B407 Worn Throttle Detent Power Loss Accident
B407 Worn Throttle Detent Power Loss Accident (Air Methods N687AM) On 4 September 2022 Air Methods Corp (AMC) Bell 407 N687AM from Mercy Air 22 air ambulance base in Hesperia, California crashed near Mount Baldy, California. The pilot was seriously injured. The US National Transportation Safety Board (NTSB) issued their safety investigation report on 21 August 2024. The Accident Flight The NTSB lists the 58 year old pilot’s experience as 3447 hours total, 264 hours on type. In his statement the pilot explains he was tasked to support a public relations event for the Mount Baldy Fire Department and… …consisted of flying water and other supplies and people from a base camp at Cow Canyon Saddle to the summit of Mount Baldy, dropping them off and returning to the base camp to pick up more supplies. The base camp is at approximately 4300 feet MSL. The summit of Mount Baldy is at 10064 feet MSL. The summit is approximately 4 nautical miles from the base camp. The pilot was using the base’s spare aircraft. He anticipated 5 trips would be needed. After completing the second delivery to the summit… I flew down-canyon to lose altitude and set up for a steep approach to the confined area landing zone at Cow Canyon Saddle. I slowed from 60 knots to 40 knots as I turned final. Shortly after turning final I saw the low RPM warning light and heard the low RPM warning horn. There were no other warning lights illuminated. There were no other audio annunciations. The controls were responding normally. The engine did not sputter. I saw that the rotor RPM dropped to approximately 95%. I lowered the collective and the rotor RPM went back up to 100%. I don’t remember looking at the throttle. I aborted the approach and turned left, down-canyon. I made a Mayday call to the firefighters at Cow Canyon Saddle. I told them I had a partial engine failure and that I was looking for a place to land. I attempted to raise the collective and once again the low RPM warning light and horn came on. I lowered collective again and proceeded down-canyon with a descent rate of 600-700 feet per minute. I did not attempt to put the FADEC into Manual mode because I didn’t want to divert attention away from looking for a place to land. I didn’t see any good places to land. I considered landing on the main road but decided against it because of the power lines along the road and the narrowness of the road. I saw a small paved road in a clearing at the bottom of the canyon and decided to land there. I did not autorotate. I decided to use what power the helicopter had for landing. There were trees and powerlines down-canyon from the clearing. I was slightly too high to land in the clearing so I flared into the top of a tree on the downcanyon side of the clearing. The flare brought the helicopter to a stop. I started to level the helicopter with forward cyclic. I pulled full collective to cushion the impact. The helicopter came to rest on its right side. The Safety Investigation The NTSB explain that: The engine control unit captured data consistent with main rotor impact. The...
read moreFatal Offshore S-76C++ LOC-I & Water Impact Brazil 2022: CENIPA Investigation
Fatal Offshore S-76C++ LOC-I & Water Impact Brazil 2022: CENIPA Investigation (Lider PR-LCT) On 16 March 2022 Sikorsky S-76C++ PR-LCT of Líder Táxi Aéreo struck the sea on approach to a Petrobras Normally Unattended Installation (NUI), Manati 1 (9PMM), after a Loss of Control In-flight (LOC-I). The aircraft capsized but was kept afloat by its Emergency Flotation System (EFS). The Aircraft Commander died but the other 12 occupants were rescued with only minor injuries. The Brazilian accident investigation agency CENPIA published their safety investigation report, on 5 August 2024. The Accident Flight & Crew Background The helicopter departed Salvador Bahia for a c 22 mins flight to the offshore installation. Four of the the 11 passengers had not completed Helicopter Underwater Escape Training (HUET). Survivors reported that it was common practice for crews to ask the passengers whether they had received the HUET training [before departure], but, specifically in the case of the accident the question was not made. This indicates that an absence of passenger HUET qualification was common. It also meant there was nothing to stop two untrained passengers on this flight being sat next to push out windows they had not gained familiarity with using through practical training. CENIPA describe the safety briefing given to passengers. It does not appear to have included the brace position. The passengers were equipped with life jackets but no Personal Locator Beacon (PLB) or Emergency Breathing System (EBS). The pilots had life jackets and PLBs but no EBS. Both pilots were starting a two week period on-duty. For this flight the Co-pilot was Pilot Flying (PF) and the Aircraft Commander was Pilot Monitoring (PM). The Aircraft Commander had 8670 hours flying experience, 7393 on type. He