AD after Two Fatal Bell 430 Accidents: Main Rotor – Pitch Link Clevis Fractures Angola and South Africa
Airworthiness Directive after Two Fatal Bell 430 Accidents: Main Rotor – Pitch Link Clevis Fractures Angola and South Africa Transport Canada has issued Airworthiness Directive (AD) CF-2021-26 to inspect the main rotor pitch link clevises and rod ends of the Bell 430. This followed two accidents that cost the lives of 11 people. The AD is considered an interim action and a further AD could follow. They explain: In January 2021, a model 430 helicopter experienced an in-flight failure of a main rotor pitch link clevis resulting in loss of control of the helicopter and fatal injury to the five occupants on-board. That accident occurred on 21 January 2021 to B430 ZT-RRT, operated by National Airways Corporation (NAC) as an air ambulance for Netcare 911, while en-route from Johannesburg to Pietermaritzburg in South Africa. The Accident and Incident Investigations Division of the South African CAA has already published a preliminary report. That describes how approximately 1.5 hours into the flight and while cruising at 725 feet AGL, eyewitnesses report that “the helicopter suddenly started to spin around whilst losing height rapidly” and “saw what looked like helicopter parts breaking off before it crashed and burst into flames”. The wreckage was scattered over a 500 m radius. All 5 persons on board died. The Transport Canada AD states that in that accident: The main rotor pitch link clevis part number (P/N) 430-010-432-101 fractured at the exposed thread area above the nut and the fracture was consistent with fatigue damage. Inspection of the failed part from the 2021 accident determined that the universal bearing P/N 212-010- 412-001 of the main rotor pitch link assembly was found with excessive wear and had increased resistance to rotation. Restriction in freedom of movement of the universal bearing can cause increased loads on the main rotor pitch link assembly and subsequent fatigue failure of the clevis prior to its life limit. The accident investigation is still ongoing. They go on to reveal that: A similar accident previously occurred in September 2016 on a model 430 helicopter where the main rotor pitch link clevis was found to have fractured at the neck area via fatigue damage that originated at a corrosion pit. That accident occurred on 26 September 2016 to B430 D2-EYI of Heli Malongo. This offshore helicopter was returning from an oil and gas installation when it crashed into the sea. Transport Canada explain that: This condition, if not corrected, could lead to crack initiation at the main rotor pitch link clevis neck or threaded area and consequent failure of the main rotor pitch link, resulting in loss of control of the helicopter. To address this unsafe condition, this AD requires an initial special detailed inspection (SDI) of the main rotor pitch link clevises and detailed visual inspection (DVI) of the universal bearings, and rectification, as required. This AD also mandates a repetitive DVI of the main rotor pitch link clevises and universal bearings, and rectification, as required. Bell issued Alert Service Bulletin (ASB) 430-21-60 to provide instructions for inspection and replacement of the affected parts. The Bell ASB states no reason for the inspection. UPDATE 1 Match 2022: SA CAA Final Report Issued for ZS-RRT The SA CAA final report states the probable cause was: The clevis on the pitch control lever of the Orange blade failed in-flight, resulting in the instability of the main rotor disc which,...
