A Screw in the Wrong Place…A Loss of Hoist Cable
A Screw in the Wrong Place…A Loss of Hoist Cable (Honda Airways AW139 JA03FD Breeze-Eastern Hoist) On 17 February 2024, Leonardo AW139 JA03FD of Honda Airways, operated for the Saitama Disaster Prevention Air Squadron, inadvertently released the hoist cable and test load during a post-maintenance hoist check at Honda Airport, Kawajima. The Japan Transport Safety Board (JTSB) issued their safety investigation report on 25 May 2025. The Serious Incident Flight The helicopter’s hoist cable had been replaced and so a post-maintenance check flight was necessary. On board were two pilots, an Air Squadron Officer (ASO – the hoist operator) and a mechanic (‘Mechanic A’, acting as a hoist instructor). The JTSB explain: The load test required after cable replacement, confirms each function of hoist operates normally with maximum hoist load, 600lb (about 272 kg). In this case, the cable had been replaced the day before by Mechanic B and C, and it was planned to conduct load test, with 136 kg…and [then] 272 kg….on the hook at the end of the cable. This would be achieved using two and then four 68 kg weights. At about 10:17, for the first load test, the helicopter reeled out the cable to the ground at a hovering height of about 50 ft, and ground crew hooked a 136 kg weight. The helicopter then climbed to hovering altitude of about 340 ft, the Air Squadron Officer began to reel out cable to the maximum length (about 300 ft), which was for Mechanic A to confirm that it would automatically stop at the maximum length. As the cable reached its maximum extension “the weight fell to the ground along with the cable” near Taxiway E4. There were no injuries or damage. The helicopter had an electrically operated Breeze-Eastern hoist: The cable is 307 ft (about 93.5 m) long, has a diameter of 4.75 mm, and is wrapped on an aluminum drum. The cable is inserted in the slot of drum and fixed by tightening the screw against the cable strand. As the end of the cable is welded to prevent fraying, the screw must contact the cable strand and not the welded end. The hoist is fitted with limit switches which automatically stop the drum when remaining cable gets to 3.5 to 4.5 wraps. Unacceptable ‘bird caging‘ damage had been found on the previous cable fitted to the hoist so on 15 February 2024 ‘Mechanic B’ (a licenced engineer) began to unwind the old cable using the thumb wheel on the hoist pendant. Mechanic B stopped unwinding when the full-out limit switch actuated and the drum stopped, confirmed that the number of cable wrap which was 4 remaining on the drum and took a photo with his smartphone. And then, Mechanic B removed the screw which fixed the cable end…to pull out the old cable from the slot on the drum and completed the day. The AW139 Aircraft Maintenance Manual (AMM) however required the limit switch be overridden and the cable fully paid out. The AMM also discusses this screw, saying: Make sure that the screw engages sufficiently the cable end to safety the cable correctly into the drum shoulder. To do this, you can see only a small part of the cable white mark that goes out of cable housing in the drum shoulder...
