Pilot Debrief

GRUMMAN ACFT ENG COR-SCHWEIZER G 164A near Five Points, CA — 2015-06-21

Final reportWPR15LA194
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Date
2015-06-21
Location
Five Points, CA, USA
Aircraft
GRUMMAN ACFT ENG COR-SCHWEIZER G 164A
Registration
N8598H
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Takeoff roll

Probable cause

Maintenance personnel’s improper reassembly of the engine during overhaul, which led to the failure of the supercharger-blower due to a lack of lubrication and the subsequent total loss of engine power during takeoff.

NTSB narrative

The pilot reported that, shortly after takeoff for the aerial application flight, the engine lost power. The pilot subsequently initiated a forced landing to a field. The airplane impacted the ground and flipped over. The engine manufacturer's table of limits specified that the minimum side clearance/tolerance between a starter shaft circumference and a starter shaft bushing should be 0.002 inch. However, during postaccident examination, there was no measurable clearance between the starter shaft circumference and the starter shaft bushing, which impeded oil flow to the impeller shaft and bearings and resulted in the failure of the supercharger-blower due to a lack of lubrication. The engine had accumulated 2.0 hours since its last major overhaul, and it is likely that maintenance personnel improperly reassembled the engine during the overhaul.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Performing maintenance checks before the flight could have prevented engine failure.

NTSB coding

Evidence available

  • Photos
  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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