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 which originated at Foothills Regional Airport (MRN), Morgantown, North Carolina. The aerial photography flight was conducted under the provisions of Title 14 Code of Federal Regulations 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.
According to the pilot, they departed Asheville Regional Airport (AVL), Asheville, North Carolina around 1045 and flew in the local area, filming, until they needed to refuel. The pilot then landed at MRN. The helicopter was fueled with 19 gallons of fuel, filling the fuel tanks to 25 gallons of total fuel. The pilot then departed MRN and flew southwest toward AVL. After about 20 minutes, the passenger spotted an area of “kudzu” he wanted to film. The pilot performed a 360-degree turn and approached the area “straight and level between 30-40 knots to maintain translational lift.” As the helicopter was abeam the “kudzu” the pilot heard a pitch change in the engine and noted that the engine/rotor rpm was “in the bottom of the green,” and dropping lower. The helicopter was also descending into the trees. The pilot lowered the collective slightly and increased the throttle “to get the rpm back,” however the helicopter continued to descend. The engine continued to run, but it was “bogging down.” Shortly after, the helicopter impacted the “kudzu,” and rolled to the left.
The passenger reported that they were "several hundred feet above the trees," and as they started to pass the first batch of kudzu he noticed they "were a little closer than usual." Shortly after, the pilot stated, "she's settling". According to the passenger, the pilot didn't sound concerned and he continued filming. About 10 seconds later, the pilot stated, "we're going to go down". The passenger noted they were "right on top of the trees going about 5-10mph."
The passenger reported that the helicopter came to a very slow stop above the trees and then felt like they were slowly sinking. He stated that the engine felt like "it was bogging down," just prior to the helicopter beginning a slow, vertical decent until the rotor blades impacted trees and the helicopter dropped to the ground.
PERSONNEL INFORMATION
The pilot held a commercial pilot certificate and a flight instructor certificate with ratings for rotorcraft-helicopter and instrument helicopter. His most recent FAA second-class medical certificate was issued on November 19, 2007.
The pilot reported 441 hours of total flight experience, 221 of which were in make and model of the accident helicopter. He also reported 33 hours in the previous 90 days, all of which were in make and model.
AIRCRAFT INFORMATION
The helicopter was powered by a single Lycoming HO-360-C1A, 180-horsepower engine. It was manufactured in 2001.
The most recent annual inspection was completed on April 6, 2010, at a total aircraft time of 3,749 hours.
A weight and balance calculation was performed for the accident flight, which resulted in an approximate weight of 1,670 pounds. The maximum gross weight for the helicopter was 1,750.
METEOROLOGICAL INFORMATION
The weather reported at AVL, 18 nautical miles to the southwest, at 1354, included wind from 190 degrees at 5 knots, 10 miles visibility, clear skies, temperature 29 degrees C, dew point 17 degrees C and altimeter setting 30.19 inches mercury.
The calculated density altitude was 4,400 feet.
WRECKAGE AND IMPACT INFORMATION
Examination of the helicopter by a Federal Aviation Administration (FAA) inspector revealed that the main rotor blades sustained substantial damage. The helicopter was removed from the accident site and transported to a secure facility for further examination. The engine was test run on the helicopter, and would not start initially. The spark plugs were removed from the engine and the number 2 and 4 cylinder plugs were oil-fouled. They were cleaned and reinstalled and the engine was started again. It ran and power was increased to about 1,500 rpm. A magneto check was performed and a 50-rpm drop was noted on each magneto. An idle mixture check was performed as the helicopter was shut down. According to the inspector, the engine appeared to be running rich with arise of about 150 rpm.
ADDITIONAL INFORMATION
The passenger provided a videotape which was taken during the accident sequence. Examination of the video revealed that the engine continued to run, with no change in power, during the accident 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.
Among the conditions listed which were conducive to settling with power were: attempting to hover out of ground effect without maintaining precise altitude control, and downwind or steep power approaches at low forward airspeed.