West Palm Beach, FL, USA
N8785L
Piper PA-25-235
N341ZG
Robinson R22 Beta
The CFI and student in the Robinson helicopter had been flying for approximately 46 minutes and the CFI elected to finish the training session with her demonstration of a 180-degree autorotation. The pilot of the Piper airplane had been towing gliders earlier and after landing following another tow, the next glider was connected. An occupant of the helicopter announced on the common traffic advisory frequency (CTAF), "North County traffic helicopter one Zulu Gulf is turning left downwind at (500) feet for practice one eighty autorotation North County." The pilot of the Piper airplane reported seeing the helicopter just starting the downwind leg and made an announcement on the CTAF announcing his takeoff. The transmissions recorded on the CTAF did not include ground communications. Witnesses noted the helicopter on the downwind leg while the airplane began the takeoff roll. The helicopter was then observed to make a left turn and was noted by the pilot of the glider being towed to be slightly above and behind to his left and was paralleling the flight path of the airplane. The airplane and helicopter collided; following which, the airplane continued straight ahead for a short distance before descending nose and left-wing low into a marsh. The helicopter impacted the ground. Postaccident examination of both aircraft revealed the main rotor of the helicopter contacted the left main landing gear tire and section of leading edge of the left wing of the airplane. The airport did not have a memorandum of agreement with any operators at the airport pertaining to helicopter and fixed wing operations to runway 8L.
On August 16, 2003, about 1146 eastern daylight time, a Piper PA-25-235 (Piper), N8785L, registered to Barry Aviation, Inc., and operated by Barry Aviation Florida, Inc., and a Robinson R22 Beta (Robinson), N341ZG, registered to and operated by Ocean Helicopters, Inc., collided in-flight at the North Palm Beach County General Aviation Airport, West Palm Beach, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the Piper airplane, which was towing a glider when the collision occurred. No flight plan was filed for the Robinson helicopter that was operating in accordance with 14 CFR Part 91 as an instructional flight. Both aircraft were substantially damaged, and the commercial-rated pilot of the Piper airplane sustained serious injuries; the pilot of the glider was not injured. The certified flight instructor (CFI) and pilot-rated student of the Robinson helicopter both sustained minor injuries. The flight of the Piper airplane was originating at the time of the accident; the flight of the Robinson helicopter originated about 1058, from the North Palm Beach County General Aviation Airport. The pilot of the Piper airplane reported that he had towed gliders in the accident airplane earlier that day, and after landing following another glider tow, the next glider was connected. He kept the engine running and monitored the radio while the glider pilot was getting ready. The individuals who were handling the wings signaled for him to take up the slack in the tow cable. He leaned his head out the window to confirm the line was taught, the glider canopy was secure, and looked for the rudder wag from the glider. He closed his window, and checked for traffic in his entire field of view. He reported hearing radio calls for aircraft using runway 8R, but did not hear any radio calls for conflicting traffic for runway 8L during the entire taxi back from the previous landing and hook-up process. He did see a helicopter just starting the downwind leg for runway 8L. He made a radio call stating, "North County traffic, tow plane and glider departing 8L off the grass, North County." He began the takeoff roll and shortly before crossing the intersection of runways 13 and 31 while at an altitude of approximately 100 feet, he noticed off the left side a orange helicopter closing and descending at a high rate of speed. He felt an impact and vibration, and saw debris come off the aircraft. His aircraft and the helicopter separated quickly, and he tried to maintain control of the airplane but it entered a left bank upon impact. He pulled the towline release handle, and the airplane was "uncontrollable in sustained flight." He was unable to counter the left rolling tendency with full right aileron applied. He attempted to maintain flying speed by keeping the nose down and the wings level. Before impact with terrain, the airplane was in a nose low left turn; he closed his eyes before impact. As requested by the NTSB, the student pilot of the glider being towed completed a NTSB "Witness Statement" form. He reported either in the NTSB Witness Statement form or in a sworn statement that he did not have a radio with him before entering the glider, but when he got in the glider to "strap up and run my checklist and attach the tow rope I heard no radio calls by any aircraft." At the completion of the checklist he looked