Pilot Debrief

GRAY JIM ROBERT EXEC near Caldwell, ID — 2017-12-17

Final reportWPR18LA050
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Date
2017-12-17
Location
Caldwell, ID, USA
Airport
EUL
Aircraft
GRAY JIM ROBERT EXEC
Registration
N716JB
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Taxi

Probable cause

Failure of the oil pressure gauge line, which resulted in oil exhaustion and a total loss of engine power.

NTSB narrative

The private pilot was performing hover-taxi maneuvers in the experimental amateur-built helicopter when the engine lost all power, which resulted in a forced landing in a field during which the airplane landed hard. Postaccident examination revealed that the engine had seized due to oil exhaustion after the oil pressure gauge line had failed, causing most of the engine oil to be expelled overboard with an insufficient quantity of oil in the sump for engine operation. The pilot, who was also the helicopter builder, had installed the oil pressure gauge line, which was made of automotive-grade nylon tubing, about 1 year before the accident. Because the helicopter had an experimental airworthiness certificate and was considered to be an amateur-built aircraft, the pilot could use non-aviation grade components. The pilot discarded the oil line before it could be examined, so its failure mode could not be determined.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have checked oil levels before flight to prevent engine power loss.

NTSB coding

Evidence available

  • 2 docket documents
View NTSB final reportView NTSB docket

Docket documents2

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