the FAA and the GSA. It would be useful to compare the safety of Federal
public aircraft versus other aircraft engaged in the same kinds of flying activities.
However, the development of separate, independent activity data collection systems by
the FAA and the GSA is leading to the co llection of flight hour data in terms of
incompatible categories of pur pose of flight. This will make it difficult, if not impossible,
to compare accident rates fo r Federal public aircraft vers us other public aircraft forAnalysis
40 Safety Study
specific kinds of flying activ ities. The GSA and the FAA should define purpose-of-flight
categories in the FAIRS that correspond to pur pose-of-flight categories in the GA survey.
The Safety Board last addre ssed deficiencies in nonairlin e flight activity estimates
in its 1979 study, Single-Engine Fixed-Wing General Aviation Accidents .34 In that study,
the Safety Board analyzed accident rate s for specific models of GA aircraft.35 The analy-
ses revealed large differences in model-speci fic accident rates, but the studys authors
could not control for aircraft-s pecific differences in terms of pilot characteristics, region,
or purpose of flight . This led to difficulty interpreting differences in model-specific acci-
dent rates. As a result, the Safety Board re commended that the FAA collect more detailed
GA activity data so that more specific rate s could be calculated an d the safety perfor-
mance of different aircraft types could be more carefull y evaluated. The Boards recom-
mendation was phrased as follows:
Generate, through a stratified sampling of general aviation pilots, the date,
duration, aircraft make and model, the geographical location of the flight, and the
flight time in IFR, high density altitude , and wind conditions, all on a per flight
basis; the data collected should include the pilots total time, time in each type
aircraft flown, age, occupation, certificate, and medical waivers. (A-79-44)
The FAA formed a committee in 1980 which sought to identify human
factors/exposure data and the alternatives to acquiring such data. However, after the
Safety Board attended several m eetings with the FAA, it b ecame clear that the FAA was
not likely to take meaningful action related to recommendation A-79-44. The
recommendation was classified Closed-Unacceptable Acti on by the Safety Board on
December 1, 1986. However, detail ed, accurate statistics desc ribing flight activity remain
crucial for monitoring the safety of general aviation and for monitori ng the safety of air
taxi and public aircra ft operations as well.
34National Transportation Safety Board, Single-Engine Fixed Wing General Aviation Accidents ,
Aviation Special Study, NTSB/AAS-79/01 (Washington, DC: NTSB, 1979).
35This would not be possible today, because the FAA no longer collects flight hours for specific aircraft
models.Analysis
41 Safety Study
Conclusions
As a result of this safety study, the Na tional Transportation Safety Board draws the
following conclusions:
1. A comparison of public and general aviation aircraft accident rates, based on
imprecise FAA activity estimates, reve aled that, during the period 19961999, public
aircraft experienced fewer acc idents per flight hour than general aviation aircraft, but
more than aircraft performing scheduled operations under 14 CF R Part 135 or Part
2. About 64 percent of public a ccident aircraft were enga ged in local flying, compared
to only 48 percent of genera l aviation accident aircraft . Furthermore, local public
aircraft accident flights we re more likely than local ge neral aviation accident flights
to have crashed at an off-airport location.
3. A higher proportion of fatal pub lic aircraft accide nts began with an in-flight collision
(46 percent for public airc raft versus 29 percent for general aviation aircraft).
4. Both fatal and nonfatal public aircraft ac cidents were more likely than general
aviation accidents to have o ccurred during a maneuvering pha se of flight (42 percent
of public aircraft versus 26 percent for ge neral aviation aircraft involved in fatal
accidents, 20 percent for public aircraft versus 10 percent for general aviation aircraft
for nonfatal accidents).
5. The most common causes or related fact ors reported by accident investigators for
both public and general aviation accident aircraft were pi lot-related (83 percent for
fatal public aircraft accident s versus 88 percent for fata l general aviation accidents),
followed by environment-related and aircraft-related factors.
6. Accident-involved public airc raft pilots were more highl y qualified than accident-
involved general aviation aircra ft pilots in that they we re more likely to hold a
commercial pilot rating (64 percent for publ ic versus 36 percent for general aviation)
and they were more likely to hold an ai rline transport pilot rating (24 percent for
public versus 12 percent for general aviation).
7. Accident-involved public airc raft pilots were more li kely than accident-involved
general aviation pilots to hold an instrume nt rating (78 percent for public versus 50
percent for general aviation).
8. The definition of public use provided on General Aviation and Air Taxi Activity
Survey forms used to collect the data fo r estimating public airc raft flight hours is
broader than the statutory de finition for public aircraft.
