Training Weaknesses Feature in Fatal MD600N Accident
raining Weaknesses Feature in Fatal MD600N Accident (ZK-ILD) On 14 June 2018 MD Helicopters MD600N ZK-ILD of Helicopters Hawkes Bay made a forced landing while conducting an aerial visual survey of farmland at Ngamatea Station, near Taihape, with 5 persons onboard. The helicopter was destroyed and one occupant died. The Accident Flight The New Zealand Transport Accident Investigation Commission (TAIC) say in their safety investigation report, issued on 20 June 2021 that: The pilot was type rated for the MD600N, with 45 hours on type and 9,659 hours total helicopter time. The pilot was also the chief executive of the operator and the senior person responsible for flight and ground operations. Approximately 24 minutes after departure and while descending at about 300 feet above ground level, the pilot informed the occupants by intercom of a problem with the helicopter. The pilot continued to fly on a relatively straight flight path for about another 1,300 metres, before turning the helicopter to the left and descending to land. The pilot did not inform the occupants that they were about to land The helicopter struck the ground hard and remained upright, while the engine continued to produce high power. The helicopter became airborne again and rotated about 90 degrees to the right before it hit the ground again. This, combined with an imbalance in the rotor system from the ground impact damage, resulted in a severe shaking of the airframe, which destroyed the helicopter. The pilot and occupant seated in the front of the helicopter received severe head injuries and were unconscious when it came to rest. The pilot had no recollection of the accident flight, and the occupant in the front of the helicopter died in hospital the following day. The other company pilot seated in the rear-right seat of the helicopter also received severe head injuries, but later was able to recall the accident flight. The two occupants seated in the centre seats reported remaining conscious throughout the accident sequence and received minor injuries. After the accident sequence they vacated the helicopter, observed a fire in the engine compartment and subsequently removed the other occupants from the helicopter. They then extinguished the fire with a hand-held fire extinguisher. The occupant seated in the front-left seat was fatally injured. Two occupants received serious injuries and two received minor injuries. The TAIC Safety Investigation and Findings TAIC report that: During the survey flight, the helicopter’s electronic engine control unit detected and recorded a number of faults, resulting in the ‘full authority digital engine control’ [FADEC] system changing to ‘fuel flow fixed’ mode. The fuel flow fixed mode resulted in the rotor speed varying beyond normal operating parameters. The pilot was not able to control the varying rotor speed and a forced landing ensued. [The] automatic governing of the engine power failed due to an undetermined intermittent fault. The intermittent fault had occurred on previous occasions. It was likely that it had not been rectified due to its intermittent nature and the difficulty in performing fault diagnosis using the flashing light method. That method was used as the licenced engineer “did not have access to a computerised maintenance tool”. Consequently, they were required to observe a sequence of flashing caution lights and compare them to a list of faults in the maintenance manual. During the occurrence… The FADEC system was not switched to manual mode, which would have allowed the pilot...
