Fukushima Police Leonardo AW139 Accident: JTSB Update
Fukushima Police Leonardo AW139 Accident: JTSB Update (JA139F) On 25 February 2020 the Japan Transport Safety Board (JTSB) issued an update (in Japanese) on an accident that occurred on 1 February 2020 to Leonardo Helicopters AW139 JA139F of the Fukushima Prefectural Police Aviation Unit. It is understood that the aircraft was transferring human heart for a transplant operation. All seven occupants were injured, four seriously. Our translation is below: UPDATE 21 January 2021: The JTSB have released a further update (in Japanese only). They confirm the helicopter departed Aizuwakamatsu Central Hospital carrying transplant organs at c08:00 A total of seven people, including the captain, co-pilot, two mechanics, and three passengers, were on board… The helicopter descended after flying over the Ou Mountains. It encountered a strong tailwind, so the ground speed increased to 190-200 knots. At around 08:07, the attitude of the aircraft suddenly changed, and it became difficult to manoeuvre… …at around 08:08, the main rotor blade and tail drive shaft came into contact with each other over Mihota Town, Koriyama City, Fukushima Prefecture… The aircraft crashed. JTSB say: To analyze the cause of contact [the main rotor blade and tail drive shaft], further factual infomation is needed. The JTSB will continue to investigate… In addition, we will hear opinions from the parties involved into the cause and inquire the opinions of the representatives participating the investiogation. The investigation is supported by representatives and advisors from Italy, the designing country of the accident aircraft, Canada, the country that designs and manufactures engines, and the United States, the country that designs the aircraft equipment. Other Safety Resources Retreating Blade Stall Incident: HEMS BK117B2 VH-VSA Italian HEMS AW139 Inadvertent IMC Accident Fatal Night-time UK AW139 Accident Highlights Business Aviation Safety Lessons ADA AW139 A6-AWN Ditching off UAE, 29 April 2017: Final Report Tail Rotor Lightning Strip Damages AW139 Main Rotor UPDATE 9 May 2020: Ungreased Japanese AS332L Tail Rotor Fatally Failed UPDATE 18 July 2020: Vortex Ring State: Virginia State Police Bell 407 Fatal Accident UPDATE 31 July 2020: AW139 Brownout Accident with the Nigerian VP Aboard UPDATE 23 August 2020: NTSB Investigation into AW139 Bahamas Night Take Off Accident UPDATE 14 October 2020: Swedish SAR AW139 Damaged in Aborted Take-off Training Exercise Aerossurance has extensive air safety, operations, SAR, HEMS, airworthiness, human factors, aviation regulation and safety analysis experience. For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest...
read moreFatal MD600 Collision With Powerline During Construction
Fatal MD600 Collision With Powerline During Construction (High Line Helicopters N602BP) On 8 April 2018 MD Helicopters MD600N N602BP, operated by High Line Helicopters as a Part 133 external load flight, was destroyed when it collided with power line support structure in Smethport, Pennsylvania during a utility construction project. The pilot was seriously injured and two linesmen were fatally injured. According to the US National Transportation Safety Board (NTSB) investigation report issued in December 2019: High Line Helicopters was hired as an independent contractor by J.W. Didado Electric, LLC, a subsidiary of Quanta Services, Inc., to transport J.W. Didado employees to job sites for new power line construction. First Energy Corporation hired J.W. Didado to perform the construction. Three power lines, which were newly constructed in mountainous terrain and oriented approximately east/west, were supported by structures that were constructed of either wood (dual pole, H-frame) or steel (single pole). A static line was affixed to the top of the structures above the power lines. The purpose of the flight was to remove the static line from the wheeled pulley device (dolly) that temporarily secured the static line and permanently secure the static line to the structures (“clipping wire”). One lineman completed the task from the skid of the hovering helicopter, and another lineman inside the helicopter passed tools and equipment back and forth to the lineman on the skid. The pilot then repositioned the helicopter so that the linemen could repeat the steps on the next structure. During a postaccident interview, the pilot reported that he and the linemen (the crew) met earlier in the day and flew to one of the structures to assess the work and tools required to complete the task. The helicopter then returned to the landing zone and was refueled before departing on the accident flight. The crew completed one structure, and the pilot hovered the helicopter into position so that work could begin on the next structure. …the pilot stated that the pole where the accident occurred was at “a slight inside angle” but was considered to be a “safe” area in which to work. According to the pilot and