read moreCold Comfort Conference Call: USAF F-35A Alaska Accident
Cold Comfort Conference Call: USAF F-35A Alaska Accident On 28 January 2025 US Air Force Lockheed Martin F-35A 19-5535 of the 355th Fighter Squadron crashed and was destroyed at Eielson Air Force Base (AFB), Alaska (a total loss valued at $196.5 mn). The pilot ejected and suffered only minor injuries. The USAF released their Accident Investigation Board (AIB) report on 26 August 2025. A USAF AIB does not conduct a safety investigation (a separate Safety Investigation Board [SIB] is convened but their report is not released publicly), instead (our emphasis added): In accordance with AFI 51-307, Aerospace and Ground Accident Investigations, this accident investigation board conducted a legal investigation to inquire into all the facts and circumstances surrounding this Air Force aerospace accident, prepare a publicly-releasable report, and obtain and preserve all available evidence for use in litigation, claims, disciplinary action, and adverse administrative action. The Accident Flight A Landing Gear Fault After Take Off The accident aircraft was number 3 of a flight of four 355 FS F-35As, callsign YETI, that was to conduct an Air Combat Maneuvers (ACM) sortie with two other F-35As, callsign CHEVY. The 355 FS is part of the 354th Fighter Wing (354 FW). The pilot of YETI 3 was a current F-35A evaluator and instructor pilot with 2702 hours in total (555 hours on type). Shortly after takeoff, the pilot of YETI 3 received an OVERSPEED GEAR caution. They identified that instrumentation showed yellow and black hash marks for the Nose Landing Gear (NLG) that indicated ‘gear in-transit’. Their wingman reported the NLG door was “open by about 2 inches”. The pilot followed the necessary checklists, which included lowering the gear and conducting flight control system resets. The NLG was initially angles c25 degrees left. This was reduced to c17 degrees during this fault finding. Calling a ‘Conference Hotel’: Fault Finding Technical Support Call with Lockheed Martin The pilot then requested a ‘Conference Hotel’, namely a conference call with Lockheed Martin engineers. This was swiftly organised through the on-duty Supervisor of Flying (SOF) at Eielson AFB. Although the AIB don’t say when this call was requested it appears to have been set up in less than 20 minutes. On the call were the Eielson SOF, a “senior 354 Operations Group (354 OG) leader” and 5 Lockheed Martin engineers (a senior software engineer, a flight safety engineer and three landing gear systems engineers). The Eielson SOF was in turn in contact with the pilot. According to the AIB report the engineers… …requested information on, among other things, how much fuel the MA [Mishap Aircraft] had remaining, direction of the NLG wheel, and health reporting codes [HRCs]. The AIB then says that they… …did not request or receive information about where the mishap was occurring and ambient air temperature. That’s an odd observation because presumably they did know the call was arranged by the Eielson SOF, that Eielson AFB is in Alaska and that in January Alaska is rather chilly…! Initially an arrestor landing was mooted, but the pilot pointed out that “cable arrestment must be in a 3-point attitude” according to the published procedures, meaning the NLG would have to be on the ground prior to the cable engagement. That course of action was abandoned because of the concern that an uncentered nose wheel could...
read moreFlat Light B206L4 Alaskan CFIT & 11 Hour Emergency Response Delay
Flat Light B206L4 Alaskan CFIT & 11 Hour Emergency Response Delay (Maritime Helicopter, Bell 206L4 M311NH) On 20 July 2023 Bell 206L4 N311MH of Maritime Helicopters, was destroyed when it impacted the surface of Lake Itinik, c30 miles east of Wainwright, North Slope, Alaska. The pilot and three passengers died. The helicopter was contracted by the Alaska Department of Natural Resources (DNR) to transport scientists to various remote locations. The US National Transportation Safety Board (NTSB) published their safety investigation report on 20 August 2025. The Accident Flight The NTSB explain the pilot recently retired from the US military and this was his first civil job as a pilot, commencing in October 2022. NTSB state he had about 1,900 hours of flight experience in helicopters, 80 on type, 140 in Alaska. The pilot flew the helicopter from Fairbanks to Utqiagvik (formerly Barrow) two days before the accident flight and had flown the previous day. On the day of the accident the helicopter departed on a Visual Flight Rules (VFR) flight at c 10:01 Local Time according to data from the aircraft’s Honeywell SkyConnect satellite tracking system, which broadcast every 3 minutes. According to the NTSB: Management personnel from Maritime Helicopters, as well as personnel from DNR had real-time flight following capabilities of the accident helicopter. It appears the morning departure had been delayed by fog according to a message to the DNR from one of the passengers. It was on