Archer, FL, USA
N2166U
Brantly B-2B
A witness said he heard the "usual engine pop" occur about 5 or 6 times as the main rotor increased speed, and shortly after, the helicopter lifted off and rose to an altitude of about 5 or 6 feet. He again heard a loud "pop", like a loud backfire, or the bang of metal hitting metal, and saw the helicopter rock to the left, right, and left again, i.e. from side to side, and the nose pitched down. The helicopter then rolled to the left again, and one of the main rotor blades struck the concrete helipad, breaking a blade. The helicopter then descended, and impacted the concrete helipad on the left side. The rotor blades continued to rotate, and repetitively struck the ground, throwing debris over a wide area and the cockpit area subsequently erupted into flames. Postcrash examination of the helicopter revealed that the damage to the tail boom, as well as the tail and main rotor systems were consistent with overload. The tailboom separated at the aft edge of the horizontal stabilizer's location, and the tail rotor drive shaft was bent forward of the 90-degree gearbox, at the tailcone attach point. The examination revealed no evidence of preaccident anomalies with the engine or transmission. Control continuity was not established due to fire damage. Cyclic pitch control and collective push pull tubes from each respective bellcranks had melted with only molten aluminum deposits remaining under the hardware on the end of each bellcrank. Push/pull tubes from the antitorque pedals, which connect to a bellcrank and subsequently to dual cables which run the length of the empennage had extensive fire damage, and the lateral push rod had separated at both ends. The vertical push rod was separated at the lower attach end aft of the tailcone attach point. The student pilot/owner's wife, as well as witnesses stated that the student had transported the helicopter to the accident location via trailer to obtain flight instruction from the PIC. FAA records indicated that the PIC did not possess a current flight instructor certificate, and had last been issued a flight instructor certificate in on March 25, 1985 which had expired on March 31, 1987. Information from the PIC's logbook showed that he last received a biennial flight review on January 19, 1999.
HISTORY OF FLIGHT On February 11, 2001, about 1509 eastern standard time, a Brantly B-2B helicopter, N2166U, registered to B and W Helicopters Inc., and operated by a private individual as a Title 14 CFR Part 91 instructional flight, crashed while attempting to take off from a helipad at the Flying Ten Airport, Archer, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The helicopter was destroyed, and the commercial-rated pilot in command (PIC) and student pilot/owner sustained fatal injuries. The flight was originating at the time of the accident. One witness said that he was in the trailer at the airport, close to the helipad, and he had observed the helicopter complete an earlier uneventful flight, with only the PIC on board. He stated that upon returning to the airport, the PIC performed hover tests prior to landing and disembarking the helicopter. The PIC then held a conversation with the student/owner, and they both embarked the helicopter. During startup, the witness said he heard the "usual engine pop", which occurred about 5 or 6 times as the main rotor increased speed, and shortly after the helicopter then lifted off, and rose to an altitude of about 5 or 6 feet. He said he again heard a loud "pop", like a loud backfire, or the bang of metal hitting metal, and saw the helicopter rock to the left, right, and left again, i.e. from side to side, and further stated that the nose had pitched down. The witness said he then saw the helicopter roll to the left again, and one of the main rotor blades struck the concrete helipad breaking a blade. The helicopter then descended, impacting the concrete helipad on the left side, with the rotor blades continuing to rotate and repetitively strike the ground. He said the helicopter thrashed around on the helipad as the blades rotated with sparks being produced as the blades rotated, and debris was being thrown over a large area. He said he then saw a momentary flash around the area of the helicopter's canopy, but the flash seemed to disappear or die down, but shortly thereafter, the whole cockpit area of the helicopter erupted into flames. A second witness stated that he saw the helicopter take off on the earlier flight and return and the flight had been uneventful. He further stated that during the second flight, he saw the helicopter take off and ascend about 4 or 5 feet off the ground, then it reared back on its tail, settled on its skids, and turned around one and a half times prior to flipping over on its side and erupting into flames. A third witness stated that he saw the helicopter take off and reach an altitude of about 5 or 6 feet, then it appeared as if someone did something too quickly, and the helicopter contacted the ground with the tail rotor first, made a turn of one to one and a half times and came down on its left side. He said it bounced around, and burst into flames as the rotor blades hit the ground. PERSONNEL INFORMATION The PIC held an airline transport pilot certificate with a multiengine land rating, as well as a commercial pilot's certificate with helicopter, airplane single engine, and instrument ratings, and an FAA airframe and powerplant mechanic's license. He also held a first class medical certificate, issued on October 26, 2000, and the medical certificate stipulated no limitations. On his application for the medical certificate, the PIC reported that he had 5,100 total flight hours, with about 50 flight hours having been flown in the last 6 months. Excerpts of the PIC's logbook, which PIC's wife provided to the NTSB, showed that the PIC had about 4,866 total flight hours, with about 2,040 flight hours in helicopters. Logbook