the operator, the helicopter was hovering “inside the bite,” which was the triangular area comprising the wire from the uphill pole, the turn at the accident pole, and the wire to the downhill pole. The “base” of the triangle was the horizontal line from the uphill pole to the downhill pole. The operator indicated that the “bite” had a vertical dimension as well. When asked to describe operations “inside the bite,” the [operator’s] safety director stated that it was the area where, once the helicopter was inside it, the wire would move toward the helicopter if the wire became loose from the dolly. Once the helicopter was in position, the lineman on the helicopter skid attached the first half of the armor rod ahead of the dolly and manipulated the line and the dolly to complete the wrap. The pilot and the linemen began work without installing a safety strap. According to the operator’s director of safety, the safety strap aboard the helicopter was “not long enough” to install it before work began…and that a “choker safety” should have been used. When asked if the company’s standard operating procedures directed that the crew retrieve the choker safety, the director...
read moreUSAF T-6A Texan II Lost in Inverted Stall
USAF T-6A Texan II Lost in Inverted Stall On 1 May 2019 US Air Force (USAF) Beechcraft T-6A Texan II 07-3890, crashed 21 miles NE of Sheppard Air Force Base (AFB), Texas. The crew safely ejected using Martin Baker Mk 16 ejection seats and suffered only minor injuries. The aircraft, valued at approximately $5.7 million, was destroyed. The Accident Flight On board were an instructor from 97th Flying Training Squadron (FTS) and a ‘student’ from 89 FTS (both part of the 80th Flying Training Wing). The instructor had 2,153.6 military flight hours, 795.7 hours in the T-6A. The ‘student’ had 4,846.6 total hours logged as a pilot in the Italian Air Force. They had been assigned as a T-6A instructor at Sheppard AFB from 2011-2013, flying 1,290.2 hours in the T-6A. They were regaining currency by undertaking Pilot Instructor Training (PIT). The 89th FTS is comprised of 60 personnel from 13 NATO nations, and trains mores than 100 student pilots and 24 instructor pilots annually in support of Euro-NATO Joint Jet Pilot Training Program. The USAF Accident Investigation Board (AIB) report explains that: While setting up a training maneuver with building cloud formations, the Instructor flew the aircraft in an unintentional nose-high trajectory with decreasing airspeed. At 13:12:52L the aircraft passed through 12,800 feet MSL, 60º nose-high with airspeed decreasing below 100 knots. In an attempt to regain airspeed, the instructor tried to lower the nose of the aircraft towards the horizon and penetrated the weather. Next, the instructor attempted to roll wings level while still in a [30º] nose-high attitude with insufficient airspeed and high-power setting. This resulted in a left torqueroll, placing the aircraft into a power-on, inverted spin while still in Instrument Meteorological Conditions (IMC). A left torque-roll occurs when aerodynamic forces are insufficient to overcome the rolling motion induced by the propeller. The instructor recognized the inverted state of the aircraft but never completed the critical action of pulling the Power Control Lever (PCL) to IDLE. Maintaining the high power setting prolonged the state of the spin and pushed the aircraft into a steeper nose-low attitude. Due to the disorienting nature of the inverted spin entry, coupled with IMC, unusual negative gravitational forces, and the aircraft’s propensity for pro-spin rudder, the instructor could not identify and input the appropriate controls for timely recovery. Furthermore, due to the negative G’s, the instructor’s distorted body position affected the view of the altimeter, which was partially obscured by the glare shield. This prevented the instructor from seeing the specific altitude displayed in the upper portion of the altimeter, but did allow recognition of the downward trend. The crew ejected at 10,830 feet MSL as the aircraft continued to spin 60º nose-low with inconsistent airspeed indications https://youtu.be/cIwEG7opxtg USAF AIB Human Factor’s Analysis The investigators applied the the DoD Human Factors Analysis and Classification System (DoD-HFACS) taxonomy based on the work of Wiegmann and Shappell. They identified following human factors: Fixation (PC102): This occurs when an individual is focusing all conscious attention on a limited number of environmental cues to the exclusion of others. “Post mishap, the instructor reported focusing attention over the right shoulder at the horizon”. Environmental Factors Affecting Vision (PE101): “During this attempted recovery, the aircraft entered the weather, lost outside visual references, and departed controlled flight”. Checklist Not Followed Correctly (AE102): “Both inverted spins and spins in IMC are prohibited maneuvers in the T-6A” and the instructor “did not pull the PCL back to...