the ground for c10 minutes Atqasuk Airport (PATQ) but the satellite tracking system last received data at 11:04. Noticeable is the helicopter was never above 266 ft msl. NTSB note that the day before Sky Connect Tracker data for the same pilot and helicopter showed “an average altitude of about 200 ft msl with an average airspeed of about 105 knots”. No information is provide by NTSB on where the helicopter was heading of what the scientists’ objectives were. At about 11:12 the Sky Connect system sent out an overdue aircraft report, but that report went unnoticed by the operator or the DNR. The accident helicopter was expected to return to Utqiagvik by 20:30 The helicopter was reported overdue at 22:30 by an employee of the State of Alaska Geological Survey [part of DNR]. The North Slope Borough (NSB) Search and Rescue (SAR) Sikorsky S-92A was tasked to search for the missing helicopter. NSB have an S-92A and a Bell 412 that are being replaced by two Leonardo AW189s. The partially submerged, fragmented helicopter wreckage was found in the shallow waters of Lake Itinik…a large, oval-shaped arctic lake more than three miles wide in some areas. The lake is surrounded by “flat, featureless, arctic tundra“. The NTSB Safety Investigation Examination of the wreckage revealed no pre-impact issues with the helicopter. NTSB comment that: Archived satellite tracking data indicated that the helicopter was flying about 88 ft above ground level (agl) at 93 knots shortly before impacting the water. Although there was a possibility of some overcast clouds and restricted visibility in fog/mist over the accident site, there were no observations or forecasts for any significant turbulence, low-level wind shear, convective activity, or icing over the area at the time of the accident. However, the NTSB mention: Due to fiber optic outages, there were a limited number of FAA weather...
read moreAir Methods Helicopter Air Ambulance Night Take Off Tree Strike
Air Methods Helicopter Air Ambulance Night Take Off Tree Strike (BK117B2 N880SL, Hartford, IL) On 24 April 2025 Air Methods (ARCH) Airbus BK117B2 air ambulance N880SL was destroyed taking off from outside a fire station in Hartford, Illinois. The three occupants were all seriously injured. The US National Transportation Safety Board (NTSB) issued a remarkably rapid but sadly perfunctory final report on 20 June 2025. This article has had to draw heavily on content from the NTSB Docket that were unused in the final report. The Accident Flight The pilot (7404 hours total, 1277 on type) arrived at the Air Methods’ Granite City, Illinois base at c 18:30 for a night shift. Shortly after completing the pre-flight on the helicopter the flight nurse asked if the helicopter would still being going to a ‘public relations’ event at the Hartford Fire Department, landing at an ad hoc “confined area landing zone” next to the fire station. The PR event was actually inter-agency training. The pilot recalled that the outgoing pilot… …described the obstacles surrounding the LZ, powerlines on the north and east sides with trees on the west and south side. I also reviewed the aerial photo of the LZ in Google Earth. I anticipated landing either from the north or south along the north/south road just east of the grass LZ. I also noted some map features to help me locate the LZ once I was over Hartford. Ryan offered to drive up to the LZ to be present on the ground with a flashlight to help me locate the LZ. Given the information I received I made the decision to go forward with the PR. The manifest and Air Methods Flight Risk Assessment Tool (FRAT) were completed and submitted to the company Operational Control Center. The FRAT score, timed at 19:11, was 18 based on four items scoring 4 or 5 each (a PR flight scores a 4). There is no information that elaborates on the current Air Methods FRAT methodology in the Public Docket. The form used has 43 questions scoring from -1 to 150, suggesting 18 is probably a low score. The NTSB report doesn’t discuss Air Methods’ procedures. The public docket contains two brief extracts from the Air Methods’ General Operations Manual (GOM) (2 pages) and Training Manual (4 pages). An extract from each follows: The BK117B2 has a D-value (i.e. overall dimension) of 13 m (42 ft 8 in) and a main rotor diameter of 11 m (36 ft 1 in). On arrival at Hartford, the pilot performed a high level recce to identify the site and the adjacent obstacles (a tree and power lines). The site is shown below: The BK117B2 width quoted above by the NTSB is the 7.78 m minimum width when parked, not the width of the rotating main rotor! Strictly, with the east/west road closed the site width would be greater than 70 ft so assuming the minimum dimension is indeed (as shown) 77 ft and the BK117B2 D-value this is a 1.8 D site vs the ‘normally’ 2 D size specified in the GOM. Seen from ground level the site has trees on two sides (we estimate as c 15 m high) and electricity wires (c 8 m high) on the other two (the wires along the north/south road...
