Amateur-built BR-1 N677DB accident near Brigham City, Utah

Probable cause

A loss of engine power as a result of a failure of the primary and backup ignition system.

NTSB analysis

The experimental amateur-built airplane was being flown to test airplane maneuvers. The pilot reported that about 20 minutes after takeoff, the engine lost complete power. An annunciation light indicated that the primary ignition system was not operating, so the pilot switched to the backup ignition system and then the backup battery, but the engine did not respond. The pilot executed a landing into a field.

During landing the landing gear caught in the rough, soft ground, and the airplane cartwheeled.

A postaccident examination of the engine revealed a short circuit in the primary ignition system, but the source of the short circuit could not be determined. Although the ignition system had both a backup power source and backup ignition coils, they shared a common power bus with the primary ignition system. A short circuit of this bus would have rendered both the primary and backup ignition sources inoperable.

Text from the NTSB. Open the NTSB docket for WPR16LA129 for the full record.