History of Flight
On June 21, 2010, at 1400 eastern daylight time, a Schweizer 269C-1 helicopter, N247FG, was substantially damaged when it impacted terrain following a loss of engine power in Asheville, North Carolina. The certificated commercial pilot and the passenger were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight that originated at Foothills Regional Airport (MRN), Morgantown, North Carolina. The aerial photography flight was conducted under Part 91.
The purpose of the flight was for the passenger to film footage for a documentary, specifically capturing the local “kudzu,” an invasive plant species. The pilot reported departing Asheville Regional Airport (AVL) around 1045 and flying locally until needing to refuel. The pilot landed at MRN, where 19 gallons of fuel were added, bringing the total to 25 gallons. After departing MRN and flying southwest toward AVL for about 20 minutes, the passenger spotted an area of kudzu. The pilot performed a 360-degree turn and approached “straight and level between 30-40 knots.” As the helicopter passed abeam the kudzu, the pilot heard a pitch change in the engine and noted that the engine/rotor rpm was at the bottom of the green arc and dropping. The helicopter descended into the trees. The pilot lowered the collective slightly and increased the throttle, but the descent continued. The engine continued to run, “bogging down.” Shortly after, the helicopter impacted the kudzu and rolled to the left.
The passenger reported being several hundred feet above the trees and noticing they were closer than usual. The pilot stated “she's settling,” and about 10 seconds later said “we're going to go down.” The helicopter came to a very slow stop above the trees and then slowly sank until the rotor blades struck trees and the helicopter dropped to the ground. The engine felt like it was bogging down.
Personnel Information
The pilot held a commercial pilot certificate and a flight instructor certificate with rotorcraft-helicopter and instrument helicopter ratings. His most recent FAA second-class medical certificate was issued November 19, 2007. He reported 441 total flight hours, with 221 hours in make and model, and 33 hours in the previous 90 days, all in make and model.
Aircraft Information
The helicopter was powered by a single Lycoming HO-360-C1A, 180-horsepower engine and was manufactured in 2001. The most recent annual inspection was completed April 6, 2010, at a total aircraft time of 3,749 hours. Weight and balance for the accident flight resulted in an approximate weight of 1,670 pounds; maximum gross weight was 1,750 pounds.
Meteorological Information
Weather reported at AVL at 1354 included wind from 190 degrees at 5 knots, 10 miles visibility, clear skies, temperature 29°C, dew point 17°C, and altimeter setting 30.19 inches of mercury. The calculated density altitude was 4,400 feet.
Wreckage and Impact Information
Examination by an FAA inspector revealed substantial damage to the main rotor blades. The helicopter was transported to a secure facility. The engine was test run on the helicopter: it would not start initially; spark plugs from cylinders 2 and 4 were oil-fouled. After cleaning and reinstalling the plugs, the engine started and power was increased to about 1,500 rpm. A magneto check showed a 50-rpm drop on each magneto. An idle mixture check indicated the engine was running rich, with a rise of about 150 rpm.
Additional Information
The passenger provided a videotape taken during the accident sequence. Examination of the video revealed that the engine continued to run with no change in power during the sequence.
According to the FAA Rotorcraft Flying Handbook, vortex ring state (settling with power) describes an aerodynamic condition where a helicopter may be in a vertical descent with up to maximum power applied and little or no cyclic authority. The term “settling with power” comes from the fact that the helicopter keeps settling even though full engine power is applied. Conditions conducive to settling with power include attempting to hover out of ground effect without precise altitude control and downwind or steep power approaches at low forward airspeed.