read moreOceanGate Titan: Toxic Culture & Fatal Hubris
OceanGate Titan: Toxic Culture & Fatal Hubris – An Analysis of the USCG Investigation The US Coast Guard (USCG) released its Report of Investigation (ROI) on the loss of the Titan submersible, built and operated by US company OceanGate, on 18 June 2023. The Titan imploded at a depth of c 3350 m after a catastrophic loss of structural integrity of the submersible’s carbon fibre hull. This occurred during a commercial dive to the wreck of the RMS Titanic, killing five people, including Stockton Rush, the CEO of OceanGate, and 3 fare paying passengers (or ‘Mission Specialists’ in OceanGate’s lexicon). Viewers of the Netflix documentary Titan: The OceanGate Disaster will not be surprised that investigators commented on a toxic workplace environment within OceanGate that was the antithesis of ‘psychological safety‘. The Hubris of Oceangate CEO Stockton Rush It is claimed that Rush saw his company as the “SpaceX for the ocean” and in a crucial January 2018 meeting that resulted in terminating a highly experience dissenting director (discussed further below) described his approach as being “a religion”. In March 2018 the Marine Technology Society (MTS) presciently warned Rush that OceanGate’s approach, in contrast to the “diligent engineering discipline and professional approach…and adherence to a variety of safety standards” by the rest of the industry, could lead to “catastrophic” results. “I think it was General MacArthur who said ‘You’re remembered for the rules you break’,” Rush said in one 2021 interview: @swiftness0427 CEO Stockton Rush: “I have broken some rules to make this. (…) The carbon fiber and titanium there is a rule that you don’t do that. Well, I did.“ Titan ship built by Ocean Gate Expeditions #titan #titanic #oceangate #oceangateexpeditions #implosion ♬ original sound – Mike Swift ❌⭕❌⭕ – Swiftness ❌ “You know I’ve broken some rules to make this [the Titan submersible]… It’s picking the rules you break that are the ones that will add value to others and add value to society”. In a Vanity Fair article in August 2023 reported that Rush declared “If you’re not breaking things, you’re not innovating,” at the 2022 GeekWire Summit, echoing the Silicon Valley ‘move fast and break things’ ethos. Rush added: If you’re operating within a known environment, as most submersible manufacturers do, they don’t break things. To me, the more stuff you’ve broken, the more innovative you’ve been. Vanity Fair commented: In a culture that has adopted the ridiculous mantra “move fast and break things,” that type of arrogance can get a person far. But in the deep ocean, the price of admission is humility—and it’s nonnegotiable. The abyss doesn’t care if you went to Princeton, or that your ancestors signed the Declaration of Independence. If you want to go down into her world, she sets the rules. Rush was a indeed a Princeton graduate with two distant relatives who had signed the US Declaration of Independence. His wife, Wendy Rush, was descended from a couple who died on the Titanic. Rush boasted he could “buy a congressman” if needed. The generic characteristics of hubris include: Rush would score high against this list. OceanGate: A Toxic Workplace Environment This article will primarily focus on the workplace culture at OceanGate (and three organisationally focused sections [from pages of 296-304] of the USCG report) as it provides relevant lessons for safety...
