News & Comment

Drift into Danger: AW109SP Night HLS Accident

Posted by on 7:12 am in Accidents & Incidents, Airfields / Heliports / Helidecks, Business Aviation, Helicopters, Human Factors / Performance, Regulation, Safety Culture, Safety Management, Survivability / Ditching

Drift into Danger: AW109SP Night HLS Accident (G-RAYN, North Wales) On 1 November 2022, a Leonardo AW109SP, G-RAYN, struck trees and crashed during a nighttime departure from an unlit landing site, in a field at Nantclwyd Lodge, near Llanelidan, Denbighshire. The UK Air Accidents Investigation Branch (AAIB) issued their safety investigation report on 18 April 2024. History of the Day’s Operations The pilot (who had 3,815 hours in total, of which 1,565 were on type) flew G-RAYN from Biggin Hill, Kent on the morning of 1 November 2022, to transport passengers to North Wales for a day’s game shooting. The helicopter was owned by the lead passenger, but maintained and routinely operated commercially for third-parties by an approved air operator.  When used privately by the owner, the flights were conducted as NCO flights (‘non-commercial air operations with other-than complex motor-powered aircraft’), using a pilot approved by the operator.  This pilot had at that point worked for the operator for 5 years but was contracted directly by the owner for an NCO flight. The pilot arrived at Biggin Hill at approximately 0645 hrs. His scheduled duty check-in time was 0700 hrs, 30 minutes before takeoff. While he had arrived early, much of that extra time was taken up with an unanticipated supportive conversation with a very recently bereaved colleague. The pilot self-briefed the weather, refuelled G-RAYN to approximately 600 kg of fuel and completed the prescribed pre-flight walk round check of the helicopter before taking off at 0727 hrs. The helicopter landed at the owner’s private landing site at Lisvane, near Cardiff, at 0830 hrs to collect the passengers. Because the flight was in support of the helicopter owner, who was a frequent flyer, the pilot did not consider that a refresher pre-flight safety briefing was required. He was not aware that some of the passengers had not flown in that model of helicopter before. The flight to North Wales was uneventful and the helicopter landed near Llanelidan at 0920 hrs at a site listed in the operator’s Company Landing Site Directory (CLSD) as ‘LEA2’.  The site was a flat area of grass adjacent to a row of trees and a shooting lodge. The ground sloped down and away toward several isolated trees to the north west, as indicated by the chevrons above. The pilot departed to Hawarden aerodrome to refuel. The return flight had originally been scheduled as a day departure at 1630 hrs.  The takeoff became delayed until after just after nightfall (that occurred at 1718 hrs). The pilot’s recollection was of having approximately 340 kg of fuel on board the helicopter before the flight and that he “took his time” after engine start to burn off additional fuel because he knew the helicopter would be close to its maximum takeoff weight (MTOW). The landing site was unlit but the pilot was satisfied there were sufficient visual references available for him to safely conduct a vertical departure. The helicopter’s external lights were illuminating the area immediately around the helicopter and he could see what he described as a “vague horizon” ahead. The pilot judged that lights from the shooting lodge’s windows to his right would be an adequate lateral marker for the departure climb. During take off from the unlit ad hoc landing site, at a height of...

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Fatal Fall after HESLO Helicopter Hooks Worker

Posted by on 12:08 pm in Accidents & Incidents, Helicopters, Human Factors / Performance, Mining / Resource Sector, Safety Management, Special Mission Aircraft

