Amateur-built BOWERS FLY BABY 1A N6054Q accident near Mariposa, California

Probable cause

The partial loss of engine power due to an improperly maintained carburetor and the pilot's subsequent failure to maintain aircraft control.

NTSB analysis

The plans-built single-seat airplane had been constructed about 8 years before the accident by another individual, who had flown it about 30 hours before it was purchased by the current owner/pilot. In the year since the purchase, due to the low build-quality of the airplane, the pilot had made several modifications and repairs to the airplane. The accident flight was the pilot's fifth flight in the airplane. Review of the pilot's flight logbook indicated that his most recent flight review occurred about 7 years before the accident and that he had flown only 15 hours in the 2 years before the accident.

A witness reported that shortly after takeoff, when the airplane was about 3 miles from the airport, the engine began making a sound as if power was intermittently being interrupted. The nose of the airplane began to pitch up aggressively as it flew out of view. The wreckage location, wreckage distribution, and impact signatures indicated that the airplane struck the ground in a steep nose-low attitude, consistent with an aerodynamic stall event.

Postaccident examination of the carburetor revealed multiple maintenance-related discrepancies, any one of which could have resulted in the loss of engine power. Additionally, before the accident, the pilot reported to a friend that the airspeed indicator was not reliable and that the airplane exhibited roll control anomalies. Both of these conditions would have hindered the pilot's ability to safely operate the airplane.

Text from the NTSB. Open the NTSB docket for WPR14FA165 for the full record.