had been an S-76 instructor since 2012. The Co-pilot (5800 hours, 1382 on type) had flown for CHC from 2008-2016 (and been an Aircraft Commander 2010-2016). However in 2016 he had been made redundant at a time of contraction in offshore operations (the offshore fleet in Brazil declined from 100 helicopters in 2014 to 70 in 2016, with a number of contracts terminated in 2015). In 2020 Petrobras is reported to have used a reverse auction process to drive down prices after COVID hit. The Co-pilot did not resume offshore flying until December 2020 upon recruitment by Lider. The Co-pilot underwent 36 hours of initial simulator training 22-30 January 2021, needing 8 hours more than the standard course to gain an “acceptable” grade (the middle of 5 grades), with the comment “minimally qualified to perform his duties on board…” The SIC reported that, on that occasion, during the initial training sessions on the flight simulator, he had some trouble due to the automation of the S-76C++ helicopter. The SIC started flying operationally in February 2021 and over the next two months with an instructor accumulated 104:20 flying hours. However, he then spent 10 months on a medevac stand-by roster logging just 36:40 flying hours and 22 offshore landings (most of which appear to have been as PM). Despite this, on the day of the accident the Co-pilot was commencing “operational-experience training” in preparation for promotion to be an Aircraft Commander with Lider. In early 2022 the oil price was spiking as Russia invaded the Ukraine. The Co-pilot (or SIC) was therefore seated in the right hand...
read moreDeadly Delay: Catastrophic USAF CV-22B Osprey Gear Box Failure
Deadly Delay: Catastrophic USAF Bell/Boeing CV-22B Osprey 10-0054 Gear Box Failure On 29 November 2023 US Air Force (USAF) Bell/Boeing CV-22B Osprey tiltrotor 10-0054 (call sign Gundam 22) of the 21st Special Operations Squadron (21 SOS), impacted the water 1/2 mile off the coast of Yakushima Island, Japan, while on approach to Yakushima Airport. The aircraft was destroyed, and all 8 crewmembers sustained fatal injuries. After this accident the V-22 fleet was grounded until 8 March 2024. The USAF Accident Investigation Board (AIB) issued its report on 1 August 2024. Context of the Accident Flight The report notes that 21 SOS was a small unit with a high operating tempo. The period before the accident was reportedly particularly intense because of Air Force Special Operations Command (AFSOC) directions on achieving flying training requirements and several aircraft being down for base maintenance. The unit were also suffering a shortage of flight engineers / rear crew. The aircraft was part of a two-ship formation, with a third airborne spare aircraft, that departed Yokota Air Base, near Tokyo, at 10:43 local time for a exercise with other US military units. The Aircraft Commander (AC), a Major with 1363 total flying hours, 953 on type over c 7 years. He was the lead air integration planner for the exercise and also the Airborne Mission Commander (AMC), unusual according to the AIB but allowed within AFSOC procedures. He was also an advocate of the type on Reddit as UR_WRONG_ABOUT_V22. This exercise had been months in the planning and there had already been a rehearsal on 7 November 2023. On the day it was decided the V-22s would depart 30 minutes earlier than planned due to forecast headwinds and changed plans to refuel at MCAS Iwakuni. 10-0054 had 19 deferred defects (‘Red Diagonal’ or ‘/‘ items in USAF parlance). These are not listed or elaborated upon in the AIB report however. The AAIB report discussed the last aircraft maintenance on 10-0054 but does not mention the Time Since New and Time Since Overhaul of the left-hand proprotor gearbox (PRGB), the key assembly involved in the accident. The Accident Flight On departure at 10:43 10-0054 had suffered a mission computer ‘warm-start‘, resulting in a “software glitch”. En route they had to complete a 29 step checklist procedure to address this. They arrived at MCAS Iwakuni at 12:31 after a 348 NM flight. While there the crew of 10-0054 also had to deal with a number of advisory messages and several equipment failures, including two further warm-starts. They then departed at 13:09 to rendezvous with a US Marine Corps (USMC) Lockheed Martin KC-130J Hercules for air-to-air refuelling, en route to Kadena AB. While en route at 13:50 the crew received the first left-hand PRGB CHIP BURN visual advisory on the Control Display Unit (CDU). This indicated an automatic ‘fuzz burn’ had occurred on a PRCG magnetic chip detectors. The chip detector fuzz burn feature is designed to burn off minor metallic debris but not large chips. Repeated fuzz burns however could indicate a incipient failure. When a fuzz burn can’t remove more substantial debris, a chip caution is displayed. Each PRGB transmits power from one of the V-22’s Rolls-Royce T406 engines to one of the V-22’s proprotors, reducing the speed by 38:1 while increasing the torque. The AIB...