read moreS-61N Damaged During Take Off When Swashplate Seized Due to Corrosion
S-61N Damaged During Take Off When Swashplate Seized Due to Corrosion (G-ATBJ) British International Sikorsky S-61N G-ATBJ was preparing to fly from Marchwood Military Port in Hampshire to a maintenance base on 1 February 2018 when a series of factors resulted in a dramatic dockside drama. The Accident Flight In their safety investigation report, published 3o January 2020, the UK Air Accidents Investigation Branch (AAIB) explain that: G-ATBJ had previously been operating in the Falkland Islands for four years until its last flight on 31 December 2017. It was then prepared for return by sea to the UK. This included having its main and tail rotor blades removed; no covers were used to protect the rotor head and transmission. On 8 January 2018, the helicopter was moved onto a roll-on/roll-off sealift ship…G-ATBJ was transported below decks during the voyage…to Marchwood…where it was unloaded on 29 January 2018. The following day, the helicopter was prepared for flight which included having its main and tail rotor blades fitted; a ground run was then performed by flight crew [the same Aircraft Commander who was to make the ferry flight but a different Co-Pilot]. It appears these were done in haste due to concerns about a limited number of external batteries and no external power cart being available. On the CVR recording there was comment yo… …just check that the blades were moving in “the right sort of way”. During the check, the range of cyclic pitch movement recorded was between -12% aft and 18% forward as opposed to the full range of movement required by the procedure of approximately -44% aft to 26% forward. On the next day… …the co-pilot performed the external checks while the commander commenced the internal checks. Two of the operator’s engineers were also in attendance and remained outside the helicopter throughout. The crew discussions indicated the need to progress quickly [also due to to battery concerns]. They initially encountered difficulties with the engine start. Subsequently: The engine 2 start was successful but, because the subsequent checks required the rotors, and hence the hydraulic pumps and electrical generators, to remain disengaged, the commander commented that they needed to be “as quick as we can” to minimise the use of the battery to pressurise the hydraulics from the DC motor-generator (motorising). During the after-start checks, a flying controls servo system check was completed, but not to the full extent of control movement. The pilots believed that a full and free check to the extremities of the controls’ movement was not possible as the helicopter’s electrically-driven hydraulic pumps would have disengaged under a high demand as they were being powered by the battery. However, the helicopter manufacturer has advised that, if the controls are moved slowly, full movement could be obtained without the pumps disengaging. During these checks the Pilot Flying (PF) stated “…and they [main rotor blades] are moving in the right sense…I’m not doing full and free, we haven’t got time.” Both pilots highlighted that they did not intend to avoid full and free checks, but they felt that they were not achievable in the circumstances having previous experience on the S-61 after failed attempts using batteries. The helicopter’s rotors were then engaged and the crew then started engine 1. Pre-flight checks were completed and ATC clearance to depart was received. The commander released the parking...