information also showed that the PIC's last biennial flight review had been conducted on January 19, 1999. Records obtained from the FAA Airman's Certification Branch revealed that the PIC did not possess a current flight instructor certificate. The records showed that the PIC had last been issued a flight instructor rotorcraft helicopter certificate on March 25, 1985, and it expired on March 31, 1987. The student pilot/owner possessed a third class medical certificate, issued on June 23, 2000, with the requirement that he have available spectacles for near vision, and limiting his license's validity to 15 months following the month examined. The student/owner's logbook indicated that he had completed three previous training flights in helicopters, accumulated a total flight time of about 2 flight hours. A witness stated that as the helicopter was taking off on the accident flight, he observed the PIC in the left seat, and the studentpilot/owner in the right seat of the helicopter. AIRCRAFT INFORMATION N2166U, a Brantly B2B, serial number 328, was manufactured in 1963. According to the student pilot/owner's wife, the helicopter had been recently purchased by her husband with the intent for him to learn to fly helicopters. The helicopter's records were not available to the NTSB, but according to information the previous owner had provided, at the time of the accident, the helicopter had accumulated about 1120 total flight hours. The previous owner's records also showed that on May 9, 2000, the aircraft received a 25/50/100-hour inspection, and it last received an annual inspection on February 15, 1999. The helicopter was equipped with a Textron Lycoming IVO-360-A1A engine, serial number L-141-58, which the previous owner's records showed to have accumulated about 1134 hours since field overhaul. The student pilot/owner's wife said that she, her husband, and an FAA licensed mechanic removed the main rotors to facilitate transportation via trailer from their home in Pennsylvania to Archer, Florida, and that the helicopter had recently been transported on a trailer to Archer, Florida where her husband would be receiving flight instruction from the PIC. She also said that she spoke with her husband via the telephone the day before the accident, and her husband told her that he and the PIC had installed the rotor blades, and that they would commence flying the helicopter on February 11, 2001. WEIGHT AND BALANCE At the time of the accident, the estimated takeoff gross weight of the helicopter was about 1690 pounds, and the estimated center of gravity (CG) was 104.12. According to the Brantly B2B flight manual, the maximum takeoff weight of the helicopter is 1670 pounds, with a most forward CG limit of 104.3 inches from datum, and an aft limit of 107.0 inches from datum. METEOROLOGICAL INFORMATION The Gainesville Regional Airport (GNV) 1453, surface weather observation was skies clear, visibility 10 statute miles, temperature 73 degrees F, dew point temperature 55 degrees F, wind from 020 degrees at 7 knots, altimeter setting 30.21 inHg. WRECKAGE AND IMPACT INFORMATION N2166U crashed on the concrete helipad near a hangar located on the southeast corner of the Flying Ten Airport, Alachua County, Florida. Examination of the crash site showed that the helicopter came to rest on its left side, on a bearing of about 220 degrees magnetic. The main wreckage consisted of the burned out cockpit area, with the engine, mast, and tail sections still attached. There were impact related signatures, as well as debris spread over a wide area, consistent with the helicopter having had power applied when it impacted. Damage had occurred to surrounding structures, parked cars, as well as an airplane with some helicopter related debris being located about 300 feet away from the main wreckage. On the concrete helipad where the main wreckage lay, there was oil, soot and fire damage. The main wreckage lay on its left side, with the left skid having detached and laying under what remained of the helicopter's cabin. The cabin had been consumed by fire, with evidence of intense heat damage in the area of the fuel tank and battery. The firewall remained intact, but its forward surface facing the cabin exhibited heavy fire damage, with some evidence of fire related damage spreading to the mast and main rotor hub. The aft portion of the firewall, aft, exhibited some sooting, minimal thermal damage. The main rotor system's hub had remained intact, but the rotor blades had been damaged and were all mostly absent, with only fragments/small portions of blades remaining attached to the hub. Examination of the blade attach lugs on the main rotor hub/mast exhibited no witness marks. Fittings were in place and damage at the mast attach points were consistent with overload. Examination of recovered fragments of the main rotor blades revealed damage to the "red" main rotor blades consistent with that blade having impacted first. Main rotor blade extensions had separated on the three outboard sections of the main rotor blades, outboard of the hinge, with the damage being consistent with overload conditions. Outboard rotor blades had curled upward on all blades, with the outer 1/2 of the blades having shattered and/or fragmented as a result of impact with the ground. The drag link clevice on the red blade was found about 40 feet away from the main wreckage, and its examination revealed a dissimilar appearance on the clevice ear. The clevice fork and fork lag damper were retained for further examination at the NTSB's Materials Laboratory, Washington D.C. The tail rotor system exhibited damage consistent with it rotating at the time of impact. The tailboom had separated at the aft edge of the horizontal stabilizer's location, and the left stabilizer had separated, and was found about 10 feet to the right front of the main wreckage. The tail rotor drive shaft was bent about 3 feet forward of the 90-degree