Amateur-built GLASAIR II N8176J accident near Darby, Montana

Probable cause

The pilot’s impact with terrain during a go-around following an attempted precautionary landing due to a low oil pressure indication. The reason for the low oil pressure indication could not be determined based on the available information.

NTSB analysis

The pilot was conducting a local flight with a passenger when he received a low oil pressure warning, and he decided to perform a precautionary landing to a nearby grass runway. While on final approach for landing, the pilot determined that the airplane was high and fast, and he attempted to slip to slow the airplane and descend quickly, but about halfway down the runway, chose to go around and began a turn to land in the other direction. About three-quarters of the way through the turn, the pilot “felt the airplane begin to stall.” He pushed the nose down and the airplane contacted the ground in a left-wing-low, nose-down attitude.

The automotive conversion engine was rotated by hand after removal of the flywheel dampener plate. About 2 quarts of oil was drained from the engine. Examination of the crankshaft and connecting rods revealed no anomalies. The oil filter and adapter were removed, and black RTV sealant was noted around the base of the filter adapter. The oil filter element was inspected and found to contain a sliver of black RTV material; however, based on the available information, the reason for the low oil pressure indication could not be determined.

Text from the NTSB. Open the NTSB docket for WPR21LA219 for the full record.