Pilot Debrief

BOWERS FLY BABY 1-A near Jefferson, GA — 2012-01-08

Final reportERA12LA141
Sign in to save
Date
2012-01-08
Location
Jefferson, GA, USA
Airport
19A
Aircraft
BOWERS FLY BABY 1-A
Registration
N4626
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Takeoff roll

Probable cause

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.

Contributing factors

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 narrative

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.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted takeoff due to engine issues before becoming airborne.

NTSB coding

Evidence available

  • Photos
  • 13 docket documents
View NTSB final reportView NTSB docket

Docket documents13

Related mishaps