Piper PA-36-375 N2386X accident near Avoca, Nebraska

Probable cause

A partial loss of engine power due to the loose left magneto which resulted in erratic engine timing.

NTSB analysis

The pilot reported that, during an aerial application flight, the engine lost power and the airplane began to descend. He added full power and pushed the propeller control full forward, but did not feel the engine respond and the airplane continued to descend. After he dumped the hopper tank, he still was not able to stop the airplane’s descent, and the airplane touched down in the field and continued through a cattle fence, resulting in substantial damage to the fuselage and left wing.

The airplane was recovered to a secure facility for further examination. There was a crack observed between the Nos. 1, 2, and 3 cylinders that was most likely the result of impact damage. Examination of the magnetos revealed that, while still attached to the engine, the left magneto could be rotated at its flange. Both magnetos were removed and spun by hand and both magnetos produced spark at their terminal leads. The right magneto made a “clunking” sound when rotated and rattled when shaken. Further examination revealed that the right magneto coil wedges were loose in the housing. The coil wedges appeared to have been initially wedged in place, but only exhibited minimal marring, and may not have been secured sufficiently.

That the left magneto was found loose and could be rotated at its flange, it’s likely it was out of time. Although the right magneto coil wedges were loose in the housing, it is more likely the left magneto firing at the wrong time would have had the most significant impact on the engine only being able to produce partial power.

Text from the NTSB. Open the NTSB docket for CEN24LA269 for the full record.