History of Flight
On November 14, 2009, at approximately 0201 Pacific standard time, an Aerospatiale AS350BA helicopter, registration N5793P, collided with terrain near Doyle, California. Mountain Lifeflight was operating the helicopter under 14 Code of Federal Regulations Part 91. The commercial pilot and two passengers sustained fatal injuries; the helicopter was substantially damaged by impact and post-crash fire. The cross-country positioning flight departed Reno, Nevada, about 0143 with a planned destination of Susanville, California. Visual meteorological conditions prevailed, and a company flight plan had been filed.
The helicopter had departed its home base at Susanville Airport at 0016, picked up a patient at Banner Hospital in Susanville, departed at 0038, and arrived at Renown Hospital in Reno at 0111. It departed Renown at 0143, and the medical crew made position reports every 10 minutes to dispatch. At 0153, they reported Hallelujah Junction. At 0201, dispatch received a transmission that the helicopter was going down.
A witness on Highway 395 observed the helicopter flying straight and level, then descending vertically at a rapid rate. The witness lost sight behind terrain and saw a fireball. The wreckage was about 1/4 mile west of Highway 395.
Personnel Information
The 39-year-old pilot held a commercial pilot certificate with rotorcraft-helicopter and instrument helicopter ratings, and a certified flight instructor certificate with rotorcraft-helicopter rating. He held a second-class medical certificate issued May 20, 2009, with no limitations. His total flight time was 6,055 hours, with 49 hours in the last 90 days and 10 in the last 30 days. He had 4,815 hours in the AS350, and completed a flight review on August 3, 2009. He had 53 hours with the company and 46 hours of this mission type. He had 248 hours of night experience, with 15 hours in the previous 8 months. He reported for duty at 1900 on the accident date, and had flown the same mission earlier that evening with different crew members. Both crew members reported the pilot was in good spirits and appeared rested.
Aircraft Information
The helicopter was originally manufactured in 1982 as an AS350D, serial number 1476, and converted to AS350BA. On July 18, 2008, the operator replaced the Turbomeca Arriel 1B engine with a Honeywell LTS-101-600A-3A engine under a Soloy LLC Supplemental Type Certificate. Total airframe time at the last 250-hour inspection on October 8, 2009, was 5,827 hours. The engine had 7,020 hours total time and 751 hours since major overhaul. The helicopter was configured with a 60% fuel load.
Meteorological Information
The closest weather station was Reno (KRNO), 25 nautical miles at 150° from the site, elevation 4,415 feet. A METAR at 0155 reported wind from 340° at 6 knots, visibility 10 miles, broken clouds at 5,500 feet, temperature 4°C, dew point -3°C, altimeter 29.96 inches. Doppler radar showed no precipitation. Cloud bases were around 9,900 feet msl at KRNO and 9,100 feet at Truckee. Infrared imagery indicated cloud tops near 13,000 feet. Rawinsonde data indicated light clear icing at upset altitude with potential for moderate clear icing in/near clouds. An AIRMET ZULU for ice between 4,000 and 12,000 feet msl was active near the accident site. Crew members on the earlier flight reported no clouds or very few, and a very dark night with little moon.
Wreckage and Impact Information
The debris path was 305 feet along a magnetic heading of 230 degrees, on a 20-degree downslope. The first identified point of contact had three parallel ground scars with a recognition light fixture. The tailboom separated with tail rotor attached, coming to rest at 58 feet. The cockpit area and instrument panel were at 140 feet, highly fragmented and burned. The main rotor gearbox with blades came to rest after an earth berm. The engine split open at 220 feet. The sun gear from the main rotor gearbox was found at 292 feet. All three main rotor blades exhibited chordwise bending and trailing edge splitting. The tail rotor remained attached to its gearbox.
Medical and Pathological Information
The Washoe County Medical Examiner determined the cause of death as multiple blunt force injuries. Toxicological testing of the pilot found no volatiles or tested drugs.
Tests and Research
Examination of the wreckage at Plain Parts, Sacramento, on November 18, 2009, found the hydraulic pump properly greased. The tail rotor drive train could be rotated manually. A woodruff key in the tail rotor drive sheared and fractured, consistent with overload. Engine examination at Honeywell on December 1-2, 2009, revealed rotational witness marks on various components, including the matched idler gear assembly, power output gear, axial compressor rotor blades, and compressor impeller vanes. Metal spray deposits were found throughout the engine. Examination of the three servos, sprag clutch assembly, spool bearings, and line replaceable units (PT governor, fuel control unit, overspeed limiter, flow fence actuator) found no anomalies. NTSB materials laboratory examinations found the adaptor shaft fracture consistent with bending overstress under longitudinal tension. The annunciator panel sustained heavy fire damage; no filaments exhibited evidence of hot stretching.