NTSB Identification: ERA12LA141
14 CFR Part 91: General Aviation
Accident occurred Sunday, January 08, 2012 in Jefferson, GA
Probable Cause Approval Date: 04/10/2013
Aircraft: BOWERS FLY BABY 1-A, registration: N4626
Injuries: 1 Fatal.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The airplane was about 200 feet above ground level when it stalled, spun about one-half turn to the right, impacted the ground in a nose down attitude, and burned. A witness reported that the pilot was attempting to diagnose an engine problem prior to departure. The witness also said that the engine was running rough and backfiring. A postaccident examination revealed that the right magneto distributor gear was unsecured inside the housing, and galling signatures were present. The galling signatures were 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; however, it is 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. It is probable that the unsecured distributor gear reduced engine performance, which resulted in a partial loss of engine power. The probability also exists that, at the time of the accident, the airplane was being operated in conditions conducive to serious carburetor icing at cruise power; however, the investigation could not conclusively determine that carburetor icing occurred.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot’s failure to maintain airplane control which resulted 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. Full narrative available
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