Pilot takes off with malfunctioning engine

Aircraft: Bowers Fly Baby 1-A. Injuries: 1 Fatal. Location: Jefferson, Ga. Aircraft damage: Destroyed,

What reportedly happened: A witness told investigators that the pilot was attempting to diagnose an engine problem prior to the accident flight. The witness said that the engine was running rough and backfiring during takeoff.

When the airplane was about 200 feet AGL, it stalled, spun to the right, hit the ground and caught fire.

The post-accident examination revealed that the right magneto distributor gear was unsecured inside the housing. There were marks consistent with damage found after the gear became loose while the engine was under power.

Since limited maintenance records were available, it could not be determined how many flight hours had accumulated since the last engine overhaul.

Investigators determined that it was probable that the cotter pin was not installed in either magneto rotor drive shaft and that the right magneto’s castellated nut came loose during engine operation and that the unsecured distributor gear reduced engine performance, resulting in a partial loss of engine power.

Probable cause: The pilot’s failure to maintain control, resulting in an aerodynamic stall and spin. Also causal was the partial loss of engine power during the initial climb due to the improper installation of a magneto.

Contributing to the accident was the pilot’s decision to take off with an engine problem and the mechanic’s failure to detect the missing magneto rotor cotter pins during the last engine overhaul.

NTSB Identification: ERA12LA141

This January 2012 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.