NTSB Safety Alert SA-057 - Helicopter Landing Sites Free from Debris

Helicopter Landing Sites: Free from Debris

Foreign object debris can foul rotor systems and cause damage

The problem

 Unsecured or improperly secured foreign object debris (FOD) at helicopter landing sites

can migrate due to the effects of main rotor system downwash and upwash and foul the

main or tail rotor systems.

 Examples of FOD that are light enough to migrate and a ffect the helicopter include towels,

ropes, tarps, bags, tents, equipment covers, loose tree branches, tumbleweeds, and hats

worn by ground personnel.

 Contact with FOD at a landing site can lead to a loss of helicopter control and accidents.

Related accidents

The National Transportation Safety Board (NTSB) has investigated several accidents in recent

years involving FOD at helicopter landing sites:

 The pilot of an Airbus (formerly Eurocopter) EC135 P2+ helicopter reported that, while

landing at a public safety training center, he felt the helicopter shudder unexpectedly. The

pilot immediately landed the helicopter without further incident. A postflig ht examination

revealed that a towel had been ingested into the fenestron (see figures 1 and 2). The towel

ingestion resulted in separation of the fenestron hub cover , which was subsequently

ingested, substantially damaging the helicopter. The pilot report ed that the towel came

from an unsecured storage conta iner near the landing site. ( GAA16LA056 )

Figure 1. Fenestron with towel pieces.

Figure 2. Lower fenestron housing.

SA-057 November 2016  The pilot of an Airbus (formerly Eurocopter) AS350 B3 helicopter was conducting a remote,

high-altitude landing on a mountain during a rescue mission when the main rotor system

was fouled by a rope that was not properly secured by ground personnel during the loading

process. The helicopter abruptly rotated to the left, began to shake violently, and impacted

terrain before the pilot regained con trol of it and made an emergency landing. A postflight

examination revealed substantial damage to the main rotor system, tail boom, and

empennage (see figures 3 and 4). ( GAA15CA258 )

 After the pilot landed an MD Helicopters MD 500D (formerly Hughes 369D) helicopter at a

remote landing site near secured bundles of trash, the helicopter started to shake abruptly.

The pilot maintained control of the helicopter until the shaking subsided and shut down the

engine. A witness reported that a tarp from a nearby trash bundle had migrated up into the

main rotor blades. As a result of the entanglement, one of the main rotor blades separated

from the helicopter. ( WPR13CA406 )

 The pilot of a Robinson R22 Beta helicopter landed the helicopter on a private landing pad

in a position that placed the tail rotor system near tarps that were held on the ground by

boards and stones. As the pilot was preparing to shut down the helicopter, the tarps were

lifted into the t ail rotor system. The helicopter rotated several revolutions on the ground,

struck a parked trailer, and caught fire. ( CEN13LA115 )

What can you do?

 When choosing a landing site, avoid areas close to construction activities and trash

storage. Consider the effects of main rotor system downwash and upwash on FOD

migration when selecting a landing site, based on the site conditions and the size of the

helicopter.

 Keep in mind that wind speed and direction can aid in the migration of FOD to landing sites.

Rain water and drainage can also stream FOD along the path of least resistance.

 Ask available personn el to conduct a sweep of the landing site for FOD that could affect

the helicopter. If personnel are not available, visually scan for FOD on the landing site while

conducting your high and low reconnaissance before you land. If the conditions permit,

check for FOD while conducting your ground reconnaissance before you take off.

 Have personnel at the landing site remove or secure any headgear (such as helmets, hats,

and knit caps). Ensure any additional clothing, gear, and equipment items are secured and

kept clear of the main and tail rotor systems.

Figure 3. Main rotor system

(Starflex assembly).

Figure 4. Empennage (horizontal stabilizer

and vertical fin).

SA-057 November 2016  Incorporate the Perceive, Process, Perform (3P) risk management model for selecting an

appropriate landing site. This model (resources for which are provided below) can help you

develop the aeronautical decision -making and risk management skills to help identify the

potential for FOD, evaluate its potential impact on flight safety, and implement the best

course of action to mitigate the risk.

 Educate and train flight crews who routinely work with ground personne l at landing sites

(such as helicopter air ambulance companies, law enforcement organizations, and military

units that coordinate with first responders on the ground ) about how to identify, secure, or

remove FOD that could affect the helicopter.

Interested in more information?

The following Federal Aviation Administration (FAA) resources are accessible via www.faa.gov :

 Advisory Circular (AC) 00 -59, “ Integrating Helicopter and Tiltrotor Assets into Disaster

Relief Planning ,” provides guidance about helicopter landing site planning and usage

during disaster relief operations.

 FAA-H-8083 -21A, “ Helicopter Flying Handbook ,” provides guidance about how to conduct

a high, low, and ground reconnaissance.

 FAA-H-8083 -25B, “ Pilot’s Handbook of Aeronautical Knowledge ,” provides guidance in

chapter 2 -15 about how to incorporate the 3P risk management model during all phases of

flight.

 AC 135 -14B, “ Helicopter Air Ambulance Operations ,” provides guidance in section 3 -8 for

establishing procedures for conducting airborne and ground reconnaissance of landing

sites and heliports, with particular emphasis on off -airport landing sites or heliports not used

on a routine basis.

The FAA Safety Team (FAASTeam) provides access to online training courses, seminars, and

webinars to provide education that focuses on accident and incident causal factors, special

emphasis items, and regulatory issues. Course ALC -28, “ The Art of Aeronautical Decision -

Making ,” provides information about the 3P risk management model. This course (and many

others), as well as seminar and webinar information, can be accessed from the FAASTeam

website at www.faasafety.gov . (Course access requires logi n through an existing or new free

FAASTeam account.) -

The NTSB’s Aviation Information Resources web page, www.ntsb.gov/air , provides convenient

access to NTSB aviation safety products. The reports for the accidents referenced in this

safety alert are accessible by NTSB accident number from the Aviation Accident Database link,

and each accident’s publi c docket is accessible from the Accident Dockets link for the

Docket Management System . This safety alert and others, such as SA -026, “ All Secure, All Clear ,”

(which emphasizes securing items inside an aircraft) and SA -054, “ Control Foreign Object

Debris ,” (which emphasizes keeping track of tools and objects during aircraft maintenance) can

be accessed from the Aviation Safety Alerts link.