NTSB Safety Alert SA-041 - Pilots Perform Advanced Preflight After Maintenance

Pilots: Perform Advanced Preflight After Maintenance

Be vigilant for flight control and trim anomalies

The problem

 In-flight emergencies, accidents, and deaths have occurred after pilots flew aircraft

with incorrectly rigged flight control or trim systems.

 Four such mishaps within a 2 -year span share common safety issues:

o Maintenance personnel who serviced or checked the systems did not

recognize that the control or trim surfaces were moving in the wrong direction.

o Pilots who flew the airplane s did not detect the control anomalies during their

preflight checks.

 In many cases, although maintenance personnel made mistakes, the pilots could

have prevented the accidents by performing thorough or advanced preflight checks.

Related incident and accid ents:

 In December 2014, the pilot of a Cessna T182T airplane experienced extreme

nose -down control forces on the yoke shortly after takeoff. The airplane had just

undergone maintenance on the elevator trim system, and the mechanic briefed the

pilot about the work before the flight. Both the pilot and the pilot -certificated

passenger needed to pull hard aft on the yoke to prevent the airplane from pitching

down, even though the elevator pitch trim indicator showed a nearly full nose -up trim

position. The pi lot remembered that work had been done on the elevator trim system,

and he thought that there might be some kind of control -reversal problem. While

maneuvering for the emergency landing, the pilot applied nose -down trim control

inputs and found that the ex treme control forces lessened, and he successfully

landed the airplane. The elevator trim control cables were misrigged such that the

elevator trim control was reversed. The airplane’s checklist for the exterior inspection

of the empennage during preflight included “Trim Tab – CHECK security.”

(CEN15IA079 )1

1 These pilots and the mechanic are featured in the NTSB’s safety video, “ Airplane Misrigging: Lessons

Learned from a Close Call ,” which is available on the NTSB’s safety videos web page at

http://www.ntsb.gov/safety/safety -alerts/Pages/Safety -Videos.aspx .

SA-041 March 2015 , revised December 2015  In October 2013, the private pilot and pass enger in a Piper PA -22 received serious

injuries when the airplane crashed during takeoff on its first flight since an annual

inspection in which frayed elevator control cables were replaced. During the takeoff

roll, when the pilot applied forward stick co ntrols to raise the tail, the tail did not rise,

and the airplane instead “jumped” off the runway. The pilot reduced engine power

and attempted to control the airplane’s pitch, but the airplane responded abnormally

and crashed. The elevator control cables were installed incorrectly such that the

elevator moved in the direction opposite to that commanded. The pilot’s preflight

check of the airplane was also inadequate. (ERA14LA015 )

 In July 2014, the pilot of a Piper PA -12 airplane was fatally injured after his airplane

pitched up steeply during takeoff and crashed. The investigation found that the

eleva tor control cables were installed incorrectly such that the elevator moved in the

direction opposite to that commanded. The preflight checklist for the airplane required

the pilot to verify that the flight controls were free and correct. (ANC14FA050 )

 In May 2013, the pilot of a Schweizer SGS 2 -33A glider received serious injuries after

the glider cras hed due to improper rigging of the rudder control cables. The glider had

just received an annual inspection, and its rudder had been removed and reinstalled.

If the pilot had conducted a thorough preflight inspection, he should have been able

to detect tha t the rudder control cables were rigged incorrectly. (ERA13LA229 )

What can pilots do?

 Become familiar with the normal directional movement of the flight controls and trim

surfaces of the aircraft you fly before it undergoes maintenance. It is easier to

recognize “abnormal” if you are already very familiar with what “normal” looks like.

 After maint enance, check systems more thoroughly than the normal preflight

checklist implies. For example, if a preflight checklist states, “Trim – Set Takeoff,”

verify not only the trim setting but also proper directional travel.

 Be prepared to abort the takeoff if something does not seem right.

 Avoid interruptions and distractions during your preflight inspection to ensure that you

do not skip or misevaluate the items you are checking.

 If you suspect that there is a problem with a flight control or trim system, ask qualified

maintenance personnel to inspect the aircraft. Do not attempt to perform such work

yourself if you are not appropriately qualified, certificated, and authorized to do so.

Interested in more information?

The accident reports for each accident summarized in this safety alert can be searched by

accident number from the NTSB’s Aviation Accident Database & Synopses web page at

http://www.nts b.gov/_layouts/ntsb.aviation/index.aspx .2 Each accident’s public docket is

available on the NTSB’s Accident Dockets web page at http://dms.ntsb.gov/pubdms/ .

2 Less-recent fatal accidents that may also be of interest are CHI05FA038 , CHI08MA270 , and

DCA03MA022 .

SA-041 March 2015 , revised December 2015 The Federal Aviation Administration (FAA) Safety Team ( FAASTeam ) pamphlet, “ Advanced

Preflight ,” (FAA -M-001) provides guidance to help pilots develop the necessary knowledge

and techniques to reduce t he risk of undetected maintenance problems, including how to:

 Conduct a complete review of maintenance -related records and data

 Develop an “additional items checklist” to be used in conjunction with the aircraft’s

preflight checklist

The pamphlet can be accessed (without login) from the FAASTeam website at

http://www.faasafety.gov/gslac/ALC/libview_normal.aspx?id=63083 .

The FAA’s Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083 -25A) discusses

aeronautical decision -making and risk management in chapter 17 . It provides basic tools to

help pilots assess risk and manage it in a positive manner; proper preflight inspections are

an important part of risk management and risk intervention. The Risk Management

Handbook (FAA-H-8083 -2) provides a more in-depth discussion of risk management

principles. Both handbooks can be accessed from the FAA’s website at www.faa.gov .

An online article in Flight Training (an Aircraft Owners and Pilots Association publication),

“How to Pre -flight an Airplane: Understanding How Is as Important as Actually Doing It ,”

provides tips on checking controls and other items. It is

available at http://flighttraining.aopa.org/students/presolo/skills/howtopreflight.html .

An online article, “ Things You Miss on Preflight ,” provides several anecdotes about

preflight -related mishaps. Originally from Aviation Safety magazine, it can be found at

http://www.avweb.com/news/redundant/preflight_pilot_airplane_flight_ntsb_inspection_207

912-1.html .

Related regulations:

 Title 14 Code of Federal Regulations (CFR) 91.7 states, in part, that “the pilot in

command of a civil aircraft is responsible for determining whether that aircraft is in

condition for safe flight.”

 Title 14 CFR 91.407 states, in part, that: “No person may operate any aircraft that has

undergone maintenance...unless…it has been approved for return to service.” Also,

“no person may carry any person (other than crewmembers) in an aircraft” that has

undergone certain maintenance until the aircraf t has received an operational check

flight that is logged in the aircraft records.

This NTSB safety alert and others can be accessed from the NTSB’s Safety Alerts web

page at http://www.ntsb.gov/safety/safety -alerts/Pages/default.aspx or searched from the

NTSB home page at http://www.ntsb.gov/Pages/default.aspx .