History of Flight
On September 27, 2009, at 1900 Pacific daylight time, an Arrow Falcon Exporters OH-58A+ helicopter, registration N298CP, departed from a landing zone in a field 24 miles west of Myrtle Creek, Oregon. The flight was conducted under 14 CFR Part 137 by Reforestation Services, Inc. The helicopter was equipped with agricultural application equipment, but the chemical tanks were empty. The intended purpose was to survey the area for spraying.
During takeoff, the pilot sensed greater than usual power was necessary to clear trees approximately 10 to 12 feet tall at the edge of the landing zone. Engine instruments indicated normal readings with 100 percent torque. Shortly after, the pilot heard popping sounds from the engine. After clearing the trees, at an airspeed between 20 and 30 knots, the helicopter would not accelerate and settled into the trees despite application of full collective.
Personnel Information
The pilot, age 46, held a commercial pilot certificate with rotorcraft-helicopter and instrument-helicopter ratings issued May 22, 2008, and a second-class medical certificate issued June 12, 2009. He reported 14,250 total flight hours, with 1,500 hours in the accident make and model. His most recent flight review was on June 4, 2009, in a Bell 206B.
Aircraft Information
The five-seat, single-engine helicopter, serial number 71-20532, was originally owned by the US Army and later transferred to the Baltimore County Police. Dakota Air Parts International purchased it on April 26, 2007, and Reforestation Services, Inc., acquired it on July 18, 2007. Arrow Falcon Exporters, Inc., refurbished it with an extended range fuel system, chemical spray system, and VHF/FM radio. It was registered as an Arrow Falcon Exporters Inc OH-58A+, N298CP, on September 13, 2007, with a restricted category special airworthiness certificate. Total airframe time was 6,705.6 hours; the most recent maintenance inspection was performed on September 16, 2009. The Allison T63-A-720 gas turbine engine had been installed since new, with approximately 1,336.2 total engine hours at the time of the accident.
Wreckage and Impact Information
The accident site was in a forest area 24 miles west of Myrtle Creek, approximately 1/2 mile from the departure area. Trees were 10 to 12 feet high, a mix of hardwoods and pines. The wreckage path was about 75 feet long, with a linear and descending pattern of tree strikes. Damage included tail rotor blades bent 90 degrees upward, tail rotor gearbox fractured from tail boom, tail boom fractured forward of the tail rotor attachment point, broken windscreen and chin bubble, a main rotor blade bent 90 degrees chordwise at the doubler, trailing edge damage from tree impact, mast bent slightly forward, and fractured transmission mounting structure.
Tests and Research
The engine was removed and shipped to Rolls-Royce in Indianapolis, Indiana, for examination and functional test on October 20, 2009. Chip detectors were clean; about 200 cc of clean oil was drained. Gas generator and power turbines rotated freely. A pneumatic leak check at 50 psi found no leaks. Damage was noted on several first- and second-stage compressor blades and vane leading edges. The engine was functionally tested to an abbreviated version of the factory production test procedure and met all parameters, producing 439 shaft horsepower (manufacturer rating 420 horsepower).