read moreAW139 Loss of Control Climbing Away from SAR Exercise
AW139 LOC-I Climbing Away from SAR Exercise (Esso Australia Leonardo AW139 VH-EXK) On 2 October 2024 Esso Australia Leonardo AW139 VH-EXK was conducting Search and Rescue (SAR) training under Visual Flight Rules (VFR), just off the coast of Golden Beach, Victoria, when it suffered a Loss of Control – In Flight (LOC-I). The Australian Transport Safety Bureau (ATSB) issued their safety investigation report on 20 May 2025. The Incident Flight The helicopter departed Longford Heliport, Victoria, adjacent to the Esso Longford gas plants, at 0816 local time for a SAR exercise. The crew consisted of the Aircraft Commander (15,402 total hours, 2,603 on type), a Flight Instructor (11,129 total hours, 3,695 on type), a Check Aircrewman, and a Hoist Operator. Esso Australia provide daytime SAR coverage in support of their Bass strait gas production. The ATSB state that on 11 June 2024, was Esso Australia issued with an CASA air operator’s certificate (AOC) and a Part 138 aerial work certificate (for SAR operations). While Esso Australia had previously operated in the private category, for at least 5 years they had operated under an AOC. ATSB say the Aircraft Commander was initially Pilot Flying (PF) and the Instructor Pilot Monitoring (PM) and that the exercise took place c 2 km offshore and… …involved retrieving a training aid amidst large swells, sea spray and encroaching fog from the north-west. The instructor estimated that the fog bank was less than one kilometre from shore at the time. However, clear skies were visible to the north and north‑east… The training aid was deployed, and the exercise commenced at about 0825. As the training progressed, the helicopter’s proximity to the fog on the left side, where the instructor was seated, was observed to be decreasing. The flight crew noted that the skies were clear to the north and northeast of their position on the instructor’s side of the helicopter. After conducting training for approximately 40 minutes, the instructor assumed control as PF and the check aircrewman assumed the role of hoist operator to retrieve the training aid. This involved hovering approximately 40 ft above the sea. Their attempt was unsuccessful however. Due to “encroaching fog” the instructor elected to depart and announced they would climb to avoid fog. At 0908, the instructor manoeuvred the helicopter onto a north-westerly heading… …and engaged the radar height hold (RHT) system while climbing using a combination of the collective beep trim and force trim release (FTR). At this time, the captain, acting as the PM, was focused on marking the GPS position of the training aid. This was to facilitate its recovery in another exercise later that day. At about this time, the helicopter inadvertently entered instrument meteorological conditions (IMC), and the instructor announced their intention to move forward to depart. The right cabin door was open and approximately 40 ft of the hoist cable was extended. The check aircrewman objected via the intercom to departing with the hoist still extended, as the post‑hoist procedures requiring the aircrew to secure the hoist cable and cabin had not yet been completed. Despite this objection, the instructor proceeded with the departure with the intention of reentering visual meteorological conditions (VMC). The instructor accelerated and continued to climb, reaching an altitude of 185 ft and an airspeed of 72 kt before beginning a shallow...
read moreAir India B787 GEnx-1B In Flight Shut Down After Maintenance Error 5 Years Earlier
Air India B787 GEnx-1B In Flight Shut Down After Maintenance Error 5 Years Earlier (VT-ANW) On 4 August 2023 Air India Boeing 787-8 VT-ANW suffered un-commanded In Flight Shut Down (IFSD) of its No 1 GE GEnx-1B engine 9 minutes after take off, forcing a return to Mumbai Airport. The Indian Aircraft Accident Investigation Bureau (AAIB) published their safety investigation report in May 2025. This was the source of the illustrations below. Note: This article was prepared a week a go but publication was delayed as AAIB published their Preliminary Report on 11 July 2025 on the unrelated fatal accident involving Air India 787-8 VT-ANB at Ahmedabad on 12 June 2025. The Safety Investigation A post-incident engine strip released the release of an High Pressure Compressor (HPC) Stage 10 blade was the cause of the IFSD and Electronic Engine Control (EEC) auto-restart attempts were unsuccessful due to distress from the blade’s release. There are two locking lugs for each HPC stage. These secure the blades in a circumferential fashion to prevent blade release from the load slot. During installation a set screw is torqued, raising