Aviation Accident Summaries

Aviation Accident Summary ANC23LA005

Kenai, AK, USA

Aircraft #1

N8119D

PIPER PA-22-160

Analysis

Shortly after takeoff, the engine lost power and the propellor began to windmill. The flight instructor conducted emergency procedures but was unable to regain engine power. The flight instructor determined that they did not have sufficient altitude to make it back to the airport and he selected a road on which to make a forced landing. To avoid a car, the pilot turned slightly towards the edge of the road and was pulled into a snow berm, where the aircraft came to a full stop. The airplane sustained substantial damage to the right wing and fuselage. A postaccident examination of the engine found the crankshaft drive gear bolt was missing and the gear alignment dowel pin on the crankshaft was broken. The missing bolt was not found during the postaccident examination. The engine was last disassembled in 1983 and the accessory gearbox was opened for an oil pump rebuild in 2006; the investigation was not able to identify how long the engine had operated with the bolt missing. The crankshaft drive gear drives the accessory gear box and, according to the engine manufacturer, failure of the gear or the gear attaching parts would result in complete engine stoppage.

Factual Information

On October 26, 2022, about 1656 Alaska daylight time, a Piper PA-22-160, N8119D, sustained substantial damage when it was involved in an accident in Kenai, Alaska. The flight instructor and the pilot receiving instruction, who was a private pilot, sustained no injuries. The airplane was operated by the instructor pilot as a Title 14 Code of Federal Regulations Part 91 general aviation flight. The purpose of the flight was to conduct pilot training. The airplane took off from the Kenai Municipal Airport, Kenai. Shortly after takeoff, the engine lost total power and the propellor began to windmill. The flight instructor conducted emergency procedures but was unable to regain engine power. The flight instuctor informed the airport tower of their loss of engine power and was cleared to land back at the airport. He determined that they did not have sufficient altitude to make it back to the airport and landed on a road about 2 miles southeast of the airport. During the landing, to avoid a car, the flight instructor turned slightly towards the edge of the road and was pulled into a snow berm where the airplane came to rest. The airplane sustained substantial damage to the right wing and fuselage. A postaccident examination of the engine revealed that the crankshaft drive gear was missing a bolt and a broken dowel pin on the crankshaft. The missing bolt was not found during the postaccident examination. The engine was last disassembled in 1983. The accessory gearbox was opened for an oil pump rebuild in 2006. The crankshaft drive gear drives the accessory gear box and, according to the engine manufacturer, failure of the gear or the gear attaching parts would result in complete engine stoppage.

Probable Cause and Findings

Improper installation of the crankshaft drive gear by maintenance personnel, who failed to install all required hardware, resulting in an in-flight engine failure.

 

Source: NTSB Aviation Accident Database

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