Fatal Fall after HESLO Helicopter Hooks Worker (AS350BA C-FHAU) On 20 August 2023, the Expedition Helicopters Airbus AS350BA C-FHAU, was involved in a fatal accident in which a ground crew member died during Helicopter External Sling Load Operations (HESLO). The Transportation Safety Board of Canada (TSB) released its safety investigation report on 28 March 2024. The Accident The TSB explain the helicopter was being flown by a single pilot and moving drilling equipment with a 100 ft longline, in support of mining company Angus Gold‘s exploration activities being conducted by drilling contractor G4 Drilling Canada Ltd approximately 25 nm west of Wawa, Ontario. The pilot had over 4,580 hours total flight time, with 1,210 hours conducting longline operations.  The pilot’s door was replaced by a vertical reference bubble window was installed. The conditions allowed day Visual Flight Rules (VFR) flight. The winds at Wawa were reported as being “from the north at 10 knots, variable from 320° to 050° true”. The pilot’s task consisted of transferring surface drilling equipment by longline from an old drill site on an island to a new drill site on a nearby peninsula, approximately 900 feet away. The G4 ground crew consisted of a foreman, an assistant foreman, a driller, and a helper. The pilot started his duty day at approximately 0615 [Local Time] and flew various short flights for about 2.5 hours. He was then off duty until the first drilling equipment transfer flight, which started at approximately 1520. The foreman and the assistant foreman were stationed at the old site, preparing and attaching the drilling equipment to the longline, while the driller and helper were at the new site receiving, positioning, and detaching the drilling equipment from the longline. TSB explain that: The foreman, driller, and helper had completed all required common core training modules including the speciality module on loading and unloading personnel and equipment from helicopters. However: The investigation did not reveal any documentation indicating that the assistant foreman was qualified as a driller or that he had received any of the required common core or specialty module training. The initial loads were successfully moved. By approximately 1630, only the drill shack cage remained to be moved. This cage was to be placed over the drill and equipment on the drilling platform at the new site. On arrival taglines would be used by ground personnel to rotate the cage to align it.  However… When the helicopter reached the new site with the cage, the pilot, the driller, and the helper had difficulties positioning the cage. After several unsuccessful attempts, the pilot decided to bring the assistant foreman to the new site to help. The pilot flew back to the old site, released the cage, picked up the assistant foreman and took him to the new site. The pilot then returned to collect the cage and delivered it to the new site. At approximately 1700, the pilot positioned the helicopter into the wind and lowered the cage over the drill. The driller and helper each held 1 tag line and the assistant foreman held 2 tag lines. When the pilot looked down through the vertical reference window, he could see the driller and the helper only, because a piece of plywood on top of the cage was blocking his view of the assistant foreman....

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HEMS H145 Bird Strike

Posted by on 2:30 pm in Accidents & Incidents, Helicopters, Regulation, Safety Management, Special Mission Aircraft, Survivability / Ditching

HEMS H145 Bird Strike (HB-ZQJ) On 24 March 2021 Airbus H145 air ambulance HB-ZQJ of Schweizerische Luft-Ambulanz was damaged by a bird strike in the cruise.  The 1.3 kg bird penetrated the lower cockpit window at rudder pedal level. The Swiss Safety Investigation Board (SUST) issued their safety investigation report in French on 10 March 2024. The Flight The helicopter was undertaking a night patient transfer from Yverdon-les-Bains Hospital to Vaudois University Hospital in Lausanne (both hospitals have elevated helipads). On board were one pilot, two medical personnel and the patient. At 22:01 Local Time, 5 minutes into the flight, the helicopter was in the cruise at c 1000 ft AGL on autopilot when the bird strike occurred over Bretigny-sur-Morrens. The pilot felt a pain in his right leg having been impacted by remains of the bird… [The pilot] took manual control of the helicopter, reduced speed and ensured that the power and airworthiness of the helicopter were not affected by the impact. Despite entry at foot height the pilot was also hit in the head by debris.  The pilot’s helmet “had numerous stains from the bird.” The helicopter diverted to their base at Lausanne. SUST Analysis and Conclusions  SUST do not report the bird species but explain: The impact of the bird surprised the crew while the helicopter was cruising at night. It was therefore not possible to detect the presence of birds and attempt an avoidance maneuver. The shattering of the canopy with the penetration of the bird and the projection of the remains into the dark cabin must have caused a stressful situation which was well managed by the pilot. …the decision to divert to home base was appropriate. Of note is: The pilot’s equipment including helmet, robust suit and mountain boots contributed to the pilot’s physical integrity. Aerossurance customers who operate the H145 fly HEMS, helicopter hoist and military missions with the helicopter and operate with a similar ‘aircrew equipment assembly’ standard. Design & Certification Standards The current H145 lower cockpit windows are 2mm acrylic, reinforced round the edges. The current windshields are 6mm acrylic. The H145 is a derivative of the original BK117 (the four main rotor blade H145 is the BK117D2 and the five bladed H145 the BK117D3). While, as per the Changed Product Rule (Part-21.A.101), the certification basis for some changed H145 elements are recent amendments of CS-29, the EASA H145 Type Certificate Data Sheet (TCDS) states that otherwise FAR 29 Amdt. 40 from 1996 applies for all the other applicable requirements, except for three reversion to FAR 29 Amdt. 16 from 1978, significantly including “FAR 29.631 (for cockpit windscreens only)“. FAR 29 only introduced a bird strike requirement at FAR 29 Amdt. 40 in 1996: The rotorcraft must be designed to ensure capability of continued safe flight and landing (for Category A) or safe landing (for Category B) after impact with a 2.2-lb (1.0 kg) bird when the velocity of the rotorcraft (relative to the bird along the flight path of the rotorcraft) is equal to VNE or VH (whichever is the lesser) at altitudes up to 8,000 feet. Compliance must be shown by tests or by analysis based on tests carried out on sufficiently representative structures of similar design. So the H145 cockpit windscreen was not required to meet the 1996...