the locking lug into the locking slot in the spool, but this depends on the correct positioning of the lug in the slot. Investigation found that “the LH locking lug was installed out of the lock slot and the RH locking lug was installed partially inside the lock slot”. This improper installation caused the release of the blade. The last maintenance action on the HPC stage 10 blades had occurred at the GE EvergreenEngine Services (GEEVES) facility in Taiwan in 2018. Unfortunately, but perhaps understandably due to the time having passed, the Indian AAIB report goes no further to understand the circumstances of the 2018 maintenance and the human factors that may have affected the maintenance. Safety Resources You may also find these Aerossurance articles of interest: B787 GEnx Fan Shaft Failure (Air India 2012) Uncontained PW1524G Failure During CS100 Certification Testing Machining Defect Cause of V2500 Failure Power of Prediction: Foresight and Flocking Birds NTSB Recommendations on JT15D Failure to Meet Certification Bird Strike Requirements CFM56-7 HPC Titanium Fire Due to VSV Maintenance Assembly Error (United Boeing 737-924) B767 Fire and Uncommanded Evacuation After Lockwire Omitted Japanese Jetstar Boeing 787 GEnx-1B Engine Biocide Serious Incident 17 Year Old FOD and a TA-4K Ejection NDI Process Failures Preceded B777 PW4077 Engine FBO T-Bolt Trouble: Unrecorded Maintenance on US HEMS BK117C2/H145 and Loss of TR Pitch Control Fatal $16 Million Maintenance Errors CHC Sikorsky S-92A Seat Slide Surprise(s) Loose B-Nut: Accident During Helicopter Maintenance Check Flight USAF RC-135V Rivet Joint Oxygen Fire The Missing Igniters: Fatigue & Management of Change Shortcomings B1900D Emergency Landing: Maintenance Standards & Practices Crossed Cables: Colgan Air B1900D N240CJ Maintenance Error Engine Maintenance Introduced FOD that Caused an EC120 Power Loss SAR AS365N3 Flying Control Disconnect: BFU Investigation Engine & Emergency Flotation Failures – Greenland B206L4 Ditching Flying Control FOD: Screwdriver Found in C208 Controls Lost Tool FODs Propeller Blade, Penetrating Turboprop’s Fuselage Dash 8 Q400 Return to Base After Pitot System Contaminated By Unapproved Test Kit Lubricant Dash 8 Q400 Control Anomalies: 1 Worn Cable and 1 Mystery We have written several general articles related to maintenance safety: Professor James Reason’s 12 Principles of Error Management How To...
read moreBrazilian Helideck Rollover After Precautionary Landing
Brazilian Helideck Rollover After Precautionary Landing (Delta Aero Taxi Airbus AS350B on YM OPUS) On 9 June 2022 Airbus AS350B PT-HMD of Delta Aero Taxi rolled over on the helideck of bulk carrier YM OPUS in the Bay of São Marcos, Brazil after making a precautionary landing. The Brazilian accident investigation agency CENPIA published their safety investigation report on 2 June 2025. The Accident Flight The pilot (2600 total hours but only 17:25 on type) was returning onshore after dropping passengers on the bulk carrier SM GEMINI 2. The passengers had disembarked with the rotors running and a passenger had closed the helicopter door. Shortly after the pilot reported “hearing an abnormal noise and experiencing unusual aircraft vibration”. He reduced speed to c 60 knots “but the phenomena persisted”. Upon inspecting the aircraft interior during flight, he noticed that the left door was notclosed appropriately. This led him to suspect that the noise originated from a seat belt buckle striking the fuselage. The pilot decided to perform a precautionary landing the YM OPUS. Upon landing the pilot reportedly “locked the controls” and while rotors running intended to step out and check the door. Though prohibited by the Brazilian Code of Aeronautics, disembarking while rotors running was described as “habitual” in that operator. At that moment, the helicopter tipped over while he was still inside the cabin. The pilot suffered minor injuries. Safety Investigation External dents support the pilot’s hypotheses of a seat belt stuck outside the door. However: …photographic evidence from the accident site showed that the position of the collective pitch control was fully up, indicating that it had not been locked. The cyclic control, on the other hand, had its friction fully tightened. CENIPA found the operator did not have specific training for operating from offshore helidecks and that offshore operations were not part of their approved Operations Specifications. CENIPA note that: Airbus Helicopters’ Safety Information Notice (SIN) nº 3268-S-00 warned about incidents in which helicopters inadvertently lifted off due to collective pitch movement without pilot input. The notice concluded that failure to lock the collective