Amateur-built Glasair 3 N121CH accident near Oxford, Maine

Probable cause

A loss of engine power for reasons that could not be determined.

NTSB analysis

The purpose of the flight was to evaluate the experimental airplane’s takeoff and landing performance in accordance with the experimental aircraft phase one flight testing program. Following normal engine run-up and ground operations, and after multiple takeoffs and landings at another airport without incident, the pilot returned to the departure airport.

While on the downwind leg of the airport traffic pattern, the pilot noted some engine roughness after reducing the engine power to 25 inches manifold pressure. He attempted to troubleshoot the problem with the ignition switches and the fuel selector. After returning the magnetos to the BOTH position, the engine lost all power. He turned the airplane toward the airport while again checking the ignition switches, then focused on performing a forced landing.

The airplane did not have enough altitude and airspeed for the pilot to safely glide the remaining distance to the runway; after clearing a line of trees, the airplane impacted the perimeter road, struck a fence, and slid on its belly into the runway overrun area, stopping 100 ft short of the threshold. The airplane sustained substantial damage to the wings and fuselage.

Postaccident examination of the airplane did not reveal any anomalies that would have prevented normal operation. Examination of the engine and all of its components was performed at the manufacturer, and two engine runs in a test cell were performed satisfactorily. The reason for the loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for ERA24LA335 for the full record.