Primary finding
Probable cause
The failure of the wooden propeller.
Investigator assessment
Analysis narrative
During takeoff, at about 100 feet in the air, near the end of the runway, the pilot heard a loud bang and immediately felt an increasing vibration. He reduced engine power and maneuvered to return to the runway. As he lined up for the runway, the engine was producing power but he felt no thrust. The airplane lost altitude and the pilot landed in a rough pasture short of the runway. The landing gear separated and the left wing buckled before coming to a stop. Post-accident examination of the airplane by a Federal Aviation Administration inspector revealed the brass tip separated from the wooden propeller and the blades separated to the hub section. The missing pieces of propeller were not located.
Source record
Factual narrative
The pilot of the DeHavilland DH-82A stated that shortly after takeoff he heard a loud bang over the engine noise and through the headset, followed immediately by severe vibration which increased until he reduced the power from take off to low cruise. The airplane was about 100 feet in the air and very near the end of the runway when the trouble started. The pilot elected to try to continue the climb and return to the field as quickly as possible. He was able to maintain sufficient airspeed while he turned around and lined up with the runway. Before he made the runway, the engine, though still running, felt like it stopped providing any thrust. The airplane was no longer able to maintain altitude and touched down in a pasture just before the runway. What appeared from the air to be a relatively smooth pasture; however, the terrain was rough and the impact sheared the landing gear. The left wing buckled as it settled to the ground. The pilot estimated that the total time from lift off to touchdown was approximate 2 to 3 minutes. The responding FAA inspector stated that examination of the engine revealed no discrepancies with it and its components. The wooden propeller was destroyed, split to the hub section. The propeller brass tip cap separated which started the initial vibration and tearing the propeller apart; consistent with the pilot’s account of having engine power but no thrust. The missing sections of the propeller were never located.