R44 Force Lands After Improper Repair
Robinson R44 N3254E Force Lands After Improper Repair On 21 July 2017 Robinson R44 II N3254E landed hard during an emergency autorotation in Van Nuys, California. The National Helicopter Service and Engineering Company were operating the R44 on a 1 hour Part 91 revenue sightseeing flight around the Los Angeles area. The pilot sustained minor injuries but the three passengers were seriously injured. Accident Flight The US National Transportation Safety Board (NTSB) say in their safety investigation report that: The pilot reported that the tour was uneventful, and as they approached the airport for landing, he heard an unusual sound. He glanced down at the engine tachometer, and it was higher than normal, indicating above 110%. The pilot began manipulating the engine throttle to reduce power and bring the engine and rotor speeds into alignment, but the rotor RPM began to decay. He was concerned that the engine might overspeed if he adjusted the throttle higher, and presumed that there was likely an unrecoverable failure in the transmission system, so he initiated an autorotation. The pilot stated that at no point during the flight did he receive any instrument panel annunciations or indications of a problem. He did not scan the instrument panel during the descent because his focus was on flying the helicopter and looking for a landing spot. He stated that trees and power poles blocked his landing approach, and he therefore did not have sufficient speed or space to perform an adequate flare, and the helicopter landed hard. He reported that the engine continued to operate during the descent… The helicopter came to rest on a street in a densely populated residential neighbourhood. The landing skids had spread during the impact, and were level with the belly, and the emergency…floats had deployed. The floats had been armed for the flight, and they appeared to have deployed during the hard landing. The entire airframe exhibited buckling damage, and the belly was crushed. The tail rotor gearbox struck a fence, and had partially detached. Both main rotor blades remained attached to the mast, but one was bowed downward and the other was bent slightly upward. The pilot commented that… …although he has trained for emergency events, he was shocked at how quickly everything transpired. NTSB Safety Investigation and Analysis The helicopter was equipped with a “Tourmaster” GPS enabled video recording unit, manufactured by Rugged Video LLC. The unit was typically used by air tour operators to record video, audio, and GPS data for customers as a memento of their flight. Review of onboard video and a spectrographic analysis of the recorded audio revealed that the engine rpm initially decreased but then appeared to be restored a few seconds later while the helicopter slowed. For about the next 40 seconds, the engine continued to operate at the same rpm and the helicopter continued to slow and gradually descend. The engine rpm then quickly decreased, and the helicopter rapidly descended in a manner consistent with the pilot initiating an autorotation. Examination of the helicopter… …did not reveal evidence of any mechanical malfunctions or failures that would have precluded normal operation, and witness signatures indicated that the engine was producing power at the time of ground impact. However, a wire within the right magneto, which provided a signal to both the engine governor and engine tachometer on...
read moreS2000 Runway Excursion at the Start of the Take Off Roll
S2000 Runway Excursion at the Start of the Take Off Roll (SE-LRA at Linköping) On 8 May 2019, Saab 2000 SE-LRA, operating as a transport flight for Saab, suffered a runway excursion at the beginning of the takeoff roll from Linköping/Saab airport, in Sweden. The Swedish Accident Investigation Board (the Statens Haverikommission [SHK]) say in their safety investigation report that: The captain taxied to the runway using the nose wheel steering tiller without any difficulties. After lining up, the crew conducted the daily propeller overspeed test in accordance with the checklist and proceeded directly with the takeoff run. It is clear from the captain’s interview that for some reason they omitted to depress the tiller and activate the nose wheel steering. The result was a quick aircraft yaw to the left. The aircraft left the runway surface with the left main landing gear just before reaching the two diagonal military taxiways, passed one of them and headed back on to the runway where it slowed down and stopped in the middle of the runway. The air traffic controller in the tower noted that the aircraft yawed abruptly to the left but did not see the aircraft actually leaving the runway surface. After the aborted takeoff, the air traffic controller informed the crew of his observations. Damage to a runway edge light was discovered on inspection. SHK Safety Investigation and Analysis Data from the flight data recorders (DFDR and QAR) were available and SHK has analyzed the relevant parameters. However, data from the nose wheel steering angle and brake pressure are not recorded by DFDR/QAR. The nose wheel steering indicated no technical faults before or during the incident. [W]eather and prevailing runway conditions were within the aircraft’s limitations. The dry surface allowed for good friction and aircraft control via nose wheel steering and wheel braking. The take-off was initiated directly from partial power, which resulted in an abrupt course change and provided for only a very limited time to recover before the aircraft left the runway. Contributing was the fact that the nose wheel angle probably was not parallel with the runway heading at brake release. One possible explanation for this could be the aircraft vibrations caused by the propeller test, where both propellers in turn reduce the power momentarily. SHK also note the pilot regularly flew the Bombardier Global 6000 (BD-700) which has a steering hand wheel that does not, unlike on the Saab 2000, need to be pressed to select. SHK Conclusions The direct cause of the runway excursion was a lapse in activating the nose wheel steering tiller during the initial takeoff phase. This led to a delayed correction of the aircraft’s lateral deviation. A contributing factor may have been that the pilot alternated between flying two aircraft types where the nose wheel tiller is used in different ways. No safety recommendations were made. Safety Resources On error management: Professor James Reason’s 12 Principles of Error Management Back to the Future: Error Management …and our review of The Field Guide to Understanding Human Error by Sidney Dekker presented to the Royal Aeronautical Society (RAeS): The Field Guide to Understanding Human Error – A Review Runway Excursion Exposes Safety Management Issues G200 Leaves Runway in Abuja Due to “Improper” Handling CRJ900 Skids Sideways Down Finnish Runway AAIB: Human Factors and the Identification of Saab 2000 Flight Control Malfunctions Twin Otter Nose Wheel Steering Misused...
read moreFukushima 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 more
Recent Comments