A HEMS Helicopter Had a Lucky Escape During a NVIS Approach to its Home Base
A HEMS Helicopter Had a Lucky Escape During a NVIS Approach to its Home Base (Norsk Luftambulanse Airbus Helicopters EC135P3 LN-OOZ ) On 6 November 2020 a HEMS Airbus Helicopters EC135P3 (H145) LN-OOZ of Nordic Air Ambulance was damaged when it briefly contacted the ground after Inadvertent Entry into IMC (IIMC) while on approach to Ringsted, Denmark. The helicopter initiated a successful go-around and diverted to Slagelse Hospital. The Serious Incident Flight The Danish Accident Investigation Board (DAIB or Havarikommissionen for Civil Luftfart og Jernbane) promptly issued their safety investigation report on 22 June 2021. They explain that the Norwegian operator had conducted HEMS operations in Norway since 1977 and in Denmark since 2011. The Danish operation comprised of four bases, each with one EC135. Onboard were… …the commander (CDR) sitting in the right hand pilot seat, the HEMS technical crew member (TCM)/paramedic sitting in the left hand pilot seat and the medical doctor (MD) sitting in the right hand cabin seat. Both the CDR and the TCM had completed the operator’s initial and recurrent Night Vision Imaging System (NVIS) training. The CDR had 13,170 of flight experience, 1,728 hours on type and 320 using Night Vision Googles (NVGs). The TCM had flow 1,766 hours on the EC135 and had 290 hours experience with NVGs. They were working a 24-hour shift pattern. They had completed a tasking at Odense Hospital (EKOH) at 18:00. Because they had been on ‘active duty’ for more than the normal limit of 14 hours, they had requested a reserve crew be activated to take over at their home base at Ringsted (EKRS) on their return. Active duty is here defined from time of callout “until minimum one hour after block-on time”. If there were less than two hours between being on-block and the next callout, the entire time is counted as active duty. The EKRS has an Automatic Weather Observation Station (AWOS) which the crew checked online. At that time, the symbol presenting EKRS showed a grey square, which the flight crew interpreted as no weather information was available. The flight crew was not aware that if a grey square was tapped, available data for the location would be presented, alongside with slashed lines representing missing data. In fact, a partial AWOS failure had occurred least two days prior. The only means to identify the failure and initiate a repair was the duty crew. However… Due to fog and reduced visibility, the CDR was aware that the weather conditions at EKRK [Roskilde] were below VFR minima. While en route back to EKRS they were asked… …if they could respond to a medical emergency in the outskirts of Slagelse. In accordance with the operator’s procedures… ….the flight crew had after an internal consultation accepted the extra HEMS mission and the subsequent flight to EKRS. [They] landed at 18:27 hrs at an industrial site in Slagelse, and attended the medical emergency. After about 30 minutes on site the medical emergency was dealt with and the crew prepared to return to EKRS. The flight crew used NVG during the departure from Slagelse, and the helicopter climbed to 1200 ft above mean sea level (amsl) towards EKRS. The flight crew went “NVG Off” (swung their helmet mounted NVG upwards to allow unaided vision)… En route to EKRS, the crew observed sporadic fog and fog patches close to the ground towards the south, while weather conditions were clear towards the north. The TCM went “NVG On” approximately 10 nautical...