read moreLoss of Bell 412 off Brazil Remains Unexplained
Loss of Bell 412 off Brazil Remains Unexplained (Lider B412 PT-HUW near Petrobras P-07, Campos Basin) On 27 March 2013, Bell 412SP PT-HUW of Líder Táxi Aéreo suffered an accident on approach to the Petrobras P-07 semi-submersible production installation in the Bicudo field in the Campos Basin off Macaé. The Accident Flight The Brazilian accident investigation agency CENIPA issued their safety investigation report on 29 March 2021, an unimpressive 8 years and 2 days after the accident. They explain that the helicopter had departed on a c20 minutes inter-field flight from the FPSO Rio De Janerio to the P-07 with two crew and one passenger. The Aircraft Commander, a former military pilot, had approximately 6000 hours of flight time, 1000 on type. The Co-Pilot had 1800 hours, 200 on type. At the time…it was raining, with continuous wind of 360° and 25kt, and clouds at 2,500ft…. On approaching the platform, close to the landing area, the weather conditions deteriorated, impairing visibility. At the time of the final approach for landing on the P-07 platform, the pilots reported hearing a noise followed by a strong vibration in the aircraft. The images from the platform camera recorded a flare, with a large pitch up angle, performed by the helicopter however, on an interview; the pilot did not manifest having performed such a maneuver. The maximum intentional pitch up is limited to 30º in the Bell Rotorcraft Flight Manual. While not clarified in the report, we believe the Aircraft Commander was the Pilot Flying. CENIPA do not report any interview feedback from the Co-Pilot (who would therefore have been Pilot Monitoring), nor is there any further analysis of the video recorded. Afterwards, the crew made a right turn, aborting the landing and starting a descent for emergency landing [ditching] in the water. The impact occurred with low rate of descent and low speed of horizontal displacement. This suggests a controlled ditching was achieved rather than a more severe water impact. CENIPA note the sea was “rough”, though no numeric scale was given. On contact with the sea the helicopter immediately rolled over and the main rotor blades struck the water. The emergency flotation system reportedly activated automatically, and the aircraft remained floating inverted. The three occupants evacuated the aircraft via the emergency exits, presumably underwater, without assistance. They were recovered uninjured by Fast Rescue Craft (FRC) from the P-7. They had previously undertaken Helicopter Underwater Escape Training (HUET), but no other detail is recorded on their egress. It’s not clear if they were equipped with an emergency breathing system, but we suspect this was unlikely in Brazil in 2013. There is no mention on how their life jackets performed or what life rafts were fitted. Subsequently, during an attempt to salvage the aircraft via strop attached to the Main Rotor Head, the Main Gear Box separated from the fuselage, which sank in water depth of 111 m. Its not clear why, but some past salvage attempts have failed if the lift is not paused to allow water to drain from the cabin. CENIPA Safety Investigation The investigators comment that: [T]here was no way to determine whether the attitude shown in the video recording was intentionally performed by the pilot or if it was the result of some other factor. It was not possible to rule out the hypothesis that the meteorological conditions at the time of the aircraft’s approach...
read moreSécurité Civile EC145 Mountain Rescue Main Rotor Blade Strike Leads to Tail Strike
Sécurité Civile EC145 F-ZBQF / Dragon 64 Mountain Rescue Main Rotor Blade Strike Leads to Tail Strike near Pau On 6 June 2020, Airbus Helicopters EC145 (BK117C2) F-ZBQF, callsign Dragon 64 of the Sécurité Civile based at Pau, was damaged after a rotor strike during a mountain rescue near Laruns, Pyrénées-Atlantiques. History of the Flight Investigators of the BEA-Etat (BEA-E) explain in their safety investigation report, issued in French on 17 July 2021, that the helicopter had been tasked to provide assistance to an injured hiker in the area of the Col de la Taillandère at an altitude of 1,880 meters (6,167 feet). At 12:21 the crew spotted the injured climber. Having done a site recce the helicopter landed about 100 m below the casualty. The helicopter was shut down and the three-person mountain rescue team climbed up to the casualty. On board the helicopter were a crew of two; the pilot, who had 10,753 flight hours in total, 3,235 on type and a mechanic / hoist operator, who had 4,912 flight hours in total, 2,655 on type. Both had severed at that Sécurité Civile base since 2003. The pilot was on their first shift after a rest period. The hoist operator was on their second day after a rest period, but