Shortly After Takeoff, The Engine Lost Power And The Propellor Began To Windmill

Location: Kenai, Alaska Accident Number: ANC23LA005
Date & Time: October 26, 2022, 16:56 Local Registration: N8119D
Aircraft: Piper PA-22-160 Aircraft Damage: Substantial
Defining Event: Loss of engine power (total) Injuries: 2 None
Flight Conducted Under: Part 91: General aviation - Instructional

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. 

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- Improper installation of the crankshaft drive gear by maintenance personnel, who failed to install all required hardware, resulting in an in-flight engine failure.

FMI: www.ntsb.gov