read moreAlpine MAC ANSV Report: Ascending AS350B3 and Descending Jodel D.140E Collided Over Glacier
Alpine MAC ANSV Report: Ascending AS350B3 I-EDIC and Descending Jodel D.140E F-PMGV Collided Over Rutor Glacier On 25 January 2019 Airbus Helicopters AS350B3 I-EDIC, operated by GM Helicopters, and Jodel D.140E F-PMGV of the Megève Aeroclub, collided in mid-air over the Rutor glacier, La Thuile, Italy. The mid-air collision (MAC), caught dramatically on video, occurred in Class G (i.e. uncontrolled) airspace while both aircraft operated under Visual Flight Rules (VFR). Five of the six occupants of the helicopter and two of the three occupants of the light aircraft were killed. One occupant from each aircraft miraculously survived, albeit seriously injured. The Air Accident Flight Italy’s Agenzia Nazionale per la Sicurezza del Volo (ANSV) explain in their safety investigation report, issued on the 11 June 2021, that the Jodel D.140E had taken off from Megève Altiport in France at 13:00 Local Time on a training flight, which was to include glacier landings. The flight instructor on board had over 16,000 hours of flying experience. The helicopter had picked up a party of skiers and their guide at 13:24 LT at Lago dei Seracchi-Cascate in Italy. The helicopter pilot had 7,120 hours of experience. At 13:25:36 hrs the two aircraft collided at an altitude of c 9,100 ft AMSL about 900 m within Italy. The wreckage was distributed over 250 m along a North-South axis. The helicopter was equipped with a Kannad 406 ELT. This did not activate. ANSV Safety Investigation Among the items recovered at the accident site were two GoPro cameras. One was installed on the right front windscreen of the helicopter and the other on the helmet of the mountain guide, seated on the left front seat of the helicopter.. The following are screenshots from the pilot camera video. They start at the take-off at Lago dei Seracchi and conclude at the impact. Below are images from the mountain guide video at the time of impact: Neither camera showed an indication of another aircraft until the impact. ANSV explain that: An analysis of the environmental audio recorded by the pilot camera has been carried out. The audio recorded by the mountain guide camera was not usable. From this analysis it has been possible to deduce, with difficulty, due to the excessive signal strength associated with engine and main rotor noise compared to human voices, that during the 65 seconds between take off and collision, the pilot and the mountain guide have discussed some aspects of the landing site (Vedette del Rutor) and ground tracks; the same analysis has not revealed any radio calls made by the pilot or answered by him during that time. Based on the videos, the distribution of the wreckage and the observed damage, the ANSV reconstructed the following impact dynamics: While the helicopter was climbing from Lago dei Seracchi-Cascate (Superiore)…at an altitude of 2777 m AMSL, with a ground direction of 191°, and a GS of about 47 km/h, the collision took place in flight with the aeroplane, positioned a few feet higher than the helicopter and with a flight direction substantially similar to the latter. The ANSV believe the Jodel aeroplane had most likely arrived in the area at 13:15 LT and after doing landing site recces was probably on final approach for its first glacier landing. Based on GPS data…the helicopter’s climb rate in the last 30 seconds of flight was about 1200ft/min. The initial impact was between the forward blade of the helicopter...
read moreNTSB Report on Miami Air International Jacksonville B737-800 Runway Excursion
NTSB Report on Miami Air International Jacksonville Boeing 737-800 N732MA Runway Excursion On 3 May 2019 Boeing 737-81Q (WL) N732MA of Miami Air International suffered a nighttime runway excursion on landing in a thunderstorm at Jacksonville Naval Air Station, Florida. The aircraft, which was conducting a charter flight for the US DoD, came to rest in the St. Johns River. Only 1 minor injury occurred to the 143 occupants. The Accident Flight The US National Transportation Safety Board (NTSB) explain in their safety investigation report, published on 4 August 2021, that the takeoff from Guantánamo NAS, Cuba, climb and cruise had been uneventful. The No. 1 (left) thrust reverser was inoperative and was deferred in accordance with the Minimum Equipment List (MEL) as a Category C item. The aircraft commander (aged 55, with 7500 hours total flying time, 2204 on type) was the pilot flying. The co-pilot (aged 47, also with 7500 hours total flying time, but mostly in light aircraft, and only 18 hours on type) was the pilot monitoring. The aircraft commander was also performing check airman duties as the co-pilot was in the process of completing operating experience training. During the approach to Jacksonville NAS, the flight crew had two runway change discussions with air traffic controllers due to reported weather conditions (moderate to heavy precipitation) near the field; the pilots ultimately executed the area navigation GPS approach to runway 10, which was ungrooved and had a displaced threshold 997 ft from the threshold, leaving an available landing distance of 8,006 ft. As the airplane descended through 1,390 ft mean sea level (msl), the pilots configured it for landing with the flaps set at 30º and the landing gear extended; however, the speedbrake handle was not placed in the armed position as specified in the Landing checklist. At an altitude of about 1,100 ft msl and 2.8 