noticeably had only had 4 hours sleep the previous night. At 12:43 the mountain rescue team radioed they were ready, and the helicopter took-off at 12:46. The crew were conscious that approaching clouds might stymie the rescue, so they decided to do a skid support rescue, rather than the original intent of hoisting the four people aboard. This meant the casualty and rescuers would board while one skid was in contact with the ground to minimise time (shown in this VIDEO). However, while conducting this manoeuvre, the main rotor struck the scree on the slope above the ground party at 12:48:18. This blade strike resulted in strong vibrations and the helicopter became more difficult to control. The pilot aborted the pickup and rapidly headed back to the site the helicopter had previously waited at. At the end of the descent, the pilot increased pitch attitude to reduce sink rate and speed. The tail boom, tail rotor and the vertical fins on the horizontal stabiliser all struck the ground at 12:48:28. The pilot pulled on the collective to dampen the contact, causing a yaw to the right. The helicopter touched do after a rotation of approximately 270º. The skids were partially ‘spread’. The helicopter was still vibrating severely, disrupting activation of the emergency engine cut-off. The helicopter was finally shutdown at 12:50:27. Neither crew member was injured. Less than 10 minutes after the event, the Col de la Taillandère was fully in clouds The BEA-E Safety Investigation and Analysis The BEA-E comment that: The rapid change in cloud conditions, characteristic of the mountain, gradually covering the intervention area, was a contributing factor to the event that influenced the organization of the recovery The flight crew had encountered similar weather in the past, and the investigators suggest this may have created self-induced urgency as the weather started to deteriorate. The investigators comment there was little communication between the flight crew and the rescue party. It was only at 12:40 the pilot expressed concern about the deteriorating weather to the rescue party. Prior to that the ground party had not felt unduly hurried because the aircraft was shut down. Meanwhile, the flight crew were unaware that the casualty’s injuries were not considered life-threatening. Although conducted frequently,...
read moreGOM Helicopter Ops 2000-2019: Single Engine Usage Plummets But Fatal Accident Rate Resistant
GOM Helicopter Ops 2000-2019: Single Engine Usage Plummets But Fatal Accident Rate Resistant The Helicopter Safety Advisory Conference (HSAC) has been publishing data on the Gulf of Mexico (‘GOM’) offshore helicopter fleet and its safety since 1995. We have previously looked at their 2019 data, dated 28 May 2020 and released in mid-December 2020. What is noticeable over the 20 years from 2000 to 2019 is the 63% decline in all GOM helicopter usage. But in particular there has been a big fall in single engine helicopter usage between 2000 and 2019: Single engine usage dropped 70 % (vs 43% for twins) There has been a fall in single engine helicopter usage in 17 of the 20 years between 2000 and 2019 (vs 10 of 20 for twins) The single engine helicopter fleet size has dropped 63% too (compared to just 32% for twins). So what has happened to the accident rate over 20 years? One might have expected that the increasing proportion of twin engine helicopters, more multi pilot operations, the availability of ADS-B coverage, the fewer older, less well-equipped and poorer performing helicopters (like the B206, S-76A etc) and other improvements would have a big effect. Well indeed the 5-year rolling average has decreased from 1.56 per 100k flying hours in 2000 to 0.94 per 100k flying hours in 2019, a 40% improvement. However, the fatal accident rate only decreased from 0.46 per 100k flying hours in 2000 to 0.42 per 100k flying hours in 2019, a mere 9% improvement. Not surprisingly, in 2020 due to the pandemic, there was a reduction in flying across all categories of helicopter, but it was a good year from a safety perspective. UPDATE 30 October 2021: RLC B407 Reverses into Sister Ship at GOM Heliport Aerossurance has extensive air safety, operations, SAR, 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 moreForced Landing after CAMO Underestimated Operation in Dusty Environments