left, right, and behind him to check for traffic; he did not see a helicopter or any other aircraft in the air. He looked again for traffic after signaling to the wing walkers, then signaled the tow plane that he was ready for takeoff. The pilot of the tow plane gave a return signal then made a radio call announcing the takeoff. The takeoff roll commenced and he reported that the helicopter first came into view when the tow plane and glider were airborne and climbing. He reported he first observed the helicopter when it was on a midfield downwind leg, and it continued on the downwind leg and flew out of his line of sight. The tow plane and glider continued climbing and the helicopter reappeared at a slightly higher altitude above and behind to his left and was "parallel to the left of tow plane." The helicopter descended with forward motion while the tow plane and glider continued straight ahead. The helicopter and tow plane then "slowly drifted into one another's flight paths", he never saw either the tow plane or helicopter bank away from the other aircraft before the collision. The helicopter "continued to overtake and descend on our aircraft on the left side. It descended down beside Mr. Barry's aircraft and clipped his left wing." He saw "black debris fly out from the two aircraft and the helicopter basically just plummeted to the ground." He reported that as the blade hit the wing he immediately released the towline from the glider. He estimated the impact occurred between 50 and 100 feet in altitude at the intersection of runway 8L and 13. He noted that the tow plane immediately banked to the left but continued to climb for "quite a distance." He (student pilot) landed the glider on runway 8L but continued to watch the tow plane continue to climb. The tow plane then "all of a sudden it did a sharp turn to the left, went into a spin, spun around about 360 degrees and nose-dived into the ground into a marshy area." He noted that the empennage was approximate 15 degrees short of vertical for approximately a second or two after the impact then snapped and fell back. The CFI of the helicopter reported she had been flying with a student since 11 o'clock that morning, and decided to finish the flight training with her demonstrating a 180-degree autorotation to him. When the flight was 1/2 way down the runway on the downwind leg, she made a radio call announcing that she was on a left downwind for runway 8L and was setting up for a "180-degree autorotation." As she entered the autorotation abeam the hold short line of runway 13, she looked at the glider-tow set up and confirmed that they were still stationary at the beginning of runway 8L. She continued the autorotation flying to the "tarmac strip (a combination of runway 13-31, and taxiway F)." She leveled the helicopter off at about 10 to 15 feet above ground level after having completed a flair and bringing in power to recover to a hover. The next thing she knew, "there was a sudden, at this moment incomprehensible 'crash' and the helicopter hit the ground." As she looked up, she observed the tow plane nose dive into the swamp to the left of the runway. Both she and the student exited the wreckage and walked away. As they were walking towards the fixed-base operator building, the tow plane pilot's son came by in a golf cart, offered them a ride, and "apologized for the incident." The pilot-rated student in the helicopter reported that after having flown with the CFI on the day of the accident for approximately 40 minutes, she took control of the helicopter in order to demonstrate a 180-degree autorotation to him. She entered the left downwind to runway 8L, and made a radio call on the UNICOM frequency announcing her intention of making a 180-degree autorotation landing on runway 8L. At the point she made her radio call, the tow plane and glider were "sitting at the staging area of the runway 8L and were not moving." She entered the autorotation and began the 180-degree turn. During the maneuver the CFI and himself continued to observe the airspace around them. She performed the autorotation and at the completion of the flare, leveled the helicopter at 10 to 15 feet, restored power, and entered a hover. While hovering for approximately 5 to 7 seconds, "we were struck from behind", and the helicopter crashed to the ground and rolled onto its left side. He looked out the front of the helicopter which was pointed directly down runway 8L, and noted the tow plane and glider "go over the top of the helicopter." The glider detached the towline and landed directly on runway 8L in front of the helicopter. The tow plane proceeded down the runway for short distance then banked to the left and crashed off the runway. He communicated with the CFI who helped him release his seat belt, and both exited the helicopter. They walked to the operator's office and contacted the owner. A student pilot who was airborne with a flight instructor in the traffic pattern reported in writing that he observed the tow plane and glider in