nm from the runway, the airplane was slightly above the glidepath, and its airspeed was on target. Over the next minute, the indicated airspeed increased to 170 knots (17 knots above the target approach speed), and groundspeed reached 180 knots, including an estimated 7-knot tailwind. At an altitude of about 680 ft msl and 1.6 nm from the threshold, the airplane deviated further above the 3° glidepath such that the precision approach path indicator (PAPI) lights would have appeared to the flight crew as four white lights and would retain that appearance throughout the rest of the approach. Eight seconds before touchdown, multiple enhanced ground proximity warning system alerts announced “sink rate” as the airplane’s descent rate peaked at 1,580 fpm. The airplane crossed the displaced threshold 120 ft above the runway (the PAPI glidepath crosses the displaced threshold about 54 ft above the runway) and 17 knots above the target approach speed, with a groundspeed of 180 knots and a rate of descent about 1,450 ft per minute (fpm). The airplane touched down about 1,580 ft beyond the displaced threshold, which was 80 ft beyond the designated touchdown zone as specified in the operator’s standard operating procedures (SOP). Between 2138 and 2139, about 4 minutes before [touchdown] the 1-minute recorded rainfall rate was as high as 2.4 inches per hour. At 2141, about 1 minute before the accident, the 1-minute rainfall rate was 1.2 inches per hour; it decreased to 0.6 inch per hour at 2142 then increased to 1.8 inch per hour at 2143. The rainfall rate…and the macrotexture depth and cross-slope of runway 10 could have produced water depths on portions of the runway close to...
read morePrompt Emergency Landing Saves Powerline Survey Crew After MGB Pinion Failure
Prompt Emergency Landing Saves Powerline Survey Crew After MGB Pinion Failure (First European Aviation Hughes 369D SE-JVJ) On 1 August 2019 Swedish registered Hughes (now MD Helicopters) 369D, SE-JVJ, operated by Polish company First European Aviation, was mapping Norwegian electricity distribution lines for Eidsiva Nett using both laser scanning and aerial photography when it was involved in an accident. The helicopter was substantially damaged, but the crew of two escaped unharmed. The Accident Flight The Norwegian Safety Investigation Authority (NSIA) explain in their safety investigation report published on 23 June 2021 that: Approximately 52 minutes into the flight the commander [907:30 hours total flight time, 244:30 on type] became aware of abnormal vibrations in the helicopter. The vibrations increased in intensity and approximately 20 – 30 seconds later, the commander heard a metallic sound, which, like the vibrations, was becoming louder. None of the instruments displayed fault indications. At the time, the crew did not perceive the situation as threatening, but the commander nevertheless decided to land the helicopter in order to check it. He circled two farms while taking his bearings. He chose a grassy field northwest of Nordre Fogne farm as the landing site and initiated a slow approach… During the last phase of the approach, for approx. 3 meter altitude, the crew heard a bang and the helicopter lost all power. The commander lost control of the helicopter which landed hard. The right skid collapsed, the horizontal stabiliser, and all five main rotor blades were in contact with the ground and were substantially damaged. The NSIA Safety Investigation On examination the main gearbox input pinion was found to have suffered a fatigue crack. MD Helicopters stated that they were not aware of any previous such cases. When the commander noticed the vibrations, the crack had most likely progressed close to causing…fracture. The…pinion…rotated at approximately 6,000 rpm, giving a vibration frequency of 100 Hz. This is significantly higher than the vibration frequency from the main rotor and the tail rotor. Consequently, there was no reason to suspect that the vibration came from the rotors. The NSIA would like to commend the commander for taking the vibrations sufficiently seriously to abort the flight although they were hardly noticeable. The accident illustrates the importance of taking all changes in the vibration pattern or the sound picture in a helicopter very seriously. The fact that the pinion broke at a low altitude, was decisive for the crew escaping the accident without injuries. It has not been possible to establish unambiguously why the fracture occurred. A lab report stated: The crack initiations seem to be associated with surface irregularities originating from machining and surface oxidation. Due to the fact that the fatigue initiations seem to have mainly been initiated on two opposite sides, bending loadings may have contributed to the initiations and subsequent fatigue crack growth. However, NSIA expressed concerns on continued airworthiness management and maintenance standards. Namely: At the time of the accident, the main gearbox had a total operating time of 3,749.5 hours. This is 749.5 hours more than the permitted overhaul interval of 3,000 hours. The main gearbox did not meet the requirements for extension of the maintenance interval to 4,000 hours [i.e the use of Mobil AGL gear oil]. This was because: The operator’s continuing airworthiness management system contained erroneous information relating to the main gearbox operating time. According to the information, the main gearbox had an operating time of 2,749 hours, with a remaining flight time of 261 hours at the...
