Cessna T182T N291FR accident near Crescent City, California

Probable cause

The partial loss of engine power due to the failure of both magneto capacitors.

NTSB analysis

The flight instructor noticed a flashing red turbine inlet temperature (TIT) warning light during the flight. He enrichened the fuel mixture, which returned the TIT to normal. Shortly after, the engine began to run rough. The flight instructor switched to the left magneto and the engine lost power. He then switched to the right magneto and the engine continued to run rough. He switched back to both magnetos and the engine continued to run rough. The flight instructor then adjusted the mixture and turned on the auxiliary fuel pump. Despite his actions, he was unable to get the engine to operate at a power setting sufficient to maintain altitude. The flight instructor located an open field and initiated a forced landing. The airplane landed in marshland and nosed over during the landing.

The postaccident examination of the engine revealed excessive gap on all sparkplugs and two of the sparkplug electrodes were fouled. The magnetos would not produce spark and had corrosion on their internal components. It was also noted that the pressurized magnetos did not have a moisture trap or filter installed.

The magnetos were sent to a facility for further examination, which revealed deformities on both magneto point assembly contact areas and the failure of both magneto capacitors during testing. The failure of the capacitors likely resulted in the deformities on the points surface contact areas resulting in the magnetos not producing sufficient spark for normal operation.

Text from the NTSB. Open the NTSB docket for WPR21LA098 for the full record.