position for takeoff on runway 8L. He heard a radio announcement for a helicopter autorotation to runway 8L, and saw an orange colored helicopter on a downwind heading. He then observed the tow plane and glider during the takeoff roll, and after completion of a 360-degree turn, saw the glider rolling to a stop on runway 8L. He then spotted the tow plane in a left-hand spin and impact into brush northeast of runway 8L. The student's flight instructor reported seeing the tow plane hooking up to the glider, and then reported seeing the accident helicopter take off from the "apron area" and head towards us. He heard an occupant of the helicopter announce, "he/she was planning a 'full autorotation' exercise." The helicopter entered the downwind leg of the pattern for runway 8L the next time he saw the helicopter it was at midfield and had turned left 90 degrees and was heading perpendicular towards runway 8L. He then reported the "tow plane was in motion." Several other witnesses reported in writing seeing the helicopter on the downwind leg when the tow plane began the takeoff roll. One witness (father of the glider pilot), reported the tow plane was airborne and he observed the helicopter had turned onto final, and "was rapidly overtaking the tow plane from behind and above. I recall hearing the helicopter engine throttle back shortly after it passed over my head." Another witness (son of the tow plane pilot), reported seeing the helicopter on the downwind leg then reported the tow plane departed. He also reported that shortly thereafter, "I heard the engine power of the helicopter reduced abruptly, and the helicopter started turning towards the glider and tow planes take off flight path." He reported on the radio to his father that the helicopter was "descending into you", and noted the helicopter made an immediate steep turn to the left from the downwind and was making a 180-degree turn with a high rate of descent. Still another witness (another son of the tow plane pilot), reported that the tow plane and glider were at an altitude of approximately 100 feet over runway 13/31, and noted the helicopter had descended "to the tow plane and struck the left wing of the tow plane." The NTSB Vehicle Recorders Laboratory located in Washington, D.C., prepared a transcription of communications from a recording of the North Palm Beach General Aviation Airport common traffic advisory frequency (CTAF) 123.00 mHZ. The Palm Beach International Airport Authority recorded the CTAF frequency at their facility at PBI. The recording provided to the NTSB reportedly began at 11:30:00 hours, and did not contain a time stamp. Because of this, the accuracy of the tape recording speed was not possible. According to the transcription of communications, at 5 minutes 3 seconds in the recording, a voice associated with the accident helicopter reported, "North County traffic helicopter one Zulu Golf is turning left downwind at (five hundred) feet for a practice one eighty autorotation North County." At 5 minutes 23 seconds into the recording, a voice associated with the helicopter reported, "helicopter one Zulu Golf" with the rest of the transmission unintelligible. At 7 minutes 27 seconds in the recording, a voice associated with the glider reported "glider descending for approach on runway eight right" with the next word unintelligible followed by "immediate descent." There were no recorded transmissions from the tow plane pilot. An FAA airworthiness inspector examined both aircraft and provided a written "Inspector Statement" to the NTSB. The inspector statement indicates that with respect to the Piper airplane, the leading edge of the left wing sustained an approximate 4 foot contact by a main rotor blade, and the inboard left lower wing panel located approximately 1 foot outboard from the wing root "sustained a gash from a rotor blade strike evidenced by a tear in the fabric and a forward bending of the forward spar where the rotor blade tip contacted it." Additionally, a portion of the left main landing gear tire was sliced off "by a strike from the main rotor blade." With respect to the helicopter, rubber transfer was noted on one of the main rotor blades, and paint transfer was noted on the upper surface of the other main rotor blade. According to the airport manager, at the time of the accident there was no memorandum of agreement with any operators at the airport pertaining to helicopter and fixed wing operations related to runway 8L. A document titled "Traffic Pattern Operations F45" indicates with respect to runway 8L, traffic pattern direction and altitudes for fixed wing aircraft, gliders, and helicopters.
The poor judgment by the pilot-in-command of the airplane for his initiation of takeoff after the helicopter pilot had announced intention to perform a 180-degree autorotation to the runway, and the failure of both pilots to maintain visual lookout resulting in the in-flight collision.
Source: NTSB Aviation Accident Database
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