New York, NY, USA
N552J
SIKORSKY S-76C
While maneuvering over the heliport, the co-pilot flying the helicopter maneuvered it near the center of spot H2 (designated for the size of the accident make and model helicopter), which did not include a shoulder line in accordance with Advisory Circular 150/5390-2B. While making a left pedal turn, the co-pilot allowed the helicopter to hover rearward east of the center of spot H2 towards a 12 foot tall chain link fence located behind spot H2; no ground personnel were assisting. While moving forward towards the center of spot H2, the tail rotor blades contacted a portion of the fence resulting in separation of 4 to 6 inches from each tail rotor blade, and subsequent loss of directional control. The flightcrew lowered collective and the helicopter impacted hard causing collapse of the left main landing gear. No preimpact failure or malfunction was noted to any systems of the helicopter. While heliport personnel reported the yellow line is to be used for ground taxiing only, review of an advisory circular related to heliport design revealed that with respect to taxi lines, they need to be marked as such to provide minimum clearance for the largest operating helicopter the heliport is expected to receive. Inspection of the heliport by FAA personnel 1 month prior to the accident failed to detect inadequate heliport markings.
HISTORY OF FLIGHT On October 16, 2008, about 0815 eastern daylight time, a Sikorsky S-76C, N552J, registered to and operated by Bristol-Myers Squibb Company, experienced a hard landing at West 30th Street Heliport (JRA), New York, New York. Visual meteorological conditions prevailed at the time and an instrument flight rules (IFR) flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 executive/corporate flight from Tweed-New Haven Airport (HVN), New Haven, Connecticut, to JRA. The helicopter was substantially damaged and there were no injuries to the certificated airline transport pilot, co-pilot, or the four passengers. The flight originated about 0715, from HVN. The pilot stated that the co-pilot was flying the helicopter, and the flight approached the "south finger" at JRA. The helicopter was brought to a 5-foot hover facing east, and then a 90-degree left pedal turn for spot 2 was made. When the turn was completed he felt a vibration. He looked at the instruments and did not notice any abnormal indication. The vibration increased, and he noticed the helicopter yawed left an additional 10 to 20 degrees. He assisted the co-pilot in lowering collective control, and the left main landing gear collapsed on touchdown. He retarded the throttles to idle then to off, and applied the main rotor brake. The co-pilot stated that the wind was reported to be from 110 degrees at 7 knots, and she approached the heliport into the wind. She hover taxied the helicopter towards spot 2, and began to turn to the right "into the wind" when she felt a medium vibration in the anti-torque pedals. With full right pedal applied, the nose of the helicopter continued to the left. She immediately lowered the collective and landed. Read-out of the cockpit voice recorder (CVR) revealed the flightcrew discussed the approach to the heliport and complied with the appropriate checklists. While proceeding towards the heliport, the pilot announced visual flight rules (VFR) conditions at 1,200 feet. The IFR clearance was cancelled with air traffic control and the flight proceeded VFR on top. The CVR recorded air traffic control terminating radar service and at 0811, or approximately 4 minutes before the accident the co-pilot reported disconnecting the autopilot and she will "hand fly it from here." The CVR then recorded the pilot executing the landing checklist, and lowering the landing gear. At approximately 0812:52, the CVR recorded the announcement that the flight was on approach to spot H2. At 0814:43, the co-pilot commented on the wind in relation to the landing, and approximately 9 seconds later, she advised "tail coming your way." About 4 seconds after that comment the CVR recorded the co-pilot to state that the wind was picking up with concurrence from the pilot. The next recorded sound consisted of a 0.6 second jackhammer-like sound immediately preceding the end of the recording. PERSONNEL INFORMATION The pilot, age 46, is the holder of commercial and airline transport pilot certificates. On the airline transport pilot certificate, he has a rotorcraft helicopter rating. On the commercial pilot certificate, he has airplane single engine land, and instrument airplane ratings. He was issued a first class medical certificate on October 1, 2008, with limitations that he must possess corrective lenses while exercising his airman's privileges, and the medical was not valid for any class