Piper PA-12 N92770 accident near Delta, Alaska

Probable cause

The pilot's decision to make a low-altitude turn back to the airport following a loss of engine power, which resulted in an aerodynamic stall and loss of control. Contributing to the severity of the pilot's injuries was the separation of the pilot's seat during impact.

NTSB analysis

Witnesses reported that the airplane was departing a private airstrip. It reached an altitude of about 200-300 feet above the ground when the engine lost all power, and the airplane began a left turn. During the turn, the airplane's nose pitched down abruptly, and the airplane collided with the ground in a steep, nose-down attitude. Two of the witnesses, both of whom are pilots, noted that before the loss of power, the engine made some popping noises and sounded unusual.

A postaccident examination of the airframe and engine disclosed no mechanical malfunctions. A carburetor icing probability chart indicated that the relative humidity and temperature at a nearby airport about the time of the accident was conducive to serious icing at glide power. Although carburetor icing was possible, absent any mechanical malfunctions or fuel contamination, it could not be determined why the engine lost power.

The accident site was adjacent to a road and about 300 yards from a clear field. Despite these potential landing areas, the pilot decided to attempt to return to the airstrip by initiating a turn at low altitude and low airspeed following the loss of engine power, which resulted in an aerodynamic stall and a loss of control with insufficient altitude to recover.

During the impact, the pilot's seat separated from the airframe and moved forward about 6 inches, which allowed the pilot to impact the instrument panel and subsequently contributed to the severity of the pilot's injuries.

Text from the NTSB. Open the NTSB docket for ANC11FA065 for the full record.