NTSB Safety Alert SA-048 - Flight Control Locks Overlooking the Obvious

Flight Control Locks: Overlooking the Obvious

Use Checklists to Prevent Procedural Omissions

The problem

Accidents have occurred after pilots omitted seemingly obvious procedures, such as

removing flight control locks and performing flight control checks before takeoff.

 Four accidents within a 2 -year span involved pilots who attempted flight in airplanes

with flight control locks in place.

 Errors of omission are frequently associated with interruptions, distractions, time

pressures, divided attention, and complacency about standard operating procedures

(SOPs).

Related accidents

 In May 2014, a Gulfstream G -IV overran the runway during a rejected takeoff and

crashed after the flight crew did not disengage the gust lock system or perform a

flight control check before takeoff. All seven people on board died. The investigation

found that the flight crew members had neglected to perform complete flight control

checks before 98% of their previous 175 takeoffs in the airplane. Thus, the

flight crew’s omission of this check during the accident flight indicates intentional,

habitual noncompliance with SOPs. During the takeoff roll, the flight crew detected

the problem but delayed initiating a rejected takeoff until the accident was

unavoidable. (ERA14MA271 )

 In August 2013, a Cessna 172S sustained substantial damage after crashing onto

the runway during takeoff with a “straight pin” installed as a control lock on the yoke.

The pilot had installed the pin after an earlier flight that day. The pilot said that he

performed the Before Takeoff checklist but did not check that the flight controls w ere

free and clear for fear of having his tablet knocked off the yoke mount.

(ERA13CA350 )

 In August 2013, the pilot and the pilot -certificated passenger on board an

Aeronca 7AC died when the airplane crashed during takeoff with the rudder gust lock

installed. The control lock, which was installed over the rudder and vertical stabilizer,

was about 48 inches long and constructed of about 3/4 -inch tubing covered in a foam

wrap. It could not be determined who was the pilot flying, but both pilots should have

SA-048 September 2015 , revised December 2015 noted the installation of the rudder gust lock during either a preflight inspection or a

pretak eoff flight control check. ( ERA13FA372 )

 In May 2015, a Cessna 172M sustained substantial damage after colliding with trees

during takeoff with a bolt installed as a control lock on the yoke. The pilot realized the

problem at the point of rotation and attempted first to remove the bolt before he

aborted the takeoff. The airplane’s speed was too great for the pilot to stop the

airplane before it struck the trees. ( GAA15CA088 )

What can pilots do?

 Pilots of all experience levels should follow SOPs and use checklists, which serve as

a memory aid to help counteract human performance vulnerabilities. Do not rely on

memory alone.

 Recognize that p rocedural omissions are also common in many other types of

accidents, including those involving gear -up landings, fuel starvation, incorrect fuel

pump settings, and flap misconfigurations.

 Be prepared to abort the takeoff if something does not seem right. When a pilot is

confronted with a sudden, abnormal event, responses are more likely to be delayed

or inappropriate. Having a plan will help reduce reaction time and can result in a safer

response.

 When flying alone, read the checklist aloud and touch the a pplicable switch or

control. Research has shown that touching an object while verbally communicating

enhances the probability that an activity has been accomplished.

 Avoid using improvised control lock devices that may be inconspicuous and easily

overlook ed during preflight checks.

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.ntsb.gov/_layouts/ntsb.aviation/index.aspx . Each accident’s public docket is

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

The FAA’s Risk Man agement Handbook (FAA-H-8083 -2) provides in -depth discussions of

risk management principles, including single -pilot resource management and strategies for

the effective use of checklists —not only for the aircraft but also for assessing personal

risks—in chapter 6 . Other risk management strategies, such as mitigating external

pressures on pilots that can lead to omitting checklist it ems, are discussed in chapter 3 .

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. Checklist use and proper

preflight ins pections are an important part of risk management and risk intervention. Both

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