read moreSchweizer 269C Destroyed after Missed AD
Schweizer 269C (S300C) Destroyed after Missed AD (N3625Z) On 16 August 2018 a privately operated Schweizer 269C (aka 300C) helicopter, N3625Z, was destroyed in a post-crash fire after an autorotation accident near Kindred, North Dakota. The pilot escaped uninjured. The Accident Flight The US National Transportation Safety Board (NTSB) explain in their safety investigation report, published on 24 August 2021, that the pilot (a 72-year-old doctor, with 4,089 of total flight time, 930 on type) had “purchased the helicopter in 2000, and that he passed his FAA private pilot checkride in 2001”. On the day of the accident he: ….departed Hector International Airport (FAR), Fargo, North Dakota, earlier in the morning and flew to McLeod, North Dakota, to pick-up a friend who lived on a nearby farm. [The pilot] completed an uneventful local flight with the passenger before departing…about 1015 CDT by himself for the return flight to FAR. Fifteen minutes into the flight, while cruising at 1,000 ft AGL, he: …heard a loud “snap” followed by a quick yaw of the helicopter. He immediately pushed the cyclic control forward and lowered the collective. He observed a “split needle” indication. The throttle still controlled engine speed; however, the main rotor speed did not respond to his throttle changes. He stated that the engine continued to run normally. He noted that he still had directional control through the antitorque pedals. [The pilot] immediately entered an autorotation and made one revolution while he located a suitable landing area. He maneuvered the helicopter to a nearby wheat field for landing. He estimated that the wheat crop was between 2-3 ft high. In an interview with an FAA Inspector the piloted reportedly stated “he “messed up” the autorotation because he was out of practice and had never done this maneuver to the ground before”. [The pilot] stated that the helicopter landed level on its skids, but it still had forward ground speed that caused the helicopter to briefly pitch nose-up. The helicopter subsequently pitched down before it slowly rolled over onto its right side. [T]he engine continued to run after impact, and he shut down the engine by moving the mixture control to the idle cutoff position. After the accident, he was able to exit the helicopter unaided and without injury. [The pilot] stated that he observed smoke from the right side of the helicopter (possibly near the damaged right fuel tank) and that the helicopter caught on fire after a few minutes. The Safety Investigation The FAA inspector reported that: After examining several transmission parts on scene, I found that the lower coupling drive shaft was missing all of its forward splines. The splines gave the appearance of being smeared off due to severe friction or heat. Inspection of the aircraft’s records revealed that: Records review indicated that [Airworthiness Directive] AD 93-17-13, had been complied with 5 September 2013, approximately 127 hours prior to the accident. was noted that the mechanic had signed off AD 93-17-13 with a simple entry, “Complied with AD. No defects”. This AD requires the disassembly of the lower coupling drive shaft assembly to facilitate visual inspection and lubrication every 300 flying hours. The FAA inspector speculated that: This sign off would indicate the mechanic may not have actually performed the steps required by the AD as the mechanic must reference the “method of compliance”. It is not clear why the FAA dismissed the simpler explanation that...
read moreDynamic Rollover During HESLO at Gusty Mountain Site
Dynamic Rollover During HESLO at Gusty Mountain Site (Helitrans Airbus AS350B3e / H125 LN-OFQ) The Norwegian Safety Investigation Authority (NSIA) has issued its safety investigation report on a helicopter accident that occurred near Skjelbreitjørna, Sandnes, Rogaland, Norway on 6 April 2020. It involved Airbus Helicopters AS350B3e / H125 LN-OFQ of Helitrans, one of two Helitrans AS350s conducting Helicopter External Sling Load Operations (HESLO) to support construction of a 420 kV power transmission line for power utility Statnett. The Accident Flight The NSIA report that the first tasks of the day for the pilot of LN-OFQ was to move a container weighing just under 1,100 kg from the rig area C42 near pylon 161 to pylon 151. A 15 m longline was attached to the cargo hook under the helicopter. A 6 m line extension was attached to the longline, which in turn was attached to a lifting yoke for the 2 m high container. This meant the helicopter had to climb to a height above ground level of approximately 24 m to be able to lift the container off the ground. The pilot (aged 38, with 3,228 total flight experience, 1,758 on type) had… …trained as a helicopter pilot in the USA during the period 2008 to 2010. In the USA, he flew Robinson R22 and R44 and worked as an instructor for a period. He returned to Norway and completed his conversion training to obtain a Norwegian commercial helicopter pilot licence (CPL(H)) in 2011. He started working at Helitrans the same year and was permanently employed from 2013. The pilot took off at 08:39. The