Story ID: 004AccidentsDec17
Accidents: December 2017
By: Amy Laboda
Caption: Preliminary and final reports
Word Count: 2024
PRELIMINARY REPORTS 

Piper Cheyenne Crashes in Field just after Departure

Piper Cheyenne PA-31T, July 13, 2017, Tyler, Texas—A Piper Cheyenne twin-turboprop was lost after takeoff and its ATP-rated pilot and one passenger killed in Tyler, Texas. The pilot departed Tyler airport (KTYR) uneventfully and began the climb en route to Midland Airpark (KMDD) in VFR conditions on an IFR flight plan when the aircraft suddenly lost altitude and hit the ground in a field surrounded by trees. The wreckage was found at the edge of a small pond about one-half mile from the end of Runway 17 at KTYR. There was no post-crash fire despite fuel being found at the accident site.

Investigators documented the wreckage and recovered the airplane to a secure facility for further examination by the NTSB.

Virginia State Police Bell 407 Down without Clear Cause

Bell 407, Aug. 12, 2017, Charlottesville, Virginia—A veteran Virginia State Police helicopter pilot and his camera operator were killed when the Bell 407 they were flying in support of the governor’s motorcade went down in trees and was destroyed by fire during day VFR conditions.

The helicopter had refueled at Charlottesville-Albemarle Airport (KCHO), in Charlottesville, Virginia, and the ATP-rate pilot and video operator/observer lifted off to fly cover for the governor’s motorcade. Preliminary radar data showed the helicopter at an altitude of approximately 2,200 feet msl in the area of the motorcade. Radar then showed the helicopter descending through 1,450 feet msl, at a groundspeed of 30 knots. Moments later it descended below the floor of radar coverage and radar contact was lost.

Approximately 37 witnesses to the accident were interviewed. Most reported that the helicopter was hovering, then began a rolling oscillation, rotating about the vertical axis and then descended in a 45-degree nose-down attitude, while continuing to spin, until it dropped below the treetops. They then observed a plume of smoke. Nearby security camera footage corroborated witness statements.

The main wreckage came to rest upright deep in the trees, adjacent to a house. The helicopter fuselage was in dozens of pieces and damaged from the post-crash fire, but most major components were present. A debris field several hundred feet long to the west of the main wreckage contained pieces of the tailboom, aluminum honeycomb sandwich structure from the airframe, tail rotor drive system pieces, and tail rotor control tube pieces. Several pieces of debris also landed on the roof of the house.

Examination of the tail rotor drive shafts (TRDS) revealed that the oil cooler remained installed to the airframe. The forward and aft splines were thermally damaged but did not exhibit evidence of smeared or missing spline teeth. Rotation of the forward splines resulted in rotation of the cooler fan and the aft splines. Several pieces of separated TRDS were also discovered in the debris field. Normally four hanger bearings are present on the TRDS on the tailboom. Only three bearings were recovered. On a typical installation, there was one steel TRDS segment between engine and oil cooler, then five aluminum TRDS segments between oil cooler and tail rotor. The five aluminum TRDS segments were supported by four hanger bearings. The aluminum TRDS are numbered 1 (forward-most TRDS) to 5 (aft-most TRDS). The steel TRDS was whole with evidence of heat stress, the forward end flex coupling was fractured, and the attaching hardware was present. The splines at the aft end of the steel TRDS did not show evidence of smearing or fractured teeth.

The tail rotor gearbox was firmly attached to the structure. Manual rotation of the input flange resulted in a corresponding rotation of the tail rotor. The oil sight gauge revealed the presence of oil within the gearbox. The chip detector was removed and revealed no evidence of chips or debris.

The tail rotor, which was still installed on the aft portion of the tailboom, came to rest in the top of a tree. Both of its blades (white and red) remained attached and it rotated without binding. The white tail rotor blade displayed damage to the tip consistent with contacting the left side of the tailboom. Its leading edge also displayed a damaged area approximately three inches wide approximately 15.5 inches inboard from the tip. The red tail rotor blade did not exhibit any damage.

Examination of the engine revealed hard body foreign object damage on the first stage compressor blades consistent with the engine operating at the time of the accident.

The combined engine oil and fuel filter were found loose within the wreckage. The filter elements were present, but the aluminum filter bowls were missing with evidence of melting and were not recovered. The left engine mount was fractured from the structure, and the engine was lying on its right side. Residual oil observed within gearbox was tarred; the oil from the top was bright brown in color.

Examination of the gearbox chip detectors revealed that the upper and lower chip detectors were missing their magnet. Manual rotation of the first stage compressor resulted in rotation of the gears and the spline to the turbine. The electronic control unit (ECU) was loose in the wreckage with one of its electrical connectors connected. It was damaged in the post-crash fire.

The flight control main actuators were in the debris at the main accident site near their normally installed locations and control continuity was established between the cyclic pitch control to the mixing unit.

No evidence was found suggesting that the accident was the result of a midair involving another aircraft, animal or object.

According to FAA airworthiness records and helicopter maintenance records the Bell 407 was manufactured in 2000 and underwent a 100-hour inspection Aug. 3, 2017. At the time of the accident, the helicopter had accrued approximately 6,000 total hours of operation.

The NTSB retained the wreckage for further examination.

Learjet Lost En Route near Venezuelan Coast

Bombardier Learjet 25D, Aug. 19, 2017, Naiguatá, Venezuela—A Learjet 25D with two pilots and five passengers was destroyed when it hit the water during the en route portion of its midnight flight from Caracas-Simón Bolívar International Airport to Barcelona, Venezuela. A search-and-rescue mission found aircraft parts and fuel on the water; however, no bodies were seen as of this report. The aircraft entered service in 1984.