read more“Sensation Seeking” Survey Fatal Accident
“Sensation Seeking” Survey Fatal Accident (Exact Air Piper PA-31 C-FQQB) On 30 April 2017 Piper PA-31 Navajo C-FQQB operated by Exact Air crashed 3.5 NM from Schefferville Airport, Quebec while returning there from its second magnetometric geophysical survey flight of the day. Both pilots onboard died during the Controlled flight Into Terrain (CFIT) accident. The Accident According to the Transportation Safety Board of Canada (TSB) safety investigation report the survey area was 90 NM from Schefferville Airport. The surveys were conducted at 300 feet above ground level with a crew of two. Although the regulations do not require it, the company decided to add a 2nd pilot on board the magnetometric survey flights and gave the pilots additional training in the right-hand seat on standard operating procedures (SOPs), including instrument approaches using the global positioning system (GPS). The occurrence pilots were 24 and 25 years old. [They] alternated the roles of pilot-in-command and co-pilot on each flight. Because survey flights are conducted at low altitude, the crew had conducted a reconnaissance flight over the survey area to identify potential hazards. TSB note that: The pilot-in-command had been employed by the company since March 2016. He had 462 hours total time, 112 on type. This was his first magnetometric survey contract, and he had conducted about 16 flights as co-pilot to familiarize himself with this type of aerial work before being assigned to the role of pilot-in-command the week before the accident. The pilot-in-command was the pilot flying for the accident flight. The co-pilot had been employed by the company since September 2014. He had 1693 hours total time, c650 on type. This was his 4th magnetometric survey contract, and he had trained the occurrence pilot-in-command during the first flights of the contract. The co-pilot was the pilot monitoring. C-FVTL, another Piper PA-31 of Exact Air was simultaneously taking part in the survey. The TSB investigation revealed that during the daytime return flight C-FQQB… …descended to a height of less than 100 feet AGL and maintained this altitude until colliding with the wires at 1756. Its ground speed during the last minute before the impact was 169 knots, or 286 feet per second. At 1756, while the aircraft was flying over railway tracks, it struck power transmission line conductor cables and crashed on top of a mine tailings deposit about 3.5 nautical miles northwest of Schefferville Airport. Shortly after C-FVTL arrived at Schefferville its crew realised that C‑FQQB had not landed. After unsuccessful attempts to make radio contact, a search was initiated. Less than an hour later, the wreckage of the missing aircraft was located. The Safety Investigation [No] emergency locator transmitter (ELT) signal was captured. Damage to the antenna coaxial cable likely led to the rapid discharge of the battery. However, the broken antenna and the fact that the wreckage was upside down would have made it impossible to detect the signal. This is a common phenomenon. TSB note that: The current emergency locator transmitter system design standards do not include a requirement for a crashworthy antenna system. As a result, there is a risk that potentially life-saving search‑and‑rescue services will be delayed if an emergency locator transmitter antenna is damaged during an occurrence. The left engine was separated from the main wreckage. Electrical transmission cables were found wrapped around its propeller drive shaft. TSB...