after landing was a contributing factor in such events. Safety Resources The European Safety Promotion Network Rotorcraft (ESPN-R) has a helicopter safety discussion group on LinkedIn. You may also find these Aerossurance articles of interest: Be Careful If You Step Outside!: Unoccupied Rotors Running AS350 Takes Off AS350B3 Rolls Over: Pilot Caught Out By Engine Control Differences 29 Seconds to Impact: A Fatal Night Offshore Approach in the Irish Sea CHC Sikorsky S-92A Seat Slide Surprise(s) Marine Pilot Transfer Winching Accident: referenced in the Royal College of Art (RCA) & Lloyd’s Register Foundation Safety Grand Challenge: Safe Ship Boarding & Thames Safest River 2030 Engine & Emergency Flotation Failures – Greenland B206L4 Ditching North Sea Helicopter Struck Sea After LOC-I on Approach During Night Shuttling Loss of Sikorsky S-76C+ 5N-BQG of Eastwind Off Nigeria 24 October 2024 South Korean Night Black Hole Spatial Disorientation Fatal Helicopter Accident Loss of Control, Twice, by Offshore Helicopter off Nova Scotia Offshore Night Near Miss: Marine Pilot Transfer Unintended Descent AAIB Report on 2013 Sumburgh Helicopter Accident Fatal Offshore S-76C++ LOC-I & Water Impact Brazil 2022: CENIPA Investigation SAR Helicopter Loss of Control at Night: ATSB Report NTSB Investigation into AW139 Bahamas Night Take Off Accident Night Offshore Training AS365N3 Accident in India...
read moreB214ST Tail Rotor Drive Shaft Coupling Misassembly
B214ST Tail Rotor Drive Shaft Coupling Misassembly (C-GDYZ, HTS) On 7 June 2021 Bell 214ST C-GDYZ of Helicopter Transport Services (HTS) made a forced landing 14 nm NE of Nipigon, Ontario while returning from a firefighting tasking. The pilot was seriously injured. Transportation Safety Board of Canada (TSB) released their safety investigation report on 8 February 2022. The Accident Flight The helicopter was being flown by a single pilot (8400 hours total time, 1940 on type). The aircraft was equipped with a 550-gallon collapsible water bucket on a 150-foot long line. The pilot conducted approximately 45 drops before informing the fire boss on board the bird dog/spotter aircraft that the helicopter was low on fuel and that the end of his duty day was nearing. The return trip…to the Nipigon fire base was flown at 3000 feet above sea level, about 1600 feet above ground level. The helicopter was travelling at 70 to 74 knots in a nose-down attitude of roughly 7° due to the empty water bucket when the pilot was alerted by a vibration in the tail rotor pedals and a grinding noise. Moments later, the 42° BOX OIL PRESS and 90° BOX OIL PRESS annunciators for the 2 tail rotor gearboxes illuminated, and there was an audible engine overspeed noise. The helicopter yawed to the right and the nose began to pitch down. The pilot lowered the collective control and moved the cyclic control aft to counteract the nose-down tendency, increase the main rotor rpm, and enter autorotative flight. As the helicopter began to spin, the pilot released the long line and water bucket by kicking the manual cargo release pedal. The pilot transmitted a Mayday call stating that he had lost tail rotor control. While the helicopter was descending at approximately 1000 to 1500 fpm, the pilot made 3 attempts to use some engine power to fly the helicopter to a suitable landing area near a small lake. He was able to regain some control over the adverse yaw via airflow acting on the vertical stabilizer. As the helicopter descended below treetop height, he raised the collective control to cushion the landing, at which point the low rotor rpm horn activated. At 1924, the helicopter landed on its left skid gear with almost no forward speed…and came to rest leaning to the left on soft, boggy terrain. Both pilot seats were equipped with a shoulder harness, but the occurrence pilot felt that it restricted his ability to use the vertical reference bubble window. Therefore, the pilot did not utilize the shoulder harness during long line or slinging operations. The TSB Safety Investigation Investigators identified the tail rotor was not rotating at the time of impact, indicating a loss of tail rotor drive. The Bell Model 214ST Rotorcraft Flight Manual states: A failure of this type, in powered flight, will result in the nose of the helicopter swinging to the right (left side slip) and usually a roll of the fuselage. Nose down tucking will also be present. The severity of the ships [sic] initial reaction will be affected by airspeed, cabin-loading, center of gravity, power being used, and density altitude. TSB comment that: On the occurrence flight, at approximately 1600 feet above ground level, the pilot completed [the Flight Manual] actions when he recognized the loss...
