Accident Overview
On June 22, 2013, at about 1500 eastern daylight time, a Sikorsky Aircraft Corporation (formerly Schweizer Aircraft Corporation) 269C helicopter, registration N2091E, experienced a hard landing at Flying W Airport (N14) in Lumberton, New Jersey. The aircraft was registered to Herlihy Helicopters, Inc., doing business as Helicopter Flight Services. The helicopter sustained substantial damage, and both the commercial-rated pilot and passenger were uninjured.
Flight Information
The flight was conducted under 14 Code of Federal Regulations (CFR) Part 91 as a personal local flight. It originated from Flying W Airport at about 1400. Visual meteorological conditions prevailed, and no flight plan was filed. The pilot stated the purpose was to take a friend for a one-hour local flight; the friend was possibly interested in flying lessons. Prior to departure, the pilot obtained weather information from the Automated Surface Observing System (ASOS) at South Jersey Regional Airport (VAY). At takeoff, the weather was clear and wind was not a factor.
Accident Sequence
The flight was local, and upon return, the pilot entered the traffic pattern and discussed autorotations with the passenger. He informed the passenger that he would demonstrate an autorotation with a planned power recovery. The maneuver was initiated from 1,000 feet mean sea level (951 feet above ground level) at 60 knots indicated airspeed. The pilot rolled off the throttle to the idle detent and descended, maintaining 60 knots and keeping the main rotor rpm in the upper green range. At approximately 50 feet agl, he flared. At the end of the flare, about 20 to 30 feet agl, he leveled the nose, began to increase the collective, and rolled on throttle for a power recovery. He reported that the engine sounded like it was bogging down, and the engine rpm was not increasing enough to continue holding a hover. With insufficient engine rpm, the helicopter continued to descend and contacted the runway, coming to rest upright. The pilot then secured the helicopter, and both occupants exited.
Post-Accident Examination
The operator reported that the skids were collapsed and the vertical firewall was damaged. After recovery, the engine was started by a representative of the operator with Federal Aviation Administration (FAA) oversight; it operated normally. A differential compression test of all cylinders was performed using 80 psi as a reference; all cylinders measured 70 psi or above. Furthermore, there was no discrepancy with the throttle linkage.
Relevant Manual Information
The Pilot's Flight Manual, in the normal procedures section, indicates that when performing practice autorotations, the pilot should split the needles (main rotor and engine rpm indications) by lowering the collective while keeping the throttle setting. The throttle correlation establishes a high idle rpm of approximately 2,500, which aids in preventing the engine from loading up or stalling during recovery. The emergency procedures section specifies that for engine failure above 450 feet agl, the pilot should establish a steady glide of 52 knots (60 mph), and at 50 feet, begin to steadily apply back cyclic stick to decrease forward speed. At about 10 feet agl, the pilot should coordinate collective pitch with forward cyclic stick movement 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, the pilot should 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 a level attitude, coordinate upward collective pitch control with an increase in throttle to join the needles at operating rpm. The handbook also indicates that sufficient collective pitch should be used to stop the descent, but collective pitch application must be gradual to allow for engine response.
Probable Cause
No probable cause was stated in the source.