Pilot Debrief

BEECH H35 near Holly Lake Ranch, TX — 2012-08-01

Final reportCEN12LA501
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Date
2012-08-01
Location
Holly Lake Ranch, TX, USA
Airport
16TE
Aircraft
BEECH H35
Registration
N4684D
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Descent

Probable cause

The incomplete maintenance performed by maintenance personnel, which resulted in a total loss of engine power.

NTSB narrative

The airplane’s engine lost power during the descent to the destination airport, and the airplane struck trees during the ensuing forced landing attempt. A postaccident examination of the engine revealed that the idler gear pin was not in position and no retaining bolts were found. Additionally, the nuts from the forward left, lower through bolt on the crankcase half and the forward left engine mount bolt were missing. A logbook entry indicated that the engine had been reassembled and re-installed on the airplane about 1 week before the accident due to a previous propeller strike. Based on the available information, it is likely that the improper assembly of the engine, specifically the omission of the idler gear pin retaining bolts, resulted in the idler gear falling out of its position and a subsequent complete loss of engine power.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Proper maintenance checks could have prevented the missing idler gear pin.

NTSB coding

Evidence available

  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

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