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Night Offshore Helicopter Approach Water Impact

Posted by on 7:26 pm in Accidents & Incidents, Crises / Emergency Response / SAR, Design & Certification, Helicopters, Human Factors / Performance, Offshore, Oil & Gas / IOGP / Energy, Regulation, Safety Culture, Safety Management, Special Mission Aircraft, Survivability / Ditching

Night Offshore Helicopter Approach Water Impact (Bond Offshore Helicopters EC225 G-REDU, BP ETAP CNS) On 18 February 2009 Airbus EC225 G-REDU of Bond Offshore Helicopters impacted the sea during a night visual approach to BP‘s Eastern Trough Area Project (ETAP) Central Production Facility.  The crew’s perception of the position and orientation of the helicopter relative to the installation proved erroneous.  After entering the water the helicopter floated and everyone on board was rescued.  The aircraft capsized subsequently. This article primarily summarises the extensive 171 page UK Air Accidents Investigation Branch (AAIB) safety investigation report published 14 September 2011. Background Bond Offshore Helicopters had been formed in August 2001 and commenced operations in August 2004 with a long term contract for BP for commercial air transport and for Search and Rescue (SAR) operations, known as ‘Jigsaw’.  They subsequently gained work with some smaller oil & gas customers and in February 2009 added another large oil and gas customer in Aberdeen.  They had also won contracts, commencing in 2010 in Blackpool and Norwich with the AS365N3. Their operations department was structured as follows: On 27 December 2006, at night, in poor weather CHC AS365N G-BLUN, operating from Blackpool, impacted the Irish Sea near the North Morecambe gas platform with 7 fatalities On 12 February 2007, the UK CAA Head of Flight Operations Inspectorate (Helicopters) wrote to all UK offshore helicopter operators to ask they review the following topics and inform their CAA inspector: Consequently the Bond Director of Flight Operations tasked their Flight Safety Officer with “carrying out an audit and Flight Operations Risk Assessment (FORA)” against these issues. AAIB found that the Bond Operations Manual at the time of the G-REDU accident summarised crew approach and landing duties as follows: However: There were no specific vertical or horizontal profiles set out in the Operations Manual for an offshore visual approach. More comprehensive duties, challenges and responses were set out for precision and non-precision instrument approaches. These included altitude calls and instrument crosschecks as well as any deviation from the horizontal or vertical profile of the approach. Also: There was no specific company lesson plan for teaching offshore approach and landing techniques. However, the training staff had detailed lesson plans which identified the need to use the flight instruments to monitor the approach and the Oculogravic illusions which may be experienced when pitching up. However: Neither crew member could recall receiving this information during their company training. G-REDU, registered in May 2008, was the first EC225 in their fleet, that until that point had consisted of AS332L2s. A Honeywell MkXXII Enhanced Ground Proximity Warning System (EGPWS) Terrain Awareness Warning System (TAWS) had been retrofitted to G-REDU in November 2008. This modification was not required by regulation but was “recommended” for “long term” contracts in the Aircraft Management Guidelines (AMG Report 390) of the International Association of Oil and Gas Producers (IOGP, then OGP), of which BP was a member.  This recommendation was subject to the caveat that “when an approved modification exists for the aircraft type and it is recommended by Company Aviation Advisory personnel”.  The TAWS replaced the original Automatic Voice Alerting Device (AVAD), also an OGP recommendation for long term contracts. Although recommended by OGP, AAIB note that because helicopters can “land close to or on nominally hazardous terrain or...