after April 30, 2009. He reported his total accrued flight time in rotorcraft type aircraft is 7,343 hours, of which 4,470 were in the accident make and model helicopter. He reported accruing 4,271 hours as pilot-in-command (PIC) in all aircraft, of which 2,235 were as PIC in the accident make and model helicopter. His last flight review was given in a S76C flight simulator on July 31, 2008. The co-pilot (pilot flying), age 42, is the holder of airline transport, commercial, and flight instructor certificates. On the airline transport pilot certificate she has airplane multi-engine land and rotorcraft helicopter ratings. On the commercial pilot certificate she has airplane single engine land rating, and on the flight instructor certificate she has airplane single engine rating. She was issued a first class certificate on October 24, 2006, with no limitations. She reported her total accrued flight time in rotorcraft type aircraft is 1,498 hours, of which 492 were in the accident make and model helicopter. She reported accruing 1,448 hours as PIC in all aircraft, of which 22 were as PIC in the accident make and model helicopter. Her last flight review was given in a S76C flight simulator on August 02, 2008. AIRCRAFT INFORMATION The helicopter was manufactured in 2001 by Sikorsky Aircraft Corporation as model S-76C, and was designated serial number 760518. It was powered by two Turbomeca Arriel 2S1 engines. The helicopter was maintained in accordance with the manufacturer's inspection program, and was last inspected in accordance with a 100-Hour inspection on September 11, 2008. The helicopter total time at the time of the accident was approximately 4,506 hours. METEOROLOGICAL INFORMATION A surface observation weather report taken at La Guardia Airport, New York, NY, at 0751, or approximately 23 minutes before the accident indicates the wind was from 200 degrees at 5 knots, and the visibility was 5 statute miles with mist. Few clouds existed at 700 feet, scattered clouds existed at 8,500 feet, and broken clouds existed at 12,000 feet. The temperature and dew point were 18 and 16 degrees Celsius respectively, and the altimeter setting was 29.95 inches of mercury. The La Guardia Airport is located approximately 6.3 nautical miles and 79 degrees from the heliport. HELIPORT INFORMATION The West 30th Street Heliport is a public-use facility consisting of 11 marked helipad spots designated sequentially H1 thru H11. The spots are oriented on a northeast/southwest line. Personnel from the heliport report that spots H1, H2, and H4 are the only spots designated for Sikorsky S76 operations, but when conditions allow, taxiing in and out of those spots is permitted. A representative of the helicopter operator reported the operator had been operating the accident make and model helicopter into that heliport since December 2001, and that both flightcrew members had flown into the heliport previously. A review of the Federal Aviation Administration (FAA) Airport Master Record for the heliport revealed the last inspection prior to the accident was dated September 23, 2008. Safety Board review of FAA Form 5010-1 for that inspection revealed no reference to the heliport perimeter fence located east of spot H2. Postaccident examination of the heliport was performed by a representative of the helicopter operator with Federal Aviation Administration (FAA) oversight. The inspection of the heliport revealed damage to a cap that covered a 4 to 6 inch diameter pole used to support an approximate 12 foot tall perimeter fence located between spots H1 and H2. The damaged cap was 141 inches above ground level. Further examination of the heliport revealed a solid yellow line painted on the ramp through spots designated H1 and H2. The line was located 10 feet 8 inches west of the east edge of the spots, and was also located 29 feet 8 inches from the approximate 12 foot tall perimeter fence. According to airport personnel, the yellow line was considered a ground taxi line. Spot H2 which was the intended touchdown location, did not contain a shoulder line as depicted in Advisory Circular (AC) 150/5390-2B, titled Heliport Design. FLIGHT RECORDERS The helicopter was equipped with a cockpit voice recorder that was retained by the National Transportation Safety Board (Safety Board) for summary read-out. The CVR began recording at approximately 0745, or approximately 30 minutes before the accident, and continued to approximately 0815, which was the approximate time of the accident. WRECKAGE AND IMPACT INFORMATION Examination of the helicopter was performed by representatives of the helicopter operator and manufacturer, with FAA oversight. The inspection revealed all four tail rotor blades had approximately 4 to 6 inches of blade tip separated. The tail rotor