Failure to maintain airspeed proves fatal

Aircraft: Cessna 172. Injuries: 4 Fatal. Location: Veneta, Ore. Aircraft damage: Destroyed.

What reportedly happened: According to several people at the airport, shortly after the airplane took off from the grass runway, the sound of the engine stopped. One witness reported that he saw the airplane fly over 100-foot-tall trees north of him at an altitude of about 200 feet AGL and the engine sounded normal, then suddenly quit. He saw the airplane crash into trees.

A portable electronic device was located in the wreckage, and it contained a 23-second video that was recorded during the flight and ended just before the airplane hit the trees.

Review of the video revealed that it began as the airplane initiated the takeoff roll on the grass runway. The video briefly captured the engine tachometer gauge, which displayed 2,300 rpm. Throughout the video, the engine sound was consistent and did not increase or decrease. During the final eight seconds of the video, after the airplane became airborne, a sound similar to a stall warning horn began and was heard until the end of the recording. During the last four seconds of the video, only the sky and the airplane’s propeller were visible.

During the post-accident examination, the throttle control was found in the idle position and was bent downward. Investigators determined that given the idle position of the throttle and downward bend, it is likely that the pilot reduced power before the airplane hit the trees.

The sound of the stall warning horn in the video suggests that the airplane was traveling at a slow airspeed immediately after takeoff and most likely continued in this state throughout the climb.

Although witnesses reported hearing the engine lose power, it is possible that the witnesses heard the reduction of engine power from a high power setting to an idle power setting before the airplane’s impact with trees and attributed the sound to a loss of engine power.

Toxicology tests were found positive for metabolites of marijuana within the pilot’s blood and lung tissue. Although the pilot’s use of marijuana may have affected his ability to successfully manage this flight, use likely occurred more than five hours before the accident, and the exact degree of impairments in cognition, judgment, and motor function could not be determined.

Probable cause: The pilot’s failure to maintain adequate airspeed and altitude to clear trees during the initial climb after takeoff.

NTSB Identification: WPR12FA274

This June 2012 accident report is are provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.