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Night Offshore Take-Off Loss of Control Incident

Posted by on 4:03 pm in Accidents & Incidents, Helicopters, Human Factors / Performance, Offshore, Oil & Gas / IOGP / Energy, Safety Management

Night Offshore Take-Off Loss of Control Incident (Bristow Norway Sikorsky S-92A LN-ONT) On 24 February 2020 Sikorsky S-92A LN-ONT of Bristow Norway suffered a 40 second loss of control during a night time offshore take off from the Maersk Invincible (now Nobel Invincible) jack-up drilling rig in AkerBP Valhall field the North Sea.  Control was regained and the flight continued safely to its destination. The Norwegian Safety Investigation Authority (NSIA) issued their safety investigation report on this Serious Incident on 15 February 2024. The Incident Flight The helicopter had been turned round on the rig’s helideck, ready for a return flight to Stavanger with 11 persons on board. The aircraft commander had 6,750 flying hours of experience, 2,191 on type.  He had performed 8 night deck landings in the last 90 days. The co-pilot had 5,800 flying hours of experience, 605 on type.  He had completed 11 night deck landings in the last 90 days and 211 night hours, 84 on type in the last 12 months. The operator’s pilots regularly received simulator training. This included take off and landing on offshore helidecks in various simulated weather conditions, day and night. Based on the wind direction the Pilot Flying (PF) would be the co-pilot and the commander would be the Pilot Monitoring (PM). The crew told the NSIA that, with the rain beating against the front windows, it was impossible to see any form of horizon in the dark. The entirety of the oil rig with its lights and lit structures, which could have provided visual references, was behind the helicopter. At 19:56 hrs [UTC], the first officer [the PF] brought the helicopter into a 5-ft hover above the helideck and prepared to take off into the wind. When the commander had completed the hover check, the first officer moved the collective to 80% torque to start a vertical climb to the take-off decision point (TDP). When the commander [the PM] called ‘TDP’ at 19:56:18 hrs, the first officer moved the cyclic gradually forward to a 5° nose down pitch to initiate horizontal acceleration. A 5° nose-down pitch is in accordance with the helicopter manufacturer’s recommendations and the helicopter operator’s procedures for take-off from a helideck in night-time conditions or poor weather with reduced horizontal visibility. The torque was 74% on both engines. As the helicopter transitioned forward they entered darkness, what is known as a ‘black hole’.   Such conditions typically occur over water or over dark, featureless terrain. Initially the helicopter exhibited “a low” sink rate and the commander “focused his attention on the vertical speed indicator”. When it showed a sink rate of 100 ft/min, he called out ‘We are descending’ two times. Just after that, the voice alert ‘Altitude, altitude – altitude, altitude’ indicated that the helicopter was about to drop below the minimum altitude selected on the radar altimeter [set at deck height, 260 ft]…  The commander has explained that, after the voice alert, he got the feeling that the instrument readings did not match with what he expected, and he felt that he became disoriented. A few seconds afterwards, when the helicopter had accelerated to approximately 35 kts at an altitude of 306 ft, the [pitch] angle increased by 6.4° per second to more than 25° nose up pitch up. At the same time,...