read moreAir Ambulance Bell 407 Pitch Links & Swashplate Drive Arm Bent in Double Bird Strike
Air Ambulance B407 Pitch Links & Swashplate Drive Arm Bent in Double Bird Strike (Med-Trans Corp N910GX) On the afternoon of 29 March 2024 Bell 407 air ambulance helicopter N910GX, operated by Med-Trans Corp, suffered a bird strike near Moran, Kansas. The pilot reported that the aircraft was in the cruise en route to a casualty. Due to “strong gusty winds” the pilot “elected to transit to the scene location at approximately 2500 feet MSL and 130 KIAS ” when… …the aircraft encountered a small flock of 3 birds near Moran, Kansas. The pilot had been crossing check instruments and when continuing outside visual scan, he spotted the birds and attempted to briefly maneuver to avoid contact. This attempt was unsuccessful as the late spotting of the birds did not allow further maneuvers. Subsequently, there were two loud noticeable impacts to the aircraft. Following the impacts, the aircraft began to hop vertically and aircraft controllability was in question. The pilot found the helicopter was still controllable but as the amount of damage was unknown… …the pilot began to turn into the wind to find a suitable emergency landing site as he was unsure how long the aircraft would remain controllable. An open pasture was selected as an emergency landing site. The pilot proceeded to land (trying to maintain an autorotational profile during most of the descent) and shutdown the aircraft without further issues. There were no injuries to the four occupants. The pilot and medical crew began to look over the aircraft for any noticeable damage. Initially, they could see a bent pitch change link on the rotorhead as well as a bird wing lodged in the upper wire strike prevent system. Upon further inspection, the swashplate drive link was bent as well near the bent pitch change link. The upper left corner of the pilot’s windscreen was also cracked. The US National Transportation Safety Board (NTSB) safety investigation report, issued on 18 July 2024 added nothing further, nor was the bird debris identified. Just a few weeks earlier, on 5 March 2024, Airbus AS350B3e (H125) N853MB of Med-Trans Corp, suffered a double bird strike near its destination at Fort Morgan, Colorado, that we previously discussed. In that case the windscreen was penetrated, the pilot’s visors shattered and helmet knocked off. Safety Resources The European Safety Promotion Network Rotorcraft (ESPN-R) has a helicopter safety discussion group on LinkedIn. You may also find these Aerossurance articles of interest: Med Trans Air Ambulance Pilot’s Visor Smashed in Double Bird Strike HEMS H145 Bird Strike Safety Lessons from a Fatal Helicopter Bird Strike: A fatal accident occurred on 4 Jan 2009 involving Sikorsky S-76C++ N748P of PHI that highlighted a range safety lessons. We also discuss current activity on enhancing bird strike requirements. USAF HH-60G Downed by Geese in Norfolk, 7 January 2014 Swedish Military NOE Helicopter Bird Strike Power of Prediction: Foresight and Flocking Birds looks at how a double engine loss due to striking Canada Geese had been predicted 8 years before the US Airways Flight 1549 ditching in the Hudson (which was just days after the Louisiana helicopter accident). Final Report Issued on 2008 B737 Bird Strike Accident in Rome NTSB Recommendations on JT15D Failure to Meet Certification Bird Strike Requirements USAF T-38C Downed by Bird Strike AS350B3/H125 Bird Strike with Red Kite Big Bustard Busts Blade: Propeller Blade Failure After Bird Strike AW169...
read moreNight HEMS BK117 Loss of Control
Night HEMS BK117 Loss of Control (CHC BK117C2 VH-SYB) On the evening of 21 October 2016, Helicopter Emergency Medical Service (HEMS) Airbus BK117C2 VH-SYB operated by CHC Australia suffered a serious incident over New South Wales. The Accident Flight The Australian Transport Safety Bureau (ATSB) explain in their safety investigation report that: The crew were returning [from Canberra, ACT] to their home base at Orange, New South Wales, after conducting a [HEMS] task [that saw them depart from base at 1650]. The flight was conducted as a night visual imaging system (NVIS) operation under night visual flight rules (NVFR), with the pilot and aircrew member (ACM) both wearing [ITT M949 ANVIS-9] night vision goggles (NVG). The pilot had arrived early, at 1600, for duty due to commence at 1730 as the night shift pilot. She had 5,065 hours total time, 602 on type. The pilot had c 770 hours of night experience including about 300 hours on NVIS. The pilot had completed an NVIS proficiency check flight on 9 August 2016. In contrast the ACM was on a 0730-1730 day shift. Remarkably she would not however exceed a 14 hour duty day report ATSB as ACM duty time only commenced when the aircraft was tasked. The ACM had 859 hours total experience, 465 hours on type. She had last completed an NVIS capability check flight on 31 May 2016. As an ACM, she had been trained to provide assistance to pilots in deteriorating visibility conditions and in-flight recovery procedures. The pilot planned the return flight as an NVIS NVFR flight rather than under instrument flight rules (IFR) “as it provided more diversion options along the planned route” as thunderstorms were forecast. The helicopter departed Canberra Hospital at 2010 for the return flight to Orange, with both the pilot and ACM wearing NVG. ATSB note that: NVGs are not designed to be used for flight under IFR, however, it is possible to ‘see through’ areas of light moisture when using NVGs which increases the risk of inadvertently entering IMC. They report that: Approximately 20 NM north-west of Crookwell the pilot determined that the weather conditions were no longer suitable for continuing the flight due to closing gaps between the storms and reduced visibility ahead. After some discussion between the pilot, ACM and paramedic regarding suitable diversion sites, it was decided to divert to the Crookwell Medical helicopter landing site (HLS). They waited there until 2240 until the storm had passed. The pilot reported that she had no specific pressure or reason to return to Orange that night. However, she felt a responsibility to complete the mission and to return the helicopter back to home base if possible and safe to do so, thereby allowing further emergency medical service (EMS) or search and rescue (SAR) tasking from the Orange base The pilot reported that when the helicopter reached the take-off safety speed, she adjusted the helicopter attitude but the searchlight reflecting off the rain limited her forward visibility. She adjusted the searchlight down and to the right so she could see the ground more clearly, but the forward visibility did not improve enough for her to be comfortable with continuing the flight in that configuration. She then adjusted the helicopter’s attitude to slow the helicopter and help maintain visibility with the...
