Pilot Debrief

BEECH A36 near Abilene, TX — 2018-01-22

Final reportCEN18LA084
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Date
2018-01-22
Location
Abilene, TX, USA
Airport
DYS
Aircraft
BEECH A36
Registration
N3600A
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Climb

Probable cause

Maintenance personnel’s improper maintenance of the engine, which resulted in a catastrophic engine failure due the shifting/slipping of the No. 2 bearing and the subsequent oil starvation and total loss of engine power during cruise flight.

NTSB narrative

The private pilot was conducting a cross-country, personal flight. He stated that, upon leveling off at cruise altitude, there was a "severe vibration" coming from the engine compartment, followed by a sound of the engine "coming apart." Oil covered the windshield, and the smoke entered the cockpit. The pilot was unable to return to the departure airport because it was beyond gliding distance, so he performed a forced landing on a field with the landing gear and flaps retracted. The pilot sustained serious injuries. Postaccident examination of the engine revealed a large hole in the left crankcase half over the No. 2 cylinder attachment point and a small hole in the right crankcase half over the No. 5 cylinder attachment point. The No. 2 main bearing had shifted in the bearing saddle, which cut off the oil supply to the No. 2 rod cap bearing. Shifting/slipping of the bearing can result from either improper torque application during cylinder replacement or improper grinding of the bearing journal during maintenance. The engine had been disassembled twice before the accident. An engine logbook entry showed that the No. 2 cylinder had been removed and replaced about 328 hours before the accident. It is likely that maintenance personnel did not conduct proper maintenance on the No. 2 cylinder during reassembly of the engine and that this ultimately led to the catastrophic engine failure due the shifting/slipping of the No. 2 bearing and the subsequent oil starvation and total loss of engine power.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have returned to ABI before engine failure escalated.

NTSB coding

Evidence available

  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

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