Lumberton, NJ, USA
N2091E
SIKORSKY 269C
The pilot initiated a practice autorotation about 951 feet above ground level (agl), rolled off the throttle to the idle detent, and maintained 60 knots during the descent until 50 feet agl, at which time, he flared the helicopter. At the end of the flare, when the helicopter was about 20 to 30 feet agl, the pilot lowered the nose to level the helicopter, began to increase the collective, and rolled on the throttle for a power recovery. The pilot reported that, subsequently, the engine sounded like it was "bogging down" and that the engine rpm was not increasing enough for the helicopter to continue to come to a hover. The helicopter continued to descend and contacted the runway hard, which resulted in substantial damage to the vertical firewall. A postaccident engine run revealed no evidence of a preimpact failure or malfunction that would have precluded normal operation. According to the pilot's flight manual, when performing practice autorotations, the pilot should lower the collective while maintaining the throttle setting to prevent the engine from "loading up or stalling" during recovery. Therefore, it is likely that the pilot rolling the throttle to the idle detent at the beginning of the maneuver, which was contrary to procedures, resulted in the engine hesitating when power was applied for the recovery.
On June 22, 2013, about 1500 eastern daylight time, a Sikorsky Aircraft Corporation (formerly Schweizer Aircraft Corporation) 269C, N2091E, registered to Herlihy Helicopters, Inc., DBA Helicopter Flight Services, was landed hard at Flying W Airport (N14), Lumberton, New Jersey. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 personal, local flight from N14. The helicopter sustained substantial damage, and there were no injuries to the commercial rated pilot or passenger. The flight originated about 1400 from N14. The pilot stated that the purpose of the flight was to take his friend for a 1 hour local flight who was possibly interested in taking flying lessons. Prior to departure he obtained weather information from the ASOS at South Jersey Regional Airport (VAY), and reported that at the time of takeoff the weather was clear and the wind was not a factor. The flight departed, and flew locally then returned and entered the traffic pattern where he discussed autorotations with the passenger. He informed the passenger that he would demonstrate an autorotation with a planned power recovery, and initiated it from 1,000 feet mean sea level, or 951 feet above ground level (agl), and 60 knots indicated airspeed. He rolled off throttle to the idle detent and descended maintaining 60 knots as he had been trained to do keeping the main rotor rpm in the upper green range, and at approximately 50 feet agl, he flared. At the end of the flare, or about 20 to 30 feet agl, he leveled the nose and began to increase the collective and rolled on throttle for a power recovery, but later reported the engine sounded like it was "…bogging down, and the engine [rpm] was not increasing enough to continue hold the hover." He reported that with insufficient engine rpm, the helicopter continued to descend and contacted the runway, coming to rest upright. He secured the helicopter and both occupants exited it. The operator reported the skids were collapsed, and the vertical firewall was damaged. Following recovery of the helicopter, the engine was started by a representative of the operator with Federal Aviation Administration (FAA) oversight; the engine was found to operate normally. Following the engine run, a differential compression test of all cylinders was performed using 80 psi as a reference; all cylinders measured 70 psi or above. Further, there was no discrepancy with the throttle linkage. The normal procedures section of the Pilot's Flight Manual indicates that when performing practice autorotations, to split the needles (main rotor and engine rpm indications) by lowering the collective but keep the throttle setting. The throttle correlation will establish a high idle rpm of approximately 2,500 which will aid in preventing the engine from loading up or stalling during recovery. The emergency procedures section of the Pilot's Flight Manual, indicates that for engine failure above 450 feet agl, to establish a steady glide of 52 knots (60 mph), and at an altitude of 50 feet, begin steadily to apply back cyclic stick to decrease forward speed. At about 10 feet agl, coordinate collective pitch with forward movement of the cyclic stick to level the helicopter and cushion the landing. The FAA Helicopter Flying Handbook (FAA-H-8083-21A), stipulates that when performing a practice autorotation with a power recovery, to begin to level the helicopter with forward cyclic control when it is 3 to 15 feet landing gear height agl, and just prior to achieving level attitude, coordinate upward collective pitch control with an increase in the throttle to join the needles at operating rpm. The handbook also indicates that to use sufficient collective pitch to stop the descent, but collective pitch application must be gradual to allow for engine response.
The pilot's movement of the throttle to the idle detent at the beginning of a practice autorotation, which was contrary to procedures and resulted in the engine hesitating during the power recovery and a subsequent hard landing.
Source: NTSB Aviation Accident Database
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