Primary finding
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.
Investigator assessment
Analysis narrative
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.
Source record
Factual narrative
HISTORY OF FLIGHT On October 28, 2008, about 1900 Pacific daylight time, a Cessna P206, N2570X, was substantially damaged when it impacted terrain while maneuvering near the Valley View Airport (5S9), Estacada, Oregon. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The private pilot and his passenger were killed. Night visual meteorological conditions prevailed and no flight plan was filed for the cross-country personal flight. The flight originated from the Lexington Airport (9S9) Lexington, Oregon about 1745. According to a witness located at 5S9, the pilot called him using a cell phone about 1845 stating that the airplane had lost all electrical power. The pilot asked the witness to turn on the runway lights so he could locate the airport and land. A few minutes later, the pilot called the witness again requesting that he “flash” the runway lights to assist him in locating the airport and asked if the witness could hear the airplane. The witness stated that he went outside of his residence along with his wife and attempted to locate the airplane. A few seconds later, he observed an airplane flying overhead on a westerly heading with no lights at an estimated altitude of about 800 feet above ground level. As the airplane passed over the runway, the witness observed it initiate a left turn before losing sight of the airplane. Shortly after, the witness heard the sound of impact and called 911. PERSONNEL INFORMATION The pilot, age 54, was issued a private pilot certificate with an airplane single-engine land rating on June 25, 2008. A third-class airman medical certificate was issued to the pilot on April 3, 2007, with the limitation of “not valid for any class after.” Review of the pilot’s personal logbook revealed that as of the most recent entry dated September 28, 2008, he had accumulated 190.6 total hours of flight time, of which 1.2 hours were in the previous 30 days and 43.7 hours within the previous 90 days of the accident. The pilot had accumulated a total of 139.2 hours in the accident make/model airplane. AIRCRAFT INFORMATION The six-seat, high-wing, fixed-gear Cessna P206 airplane, serial number (S/N) P206-0070, was manufactured in 1964. It was powered by a Continental IO-520-A engine, serial number 111111-A-5, rated at 285 horse power driving a McCauley E2A43C7-3-NO two bladed constant speed propeller. According to Federal Aviation Administration (FAA) registration records, the airplane was registered to the pilot on August 22, 2007. Review of copies of maintenance logbook records revealed an annual inspection was completed on December 21, 2007, at a recorded tachometer reading of 332.5 hours, airframe total time of 6,241.3 hours, and engine time since major overhaul of 1,080.12 hours. One entry dated July 28, 2008, stated that a tach time of 401.0 hours, "removed alternator PF DOFF10300JR, SN UNK, and installed OH ALT same PN with SN H092958, installed new voltage reg. adjusted belt tension and ops checked system and found ok." At the time of the accident, the airplane had accumulated 122.5 hours since the time of the inspection. METEOROLOGICAL INFORMATION A review of recorded data from the automated weather observation station, located at the Portland Troutdale Airport, about 15 miles north of the accident site revealed at 1853 weather conditions were wind calm, visibility 10 statute miles, clear sky, temperature 11 degrees Celsius, dew point 8 degrees Celsius, and an altimeter setting of 30.21 inches of Mercury. According to the US Naval Observatory, sunset was at 1800, end of civil twilight was at 1831, and moonset was at 1756. AIRPORT INFORMATION The Valley View Airport (5S9) is an unattended airport that is operating under class G airspace. The recorded field elevation for 5S9 is 735 feet mean sea level. The airport features a single asphalt runway, 3,780-foot long and 32-feet wide, oriented on headings of 160 and 340 degrees respectively. The runway is equipped with runway edge lights, which were located along the middle 2,240 feet of the runway, which were operated by personnel on the ground. No runway visual slope indicators were installed. WRECKAGE AND IMPACT INFORMATION Examination of the accident site revealed that the airplane had struck trees and subsequently impacted the ground 0.26 miles south of 5S9. Wreckage debris and several broken tree limbs were scattered about 54 feet along an approximate 070-degrees magnetic heading from the first topped tree. The airplane came to rest inverted within thick vegetation. The left wing and right wing attach points were separated but remained attached to the fuselage via the control cables and were located adjacent to the fuselage. All primary flight control surfaces and major components of the airplane were located within the debris field. The engine and engine mounts were separated from the engine firewall. A strong fuel odor was noted at the accident site. A local resident near the accident site reported that they located a portion of the outboard left wing tip and damaged trees approximately 300 to 400 feet directly south of the accident site about one month after the accident. Flight control continuity was established from the cockpit controls to all primary flight controls. The rudder control cables were separated in the cockpit just above the rudder bellcrank and exhibited "broomstraw" signatures. The flap actuator was measured and was consistent with the flaps being in the "UP" position. The right wing fiberglass fuel tank was shattered. The right wing fuel screen was free of debris. The left fuel tank was intact; however, the left wing fuel lines were breeched at the wing root. The left wing fuel screen was free of debris. The fuel selector was observed set to the right fuel tank. No shoulder harnesses were present. Both lap belts were buckled and were cut by first responders. The airframe and engine were recovered to a secure location for further examination. MEDICAL AND PATHOLOGICAL INFORMATION The Clackamas County Medical Examiner’s office conducted an autopsy on the pilot on October 29, 2008. The Medical Examiner determined the cause of death to be "head injuries." The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. According to CAMI's report, carbon monoxide, cyanide, volatiles, and drugs were tested with positive results for 0.2 (ug/ml, ug/g) of diazepam detected within the blood, unspecified amounts of ibuprofren and naproxen detected within the blood, 0.318 (ug/ml, ug/g) of nordiazepam detected in the blood, 0.152 (ug/ml, ug/g) of nordiazepam detected in the urine, unspecified amounts of oxazepam detected in the blood and urine, 0.018 ug/ml, ug/g) of temazepam detected in the blood, and 0.352 ug/ml, ug/g) of temazepam detected in the urine. A family member indicated that the pilot had undergone a minor surgical procedure on October 14, 2008, and following the surgery was experiencing ongoing muscle spasms, for which he had been prescribed diazepam 10mg, three times a day. TESTS AND RESEARCH On November 6, 2008, the wreckage was examined at the facilities of Specialty Aircraft, Redmond, Oregon. Examination of the engine revealed that the engine was separated from the airframe. The top spark plugs, vacuum pump, alternator, fuel pump, and propeller were removed. All cylinders remained attached to the crankcase. The cylinders were examined internally using a lighted borescope and exhibited normal operational signatures. The engine crankshaft was rotated by hand using a hand tool at the upper right hand accessory drive pad. Thumb compression was obtained on all six cylinders and valve train continuity was established throughout the engine. During rotation of the crankshaft, the left a