Forced Landing after CAMO Underestimated Operation in Dusty Environments (Arriel 1 Engine Failure, Monaco Heli-Loc Airbus AS350B2 3A-MLC) On 26 September 2019 Airbus Helicopters AS350B2 3A-MLC, owned by Monaco Heli-Loc, suffered an engine failure and was damaged during an emergency landing in the French Alps. History of the Accident Flight The French Bureau d’Enquêtes et d’Analyses pour la Sécurité de l’Aviation Civile (the BEA) explain in their safety investigation report (issued in French on 24 June 2021) that the helicopter was in cruise with the pilot and three passengers onboard. The pilot, a PPL(H) holder with 600 hours total time, noticed the engine chip warning light illuminate and decided to divert to Megève altiport. Shortly after starting the descent, the pilot heard ‘a suspicious noise’, after which he retarded the engine to idle and started an autorotation. A witness saw the helicopter descending, heard a ‘detonation’ and saw smoke coming from the engine. During the final approach to Col de Véry (2,000 m), the pilot attempted to increase power. However, during the flare, the main rotor struck the tailboom and the tail rotor drive shaft was severed. The helicopter came to a rest upright on its skids having touched down at low vertical speed. Safety Investigation The helicopter was equipped with a Helisafe monitoring system. The data was downloaded and analysed by the BEA. The investigators concluded the engine chip light came joint before Point 1 9marked in red above), when the helicopter turned towards the Megève. Until Point 2, four minutes later, the engine parameters are normal. However, between Points 2 and 3 fluctuations in the recorded engine parameters indicate rapid engine deterioration. From Point 3 free turbine speed (N2) and gas generator speed (N1) rapidly diminish and engine torque drops to zero. The main rotor speed (NR) is also no longer synchronised with N2, indicating entry to autorotation. The investigators determined that the drop in NR in the 9 seconds preceding contact with the ground likely corresponds to the flare performed by the pilot. The BEA say that examination of the Safran (formerly Turbomeca) Arriel 1D1 engine revealed: The presence of metal particles on all magnetic plugs. A significant level of erosion (about 3 mm) of the leading edge of the blades of the axial compressor wheel (module 2). A significant level of erosion, greater than the tolerance values recommended by the manufacturer, of the leading edge of the blades of the centrifugal diffuser (module 3). Damage to the rear bearing of the gas generator showing significant wear of the rollers due to friction with the internal track and an adherent material due to the latter seizing up. A significant presence of laterite on all the components of module 3, and in particular the sampling of 13.5 g of laterite inside the hollow shaft. Various damages to all the rotating parts of the engine resulting from the failure of the rear bearing of the gas generator. Laterite is both a soil and a rock type that is rich in iron and aluminium. It commonly occurs in hot and wet tropical areas. The BEA determined that: Damage to the rear bearing of the gas generator is characteristic of degradation under the phenomenon of unbalance. The origin of the unbalance very probably comes from the partial detachment of the laterite present in the hollow shaft. The unbalance caused damage to the rotating parts of the engine, including the bearings, with the generation of metalic debris which found its way into...
read moreFirefighting CH-54 Flying Control FOD Find
Firefighting CH-54 Flying Control FOD Find It has been reported that on 17 June 2021 a firefighting Sikorsky CH-54B, operated by an unspecified civil contractor, had just been started up to depart for a second water-drop flight of the day in Montana for the US Forest Service (USFS). Upon performing system checks the PIC noticed resistance in the flight controls when pushing the cyclic forward. When standard checks were made and the issue wasn’t resolved, the aircraft shut down for further inspection. Upon examination by maintenance personnel: Initially the problem presented itself as hydraulic which led the mechanics to what seemed to be a suspect primary servo. The servo was replaced, but the problem persisted. Further trouble shooting was done by disconnecting flight control rods from the primary servos forward and moving the cyclic in an attempt to isolate the problem to a specific section of the aircraft. This proved to be beneficial in that the crew was able to locate the source of the cyclic obstruction. What was found was… A loose, non-flight control, standard AN4 bolt was located behind a link in the cyclic mixer. The bolt was removed, and a safety stand down inspection of the flight control system was performed with no other defects or obstructions noted. Ground control checks were performed as well as an operational check flight. All results were found satisfactory. It was reported that the aircraft was “just out of re-build and this was their first time out for the season since the re-build” and that the bolt most likely had “been dropped during the re-build and found its way into the flight controls mixer area”. The operator promptly initiated an investigation and introduced additional mitigations. Also noted by the USFS “is the importance of doing a flight control check upon every start up”. 