Piper PA28 N2184X accident near Louisville, Kentucky

Probable cause

The failure of the magnetos due to a known deficiency, which resulted in a partial loss of engine power. Contributing to the accident was maintenance personnel’s failure to comply with the applicable service bulletin.

NTSB analysis

According to the pilot, the airplane accelerated normally during the takeoff roll, became airborne, and the engine started to run "rough." He elected to land straight ahead on the remaining runway. The airplane subsequently overran the runway and collided with the perimeter fence. Examination of the airplane revealed it sustained substantial damage to the airframe.

During an examination of the left magneto, two ignition wires in the distributor cap revealed evidence of arcing, and one ignition lead was found detached from the insulator and spring. The right magneto was removed, rotated, and produced spark at each spark lead. The metal copper electrode on the right magneto distributor gear was found loose.

To address a potential decreased service life of Slick 4-cylinder magneto distributor gear assemblies, Slick/Champion Aerospace Service Bulletin SB1-15A calls for replacing distributor gear assemblies that have a copper electrode with assemblies that have a Monel electrode. A rough running engine was a symptom of the condition that the SB was intended to address. A review of the accident airplane’s maintenance logbooks revealed no entries for the repair of the magnetos or compliance with the applicable SB and that the airplane received three annual inspections since the release and the revision of the SB.

Text from the NTSB. Open the NTSB docket for ERA19LA109 for the full record.