Piper J3C-65 N98109 accident near Sterling, Alaska

Probable cause

A partial loss of engine power for reasons that could not be determined based on the available information.

NTSB analysis

The pilot reported that, while en route, the engine lost partial power, and he was unable to restore full power. During the subsequent off-airport landing, the airplane nosed over and came to rest inverted, resulting in substantial damage to the empennage and right wing.

A postaccident examination revealed no mechanical failures or malfunctions that would have precluded normal operation. According to the carburetor icing-probability chart located in the Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35, the accident flight would likely have been operating in conditions conducive to “serious icing in cruise power”; however, the pilot reported that he applied carburetor heat following the loss of power. The reason for the loss of power could not be determined based on the available information.

Text from the NTSB. Open the NTSB docket for ANC21LA047 for the full record.