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Air Ambulance Night Wirestrike at Poorly Chosen Landing Site

Posted by on 6:47 pm in Accidents & Incidents, Helicopters, Human Factors / Performance, Safety Management, Special Mission Aircraft

Air Ambulance Night Wirestrike at Poorly Chosen Landing Site (AMC AS365N3 N520CF) On 26 July 2022 Airbus AS365N3 air ambulance helicopter N520CF operated by Air Methods Corp (AMC) for Dayton‘s Miami Valley Hospital Careflight, was involved in an wirestrike accident near Hamilton, Ohio.  The three occupants sustained minor injuries.  The US National Transportation Safety Board (NTSB) issued their safety investigation report on 7 February 2024. The Accident Flight The helicopter took off at 04:28 Local Time from Warren County Airport, Ohio, heading to an ad hoc landing site near a motor vehicle accident.  The Pilot (4336 hours total, 620 on type) and one Flight Nurse occupied the front seats and one Flight Nurse was in the cabin.  The Pilot was using a Night Vision Imaging System (NVIS) and flying in night Visual Meteorological Conditions (VMC). When about 9 miles away, the Pilot contacted on-scene fire department personnel for site information. They reported that there were high voltage power lines on the south side of the landing site.  The site was marked by four illuminated orange cones. As the pilot continued to the scene, he knew the winds were calm and, therefore, he orbited the scene from the south to the north. The pilot made an approach from the south and was looking out for the powerlines… He could see the towers but not the wires.  The pilot used the landing light to try illuminate the wires without success. The pilot stated that he did not think the wires would be in and around the landing zone.  He thought the wires were farther out from the landing zone and not below the helicopter. However, as the helicopter descended for landing, the main rotor blades contacted the wires and the helicopter fell about 30 to 50 ft. The nose and left main landing gear struck the ground first at 04:55. The helicopter sustained substantial damage to the main rotor blades, main rotor gearbox, and motor mounts [sic]; additionally, the left engine was hanging off the side of the helicopter. All three occupants egressed the helicopter after the engines were shut down. A 69 year old woman, who had been involved in the road traffic collision, died at the scene. NTSB Safety Investigation Post accident examination by a Federal Aviation Administration (FAA) inspector revealed that the helicopter struck the high voltage wires, severing one wire, and then landed hard. We note that the Flight Nurses do not appear to have been interviewed nor is their presence discussed in the NTSB report or public docket other than in relation to their post accident egress.  Furthermore the fire fighters were not apparently interviewed either and their NTSB report is silent on their training and procedures for establishing an ad hoc landing site. Some free guidance on training material for first responders is provided in links below, though reliance purely on generic guidance documents, PowerPoints or videos is highly unlikely to be sufficient. There also are no details on what mapping and obstacle data was available to the pilot or what Helicopter Terrain Awareness and Warning System (HTAWS) was fitted.  According to 135.605: After April 24, 2017, no person may operate a helicopter in helicopter air ambulance operations unless that helicopter is equipped with a helicopter terrain awareness and warning system (HTAWS) that meets the requirements in TSO–C194 and...

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HEMS Air Ambulance Landing Site Slide

Posted by on 11:06 am in Accidents & Incidents, Helicopters, Human Factors / Performance, Safety Management, Special Mission Aircraft