read moreAir Ambulance Pilot’s Visor Smashed in Double Bird Strike
Air Ambulance Pilot’s Visor Smashed in Double Bird Strike (Med-Trans Corp Airbus AS3503e / H125 N853MB) On the afternoon of 5 March 2024 Airbus AS350B3e (H125) helicopter air ambulance N853MB, operated by Med-Trans Corp, suffered a bird strike near its destination at Fort Morgan, Colorado. The operator reported that: The aircraft was flying straight with SAS engaged and a 100-200 FPM decent approximately 700-1000 ft AGL. The pilot remembers scanning left for the aircraft and looking forward and seeing two large birds of prey heading at the windshield. A left turn mitigation was attempted and the medic heard the pilot call out birds, one bird impacted the pilot side window. The second bird is speculated to have hit the rotor blade. The pilot had parts of the window hit his chest, face and helmet. The helmet visor was destroyed and the helmet was removed from his head (chin strap was on, but the helmet had a quick release strap that must of been hit). The pilot side door was opened, speculatively by the pilots helmet. Despite the damage to the helmet the operator noted the helmet did its job. The pilot suffered only minor injuries. The impact and resulting wind caused momentary disorientation and the wind made it difficult to see clearly as well as all verbal communication was lost with the pilot. The pilot did a 270 degree descending left turn to land in an open field. A normal landing, shutdown and egress were performed. According to the US National Transportation Safety Board (NTSB) safety investigation report, issued on 11 July 2024 the birds were identified as red-tail hawks. These typically weighing from 690 to 1,600 g (1.5 to 3.5 lb). The NTSB determined that in fact: The birds struck the windscreen and fragments of the windscreen impacted the rotor blades. Safety Resources The European Safety Promotion Network Rotorcraft (ESPN-R) has a helicopter safety discussion group on LinkedIn. You may also find these Aerossurance articles of interest: HEMS H145 Bird Strike Safety Lessons from a Fatal Helicopter Bird Strike: A fatal accident occurred on 4 Jan 2009 involving Sikorsky S-76C++ N748P of PHI that highlighted a range safety lessons. We also discuss current activity on enhancing bird strike requirements. USAF HH-60G Downed by Geese in Norfolk, 7 January 2014 Swedish Military NOE Helicopter Bird Strike Power of Prediction: Foresight and Flocking Birds looks at how a double engine loss due to striking Canada Geese had been predicted 8 years before the US Airways Flight 1549 ditching in the Hudson (which was just days after the Louisiana helicopter accident). Final Report Issued on 2008 B737 Bird Strike Accident in Rome NTSB Recommendations on JT15D Failure to Meet Certification Bird Strike Requirements USAF T-38C Downed by Bird Strike AS350B3/H125 Bird Strike with Red Kite Big Bustard Busts Blade: Propeller Blade Failure After Bird Strike AW169 Birdstrike with a Turkey Vulture Dusk Duck: Birdstrike During Air Ambulance Flight Aerossurance has extensive air safety, flight operations, HEMS, SAR, airworthiness, human factors, helidecks, 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 moreFatal USCG SAR Training Flight: Inadvertent IMC
Fatal USCG SAR Training Flight: Inadvertent IMC (Airbus MH-65D CG-6535, 28 Feb 2012) On 28 February 2012 a US Coast Guard (USCG) Airbus MH-65D Dolphin (AS365) CG-6535 impacted the sea in Mobile Bay, Alabama with the loss of all four crew members. This followed an unintended flight into a Degraded Visual Environment (DVE) during a night Search and Rescue (SAR) training flight. The Accident Flight The helicopter was assigned to USCG Aviation Training Center (ATC) at Mobile, Alabama. It was conducting a night training flight that include approaches to the hover, basket hoists with the 41-foot Motor Vessel (MV) Solomon and rescue swimmer hoists. The crew consisted of an ATC instructor as Pilot-in-Command (PIC), a pilot under instruction as Copilot (CP), a flight mechanic hoist operator (FM) and a rescue swimmer (RS). According to the USCG accident report the PIC had 3,972 hours of total, 3,629 on type. The CP had just 263 hours, 39 on type. The CP was nearing the completion of his course, having reported to the ATC on 16 January 2012 for the 7-week MH-65D Transition Course. The weather at the time of departure and forecast for the evening was VMC. The crew completed planned training but the weather had deteriorated during the RS exercises