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: Rotor Blade Tool Control FOD Incident USAF Tool Trouble: “Near Catastrophic” $25mn E-8C FOD Fuel Tank Rupture Lost Tool FODs Propeller Blade, Penetrating Turboprop’s Fuselage Micro FOD: Cessna 208B Grand Caravan Engine Failure & Forced Landing FOD Damages 737 Flying Controls Crew Bag FOD Shatters Hawk Canopy C-130J Control Restriction Accident, Jalalabad Flying Control FOD: Screwdriver Found in C208 Controls B1900D Emergency Landing: Maintenance Standards & Practices Professor James Reason’s 12 Principles of Error Management Back to the Future: Error Management Maintenance Human Factors: The Next Generation Airworthiness Matters: Next Generation Maintenance Human Factors Aerossurance‘s Andy Evans will be running two training sessions at European Rotors in November 2021. One will be on safety leadership and the other on how to procure and assure aviation services. He discussed these in a recent European Rotors Digital Series interview: Aerossurance has extensive air safety, operations, SAR, 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 moreEC130 Door Loss Damaged Main Rotor Blades
EC130 Door Loss Damaged Main Rotor Blades (Blue Hawaiian N11QP) On 19 August 2018, Airbus Helicopters EC130B4 N11QP, operated by Blue Hawaiian Helicopters (an Air Methods subsidiary), was damaged when a cabin sliding door fell from the aircraft during a rotor track and balance (RTB) flight. There were two occupants aboard the helicopter. The passenger received minor injuries. The Accident Flight The US National Transportation Safety Board (NTSB) explain in their safety investigation report (published 24 June 2021) that this was the second RTB flight of the day from Hilo International Airport (ITO), Hawaii. The first was abandoned due to issues with the RTB equipment. Before the second flight… …the pilot conducted a walk-around inspection of the helicopter, during which he visually checked to ensure all the doors, cowlings, and equipment were closed and secured. The pilot, who had 10,014 hours of flying experience, 2122 hours on type, was sat in the left front seat. The passenger, a maintenance apprentice was sat in the right front seat. After gathering the RTB data the helicopter was en route back to ITO when the pilot lowered the collective to decelerate and began a slow descent. He then heard the left-rear sliding door suddenly slide open. The pilot looked back and saw the door off the helicopter in midair. He stated that he turned his head forward, then heard a loud noise and felt a jolt. The helicopter began to vibrate but remained controllable. The pilot initiated a precautionary landing onto a grass field. The field was part of the historic Shipman Estate (originally leased in 1856 by King Kamehameha IV to William Reed for cattle pasture). He indicated that the door appeared to have struck two main rotor blades and that he thought the door fell into the ocean. The apprentice concurred that “the door suddenly opened and separated from the helicopter”. He stated that on the takeoff for the previous flight, a maintenance technician had ensured the doors were closed correctly, but on the takeoff for the accident flight, the maintenance technician did not. RTB cabling had been re-routed between the two flights to cure the RTB system problem. The NTSB Safety Investigation The NTSB comment that the EC130 has “a sliding rear door on the left side” and there is a ‘plastic’ doorstop or ‘latch’ located on the baggage bay door. A review of the helicopter’s maintenance records [by the FAA] revealed no previous door-related issues. Examination of the helicopter revealed that… …two of the three main rotor blades exhibited dents and scratches across their undersides, generally initiating at or near the leading edge and propagating aft along the chord of the blade. Examination of the operator’s photographs and reports from the director of maintenance revealed that the helicopter’s left sliding door tracks and door latch assemblies were normal and unremarkable. The plastic latch on the fuselage was damaged, and a portion had separated from the fuselage. The sliding door was not recovered, thereby preventing examination of the door and its locking components. Continued Airworthiness Action On 10 December 2018, Airbus Helicopters issued Alert Service Bulletin (ASB) ASB EC130- 05A031 requiring an inspection of the sliding door locking system: The ASB indicated the check should be conducted with a spring scale and described an in-flight opening and loss of a sliding door as the reason for the bulletin. One month later, the EU Aviation Safety Agency (EASA) issued an Airworthiness Directive (AD 2019-0001) to make this inspection mandatory. That AD...