read moreEmirates B777 Runway Impact During Attempted Go-Around, 3 August 2016, Dubai: Accident Report
Emirates B777 A6-EMW: Runway Impact During Attempted Go-Around, 3 August 2016, Dubai: Accident Report On 6 February 2020, the Air Accident Investigation Sector (AAIS) of the UAE General Civil Aviation Authority (GCAA) released their safety investigation report into a 3 August 2016 accident. Emirates Boeing 777-31H A6-EMW, had departed Trivandrum International Airport (VOTV), India for Dubai International Airport (OMDB), the United Arab Emirates, with 282 passengers, 2 flight and 16 cabin crew members aboard. The Commander’s total flying experience was 7,457 flying hours, including 3,950 hours as a copilot and 1,173 hours as a commander on the B777. The Copilot’s total flying experience was 7,957 flying hours, including 1,292 as a copilot on the B777. Both pilots had performed go-around and missed approach exercises during their training and had performed one normal go-around as pilot flying on the B777 each within 4 months prior to this flight. History of the Flight AAIS explain that on arrival at Dubai the Aircraft Commander attempted to perform a within-limits tailwind manual landing during forecast moderate windshear. During the landing on runway 12L at OMDB the Commander, who was the pilot flying, decided to fly a go-around, as he was unable to land the Aircraft within the runway touchdown zone. The go-around decision was based on the perception that the Aircraft would not land due to thermals and not due to a windshear encounter. For this reason, the Commander elected to fly a normal go-around and not the windshear escape maneuver. The flight crew initiated the flight crew operations manual (FCOM) Go-around and Missed Approach Procedure and the Commander pushed the TO/GA switch. As designed, because the Aircraft had touched down, the TO/GA switches became inhibited and had no effect on the autothrottle (A/T). The flight crew were not aware a 6 second touch down had occurred. After becoming airborne during the go-around attempt, the Aircraft climbed to a height of 85 ft radio altitude above the runway surface. The flight crew did not observe that both thrust levers had remained at the idle position and that the engine thrust remained at idle. The Aircraft quickly sank towards the runway as the airspeed was insufficient to support the climb. As the Aircraft lost height and speed, the Commander initiated the windshear escape maneuver procedure and rapidly advanced both thrust levers. This action was too late to avoid the impact with runway 12L. Eighteen seconds after the initiation of the go-around the Aircraft impacted the runway at 0837:38 UTC and slid on its lower fuselage along the runway surface for approximately 32 seconds covering a distance of approximately 800 meters before coming to rest adjacent to taxiway Mike 13. The B777 remained intact but ” several fuselage mounted components and the No.2 engine/pylon assembly separated”. During the evacuation, several passenger door escape slides became unusable. Many passengers evacuated the Aircraft taking their carry-on baggage with them. https://youtu.be/jHhmw4xy1mY Except for the Commander and the senior cabin crewmember…all of the other occupants evacuated via the operational escape slides in approximately 6 minutes and 40 seconds. This is considerably beyond the 90 second certification target. Twenty-one passengers, one flight crewmember, and six cabin crewmembers sustained minor injuries. Four cabin crewmembers sustained serious injuries. Approximately 9 minutes and 40 seconds after the Aircraft came to rest, the center wing tank exploded… …which caused a large section of the right wing upper skin...
read moreHeli-Expo 2020 Photo Report
Heli-Expo 2020 Photo Report We bring news from the annual HAI Heli-Expo being held this year from Anaheim, California. The show has been sadly overshadowed by an S-76B accident with 9 fatalities, (including basketball star Kobe Bryant) close by in California on 26 January 2020. All show photos © Aerossurance unless otherwise stated. See also our 2015, 2016, 2017 and 2018 reports. In 2019 we were a bit slack and just tweeted! Next year Heli-Expo visits New Orleans. Aerossurance has extensive helicopter safety, design, acquisition, operations and airworthiness experience. For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest...