42 Safety Study
9. Accurate reporting of publ ic use flight hours and pur pose-of-flight information
depends on the ability of ai rcraft owners, who may be one or more steps removed
from the actual flying of th e aircraft, to obtain deta iled information about the
aircrafts flying activities during the previous year.
10. Accurate public and civil aircraft flight hour estima tes depend on the currency and
accuracy of the FAA Civil Aviation Registry. However, it can be conservatively
estimated that about 19 percen t of registry records are out dated or incorrect, impeding
flight activity sampling and estimation processes.
11. Too few public aircraft are sampled as part of the General Aviation and Air Taxi
Activity Survey; as a result, sampling er ror is much higher for estimates of public
aircraft flight hours than for estimate s of general aviation flying conducted for
personal or business reasons.
12. The General Aviation and Ai r Taxi Activity Survey que stionnaire is designed in a
way that prevents the reporti ng or estimation of public aircraft fli ght hours according
to purpose of flight.
13. Civil Air Patrol flight hours made up about 7 percent of the FAAs 1999 overall
estimate of public use flight hours despite the fact that CAP flights are not considered
public aircraft operations unde r current statutes , inflating the FA As annual estimate
of public use flight activity.
14. The Federal Aviation Interactive Reporti ng System, currently being deployed by the
General Services Administration (GSA), shou ld enhance the GSAs ability to monitor
Federal government aircraft activity and should allow the GSA to provide better
information to other Federal agencies, including the Safety Board.
15. The development of separa te, independent activity da ta collection systems by the
Federal Aviation Administratio n and the General Services Administration is leading
to the collection of flight hour data in terms of incomp atible categories of purpose of
flight. This will make it difficult, if not impossible to compare accident rates for
Federal public aircraft vers us other public aircraft fo r specific ki nds of flying
activities.Conclusions
43 Safety Study
Recommendations
As a result of this safety study, the National Transportation Safety Board makes
the following safety recommendations:
To the Federal Aviation Administration:
Revise the General Aviation and Air Ta xi Activity Survey data collection
system to more clearly distinguish between government aircraft operations
that qualify for statutory public aircraft status a nd those that do not. (A-01-
73)
Identify and implement methods inde pendent of the Ge neral Aviation and
Air Taxi Activity Survey that can be used to check the accuracy of
nonairline flight hour estimates. (A-01-74)
Implement a program that will (a) measure and track the currency of
aircraft owner contact in formation in the Civil Aircraft Registry and (b)
systematically improve the currency of this information in a measurableway. (A-01-75)
Revise the sampling strate gy of the General Aviati on and Air Taxi Activity
Survey to achieve a precision of public use flight hour es timates (in terms
of sampling error) that is equivalent to the precision of estimates for
personal, business, or corporate sub categories of general aviation. (A-01-
76)
Develop a new reporting matrix on the General Aviation and Air Taxi
Activity Survey form th at separates the administ rative purpose of flight
(for example, personal, business, corporate, regi onal, air taxi, air tours,
sightseeing, public use, air medical serv ices, search and rescue, and so on)
from the actual flying activity perf ormed (for example, transport of
passengers, flight instruction, aeri al observation, aerial application,
external load, and so on). Incorpor ate these changes in published flight
hour estimates. (A-01-77)
Revise the General Aviation and Air Taxi Activity Survey form so that
aircraft owners can report public aircraft flight hour s according to the level
of government served (Federal, State, or local) within each purpose-of-
flight category. (A-01-78)
Remove Civil Air Patrol flight hours from futu re estimates of public
aircraft activity so that the figures ar e consistent with the current statutory
definition of public aircraft. (A-01-79)
44 Safety Study
In cooperation with the General Serv ices Administration, define purpose-
of-flight categories in the Federal Aviation Inte ractive Reporting System
that correspond to purpose-of-flight cat egories in the General Aviation and
Air Taxi Activity Survey. (A-01-80)
To the U.S. General Services Administration:
Collect and maintain aircraft flight hour data from Federal agencies in such
a way that it is possibl e to distinguish Federa l public aircraft flight
operations from other Federal govern ment-sponsored fli ght operations. (A-
01-81)
In cooperation with the Federal Avia tion Administration, define purpose-
of-flight categories in the Federal Aviation Inte ractive Reporting System
that correspond to purpose-of-flight cat egories in the General Aviation and
Air Taxi Activity Survey. (A-01-82)
By the National Transp ortation Safety Board
MARION C. BLAKEY
Chairman
CAROL J. CARMODY
Vice ChairmanJOHN A. HAMMERSCHMIDT
Member
JOHN J. GOGLIA
Member
GEORGE W. BLACK, JR.
