Accident Overview
On December 9, 2021, about 1544 Pacific standard time, a Cessna P210N, registration N152BT, sustained substantial damage when it was involved in an accident near Hillsboro, Oregon. The pilot reported minor injuries. The aircraft was operating as a Title 14 Code of Federal Regulations Part 91 personal flight.
Pilot Actions
The pilot reported that the airplane had just returned to service following its annual inspection. After departure, he turned northbound toward his destination airport, about 7 nautical miles away. The airplane “struggled” to climb, and at an altitude of about 1,100 ft above ground level, it began to lose altitude. The pilot decided the airplane would not reach the destination runway and turned back toward the departure airport for a precautionary landing. During this time, he verified that magnetos, fuel, mixture, propeller, and throttle settings were correct. Shortly after, he observed spikes in the exhaust gas temperature (EGT) of three cylinders; adjusting the mixture did not reduce the EGTs, which remained in the red arc. The pilot then initiated a precautionary landing in an orchard, and the airplane came to rest upright between trees. The right and left horizontal stabilizers sustained substantial damage.
Postaccident Engine Examination
A postaccident engine run was performed. When the right magneto was selected, the engine ran up to 30 inches of manifold pressure and 2500-2600 rpm. When the left magneto was selected, the engine sound changed consistent with shutdown. With both magnetos selected, the engine ran up to 22 inches of manifold pressure and about 2200 rpm. When magnetos were turned off, the engine sound changed consistent with shutdown.
Examination of the ignition harness revealed that the wires from the magneto to the ignition block were crossed: the left magneto was set to the right switch terminal and the right magneto to the left switch terminal. Both magnetos were removed and examined. The left magneto was unremarkable. The right magneto had corrosion and green residue built up within it. Chemical analysis of the residue showed it was primarily composed of copper and silicon (dirt), along with polyamide, likely originating from nylon gears.
Maintenance History
A review of the engine logbook revealed that the right magneto was last removed and serviced about 609 hours before the accident. The recommended Champion Aerospace 4300-6300 Series Magneto Maintenance and Overhaul Manual (500-hour overhaul) was last performed on the right magneto about 850.7 hours before the accident, and the last overhaul was completed about 1389 hours (19 years) before the accident. According to the magneto manufacturer, corrosion is not an acceptable condition and corroded components should be cleaned or replaced as necessary.
A postaccident examination of the airframe and engine revealed no additional mechanical anomalies or failures that would have precluded normal operation.