Pilot Debrief

CESSNA 182 near Manitowoc, WI — 2023-11-30

Final reportCEN24LA052
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Date
2023-11-30
Location
Manitowoc, WI, USA
Aircraft
CESSNA 182
Registration
N8880T
Category
Airplane
Highest injury
Minor
Fatalities
0

Probable cause

Maintenance personnel’s improper servicing of the magnetos, which resulted in their accelerated wear, failure, and the total loss of engine power.

NTSB narrative

About an hour after takeoff, during a personal flight, the engine suddenly lost total power. The pilot then made a turn toward the nearest airport to attempt to land; however, the airplane was unable to maintain sufficient altitude and the pilot elected to make a forced landing in a wooded area. The airplane impacted terrain and came to rest inverted, resulting in substantial damage to the fuselage, empennage, and both wings. The postaccident examination of the engine revealed that neither magneto delivered spark to the spark plugs. Laboratory examination of both magnetos identified arcing damage within their distributor assemblies. The arcing melted and carbonized the distributor block and distributor gear electrodes, resulting in an excessive electrode gap and a loss of electrical continuity, which prevented the magnetos from energizing the spark plugs and likely resulted in a total loss of engine power. The arcing damage was consistent with the presence of an insulating oil film on the distributor gear electrodes. The distributor block felt strips were saturated with oil, and oil droplets were observed on and around the felt material, consistent with oil migration from the felt strips to the electrodes. The felt strips were likely oiled improperly during the most recent magneto maintenance. Although the meteorological conditions at the time of the accident were conducive to carburetor icing, neither magneto produced spark during the postaccident examination. The pilot reported that the pretakeoff engine check was nominal. The magnetos had been in service for about 150 hours before the accident. Improper oiling of the felt strips during that maintenance likely led to the oil contamination and subsequent arcing observed in both magnetos.

NTSB coding

View NTSB final report

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