Accident Narrative
On October 25, 2010, at approximately 0745 Pacific daylight time, a Cessna 340A, registration N68718, experienced an in-flight loss of control followed by an uncontrolled descent into mountainous terrain about 9 nautical miles northeast of Morton, Washington. The aircraft was substantially damaged. The airline transport certified pilot and two passengers sustained fatal injuries. The business flight was conducted under 14 Code of Federal Regulations Part 91.
The flight originated from Chehalis-Centralia Airport (CLS) at about 0725, destined for Lewiston-Nez Perce County Airport (LWS), Lewiston, Idaho. The pilot had filed an instrument flight rules (IFR) flight plan and received a clearance. Radar track data showed the pilot proceeding eastward. At 07:30:59, the aircraft was 12 nautical miles east of CLS climbing at about 1,057 feet per minute. At 07:38:43, it reached 14,800 feet mean sea level, and the pilot requested 17,000 feet. At 07:39:03, the pilot transmitted “heading back to Chehalis,” and at 07:39:10, stated “Yah, we’ve lost an engine here so we’re headed back to Chehalis.” At 07:40:03, the pilot said “We’re losing it.” This was the last transmission.
Radar data indicated the aircraft began a right turn at 8 degrees per second from 14,800 feet. At 07:39:20, it started a descent averaging 5,783 feet per minute to the last recorded return at 10,700 feet. Radar contact was lost as the aircraft continued a descending right turn.
Logging company employees about 8 miles northeast of Morton reported hearing a descending airplane loud enough to be heard over their equipment. Light rain and low clouds were present. The employees later believed their location was within one-quarter to one-half mile of the crash site.
Pilot Information
The pilot, aged 70, held an airline transport pilot certificate with multiengine land and single-engine commercial privileges, and a flight instructor certificate with single-engine and instrument ratings. His most recent FAA second-class medical certificate was issued on June 25, 2010, with a limitation for corrective lenses. He had accumulated 5,493 total flight hours, including 1,525 hours in the Cessna 340A. In the previous 30, 60, and 90 days, he had flown 8, 20, and 26 hours in the accident airplane. His most recent flight review was completed on November 12, 2009.
Aircraft Information
The 1982-model Cessna 340A, serial number 340A1527, was a twin-engine, low-wing, retractable landing gear, pressurized aircraft. It was powered by two Continental TSIO-520-NB-2 engines rated at 335 horsepower each. Both engines had accumulated 3,071.7 hours since new and 1,557.3 hours since major overhaul. The most recent annual inspection was completed on March 3, 2010, at 6,051.2 airframe hours; total time at accident was 6,107.5 hours. On August 11, 1999, the airworthiness certificate was changed from Standard to Experimental and back to Standard on September 9, 1999.
Maintenance records showed replacement of the right engine fuel pressure regulator on September 24, 2010, in response to a pilot squawk about slow power achievement. The regulator was adjusted per Teledyne Continental Motors and RAM Aircraft specifications. The aircraft flew 7.1 hours after that without further anomalies.
Weather Information
The pilot received a standard weather briefing from the Prescott, Arizona Flight Service Station at 0614. The briefer advised of stormy conditions, snow above 4,000 feet in the Cascades, possible convective SIGMETs, and Airmets for mountain obscuration, moderate turbulence below FL 180, and moderate icing between the freezing level and 15,000 feet. The Chehalis automated weather report at that time indicated wind 160 degrees at 10 knots gusting to 17, visibility 5 miles, light rain, and scattered to broken clouds.
The closest weather reporting facility to the accident site was Chehalis-Centralia Airport. At about 0735, the automated system reported wind 210 degrees at 5 knots, visibility 5 miles, light rain showers, and scattered to overcast clouds at 2,100 to 3,700 feet.
Wreckage and Impact Examination
The accident site was in a densely forested area at 2,940 feet mean sea level, about 36 nautical miles east of the departure airport. Fragmented cockpit and engine components were found in a 5-foot-deep impact crater. The debris field extended 160 feet down a 20- to 30-degree slope, fanning out over a 45-degree arc. The aircraft struck in a near-vertical, slightly right-wing-low attitude. The energy path was oriented about 060 degrees.
Major structural components were located near the main wreckage; no fire was observed. Components including engines, turbochargers, propellers, and instruments were recovered for examination.
Medical and Pathological Information
An autopsy performed on November 3, 2010, attributed the pilot's cause of death to severe blunt force injuries. Forensic toxicology detected no ethanol or drugs in muscle; carbon monoxide and cyanide were not tested.
Tests and Research
Examination of the Shadin Digiflo-L Fuel Flow Indicator revealed no data could be recovered from non-volatile memory due to impact damage. Airspeed, directional gyro, and exhaust gas temperature dial faces showed no witness marks, possibly due to damage.
Both engines were examined by a Continental Motors technician. The right engine showed no pre-impact abnormalities that would have prevented normal operation. However, its turbocharger had evidence of foreign object damage ingestion and possible loss of performance prior to impact. The left engine showed no pre-impact abnormalities, and its turbocharger had no mechanical malfunction.
Propeller examination by McCauley Propeller Systems indicated both propellers were rotating at impact. The left propeller was operating under power; the right propeller was not under significant power. No fatigue was found. All blades were near the latch pitch position; none were feathered.
Airframe examination was limited due to impact damage; navigation instruments, electrical systems, flight controls, and other components could not be evaluated.