read moreLow Recce of HEMS Landing Site Skipped – Rotor Blade Strikes Cable Cutter at Small, Sloped Site
Low Recce of HEMS Landing Site Skipped – Rotor Blade Strikes Cable Cutter at Small, Sloped Site (Eliance H145 EC-MJK) On 16 November 2020 HEMS (helicopter emergency medical service) Airbus Helicopters H145 (BK117D2) EC-MJK, operated by Eliance, suffered a landing accident near Piera, Barcelona. While the helicopter was damaged, the four occupants were unharmed. The Accident Flight The Spanish Comisión de Investigación de Accidentes e Incidentes de Aviación Civil (CIAIAC) explain in their safety investigation report (issued in July 2021) that the aircraft had departed Taulí hospital, Sabadell at 10:24 Local Time on a HEMS tasking to attend to a casualty who had fallen 3 m. On board were the Pilot, a Technical Crew Member and two medical personnel. The pilot had 2190 hours of flying experience in total (70-80 on type but 1300-1400 on the EC135). The original intent was to land on football pitch 300 m from the casualty, however: During the flight, the medical team requested the pilot to land as close as possible… [On arrival on scene at] 10:36:37 h, the HEMS TCM identified the house of the person to be assisted. Winds in the area were light, with speeds of between 5 and 8 knots from a 240º direction. Visibility was good. The pilot replied that…he would have to go around to turn into the wind. He also mentioned that there were rubbish containers and a cable in the vicinity of the patient’s home. Another option for the landing was a nearby field, but the pilot ruled it out as it was fenced off. The pilot decided to land in the area close to the patient’s home, just behind an ambulance. This was on a 17 m wide street. As the D value of the H145 is 13.64 m, and the operator required landing sites to be 2D or greater, the chosen site was too small. It was also excessively sloped. The Flight Manual slope limits are Ground sloping nose down (if tail clearance allows) max 10º Ground sloping up to the right max 12º Ground sloping up to the left max 8º Ground sloping nose up max 8º During the landing, the HEMS technical crew member, the doctor and the nurse helped the pilot to monitor the cables, poles and the position of the rubbish containers. At 10:39:16 h, the HEMS TCM warned the pilot: “Watch out, MastMoment!” and at the same time, the “MAST MOMENT” warning sounded. The HEMS TCM, “Pull up a moment, pull up a moment”. At 10:39:18 h, the “MAST MOMENT” warning sounded again, and the pilot can be heard saying: “No, now”. At 10:39:19 h, the sound of a rotor blade striking the aircraft cable cutter can be heard. And at 10:39:20 h, the “MAST MOMENT” warning sounded for the third time. At 10:39:57 h, once the helicopter was fully down and the occupants confirmed they were unharmed, they decided to disembark to assess what had happened. CIAAIC explain that: The slope in the chosen area exceeded the established limits, causing one of the main rotor blades to hit the upper cable cutter when the pilot lowered the collective to settle the aircraft after touch down. The damage extended to the cable cutter system, one main rotor blade, the front left cockpit window and one skid strut. The CIAIAC Safety Investigation The investigators comment that:. In a rigid rotor helicopter, high bending forces can be transmitted to the main rotor...
read moreAD 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...
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