gearbox (TRGB) output housing was fractured at the mounting flange area of the TRGB main case. The tail-cone vertical pylon is distorted on the right side with compression wrinkles in two areas. The left horizontal stabilizer has damage to the trailing edge gurney flap. The left main landing gear attachment fitting was broken at Station 255 bulkhead, and the left main landing gear was collapsed/folded forward. Operational testing of the pedal damper trim actuator (PD/TA) in accordance with the maintenance manual revealed the anti-torque pedals at the pilot and co-pilot seats felt smooth throughout full range of motion. The PD/TA passed the diagnostic tests including the override relief test. The digital flight control system (DFCS) autopilots (1 and 2) remained engaged throughout the test, including the fact that there were no DFCS major faults during the test. Components from the helicopter consisting of the Nos. 1 and 2 DFCS computers and yaw stabilization augmentation system (SAS) actuators, tail rotor gearbox, and tail rotor servo were removed and either tested or examined with FAA oversight. None of the components exhibited any evidence of preimpact failure or malfunction. TESTS AND RESEARCH The West 30th Street Heliport records video of the heliport from several cameras, one of which (camera No. 3) recorded part of the approach, and landing sequence. The camera did not record the tail rotor collision with the approximate 12 foot tall fence. Safety Board review of the recorded video from the No. 3 camera revealed the helicopter approached the heliport from over the Hudson River and flew over the south finger pier. The helicopter was then hover taxied over spot H1, turned left and was hover taxied towards spot H2 traveling in a northeast direction nearly over the yellow line on the ramp. The helicopter was flown to spot H2 and was turned left to the northwest but was noted to move west of the yellow line on the ramp with the main rotor centerline on or slightly west of the yellow line on the ramp, which was also west of the center point for spot H2. While airborne facing northwest near spot H2, the helicopter was flown towards the center of the spot H2. The nose of the helicopter pitched up slightly and the helicopter yawed to the right coming to rest facing a northeasterly direction nearly on the yellow line. As previously reported, the measured lateral distance between the yellow line on the heliport and the approximate 12 foot tall fence was 29 feet 8 inches. The distances from the centerline of the main rotor to the aft point of travel of the tail rotor blade is 30 feet 6 inches. Advisory Circular 150/5390-2B, defines two types of taxiways. The first is a ground taxiway which is an obstruction free corridor intended to permit the surface movement of a wheeled helicopter under its own power with wheels on the ground. The second is a hover taxiway, which is also an obstruction free corridor intended to permit the hover taxiing of a helicopter. The recommended minimum distance between the arc generated by the tail rotor and objects and buildings is 10 feet for ground taxi operations. The Advisory Circular indicates that when the size of helicopters that utilize the heliport vary, the larger aircraft may dictate the taxiway/ taxi route widths. A shoulder line, which should be marked on the landing spot should be located so it is under the pilot's shoulder when the main rotor of the largest helicopter for which the position is marked will be entirely within the 1.0 rotor diameter parking circle. According to the Rotorcraft Flying Handbook, you should use the type of approach best suited to the existing conditions, which may include obstacles, size and surface of the landing area, density altitude, wind direction and speed, and weight. Regardless of the type of approach, it should always be made to a specific, predetermined landing spot. The handbook also indicates that for rearward hovering, use of ground personnel is recommended due to limited visibility behind a helicopter. The handbook also indicates that for rearward hovering, it is important that you make sure that the area behind the helicopter is cleared before beginning the maneuver.
The failure of the flightcrew to stabilize the helicopter over its confined landing area during a hovering left-pedal turn, resulting in tail rotor blade contact with a perimeter fence component and a subsequent loss of directional control. Contributing to the accident was the inadequate markings of the heliport and heliport spots, and failure of FAA personnel to detect the inadequate heliport markings during inspection of the heliport approximately 1 month prior to the accident.
Source: NTSB Aviation Accident Database
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