read moreRCAF Chinook Loss of Control (LOC) Investigation
RCAF Chinook Loss of Control (LOC) Investigation The Royal Canadian Air Force (RCAF) is investigating a Loss of Control (LOC) incident that occurred to Boeing CH147F Chinook CH147306 at Wainwright, Alberta on 11 May 2021. At the time the helicopter was conducting “a series of familiarization flights with various Military personnel onboard” at the close of the annual Exercise Maple Resolve. The investigators explain that: Each sortie involved landing sequences to unprepared surfaces out in the assigned training area. On the third sortie of the mission, with 12 passengers and 5 crew onboard, the Chinook attempted a landing to a selected spot in a grassy field. Very shortly after touch down, due to concerning perceptions of drift, the Flight Engineer (FE) called for the pilot to abort the landing with the command “Up, Up, Up.” The pilot flying (PF) aborted the landing and started to climb the aircraft into a hover. The aircraft entered into an unstable flight regime shortly after with strong lateral oscillations causing the PF to initiate an emergency landing. Upon touch down, the FE called for an emergency egress whilst the PF initiated an emergency shutdown of the aircraft. Two of the front rotor blades made contact with the fuselage and the rear landing gear collapsed. Three personnel received minor injuries. The investigation is reportedly focusing on “material and human factors”. UPDATE 8 April 2023: The investigators have released that: The investigation concluded that Human Factors contributed to the accident due to improper procedures. The investigation recommends a publication amendment to define the term “unprepared surface” and a review of the training syllabus for landing abort procedures. 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: RCAF Investigate Defect on Newly Delivered CH-148 Cyclone (S-92) High G Drama at Cold Lake Crew Bag FOD Shatters Hawk Canopy Perception and Fatigue: RCAF CH124 Sea King Engine Failure C-130 Fireball Due to Modification Error RCAF Production Pressures Compromised Culture NH90 Caribbean Loss of Control – Inflight, Water Impact and Survivability Issues Swedish NH90 CFIT: Pilot Experience and Skating on Frozen Lake Canadian Coast Guard Helicopter Accident: CFIT, Survivability and More Culture and CFIT in Côte d’Ivoire Investigation into F-22A Take Off Accident Highlights a Cultural Issue ‘Procedural Drift’: Lynx CFIT in Afghanistan USMC CH-53E Readiness Crisis and Mid Air Collision Catastrophe UPDATE 3 October 2021: French Cougar Crashed After Entering VRS When Coming into Hover UPDATE 9 April 2022: SAR Seat Slip Smash (RCAF CH149 Leonardo Cormorant LOC-I) Aerossurance has extensive air safety, flight operations, SAR, 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 morePilatus PC-12 Collided with Pick-Up Truck During Dusk Take Off
Pilatus PC-12 Collided with Pick-Up Truck During Dusk Take Off (N1220A) On 14 September 2020 privately owned Pilatus PC-12/47E N1220A struck the aircraft owner’s own pick-up truck vehicle during a duck take off from a private airstrip at River’s End Ranch. Lake Abert near Lake View, Oregon. The three occupants of the aircraft were unharmed. The pick-up truck was unoccupied. The US National Transportation Safety Board (NTSB) report that the incident occurred at 1930 Local Time (sunset was at 1910) during take off from the 3000 x 100 ft strip. The pilot told the NTSB in a telephone interview that he “just didn’t see the truck”. There were no pre-impact aircraft defects. As of 8 January 2021 the pilot had not submitted an accident report form to NTSB. UPDATE 15 July 2021: NTSB Releases Probable Cause The pilot’s failure to maintain clearance from an object during the takeoff ground roll due to inadequate monitoring of the environment. As with most probable cause statements, this is more a statement of what happened rather than why. Safety Resources You may also find these Aerossurance articles of interest: Ground Collision Under Pressure: Challenger vs ATV: 1-0 UK AAIB Report on Two Ground Collisions S-92A Collision with Obstacle while Taxying A320 Collided with Two De-Icing Trucks Runaway Dash 8 Q400 at Aberdeen after Miscommunication Over Chocks Production Defect IFSD Triggers Night Deadstick PC-12 Landing Confusion of Compelling, But Erroneous, PC-12 Synthetic Vision Display Pilatus PC-12 Pacific Ditching UPDATE 30 October 2021: RLC B407 Reverses into Sister Ship at GOM Heliport UPDATE 5 March 2022: Taxiing AW139 Blade Strike on Maintenance Stand UPDATE 2 April 2022: Investigation into Collision of Truck with Police Helicopter Aerossurance has extensive air safety, operations, SAR, 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 moreEngine Life Limit Exceedance Caused Logging Helicopter Fatal Accident