HEMS Air Ambulance Landing Site Slide (BSAA H145 SE-JSS) On 12 February 2022 Airbus Helicopters H145 air ambulance helicopter SE-JSS, based at Mariehamn Airport, Åland island, Finland was deployed to the nearby island of Fiskö after a person fell on ice.  After landing at a confined site near the casualty, power was reduced to idle, the helicopter slid backwards and struck adjacent obstacles. The Safety Investigation Authority Finland (SIAF) issued their safety investigation report on 28 January 2024. The Accident Flight A 112 emergency call was received at 15:33.   Two roads with almost identical names are located in the municipality of Brändö, which caused confusion at first. At 15:50 it was decided to task the helicopter to attend.  The helicopter had three occupants, pilot (1,725 total hours, 1,330 on type), Technical Crew Member (TCM) and nurse.  Babcock Scandinavian Air Ambulance had provided ambulance helicopter services in Åland under a contract with Åland Health Care District from 2019 (but Babcock has since sold this business to Avincis). Shortly after becoming airborne the helicopter was passed coordinates for helipad on Korsö island, approximately 15 min flying time away.  Only when halfway into the flight, were the helicopter crew informed that the casualty was on Fiskö and they were asked to proceed direct to the accident site (about 5 km northwest of the helipad). SIAF say: At 8 km from the accident site, the pilot descended to 500 ft (150 m) above ground level.  During the approach, he reduced speed so he could identify the correct house among the buildings of the small community. They had been told that “someone would be outside waving a white cloth to help in identification”. The crew did not obtain visual contact with this person or the house during the first overflight, but during the second they spotted the house and agreed on the conduct of an off-airfield landing. Even though buildings, trees and a power line were observed in the area, the vicinity of the intended landing site and the approach path were clear of obstructions that could have jeopardized the landing. SIAF only mention this ’17 m danger zone’ in the caption of image above and don’t elaborate on landing site size requirements otherwise.  AMC1.SPA.HEMS.125(b)(4) (performance requirements for HEMS operations) states a 2 D site is required by day (which for a H145 is 27.3 m). An approach was made… After the pilot had brought the helicopter to hover, the {technical] crew member [TCM] opened the door and scanned the area below and to the left for any obstructions that would be a factor during landing. He notified the pilot of a bush to the left of the helicopter’s tail about 6 m away but paid no particular attention to the fact that the ground was partially covered with ice. SIAF also comment on their being loose articles at the site.  The pilot elected to land. Even though landing was uneventful, and the helicopter appeared stable…the pilot felt it was slightly tilted to the right. With the flight controls neutralized, the attitude indicator showed 2° to 3° right bank, well below the maximum permitted value of 8°. The pilot set the engines to idle. The crew’s attention was diverted to a person approaching the helicopter who was signalled by hand to wait.  However, seconds after the engines were...

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Undetected Cross Connection Maintenance Error Resulted in a DA42 Hard Landing During a Maintenance Check Flight

Posted by on 2:30 pm in Accidents & Incidents, Business Aviation, Design & Certification, Fixed Wing, Human Factors / Performance, Maintenance / Continuing Airworthiness / CAMOs, Safety Management