read moreEC135 Main Rotor Actuator Tie-Bar Failure
Police Airbus EC135T1 Main Rotor Actuator Tie-Bar Failure (VP-CPS, Cayman Islands) On 26 February 2019 Airbus Helicopters EC135T1 VP-CPS of the Royal Cayman Islands Police Service (RCIPS) was damaged on take off at Owen Roberts International Airport, in the Caribbean Cayman Islands. The RCIPS Air Operations Unit (AOU) was formed in March 2010 with VP-CPS, a 1999 EC135 that had previously served with the East Midlands Air Support Unit as G-EMAS. VP-CPS was withdrawn from service after the accident. RCIPS now have two H145s. The Accident Flight The UK Air Accidents Investigation Branch (AAIB) describe in their safety investigation report that at the start of a combined training and search flight… …the pilot lifted the helicopter to a height of approximately 4 feet…and felt the cyclic control stick shake and then a strong rearwards force, which he was unable to overcome. The pilot immediately lowered the collective lever, landing heavily, and moved both throttle twist grips to idle, switched off the engines and applied the rotor brake. A maintenance team arrived at the helicopter and found damage to the landing gear, tail boom, Fenestron shroud and the transmission deck. The Safety Investigation The main rotor swashplate is moved in the lateral, longitudinal and collective axes by three hydraulic actuators and together they comprise the Main Rotor Actuator (MRA). Further investigation revealed that the tie bar of the longitudinal axis actuator had broken near the fork end. Inside each individual actuator are two axial pistons, one per hydraulic system, which are linked with a tie bar. This bar is manufactured from passivated, high-strength, corrosion-resistant steel, and attached to a fork end which connects to the swashplate linkage. Tension loads from the pistons are transferred to the fork end by the tension ring segments and compressive loads are transferred through the compression ring segments. Sealant is applied to the centre bore of the fork end to prevent moisture ingress into the upper piston through the tension ring segments. To enable actuator replacement without swashplate linkage adjustment, the length of the actuator is controlled to +/- 0.1 mm by selection and fitment of a pair of compression ring segments with the appropriate length. The MRA was removed from for examination. The overall external condition was typical for the equipment, which had completed 18 years in service and 6,561 flying hours. The lateral and longitudinal axis tie bars had been replaced in 2005 after 576 flying hours, due to damaged threads. The tie bar of the longitudinal axis actuator had fractured approximately 30 mm from the end attached to the fork fitting, where the cross-section changes for an ‘O-ring’ seal. Analysis of the material found adjacent to the fracture on the tie bar revealed a high sodium and chlorine content, amongst other chemical elements, with similar deposits found on the other actuator tie bars. There was evidence of the same material on the part of the fork end located within the upper piston. The failed tie bar was removed from the actuator and the fracture surfaces were examined using Scanning Electron Microscopy with semi-quantitative Energy Dispersive X-ray (SEM‑EDX) spectroscopy. On the surface of the tie bar local to the fracture there was evidence of pitting corrosion, with several pits extending into the material [1]. On the fracture surface there was evidence of intercrystalline corrosion with crack propagation covering approximately ¾ of the fracture surface...
