The Piper PA-22-160 took off from the Kenai Municipal Airport (PAEN) in Kenai, Alaska, for a training flight.
Shortly after takeoff, the engine lost total power and the propeller began to windmill.
The flight instructor conducted emergency procedures but was unable to regain engine power.
He 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 two 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 post-accident 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 post-accident 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: Improper installation of the crankshaft drive gear by maintenance personnel, who failed to install all required hardware, resulting in an in-flight engine failure.
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This October 2022 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
What’s a missing dowel and bolt among friends? They’re lucky there was no loss of life, just hardware and insurance premium upward adjustment — assuming it was actually insured. Where is the accountability for this incompetence and professional fraud? Other professions (and mechanical repair requiring a cert is certainly arguably ‘professional’) such as surgeons, lawyers, accountants, big tractor maintenance shops. etc., work under both legal and professional expense and sanction for bad work. Your eye surgeon drops a scalpel in your eye and you are instantly blinded — Oops! Sorry about that — won’t fly. He’d be bankrupt, drummed out of the medical profession, and flipping burgers for the rest of his life. I keep raising this question time and time again: Where is the accountability for GA maintenance shop incompetence? Surely somebody out there must know. We read of these kind of crashes almost weekly on this news service. Are there court trials and recourse for bad mechanical repairs? Please tell me. Thanks/Regards/Jim
Practicality problem with your theory is every professional would be out of business at some point and every employee eventually terminated.
Solution is acquire cert to do it yourself, and there could still be a defective component failure.
James Don’t most professionals have error and omissions insurance?
An undertorqued crankshaft gear bolt, even with the lock tab, would allow the gear to slip, bite off the locator dowel, which would unkey the accessory case gears completely. Had the gear bolt not been installed, the engine wouldn’t run at all. It sounds as if this gear bolt backed out, so the bolt, lock key and dowel pin remnant have to be in the sump!
Don’t see how that engine could run 5 minutes. Much less all those years without a crank shaft gear drive bolt.
I know maintenance in Alaska is a little slow at times, but the oil pump AD should have been completed a few years before 2006. I’m just guessing on the reasons for the oil pump replacement. If the airplane was being used for flight training, then Lycoming’s TBO hours and years limits should have been followed.
I agree;
“The engine was last disassembled in 1983.”
A Part 141 flight school…in Alaska…operating an engine that hasn’t had a major overhaul in 39+ years?
That is kind of a stretch!
I can only imagine what their insurance underwriter said.
Be interesting to hear what Mike Busch thinks about this scenario.