Aviation Accident Summaries

Aviation Accident Summary ANC21LA047

Sterling, AK, USA

Aircraft #1

N98109

PIPER J3C-65

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.

Factual Information

On June 28, 2021, about 1530 Alaska daylight time, a Piper J3C-65 airplane, N98109, was substantially damaged when it was involved in an accident near Sterling, Alaska. The pilot and one passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.   According to the pilot, he fueled the airplane to capacity 2 days before the accident but had not flown the airplane since. On the day of the accident, he drained “minimal” water from the right-wing fuel tank during his preflight inspection. He added 1 quart of oil to the engine, for a total of 7 quarts. He noted that all the before takeoff checks were normal.   While en route, the airplane reached an altitude of about 2,900 ft mean sea level as the pilot planned to cross an ocean channel. The pilot reported that the engine began to “cough, sputter and make popping noises with a loss of power.” He began troubleshooting, including turning the carburetor heat control to ON, and looking for landing sites. He stated that during the descent, the engine would make intermittent power but only for brief periods of time.   The pilot notified air traffic control of the emergency and maneuvered the airplane for landing to an area of tundra. During the landing the airplane nosed over and came to rest inverted. The airplane sustained substantial damage to the empennage and right wing. The airframe and engine were examined, and no mechanical failures or malfunctions were observed.   The nearest weather observation station, located about 25 miles away, reported a temperature of 59°F and dew point of 46.4°F about the time of the accident. 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.”

Probable Cause and Findings

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

 

Source: NTSB Aviation Accident Database

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