gearbox, at the tailcone attach point. The short shaft did not rotate from the main gearbox end, however when the aft portion of the tail rotor drive shaft was manipulated by hand, there was movement to the main gear box. Examination of the short shaft forward coupling revealed a discontinuity, and when it was disassembled, the woodruff key installed on the bevel gear coupling was found to have sheared. The woodruff key and the forward short shaft coupling were retained for further examination at the NTSB's Materials Laboratory, Washington D.C. The vertical stabilizer above the forward 90-degree gearbox had broken even with the top of the forward 90-degree gearbox. The outer tube support housing and the tail rotor drive shaft broke abeam of the vertical stabilizer and the tail rotor. Both tail rotor blades were damaged with one blade exhibiting tip impact damage with the tip of the blade being curled. The other blade did not exhibit tip impact damage, but it exhibited some trailing edge damage. Control continuity from the cockpit was not established due to the fire damage in the cabin. The cyclic pitch control with its upper and lower torque tubes were found to be both attached at the front end of the bellcrank, but the aft end, where the torque tubes normally connected behind the seat had been disconnected due to the aft bellcrank being burned away with the attachment hardware having remained in position on both torque tubes. The collective push pull tube was connected at the front to the bellcrank, and its aft end was connected to the aft bellcrank at the midsection of the bellcrank , but the fittings where the collective bellcrank connects to the vertical torque tube had melted, with only molten aluminum remaining. Iron fittings were in place on the bellcrank and molten aluminum deposits were under the hardware on the end of the bellcrank. Push/pull tubes from the antitorque pedal also had extensive fire damage but the cable which were atached to them had remained attached all the way to the aft bulkhead in the tailcone area, where both cables then transitioned to a lateral push/pull rod within the pylon. The lateral push/pull rod had broken at both ends. The vertical push rod was broken at the lower attach end, 14 inches aft of the tailcone attach point. The engine had remained attached to the airframe, and as the helicopter lay on its left side, residual oil had drained from the filler tube. The engine core had remained intact, and fuel lines, and fuel carrying hoses had been largely destroyed by fire. The fuel injector servo also had received fire damage, and the fuel pump, though still attached had fire damage as well. The fuel pump was removed, and its examination showed that the was intact, but it could only be partially rotated. Examination of the fuel flow divider showed that its diaphragm had been destroyed by fire. No. 1 and 2 fuel injector nozzles were clear, but Nos. 3 and 4, had some water and fire related debris inside Both the starter and the alternator showed no preimpact anomalies. The left magneto produced a spark when field tested, and the right magneto had incurred internal fire damage which precluded testing. Both units had been secured to the case, and both drive gears had been intact. All spark plugs exhibited slight wear, and had normal gaps, and showed brown deposits, consistent with normal operation. The ignition harness had been destroyed by fire. The lubrication system exhibited good integrity, and the oil pressure screen was found to be clean, with the only observable damage do the system being that associated with fire damage to hoses. The engine assembly rotated, and there was continuity of the crankshaft, camshaft, valve train, and other accessory drives. Each cylinder produced compression when rotated, and there was no evidence of preaccident failure or malfunction. MEDICAL AND PATHOLOGICAL INFORMATION William F. Hamilton M.D., Associate Medical Examiner, District Eight Medical Examiner's Office, Gainesville, Florida, performed the postmortem examinations of the PIC, and the student pilot/owner, and according to Dr. Hamilton, the cause of death was attributed to thermal injuries. No findings which were causal to the accident were reported. The University of Florida Diagnostic Referral Laboratories conducted toxicology studies on specimens from the PIC for volatiles, carbon monoxide, and drugs, and the tests were negative. The FAA Toxicological Laboratory, Oklahoma City, Oklahoma, conducted toxicological studies on specimens from the PIC for carbon monoxide, cyanide, volatiles, and drugs, and the samples were negative. The University of Florida Diagnostic Referral Laboratories also conducted toxicology studies on specimens from the student pilot/owner for volatiles, carbon monoxide, and drugs, and the tests were positive for acetone in the urine, and were positive for Diltiazem in the blood, and for Acetaminophen and Diltiazem in the urine. The FAA Toxicological Laboratory, Oklahoma City, Oklahoma, conducted toxicological studies on specimens from the student for carbon monoxide, cyanide, volatiles, and drugs, and the samples were positive for Diltiazem in the blood and urine, and for Acetaminophen in the urine. METALLURGICAL EXAMINATION Metallurgical examinations were conducted at the NTSB's Materials Laboratory, Washington D.C., on of a fork lag damper, clevice fork, woodruff key and coupler for the tail rotor short shaft, and the examinations revealed damage consistent with overstress. ADDITIONAL INFORMATION On February 13, 2000, the NTSB released the main wreckage of N2166U to Mr. Frank Ognorn, owner, Kitty Hawke Aviation. The NTSB retained some components for further examination, and they were released to Mrs. Barbara Wable, wife of the owner of the helicopter, on July 30, 2001.
The flight crew's loss of control for undermined reasons.
Source: NTSB Aviation Accident Database
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