Undetected Cross Connection Maintenance Error Resulted in Diamond DA42NG N591ER’s Hard Landing During a Maintenance Check Flight On 25 May 2022, Diamond DA42NG N591ER departed London International Airport, Ontario, on a maintenance check flight but suffered control difficulties and was forced to make a hard landing on the grass alongside the runway.  The Transportation Safety Board of Canada (TSB) issued their safety investigation report on 5 January 2024.  We examine the maintenance human factors involved. The Accident Flight The maintenance check flight followed a 2000-hour inspection (“including a mechanical and structural inspection, and general refurbishing”) that had been completed at the Diamond Aircraft Industries facilities at London International Airport. During the take-off, when the aircraft became airborne, the aircraft yawed abruptly to the left. The pilot attempted to correct for the unexpected yaw but had difficulty maintaining directional control of the aircraft. The pilot attempted to make an emergency landing on Runway 27; however, during the approach, the pilot continued to have difficulty controlling the aircraft and instead attempted to land on Taxiway A before ultimately landing on the grass between the runway and the taxiway. When the aircraft touched down hard on the grass, the rudder and the left-wing aileron mass balance weight broke off. The landing gear collapsed, and the aircraft slid to a stop approximately 265 feet from the initial impact point. The aircraft was substantially damaged but the pilot was uninjured. The Safety Investigation & Our Comments Upon initial examination it was discovered that the rudder moved in the opposite direction to the pilot input.  Significantly, during the preceding maintenance the rudder guide tubes had been replaced. [The Aircraft] Maintenance Manual (AMM) explains that the “two fuselage cables go through Teflon tubes in the rear fuselage. The cables attach to the rudder lower mounting bracket. The cables cross over each other in the rear fuselage” Significantly: The rudder cable guide tubes are not normally replaced…during the course of regular maintenance because they are rarely found to be defective, and there is no specific requirement to change or inspect them at regular intervals. The AMM also provides some troubleshooting guidance, which suggests that rudder stiffness or catching may be caused by the rudder cables chaffing in the guide tubes. The AMM suggests to replace the rudder cables and guide tubes; however, there is no method or procedure in the AMM specific to replacing the guide tubes. The AMM system description does explain and illustrate that the cables cross over, but that is not referenced from AMM section for the task.  The AMM contains instructions for the replacement of a single cable but makes no mention that it crosses from one side to the other (i.e. assumes the other cable is in place). TSB note that the only other information was in production drawings.  These apparently could be requested, but wasn’t requested for this task.  Clearly a maintenance organisation owned by the Type Certificate (TC) Holder has an advantage accessing production data, though if it is needed its a sign of an inadequacy in the AMM. Investigators determined the tube were therefore installed… …without the aid of specific procedures, guidance, or supervision. We discuss the supervision aspect further below.  As noted above, the lack of procedures and guidance was not a ‘Failure to Follow (F2F) procedures’ by maintenance personnel (a...

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Air Ambulance EC135 Loss of Control & Main Rotor / Engine Overspeeds

Posted by on 4:54 pm in Accidents & Incidents, Helicopters, Human Factors / Performance, Safety Management, Special Mission Aircraft, Survivability / Ditching

Air Ambulance EC135P2+ Loss of Control & Main Rotor / Engine Overspeeds (Air Methods, N531LN) On 22 January 2022, an Airbus EC135P2+ air ambulance, N531LN (LifeNet 81), of Air Methods Corporation (AMC) was destroyed in an accident in Drexel Hill, Pennsylvania.  The pilot was seriously injured but the two medical personnel and the patient (a child under the age of 5) aboard escaped injury. The US National Transportation Safety Board (NTSB) issued their safety investigation report on 4 January 2024. The Accident Flight The helicopter departed Chambersburg Hospital about 12:05 Local Time, destined for Children’s Hospital of Philadelphia. The helicopter established itself in cruise at an altitude of c 3,500 ft before descending as they approached Philadelphia. At 12:53:11, Automatic Dependent Surveillance – Broadcast (ADS-B) data revealed “a series of heading and altitude excursions” before the data was lost 6 seconds later. Doorbell cam recordings on the ground captured a “high-pitched whine…volume and pitch”. The NTSB report that: Surveillance video showed the helicopter in a near-vertical, nose-down, spiralling descent. The medical crew reported that the helicopter rolled inverted.  No other evidence supported that. They however did manage to secure the patient and brace for impact. The injured pilot, who had 4,123 total hours, 185 on type) had no memory of the initiating event and limited recollection of the final seconds of the flight.  However the NTSB established that the pilot…. …arrested the rotation and recovered the helicopter from the dive but was unable to climb or hover due to insufficient engine power, thereby resulting in a hard landing… The helicopter impacted the ground upright and came to rest on its left side adjacent to a church building. All wreckage was found in a compact area with no substantial debris trail. The main fuselage was whole but… the airframe was partially separated on the upper side of the frame between the cockpit and cabin. All occupant seats remained installed within the cockpit and cabin. The aft-left seat was partially bent in a downward direction near the front edge of the seat. Although not remarked upon by NTSB, it came to rest partly on a low wall. The pilot was extracted from underneath.  The medical personnel egressed through the right cabin door, carrying the patient. NTSB Analysis The accident helicopter, manufactured in 2006, was not equipped with, nor perhaps surprisingly “was it required to be equipped with, a flight data recorder (FDR), a cockpit voice recorder (CVR), or any flight recorder system that records cockpit audio and image”. The FAA had changed Part 135 in 2017 so that helicopter air ambulance operators had to comply with a 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. Its not clear in the NTSB report how AMC were achieving that regulatory requirement. The NTSB investigators concluded that: Examination of the helicopter revealed no evidence of malfunction that would result in an abrupt departure from cruise flight. The investigators also note that: The accident helicopter was equipped an AFCS [Automatic Flight Control System] composed of a SAS [Stability Augmentation System] and autopilot systems that can control helicopter pitch, roll, and yaw through various actuators. The AFCS does not...

