Ercoupe 415 C N2076H accident near Poulsbo, Washington

Probable cause

The pilot's failure to confirm that the engine oil filler cap was secured before flight, which resulted in oil exhaustion and a subsequent total loss of engine power during cruise flight.

NTSB analysis

During the approach for an attempted forced landing into a clearing, the airplane struck trees and then collided with the ground in a nose-down attitude. The pilot sustained serious injuries during the impact but was able to call 911 on his cell phone. He subsequently died from complications related to his injuries about 2 weeks later.

Postaccident examination revealed that the engine oil filler cap had not been secured. The oil filler neck and cap were intact and undamaged. Due to the engine's design, the engine oil filler cap was located at a low point on the engine; therefore, failure to secure the cap would have resulted in a rapid expulsion of engine oil and a subsequent engine seizure. Engine examination found damage consistent with oil exhaustion and engine seizure, and the aft section of the engine compartment was coated with oil, which extended out of the cowling and onto the airplane's belly.

The pilot was operating without a valid medical certificate; the Federal Aviation Administration had denied his medical application 3 years before the accident due to a diagnosis of myelodysplastic syndrome. Although no evidence was found indicating that this medical condition was casual to the accident, it likely contributed to the pilot's death because it hindered his recovery from otherwise nonlife-threatening injuries.

Text from the NTSB. Open the NTSB docket for WPR14LA100 for the full record.