with a ceiling lowered to 400 feet and reduced visibility (4.4 nm at the nearest met station). According to the USCG accident report the crew had some difficulty maintaining position during some of the RS hoists according to witnesses on the MV Solomon. Its not clear if that was related to the weather or not. After the completion of RS hoisting, the PIC transferred the controls to the CP for over-water hover training. The CP spent two minutes practicing over-water hover position keeping using the Hover Augmentation (HOV-AUG) flight director mode. Following the over-water practice hovering, the PIC directed the aircraft to be reconfigured for forward flight and disengaged the HOV-AUG mode. Forty-four seconds prior to the mishap, the CP began a manual instrument takeoff/departure (ITO) from the over-water hover. A manual ITO is conducted without the assistance of the aircraft’s flight director modes. Based on cockpit recorded dialog, it appears that [ANVIS-9] Night Vision Goggles (NVGs) were in use by the PIC. Investigators say both PIC and CP were using NVGs when the aircraft departed. During the ITO, the PIC acknowledged that a positive rate of climb was established and discussed hoisting performance with the RS. Shortly after CG-6535 ascended above 200 feet, but below the maximum achieved altitude of 362 feet, the PIC recognized the aircraft had encountered IMC and verbalized a transfer of control of the aircraft. The PIC assumed control of the aircraft approximately 23 seconds prior to impact. Sixteen seconds prior to impact… ….the PIC stated his intention to slowly come down to try and regain visual conditions and requested that the CP provide the Radar Map page on the PIC’s multi-function display flight instrument. The PIC did not verbalize the minimum altitude he intended to descend to or alter the pilots radar altimeter warning setting. While maneuvering the aircraft without the assistance of the aircraft’s flight director, CG-6535 entered an attitude indicating a right hand turn greater than 43 degrees angle of bank, 5.5 degrees per second yaw rate to the right, and 22 degrees...
read morePilot Induced B407 HEC Power Loss
Pilot Induced B407 HEC Power Loss (Guardian Helicopters N999GH at PG&E Training Site, Livermore, CA) On 11 May 2022 Bell 407 / Eagle 407HP conversion N999GH of Guardian Helicopters was involved in an accident near Livermore, California during a Part 133 rotorcraft external-load flight. The pilot was seriously injured. remarkably, the lineman, suspended on a long line below the helicopter, escaped with only minor injuries. The Accident Flight The US National Transportation Safety Board (NTSB) safety investigation report was issued on 14 May 2024. The NTSB explain that: The pilot was performing a HEC [Human External Cargo] long-line qualification exam flight at the Livermore Electric Safety Academy, a training operations facility owned by the Pacific Gas and Electric Company (PG&E). The pilot was flying the helicopter solo from the right seat with the door removed so that he could lean outside and observe below. According to the helicopter operator, this was the second time he had taken the check ride, having not passed on the first attempt. The maneuvers were observed and monitored on the ground by a group of examiners. The pilot had about 3,500 hours of total flight time, including about 1,000 hours as a flight instructor and agricultural pilot and almost 175 hours on type. He started working for the helicopter operator about 15 months earlier. The pilot had logged c 87 hours of FAR Part 133 external load time before the accident (most in the AS350) and c 10 in the B407. After performing the initial maneuvers, the pilot transitioned to the HEC phase of the exam by carrying a lineman on a 60-ft long line. While maneuvering the helicopter at an altitude of about 175 ft above ground level (agl), the helicopter lost engine power. Multiple witnesses recounted observations that matched the pilot’s statement. All stated that the helicopter appeared to be operating without issue throughout the maneuvers until they heard a change in engine tone, with some then observing the main rotor blades slowing as the helicopter began to rapidly descend In response, the pilot selected what he thought was the “emergency” throttle detent, but the engine did not respond. The pilot maneuvered the lineman away from the landing helicopter and performed an autorotation. The helicopter landed hard and sustained substantial damage. The Safety