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Police Helicopter Unanticipated Yaw & Fatal Water Impact

Posted by on 2:42 pm in Accidents & Incidents, Helicopters, Human Factors / Performance, Safety Management, Special Mission Aircraft, Survivability / Ditching

Police Helicopter Unanticipated Yaw & Fatal Water Impact (Huntington Beach Police Department MD520N N521HB) On 19 February 2022 at 18:34 Local Time MD Helicopters 500N (MD520N) N521HB of Huntington Beach Police Department (HBPD) was destroyed when it impacted the water off Newport Beach, California in a Loss of Control – Inflight (LOC-I) accident.  The police pilot escaped with minor injuries but the police Tactical Flight Officer (TFO) was fatally injured. The Huntington Beach Police Air Support Unit was formed in 1968, only the fifth in the US.  In 1992 they introduced their first MD520N and became an all MD520N fleet in 2002. Instead of having a conventional tail rotor for anti-torque control the MD520N has a NOTAR (NO TAil Rotor) design with a variable thruster and ducted fan system.  In 2023, the unit changed over to the tail rotor-equipped MD530F]. The Accident Flight The US National Transportation Safety Board (NTSB) issued their safety investigation report on 14 December 2023 into the Newport Beach accident. The law-enforcement helicopter was performing right turns at night over an waterfront peninsula supporting officers attending a street fight involving up to 10 people. The pilot estimated “that they were flying about 500-600 agl, which is standard practice” when the helicopter yawed aggressively to the right and he… …immediately applied full left foot pedal and forward cyclic to arrest the rotation, but there was no response. He then applied right pedal to see if the pedals had malfunctioned, and observing no change, he reverted to full left pedal. He continued to apply corrective control inputs, but the helicopter did not respond and began to progress into a spinning descent. The pilot stated that the rotation became more aggressive, and he began to modulate the throttle, collective, and cyclic controls to try to arrest the rotation rate. He stated that his efforts appeared to be partially effective, as the helicopter appeared to respond; however, because it was dark, he had no horizon or accurate external visual reference as the ground approached. The engine continued to operate, and he chose not to perform an autorotation because the area was heavily populated. He then had a sense that impact was imminent, so he pulled the collective control in an effort to bleed off airspeed. The helicopter impacted the water… …on the TFO’s side in a downward right rotation. The pilot recalled a sudden smash and saw water and glass coming toward him as the canopy shattered. He felt the rotor blades hitting the water, everything then stopped, and within a few seconds he was submerged. The Pilot’s Underwater Escape & the Attempted Rescue of the TFO The police department’s personnel… …fly with a full tactical vest, an inflatable “horse collar”, Submersible Systems “Spare Air” [Compressed Air – Emergency Breathing System] tank, gun, radio, magazines, and handcuffs, all carried on their chest. The pilot held on to the collective as a reference point.  He recalled that: He waited for the helicopter to stop moving, grabbed the Spare Air mouthpiece, cleared it, and started to breath. Holding the collective with one hand he reached down and released his seat harness. His eyes were closed, and he was able to move by feel. He did not recall opening the door.. He exited the helicopter and was upside down. He tried to relax and...

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