read moreBe Careful If You Step Outside!: Unoccupied Rotors Running AS350 Takes Off
Be Careful If You Step Outside!: Unoccupied Rotors Running AS350B3 YR-DEX Takes Off The Romanian Civil Aviation Safety Investigation and Analysis Authority (AIAS) has issued their safety investigation report into an accident involving Airbus Helicopters AS350B3 YR-DEX on 29 November 2017. The aircraft, operated by Dunca Expeditii, had landed near an inoperative chairlift on a ski slope in the Mount Mic Tourist Complex, Caras-Severin County. AIAS explain that: After the helicopter was landed and the engine was stopped, the pilot placed some materials in two of the three cargo compartments of the helicopter and got into the cockpit with the intention to take off. After starting the engine, he put the twist grip into the “FLIGHT” position, at which time he noticed on the warning panel that the “DOOR” indication light was activated. At this point, without securing the collective lever, with friction applied to the cyclic and with the twist grip in “FLIGHT” position, the pilot got off to check the cargo compartment doors, starting from the right side. When he came to check the cargo compartment door on the left, the wind increased in intensity, at which point the helicopter took-off forward and banked to the right with an angle of approximately 20 degrees. This diagonal, height gaining lift-off resulted in the impact of the main rotor blades with the chairlift cable, at a distance of approximately 37 meters and at a height above the ground about 5 meters from the pilot’s take-off point in the direction of flight. The helicopter impacted the ground on its left side, with the tail boom detaching about three quarters of the circumference, the helicopter canopy being destroyed. It appears the pilot was uninjured. Previous Accidents AIAS list various accidents involving rotors running AS350s: AS350B2 SN2684 F-OGUZ Guyana 17/07/2000 (no other details available) AS350B3 SN3209 HB-ZBN Switzerland 09/10/2001 (head injury after the pilot disemarked) AS350B2 SN2345 OE-XRR Austria 01/09/2009 (rolled over) AS350B2 SN4419 ZK-IMS New Zealand 06/05/2010 (rolled over while pilot checking baggage bay) AS350BA SN2473 ZK-HBD New Zealand 23/09/2010 (rolled over while pilot arranging load) AS350BA SN1132 ZK-HKU New Zealand 09/08/2012 (not relevant as accident happened after the subsequent departure: Regulator Missed the Chance to Intervene Before Fatal Tour Accident say TAIC) AS350B3e SN7718 N840PA USA 18/05/2014 (rolled over onto pilot as he was relieving himself) AIAS Safety Analysis The Investigation Commission tried to determine the helicopter dynamics taking into account the pilot’s statement, namely: The pilot outside the helicopter, on the left-hand side The twist grip on the collective in the “FLIGHT” position The collective not secured Friction applied to the cyclic. When friction is not applied to the collective and this is not secured, due to engine helicopter vibrations, the collective can change its position. The result is the change of the main rotor blades pitch and the increase of the load, thus the helicopter is lifting off. If the position of the cyclic is not altered from the one that it has on the ground, during the lifting from the ground, the helicopter will tend to move in the direction of its position. Also, if the right pedal is not actuated to counteract the reactive torque of the main rotor, the helicopter will rotate about its vertical axis to the left. In conclusion, in the case of an uncommand lift off, the helicopter dynamics would be the following: the...
read moreB1900D Window Blowout
B1900D Window Blowout On 22 October 2018 Federal Airlines Beechcraft B1900D ZS-PHX was in cruise at 20000ft when it suffered an explosive decompression. The aircraft made a safe landing, without injury to the 13 occupants. According to the South African CAA safety investigation report, the decompression was due to the failure of the third cabin window on the right-hand side of the fuselage. This window was installed in January 2007, approximately 6,000 flying hours earlier. The first two cabin windows on each side of the B1900 are a two-pane. The rest are single-pane windows with a life of 43,600 flight hours or 61,700 pressure cycles. Laboratory examination revealed that cracking propagated from the outside surface in the centre of the window. The B1900D Aircraft Flight Manual states: …do not operate the engines with the propellers feathered except during external power starts and propeller feather checks, except that the propellers may be operated in feather at temperatures not to exceed +5°C for a maximum of 3 minutes for the purpose of airframe de-icing. Beechcraft B1900 Airliner Communiqué no. 30 (issued in December 1993) states: After a fleet inspection, 8 other windows were rejected in the operator’s fleet. The SACAA safety message was that: It is imperative that operators abide by the B1900 communiqué no. 30 during ground operations to avoid excessively heating the cabin windows. Safety Resources Our past B1900 safety articles include: B1900D Emergency Landing: Maintenance Standards & Practices Incorrectly Rigged B1900D Charlotte, NC, 8 January 2003: 21 Fatalities Crossed Cables: Colgan Air B1900D N240CJ Maintenance Error B1900C PSM+ICR Accident in Pakistan 2010 Distracted B1900C Wheels Up Landing in the Bahamas Operator & FAA Shortcomings in Alaskan B1900 Accident Alaska B1900C Accident – Contributory ATC Errors UPDATE 3 June 2020: Beechcraft 1900C Landing Gear Collapse at San Antonio, TX Aerossurance has extensive air safety, operations, airworthiness, human factors, aviation regulation and safety analysis experience. For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest updates. TRANSLATE with x English Arabic Hebrew Polish Bulgarian Hindi Portuguese Catalan Hmong Daw Romanian Chinese Simplified Hungarian Russian Chinese Traditional Indonesian Slovak Czech Italian Slovenian Danish Japanese Spanish Dutch Klingon Swedish English Korean Thai Estonian Latvian Turkish Finnish Lithuanian Ukrainian French Malay Urdu German Maltese Vietnamese Greek Norwegian Welsh Haitian Creole Persian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal...