Investigation [E]xamination of the airframe, engine, and engine control systems did not reveal any evidence of preimpact mechanical malfunction or failures. The helicopter contained fuel, was loaded within its envelope, and weather was not a factor. Onboard video recorded a section of the annunciator panel that showed some, but not all, engine warning lights, none of which illuminated at any point during the flight. The recording did capture an audio tone as the descent began that was the same frequency as the engine out and low rotor warning indicators. The video recording appeared to show the pilot was anxious throughout the flight; however, considering the nature of the work he was performing and the stress he would have been experiencing, this is understandable. It could not be determined if this contributed to the accident. The engine was test run in a test cell and it performed nominally. Significantly: Review of data recorded by the engine control unit (ECU) revealed that at the time of the loss of engine power,...
read moreHEMS Downwash Injuries: Two More Case Studies
HEMS Downwash Injuries: Two More Case Studies We return again to a safety issue we have previously highlighted, namely helicopter downwash. Case Study 1: AW169, G-KSSC, UK, 11 October 2023 On 11 October 2023 a bystander was injured when Leonardo AW169 air ambulance G-KSSC landed at Bearsted Common, Maidstone, Kent. The UK Air Accident Investigations Branch (AAIB) explain in their safety investigation report, issued 13 June 2024, that the Gama Aviation (formerly Specialist Aviation Service) / Air Ambulance Kent Surrey Sussex Helicopter Emergency Medical Service (HEMS) aircraft was on final approach to a cricket pitch, c 80 m from an emergency incident. The crew assessed the field and established that its size, approximately 80 m by 120 m, was more than sufficient to use as a HEMS landing site. In daytime a ‘2D’ sized clear area is required, which AAIB note is 30 m by 30 m for an AW169, though there are other considerations for safe operations, as this occurrence highlights. The crew decided on an approach track that avoided the cricket pavilion and some residential properties to the north-east of the pitch. This also allowed the approach to be conducted largely into wind, which was from the south-west. The crew noted that there were pedestrians at the northern end of the field and some ground covers protecting the playing surface, but the main pitch area was clear. They elected to use a helipad profile approach with a committal height of 180 ft agl to provide sufficient clearance from surface obstructions. On the final approach to land, when passing abeam the pavilion, the crew noticed that two previously unseen members of the public had appeared at the north-eastern edge of the cricket square, near the pavilion. The pilot flying stopped the descent at a height of approximately 160 ft agl to minimise the effect of the rotor downwash and extended his aiming point further into the area. As the crew established the helicopter in a hover at about 40 ft agl, one of the medical crew in the cabin noticed that the ground covers had rolled from their original position. The pilot flying decided to continue with the landing as any additional manoeuvring would risk blowing the covers further. The helicopter was shut down and shortly after the crew were made aware a woman “had suffered a cut to her leg when one of the ground covers rolled towards her, striking her”. She was subsequently taken to hospital. The Safety Investigation It was found that… …the covers were mounted on wheels which were equipped with brakes. The brakes had not been applied and the covers were moved easily. AAIB comment that: HEMS operations are inherently reactive and time sensitive. Due to the urgency involved, it is often impractical to provide formal site security measures to control access to third parties at landing sites. The applicable regulatory guidance material, GM1 SPA.HEMS.100(a), sets out the “HEMS Philosophy” that includes the concept that “potential risk must only be to a level proportionate to the task”, with the following hierarchy of protection: (1) third parties (including property) – highest protection; (2) passengers (including patients); and (3) crew members (including technical crew members) – lowest. Oddly this puts third-party property above passengers and crew and equally with third party individuals. AAIB note that: The speed...
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