Rosamond, CA, USA
N736LZ
CESSNA R172K
Same as Factual Information
The pilot/owner and three non-pilot acquaintances decided to use the airplane to fly to another airport for lunch. The pilot had owned and operated the airplane about 10 years, and reported a total time of about 550 hours in that make and model. His normal procedures included hangaring the airplane, and using a yoke-mounted iPad "mini" for in-flight information. The outbound flight was uneventful. After landing, the pilot installed the flight control lock in the pilot-side yoke shaft. After lunch, the four persons returned to the airplane for the return trip. The pilot reported that the preflight inspection and taxi out to the run-up area were normal, but during the before-takeoff check process there, he noticed that the two fuel tank gauges indicated different quantities from one another, which was unusual for the high wing airplane. The pilot decided to interrupt the before-takeoff check process, shut down the engine, and physically "stick" the tanks to accurately determine the total fuel quantity. After the pilot measured the fuel quantities, which he determined were satisfactory, he re-boarded the airplane, re-started the engine, and taxied from the run-up area onto the runway for departure. The airplane lifted off about half-way down the 3,600 foot runway, but when it was at an altitude of about 20 feet above the ground, it stopped climbing. The pilot "immediately recognized something was wrong," aborted the departure, and the airplane landed on the remaining runway. The pilot was unable to stop the airplane on the runway, and it sustained substantial damage to the fuselage as a result. None of the occupants were injured. After the accident, the pilot determined that he had left the control lock in for the takeoff. The pilot reported that he normally used the airplane manufacturer's checklists on all his flights, including this one, but the evidence in this event contradicts that account. The manufacturer's checklists explicitly specified that the flight controls be checked for freedom of travel during two separate pre-departure phases; the walk-around preflight inspection, and the before-takeoff operational checks. For undetermined reasons, the pilot omitted those items from both of those phases, and deprived himself of two opportunities to detect the presence of the control lock. Investigation revealed that the manufacturer-issued control lock had been installed backwards by the pilot, which prevented it from accomplishing one of its primary design functions, that of inhibiting pilot access to the ignition switch. Further investigation revealed that the pilot rarely used the control lock due to the fact that he hangared his airplane, and that he was unaware that he had installed it backwards. The yoke-mounted iPad limited the pilot's view of the installed control lock, which reduced the potential for visual detection. The pilot reported that the winds were "light," which reduced the likelihood of the need for flight control inputs on the ground during taxi, and thus deprived the pilot of another opportunity for detection of the locked controls. Finally, after his impromptu physical check of the fuel quantity, the pilot did not re-commence the interrupted before-takeoff checklist from the beginning, and thus missed another opportunity to detect the locked flight controls.
The pilot's improper use of the control lock, combined with his incomplete execution of two pre-departure procedures, which resulted in a takeoff with the control lock installed.
Source: NTSB Aviation Accident Database
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