helicopter carried 35% fuel (c 190 l / 150 kg). En route to pylon 151, the pilot noted that there was a strong southeasterly wind. After depositing the load and landing alongside the pilot realised that while he had navigated to pylon 151 on the line under construction, the load was actually intended for pylon 151 on an existing 132 kV power transmission line about 10 NM further to the northeast, on the eastern side of the Høgsfjord. While rotors running he… …called the client Dalekovod using his mobile phone to clear up the misunderstanding. The commander said he was in doubt as to whether he could fly the helicopter across the Høgsfjord in the prevailing winds. He then called a colleague in rig area C32, approximately 2 NM east of the helicopter. They discussed the wind conditions. Following an assessment, the commander decided to fly the helicopter over to his colleague in rig area C32 and see how the conditions developed. Positively: The commander has explained to the NSIA that he felt no pressure from the client when he made the decision to move the container. For him, it was only natural to bring it to an easily accessible place and not leave it by pylon 151. After almost 7 minutes on the ground, the pilot entered a low hover with the load to the front and right of the helicopter. He then turned anti-clockwise “ensuring that the line was getting taut in view down below on his right-hand side”. The NSIA note that data from the Appareo Vision 1000 lightweight video and flight data recorder fitted aided the investigation and showed that: …the helicopter started rolling to the left, at the same time as the nose started to pitch up. The commander moved the cyclic stick forward and to the right to counteract this movement, but the movement continued. When the helicopter had rolled 11.6 degrees to the left and with an upward nose angle...
read moreDitching after Blade Strike During HESLO from a Ship
Ditching after Blade Strike During HESLO from a Ship (B206-L1 N1422D Alaska) On 16 July 2020 Bell 206L-1 N1432D (MSN 45741) of Egli Air Haul was damaged in a collision with the mast of the Research Vessel Steadfast and then ditched while conducting a Helicopter External Sling Load Operation (HESLO). The Circumstances of the Accident The accident occurred near Augustine Island, Cook Inlet, Alaska, according to the US National Transportation Safety Board (NTSB) safety investigation report published on 20 August 2021. While the NTSB summary is disappointingly brief, the pilot’s account gives excellent detail and context. The 68-year-old pilot, who had a vast 26,995 hours of flying experience (26,769 in command, 14185 in rotorcraft in total, 14060 in command of rotorcraft and 521 on type), described that after arrival onboard the vessel the day before: I conducted a thorough helicopter safety briefing with all the personnel on board the boat. We discussed tail rotor and main rotor precautions and safety, location and operation of emergency equipment, seat belt and door operation and use. We discussed procedures for securing the helicopter to the deck using ratchet straps. We also briefed regarding sling load procedures and safety. The 33 m Steadfast is a converted 1973 Bering Sea crab fishing vessel. The helideck surface is approximately 13 m by 8.5 m. The D-value of a B206L-1 is 12.9 m so this is a sub-1D deck. During the sling load safety briefing, the Boat Engineer asked me how long my helicopter longline was. I told him “50 feet”. He asked me if it was long enough. I asked him how tall the boat mast was. He said he did not know. Nobody else on the boat knew how high it was, either. I looked up at the top of the mast from where I was standing on the helideck, judged that it was less than 50 feet, and said to the group that I thought the 50-foot line would be long enough. We completed the sling load safety briefing, covered aircraft refuelling procedures, and began preparing for the work that lay ahead for all of us. Then after dinner, I flew a couple of personnel loads (all internal loads only) and we did some work on Augustine Island and Mount St. Augustine Volcano. We ended our day without incident. On the next day: I flew one work crew off the boat out to a volcano seismic monitoring site [AC59]…[then]…took off with the longline attached to the helicopter belly hook and flew to the boat. As the boat crew was accomplishing the hovering hookup, I was observing the highest point of the boat mast was below the helicopter, so I felt that the longline would in fact be long enough. I flew the first load off the helideck to AC59, where the ground crew unhooked the load. Then I flew a second crew from the boat to Lagoon Camp (LGCP) on Augustine Island where they would spend the day receiving and handling construction materials I would be sling loading off the boat to them throughout the day. l anticipated it would require around 20 sling loads to move all the lumber and materials coming off the boat. At LGCP I shut down the helicopter. The pilot familiarised himself with the work site, set up a drum-stock refuelling station and had lunch. At around 13:30 I commenced sling load operations to LGCP....