read moreEC155 / Light Aircraft Mid Air Collision: All Survive
EC155 / Light Aircraft Mid Air Collision: All Survive (Airbus EC155B1 F-HEGT of Héli Sécurité and Nord 1203 III F-AYVV) On 8 February 2024 Airbus EC155B1 F-HEGT of Héli Sécurité and vintage single engine piston Nord 1203 III F-AYVV collided in mid air over Montmélian, Savoie. Both aircraft were damaged, but remained controllable. Their pilots managed to land, in a field for the helicopter and at Albertville aerodrome for the aeroplane. Le Bureau d’enquêtes et d’analyses pour la sécurité de l’aviation civile (BEA) issued their safety investigation report in December 2024. The Accident Flights The dark blue helicopter, flown by a single pilot (3000 hours total time) accompanied by a ‘safety pilot’ (400 hours), was transporting six passengers from Chambéry airport to the Courchevel mountain airfield. The aeroplane (white with red wing tips and propeller hub) was making a local post-maintenance check flight with a pilot (23,000 hours total time) accompanied by a mechanic to record engine parameters. The 1957 built aircraft was not equipped with, nor was it required to have, a transponder. Both aircraft were operating under Visual Flight Rules (VFR) in Class G uncontrolled airspace and were on converging flight paths in the Albertville valley at the, same altitude with a closing speed of c 280 kt. The helicopter crew described good visibility but heavy cloud cover. Despite both pilots monitoring the same radio frequency, neither was aware of the other’s presence until moments before the collision. The BEA recount: At 11:45:53, the two pilots on board the helicopter perceived F-AYVV coming towards them, at the same altitude. The pilot flying sharply turned right while pitching down while the aeroplane continued in a straight line. The aeroplane pilot who saw the helicopter at the last moment, did not have the time to carry out an evasive action. At 11:45:55, the tips of the helicopter’s [12.6 m diameter] main rotor blades came into contact with the aeroplane’s left fairing and made a cut in the root of the left wing, between the leading edge and the main spar (see Figure 1, point ❶). The helicopter pilot started an emergency descent, reducing the speed to 80 kt. While searching for an obstacle-free area for landing, he transmitted a distress message by radio and activated the emergency locator transmitter. He landed in a field less than three minutes later (point ❷). The helicopter’s landing gear sank into soft ground by c 10 cm. The damage was limited to the tips of two of the five main rotor blades, a notch on the trailing edge of one blade and blade rubbing marks the fenestron fairing that probably occurred during the landing. After checking the controllability, the Nord [pilot initiated a descent, returning to Albertville aerodrome, landing five minutes later. Cuts were found cut on the left-hand side of the engine cowling and the left-hand wing leading edge down to the spar. The left-hand wing fuel tank was torn and the he left-hand aileron control rod was severed. BEA Analysis The collision took place in Class G uncontrolled airspace, not covered by a Flight Information Service (FIS), in a mountainous area. In this class of airspace, neither a transponder or radio calls are mandatory. Maintaining separation is based on the ‘see and avoid‘ principle. See and avoid relies on flight crew monitoring...
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