Member
Adopted: October 23, 2001Recommendations
45 Safety Study
Appendix A
Partial List of Federal Av iation Safety Regulations
That Do Not Apply to Public Aircraft
14 CFR Description
43 Maintenance, preventive maintenance, rebuilding, and
alteration
61.5 FAA pilot and medical certification requirements91.7 Aircraft airworthine ss requirement standards
91.8 Aircraft flight manual, ma rking, and placard requirements
91.15 Dropping of objects requirements91.17 Prohibition of operation of ai rcraft by crewmembers who might
have used alcohol or drugs wi thin certain time frames and
circumstances
91.103 Certain preflight actions91.105 Requirement of flight crewme mbers to be at duty stations
91.107 Use of safety belts, shoulder harnesses, etc.91.167 Fuel requirements for IFR flight91.203 Requirements for airworthiness a nd registration certificates and
presence on board aircraft
91.207 Emergency locator transmitters91.311 Towing of things by aircraft91.401 Aircraft maintenance requirements
46 Safety Study
Appendix B
Statutory Definition of Public Aircraft
Title 49 United States C ode, Section 40102(a)(37)
(as amended by P ublic Law 106-181):
public aircraft means any of the following:
(A) Except with respect to an aircraft described in subparagra ph (E), an aircraft used only
for the United States Government, ex cept as provided in section 40125(b).
(B) An aircraft owned by the Government and operated by a ny person for purposes related
to crew training, equipment de velopment, or demonstration, except as provided in section
40125(b).
(C) An aircraft owned and operated by the government of a State, the District of
Columbia, or a territory or pos session of the United States or a political subdivision of one
of these governments, except as provided in section 40125(b).
(D) An aircraft exclusively leased for at least 90 continuous days by the government of a
State, the District of Columbia, or a territ ory or possession of the United States or a
political subdivision of one of these government s, except as provided in section 40125(b).
(E) An aircraft owned or operated by th e armed forces or chartered to provide
transportation to the armed forces under the c onditions specified by section 40125(c).
Title 49 United Stat es Code, Section 40125:
§40125. Qualifications for public aircraft status
(a) Definitions. In this secti on, the following definitions apply:
(1) Commercial purposes. The term commercial purposes means the
transportation of persons or property for compensation or hire, but does not
include the operation of an aircraft by the armed forces for reimbursement
when that reimbursement is required by any Federal statute, regulation, or
directive, in effect on November 1, 1999, or by one government on behalf
of another government under a cost reimbursement agreement if the
government on whose behalf the opera tion is conducted certifies to the
Administrator of the Federal Aviation Administration that the operation is
necessary to respond to a significant an d imminent threat to life or property
(including natural resources) and that no service by a private operator is
reasonably available to meet the threat.
47 Safety Study
(2) Governmental function. The term governmental function means an
activity undertaken by a gove rnment, such as national defense, intelligence
missions, firefighting, search and rescue, law enforcement (including
transport of prisoners, detainees, and il legal aliens), aer onautical research,
or biological or geological resource management.
(3) Qualified non-crewmember. The term qualified non-crewmember
means an individual, other than a memb er of the crew, aboard an aircraft--
(A) operated by the armed forces or an intelligence agency of the United
States Government; or
(B) whose presence is required to perform , or is associated with the perfor-
mance of, a governmental function.
(4) Armed forces. The term armed forces has the meaning given such
term by section 101 of title 10.
(b) Aircraft owned by governments. An aircraft described in subparagraph (A),
(B), (C), or (D) of secti on 40102(a)(37) does not qualify as a public aircraft under such
section when the aircraft is used for commer cial purposes or to car ry an individual other
than a crewmember or a qualified non-crewmember.
(c) Aircraft owned or operated by the Armed Forces. (1) In general. Subject to paragraph (2 ), an aircraft de scribed in section
40102(a)(37)(E) qualif ies as a public aircraft if--
(A) the aircraft is operated in accordance with title 10;
(B) the aircraft is operated in the performance of a governmental function
under title 14, 31, 32, or 50 an d the aircraft is not us ed for commercial pur-
poses; or
(C) the aircraft is chartered to prov ide transportation to the armed forces
and the Secretary of Defense (or the S ecretary of the department in which
the Coast Guard is operating) designate s the operation of the aircraft as
being required in the national interest.
(2) Limitation. An aircraft that meets th e criteria set forth in paragraph (1)
and that is owned or opera ted by the National Guard of a State, the District
of Columbia, or any territory or posse ssion of the United States, qualifies
as a public aircraft only to the extent that it is operated under the direct
control of the Department of Defense.Appendix B
48 Safety Study
Appendix C
Effect On the Public Aircraft Accident Rate
Of Including Civil Air Patrol Accidents
The Safety Boards public aircraft accide nt set included 24 Civil Air Patrol (CAP)
accidents. Staff chose to incl ude these accidents in the sample despite the fact that CAP
aircraft are owned by a private corporati on and CAP flights are not considered public
aircraft operations unde r current law. This decision was made after staff learned that a
large number of CAP flight hours are included in the FAAs public use flight hour
estimates.
