Cessna P206 N2570X accident near Estacada, Oregon

Probable cause

The pilot's failure to maintain clearance from trees while on approach to land at night. Contributing to the accident was the electrical system failure and the pilot's diverted attention.

NTSB analysis

During a night visual-flight-rules personal flight, the pilot reported to a witness via cellular phone that the airplane's electrical system had failed and requested that the witness turn on the runway lights. The witness stated that he observed the airplane flying over the airport on a westerly heading with no lights on. As the airplane passed over the runway and initiated a left turn, the witness lost visual contact with the airplane. Shortly thereafter, the witness heard the sound of impact. On-scene examination of the wreckage and ground scars showed that the airplane impacted trees on final approach about 1,000 feet short of the runway's approach end. Detailed examination of the recovered wreckage revealed that the top ground terminal nut that attached the alternator filter to the ground terminal of the alternator was loose. Evidence of severe wear was noted on the alternator filter attach point and the bottom alternator ground terminal nut. Copper particle splatter was observed around the ground terminal and on the alternator filter which was found to be consistent with electrical arcing. The alternator controller remained attached to the firewall. The tamper-proof seal on the controller was found separated at the seam. The controller cover was removed and a diode was observed separated from the circuit board and found loose within the cover. Evidence of heat damage was observed within the lower inboard corner of the printed circuit board where the diode was installed. No additional anomalies were noted with the engine that would have precluded normal operation and production of power. The pilot had undergone a minor surgical procedure two weeks prior to the accident, and was prescribed a medication known to cause impairment. Toxicology testing was consistent with the medication having been taken within 24 hours of the accident; however, the investigation could not definitively establish that the pilot was impaired.

Text from the NTSB. Open the NTSB docket for WPR09FA027 for the full record.