read moreAAR Bell 214ST Accident in Afghanistan in 2012: NTSB Report
AAR Bell 214ST N5748M Accident in Afghanistan in 2012: NTSB Report On 16 January 2012, Bell 214ST N5748M, crashed 7 miles south of Camp Bastion in Helmand province, Afghanistan, killing the crew of three. The helicopter was operated as a Part 135 flight by AAR Airlift Group under contract to the Department of Defense (DOD) Air Mobility Command (AMC), the air component of the US Transportation Command). The Accident Flight The helicopter, call sign ‘Slingshot 72’, was transporting military personnel between coalition bases with another 214ST (N391AL, ‘Slingshot 71’). About 1040, both helicopters departed Camp Bastion after a rotors running turnaround for Shindand Air Base on their third sector of the day. The only passengers were on Slingshot 71. They climbed to a cruising altitude of 800 – 1,000 ft. Slingshot 72 was the lead helicopter, with Slingshot 71 trailing by about ¼ to ½ mile. The US National Transportation Safety Board (NTSB), who were delegated the investigation by the Afghan Ministry of Transport and Civil Aviation, say in their safety investigation report: The SIC of Slingshot 71, who was the pilot flying, saw Slingshot 72 enter a “sharp” bank to the right; he estimated that the bank was about 70º to 80º. The SIC then saw Slingshot 72 begin to “come apart.” …he flew Slingshot 71 to the left to avoid the large amount of debris coming from Slingshot 72, which included large pieces of structure. The SIC reported that the tailboom of Slingshot 72 began to “separate and fold” and estimated that about two-thirds of the tailboom came off the helicopter. The SIC then saw Slingshot 72 pitch down about 75º to 80º, impact the ground, and burst into flames. The PIC of Slingshot 71, who was the pilot monitoring, stated that, after making a radio frequency change, he looked up and saw Slingshot 72 in a “steep pitch down.” The PIC stated that “nothing seemed wrong” with Slingshot 72 when he had looked down to make the radio frequency change. [H]e saw structure starting to come off Slingshot 72 and that the debris looked similar to “confetti.” The PIC noticed that the tailboom of Slingshot 72 appeared to be folded under the helicopter and stated that he could see the “zinc’ color of the inside of the tailboom. Afterward, the PIC observed Slingshot 72 descend “straight down,” impact the ground, and burst into flames. The PIC reported that the flight crew of Slingshot 72 made no radio transmissions indicating any problems. After US forces reached the area and secured the accident site, Slingshot 71 departed the area and landed uneventfully at Camp Bastion. The Slingshot 72 wreckage was then recovered and moved to a secure location at Camp Bastion. NTSB Safety Investigation The accident site consisted of a primary impact area and a scattered debris field, which measured about 1,575 feet north-south by 656 feet east-west. The primary impact area consisted of the main fuselage, which had been fully consumed by the postcrash fire. The forward tailboom section was found separated from the main fuselage about 49 feet north of the primary impact area, and the aft tailboom section (containing the vertical stabilizer and tail rotor) was found about 279 feet north of the primary impact area. The main debris field was located south of the primary impact area (distance unknown) and...
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