Shortly After Takeoff, The Engine Lost Most Of Its Oil, Resulting In A Partial Engine Seizure

Location: Humboldt Bay, California Accident Number: WPR24LA210
Date & Time: June 20, 2024, 10:31 Local Registration: N141PB
Aircraft: Lancair Company LC42-550FG Aircraft Damage: Substantial
Defining Event: Powerplant sys/comp malf/fail Injuries: 1 None
Flight Conducted Under: Part 91: General aviation - Personal

Analysis: Shortly after takeoff, the engine lost most of its oil, resulting in a partial engine seizure and a total loss of engine power. During a forced landing to a soft field, the airplane nosed over, sustaining substantial damage to the vertical stabilizer, rudder, and fuselage. Postaccident examination of the engine revealed that a rocker cover gasket was misaligned before the accident. The gasket was unable to maintain an adequate seal and opened during the accident flight. Oil was then ejected out of the gap between the rocker cover and cylinder head, which resulted in oil exhaustion.

Maintenance that was performed about 20 flight hours before the accident flight would have included installing the gasket. Maintenance instructions required a series of specific steps to install the gasket; based on the condition of the gasket after the accident, the instructions were likely not followed properly.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- Maintenance personnel’s incorrect installation of an engine rocker cover gasket, which resulted in oil exhaustion and subsequent loss of engine power during the initial climb.

FMI: www.ntsb.gov