Piper PA 12 N3227M accident near Willow, Alaska

Probable cause

The loss of engine power shortly after takeoff for reasons that could not be determined based on the available information, which resulted in an emergency landing and collision with trees.

NTSB analysis

According to the pilot, during the initial climb on the personal flight, the engine backfired and then lost total power. He was unable to restore power, and during the subsequent off-airport forced landing, the airplane collided with a stand of trees, which resulted in substantial damage to the wings and fuselage.

A mechanic/friend of the pilot stated that this was the first flight after engine maintenance, during which he and the pilot had been troubleshooting for excessive magneto drops and a cold cylinder. He added that they had just reinstalled the fine wire spark plugs after cleaning them.

A postaccident examination of the airplane revealed that all spark plugs exhibited normal operational signatures with no defects or anomalies noted. Both magnetos produced spark at all terminals as designed. The impulse coupler inside the left magneto was fractured, but that did not preclude the magneto from sparking. Additionally, the wiring harness from the ignition switch to the magnetos was frayed and separated. However, it could not be determined if the separation occurred as a result of the accident. Thus, the reason(s) for the loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for ANC19LA005 for the full record.