Hawker Hunter Crashes in Pacific during Maneuvers with Navy Aircraft

Hawker Siddeley MK.58, Aug. 22, 2017, Pacific Ocean near California—A Hawker Hunter MK-58, registered to Hunter Aviation International and operated by Airborne Tactical Advantage (ATAC) under contract with the U.S. Navy, was substantially damaged when it hit the water in open ocean during an exercise with a United States Navy jet fighter. The airline transport pilot aboard was seriously injured after being forced to eject from the aircraft. The Hawker Hunter is a transonic British jet-powered fighter aircraft that was developed by Hawker Aircraft for the British Royal Air Force during the late 1940s and early 1950s. 

The flight left Point Mugu Naval Air Station, in Ontario, California, in VFR conditions on an IFR flight plan for the high-speed tactical training maneuvers mission. According to the pilot's wingman, who was one nautical mile behind the accident airplane, during an adversarial exercise with a military jet fighter the Navy airplane was flying 1,000 feet abeam the Hawker Hunter's left side. It suddenly turned right and crossed in front of the Hunter. The pilot of the Hunter reacted by entering a 60-degree right turn and pitching up to follow the military fighter, but instead, the accident airplane entered a rapid left bank, immediately followed by a nose-low pitch attitude. The wingman then saw the airplane roll wings level and immediately roll into a 60-degree right turn again followed by a rapid left bank. The Hunter repeated the same sequence at least one more time before it entered a 40-degree nose-down attitude and the pilot ejected. In his recount, the wingman reported that the Hunter appeared to first depart controlled flight about 15 seconds after the military airplane crossed in front of it.

Heli Hunting Expedition Hits Hard on Power Loss

Hughes MD369A, Sept. 2, 2017, Burnet, Texas—A Hughes 369A turbine helicopter was severely damaged after its pilot was forced to perform an autorotation near Burnet, Texas. The pilot and one passenger were not injured; however, one of the other two passengers received minor injuries and the other sustainedserious injuries. The helicopter, registered to and operated by Lyft of Missoula, Montana, under 14 CFR Part 91, was in VMC conducting aerial hog hunt operations en route to the Burnet Municipal Airport-Kate Craddock Field Burnet Municipal airport (KBMQ), Burnet, Texas, when the engine lost power. The pilot performed an autorotation to a road, landing hard, which caused substantial damage to the fuselage and tailboom. 

 FINAL REPORTS

Midair Brought Down Aeromedical Rescue Flight in West Africa

BAe-125, Sept. 5, 2015, Burkina Faso, West Africa—Accurate altimetry is one of the hallmarks of the RVSM flight levels. A BAe-125 on a medical transportation flight from Ouagadougou, Burkina Faso, to Dakar, Senegal, with a French patient and two crewmembers as well as a mechanic, a doctor and two nurses was lost over the Atlantic Ocean off Senegal after an apparent midair with a Boeing 737-8FB operated by Ceiba International. Investigators determined that the BAe-125 had inaccurate altimeters, (reading 1,000 feet low) which caused the crew to put the airplane at the same altitude as the Ceiba 737, even though just one minute before the midair the pilot of the BAe-125 confirmed to ATC he was at FL340.

The aircraft departed Ouagadougou and climbed to the cruising altitude of FL340. The flight contacted the controller at Bamako Center asking if FL380 was available because of the presence of clouds ahead. The controller then cleared the flight to FL380. After negotiating several other options to avoid severe turbulence, the crew decided to remain at FL340. The flight was allowed to deviate 10 nm from the route to avoid an area of bad weather. Last radio contact with the flight happened as it was proceeding westward on Airway UA601 at a cleared altitude of FL340.

At the same time Ceiba International flight CEL71 was heading eastward on Airway UA601 at a cleared altitude of FL350.

The Boeing 737-8FB was en route to Cotonou, Benin and Malabo, Equatorial Guinea. The aircraft crossed paths with the BAe-125 at 6:12 p.m., between points DEMOL and GATIL. At 6:15 p.m. CEL71 contacted the controller at Dakar Center, stating they had observed descending traffic from the opposite direction, passing their altitude just behind them. Initially the crew referred to the event as a "near miss." The Dakar Center controller then attempted to contact the BAe-125, but there was no response. At 6:16 p.m. CEL71 contacted Dakar Center again, this time reporting that the crossing traffic likely touched their wing. However, they reported, there were no aircraft control issues. The crew chose not to land at Cotonou and continued to the final destination, Malabo. After landing they found damage on the top of the right hand winglet.

Despite several attempts, ATC made no contact with the BAe-125. At 6:22 p.m. the BAe-125 appeared on radar at Dakar, showing an altitude of FL350. The aircraft continued on the planned flight track. It passed Dakar, heading over sea. At 7:07 p.m. the aircraft began to descend. At FL330 the aircraft turned right and immediately left, passing FL126 level before it disappeared from radar approximately 59 nm from Dakar.

The aircraft was not found.

A forensic investigation of the aircraft’s maintenance logs showed that earlier that year the aircraft's altimeterss had discrepancies of more than 1,000 feet logged that, according to the operator’s own safety manuals, would prohibit it from entering RVSM space. Crew operating the aircraft nearly two months before the accident documented this, but the aircraft was returned to service and there is no documentation of the altimetry issue being corrected.