Engine Life Limit Exceedance Caused Logging Helicopter Fatal Accident (UH-1B N64RA) On 8 March 2019 the pilot of restricted category Richards Heavylift Helo Inc (Bell) UH-1B N64RA, registered to Iron Eagle Helicopters, died while conducting Part 133 Helicopter External Sling Load Operations (HESLO) at a logging site near Forks, Washington. After responding to a mayday call of “I’m going down, I’m going down I’m going d…” fellow workers found the helicopter inverted amongst trees 1/4 mile way. The Safety Investigation The US National Transportation Safety Board (NTSB) safety investigation report was published on the 5 May 2021. The pilot was the owner of Iron Eagle and had 6610 flying hours in total, 729 on type. He was reportedly averaging 30 lifts per flying hour while logging, using a grapple logging system that only requires one person on the ground (vs four for choker logging). The investigators report that: Examination of the engine revealed that the gas generator first stage [static] sealing disk had fractured and separated into three major pieces. Multiple internal components of the engine were subsequently damaged as a result, including all four turbine rotors and nozzles. Subsequently, the Honeywell T53-L13B turboshaft engine… …lost all power, necessitating a forced landing via autorotation. Due to the low altitude and densely tree covered terrain, it is unlikely that the pilot had reaction time to release the load which became entangled in the trees… The NTSB explain that: An examination of the first stage sealing disk revealed fracture features consistent with low cycle fatigue. The overhauled engine was installed into the accident helicopter about 8 months before the accident [2 July 2018]. The sealing disk was installed into the engine at the time of overhaul and had previously accrued 1,067.3 hours and 2,134.6 cycles. Documentation of engine cycles was not accomplished daily. Engine cycles were documented irregularly from July 2, 2018, to September 17, 2018, after which there was no documentation of engine cycles. [however], the helicopter was equipped with an AKV N1/N2 cycle counter. According to Honeywell SB T53-L-13B-0020 the hour/cycle life limit of the first stage sealing disk is 25,000 hours or 6,900 cycles. A review of maintenance records and the helicopter’s electronic cycle counter revealed that the sealing disk had exceeded the published life limit of 6,900 cycles. The last documented cycle value was 9,023.13. The cycle counter had recorded 12,023.19 cycles. NTSB Probable Cause A total loss of engine power due to the failure of the gas generator sealing disk as a result of the operator’s exceedance of the sealing disk life limits at too low an altitude for the pilot to accomplish a successful autorotation which resulted in the collision with terrain. 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: UH-1H HESLO Fuel Exhaustion Accident Windscreen Rain Refraction: Mountain Mine Site HESLO CFIT HESLO Dynamic Rollover in Alaska When Habits Kill – Canadian MD500 Accident Loss of Control During HESLO Construction Task: BEA Highlight Wellbeing / Personal Readiness Shocking Accident: Two Workers Electrocuted During HESLO Load Lost Due to Misrigged Under Slung Load Control Cable Keep Your Eyes on the Hook! Underslung External Load Safety EC120 Underslung Load Accident 26 September 2013 – Report Unexpected Load: AS350B3 USL / External Cargo Accident in Norway Unexpected Load: B407 USL / External Cargo Accident in PNG Load Lost Due to Misrigged Under Slung Load Control Cable Fallacy...
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