read moreAir Methods AS350B3 Night CFIT in Snow
Air Methods AS350B3 Night CFIT in Snow (N530H) On 26 October 2020 Air Methods Corp (AMC) helicopter air ambulance Airbus Helicopters AS350B3 N530H was destroyed when it suffered a Controlled Flight into Terrain (CFIT) 200 m from Whiskey Creek Airport, near Silver City, New Mexico. The aircraft came to rest just 8 m from a house. The pilot, the sole occupant, miraculously suffered only minor injuries. The US National Transportation Safety Board (NTSB) issued their safety investigation report, issued 20 August 2021. The Accident Flight A storm was approaching, and the intent was to relocate the aircraft from the AMC base at Gila Regional Medical Center (6097 ft AMSL) to the near-by Whiskey Creek Airport (6126 ft AMSL) where AMC had a rented hangar. The accident flight departed at 23:34 local time. The pilot, who had flown 4200 hours, 1956 on type, stated that night Marginal Visual Flight Rules (MVFR) conditions prevailed (which implies a ceiling between 1,000-3,000 feet and/or 3 to 5 miles visibility). The pilot described how precipitation turned from rain to snow when approaching the airport. The flight followed Highway 180 and turned south towards the airport. On the turn to finals, there was an increase in precipitation, and a reduction in visibility. The aircraft impacted terrain in a level, or slightly nose-low attitude approximately 200 m NW of the airport, just 3 minutes after take-off. The Emergency Locator Transmitter (ELT) did not activate, a common failure. The nearest weather data was from Grant County Airport (5446 ft AMSL), 8 nm south of Whiskey Creek. Visibility was 7 miles and ceiling 1300 ft AGL (i.e. c 6750 ft AMSL) at the time of the accident. The NTSB Probable Cause The NTSB determined the probable cause to be: The pilot’s failure to maintain sufficient altitude above terrain while operating in reduced visibility due to snow showers. Strictly, this is simply a statement of the circumstances of the accident. Operator’s Recommendation to Repeat an Occurrence In the accident report form, AMC recommend: Avoid VFR flight in conditions below VFR weather minimums. Avoid VFR night flight in areas of no illumination or surface reference in poor visibility. Maintain an instrument cross-check when operating in areas of low illumination or low visibility. When encountering areas of deteriorating weather pilots should divert, abort, land or execute the IIMC recovery procedure in accordance with company guidance. But What About Flight Data Monitoring? There is no mention of any examination of flight data. The FAA changed Part 135 in 2017 so that helicopter air ambulance operators had to comply with a new Flight Data Monitoring (FDM) System requirement, FAR 135.607: After April 23, 2018, no person may operate a helicopter in air ambulance operations unless it is equipped with an approved flight data monitoring system capable of recording flight performance data. FAA AC 135-14B Helicopter Air Ambulance (HAA) Operations explains that: The FDMS should record digital or analog raw data, images, cockpit voice or ambient audio recordings or any combinations thereof which ideally yield at least the following flight information: • Location; • Altitude; • Heading; • Speeds (airspeed and groundspeed); • Pitch, yaw, and roll attitudes and rate of change; • Engine parameters; • Main rotor RPM; • Ambient acoustic data; • Radio ambient audio; and • Any other parameter the operator deems necessary (e.g., high definition video recording looking forward including instrument panel and forward cockpit windshield view, intercommunications system (intercom) between pilot and medical crew, communications with air traffic...
read moreTraining 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...
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