The CAP returned 14 surveys to the FA A for the 1999 Genera l Aviation and Air
Taxi Activity Survey. On these surveys, CA P personnel classified a total of 1,263 aircraft
flight hours as public use. Base d on the FAAs sample weightin g factors for these aircraft,
these surveys contributed 75,324 flight hours (7 percent) to the FAAs overall 1999
estimate of public use flight hours. The numbe r of CAP hours included in earlier estimates
could not be calculated. In or der to avoid a bias that wo uld result from excluding CAP
aircraft from the accident sample but leaving CAP flight hours in the activity estimate,
staff decided to leave CAP accidents in the 19932000 public aircraft accident sample.
Including CAP data probably had a negligible effect on the overall public aircraft
accident rate. Thirteen CAP accidents were reported to the Safety Board between 1996
and 1999, an average of around 3 per year. A CA P accident rate can be estimated under
the assumption that annual CAP flight activity was st able during the period 19961999
and that a consistent proportion of this flight activity wa s designated pub lic use by CAP
personnel who returned GA surveys. Base d on these assumptions, staff calculated an
annual CAP accident rate of 4.31 per 100,000 flight hours, wh ich is only slightly higher
than the overall public aircraft accident rate (3.66). Furthermore, CA P data contributed a
very small proportion of the accidents (7.6 pe rcent) and flight hours (7 percent) used to
calculate the overall public aircraft accident rate, meaning that this slight difference had
very little influence on the overa ll figure. For these reasons, staff believe that the inclusion
of CAP data had a negligible effect on the overa ll public use accident rate presented in this
report.
49 Safety Study
Appendix D
Selected Portions of 14 CFR Part 47
Describing Aircraft Registration Requirements
§47.45 Change of address.
Within 30 days after any change in his pe rmanent mailing address, the holder of a
Certificate of Aircraft Registra tion for an aircraft shall notify the FAA Aircraft Registry of
his new address. A revised Certificate of Ai rcraft Registration is then issued, without
charge.
§47.51 Triennial aircraft registration report.
(a) Unless one of the registration activities listed in paragraph (b) of this section
has occurred within the preceding 36 calendar months, the holder of each Certificate of
Aircraft Registration issued under this subpart shall submit , on the form provided by the
FAA Aircraft Registry and in the manner de scribed in paragraph (c) of this section, a
Triennial Aircraft Regist ration Report, certifying--
(1) The current identificati on number (registration mark) assigned to the aircraft;
(2) The name and permanent maili ng address of the certificate holder;
(3) The name of the manufacturer of the aircraft and its model and serial number;
(4) Whether the certificate holder is--
(i) A citizen of the United States;(ii) An individual citizen of a foreign country who has lawfully been admit-
ted for permanent residence in the United States; or
(iii) A corporation (other than a corporation which is a citizen of the United
States) lawfully organized and doing bus iness under the laws of the United
States or any State thereof; and
(5) Whether the aircraft is currently regi stered under the laws of any foreign coun-
try.
(b) The FAA Aircraft Registry will fo rward a Triennial Ai rcraft Registration
Report to each holder of a Certificate of Ai rcraft Registration whenever 36 months has
expired since the latest of the following registration activities occurred with respect to the
certificate holde r's aircraft:
50 Safety Study
(1) The submission of an Applic ation for Aircraft Registration.
(2) The submission of a report or statement required by §47.9(f).
(3) The filing of a notice of chan ge of permanent mailing address.
(4) The filing of an application for a dupli cate Certificate of Ai rcraft Registration.
(5) The filing of an application for a ch ange of aircraft identification number.
(6) The submission of an Aircraft Registration Eligib ility, Identification, and
Activity Report, Part 1, AC Form 8050-73, under former §47.44.
(7) The submission of a Triennial Aircra ft Registration Repor t under this section.
(c) The holder of the Certif icate of Aircraft Registrati on shall return the Triennial
Aircraft Registration Report to the FAA Aircraft Registry within 60 days after issuance by
the FAA Aircraft Registry. The report must be dated, legibly executed, and signed by the
certificate holder in the ma nner prescribed by §47.13, except that any co-owner may sign
for all co-owners.
(d) Refusal or failure to submit the Trienni al Aircraft Registra tion Report with the
information required by this section may be cause for suspension or revocation of the
Certificate of Aircraft Registration in accordance with Part 13 of this chapter.Appendix D
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