AW169 Birdstrike with a Turkey Vulture
AW169 Birdstrike with a Turkey Vulture (N307TC of Travis County EMS STAR Flight) On 22 November 2021, Leonardo AW169 air ambulance N307TC of STAR Flight (Travis County Emergency Medical Services) suffered a birdstrike from a Turkey Vulture near Austin, Texas. The helicopter, which had six occupants, was inbound with a patient from Bastrop, Texas. It was one of three STAR Flight introduced in 2019 as the US launch customer for the AW169 in HEMS operations. The US National Transportation Safety Board (NTSB) public docket, opened 19 April 2022 explains: The medical crew member sitting in the front left cockpit seat, was the first to see the bird and announced its presence. The vulture was first seen ascending from the lower left field of view, it maintained its current track. It looked as though it was going to impact directly in the middle of the right front windshield. As soon as {the Pilot-in-Command] PIC saw the vulture, he maneuvered the aircraft to the left and started to descend in an attempt to avoid the vulture or minimize the severity of the impact location on the aircraft. Seemingly, within a couple of seconds after maneuvering the bird impacted the aircraft. PIC quickly determined that they needed to divert from the intended point of landing at Seton Main Hospital, and land at the STAR Flight Hangar Helipad (TE94) as it was just over 1 minute away. PIC felt that going to the STAR Flight hangar helipad was the most expeditious means to safely terminate the flight. The aircraft landed safely with no injuries to the occupants. When inspected on the ground the damage reportedly consisted of: Cracked front right windshield Cracked windshield support beam Cracked greenhouse window Undetermined main rotor blade surface damage. The AW169 certification basis is CS-29 Amendment 2, dated 17 November 2008. This requires compliance with the following requirement: CS 29.631 Birdstrike: The rotorcraft must be designed to assure capability of continued safe flight and landing (for Category A) or safe landing (for Category B) after impact with a 1 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 2438 m (8 000 ft). Compliance must be shown by tests, or by analysis based on tests carried out on sufficiently representative structures of similar design. Turkey Vultures typically weigh 0.8 to 2.41 kg (1.8 to 5.3 lb) so this bird mass most likely exceeded the certification requirements. The rotorcraft velocity at impact is not recorded for this impact. In a presentation on behalf of the Rotorcraft Bird Strike Working Group (RBSWG) to the 11th EASA Rotorcraft Symposium in December 2017 it was revealed that in the US 94% of the current helicopter fleet is made up of types that never needed to meet a birdstrike requirement. CS 29.631 is harmonised with US certification requirements. The AW169s nearest competitor only partially compliant with 29.631 (with the windscreens in particular being noted by the FAA as non-compliant, due to so-called grandfather rights). Safety Resources The European Safety Promotion Network Rotorcraft (ESPN-R) has a helicopter safety discussion group on LinkedIn. EASA have issued Safety Information Bulletin SIB 2021-07 on Bird Strike Risk Mitigation in Rotorcraft Operations and accompanying safety promotion material. You may also find these Aerossurance articles of interest: 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...
read moreCompressive Creep and the Loss of a UH-1H’s Tail Rotor
Compressive Creep and the Loss of a Bell UH-1H’s Tail Rotor (N3276T, Mesa, AZ) On 24 April 2020 Bell UH-1H N3276T of VNC LLC / Southwest Rotors was destroyed in an accident at Mesa, Arizona. One pilot died and the other miraculously survived but was seriously injured. The helicopter was positioning from Jacqueline Cochran Regional Airport (TRM), Palm Springs, California to Falcon Field Airport (FFZ), Mesa. The helicopter was type certificated in the restricted category under the Federal Aviation Administration (FAA) Type Certificate Data Sheet (TCDS) H7SO, held by Overseas Aircraft Support Inc since 2008. In their safety investigation report, published 3 May 2022, the US National Transportation Safety Board (NTSB) say witnesses reported… …they observed…white smoke emitting from the tail rotor area. Suddenly, the tail rotor separated from the helicopter… [which] started to spin and impacted the ground. The debris trial was 1/2 mile long. The tail rotor assembly was found at one end and the fuselage, along with most of the debris, at the other end. The NTSB Safety Investigation The NTSB report that: The tail rotor gearbox was fracture-separated at the attachment studs, and four of the fractured attachment stud pieces were found loose within the vertical stabilizer. A fifth stud piece remained stuck in the vertical stabilizer support casting, and the nut end of the sixth stud piece was not located. The chip detector was removed from the tail rotor gearbox and metallic debris was present. The tail rotor assembly was mostly whole and intact. The linkages and tail rotor blades remained secured in place. Progressive crack growth was noted on the mounting studs within the tail rotor gearbox housing. The fracture surfaces were relatively rough, consistent with low cycle fatigue or cyclic overstress crack growth under relatively high cyclic stresses. Additionally, multiple layers of primer, paint, and sealant were observed on the input quill assembly, including paint on the flange clamping surface where it had mated to the vertical stabilizer. Paint was also observed on the vertical stabilizer support casting where it had mated to the input quill as well as the washers for the tail rotor gearbox attachment hardware. The US Army Depot Maintenance Work Requirement No. 55-1560-127 contains instructions for painting the tail rotor gearbox. The instructions contain a step to “mask the top part of the outer flange of input quill sleeve and also the entire studs.” In 2012, the gearbox was removed from another helicopter, repaired, painted, and installed on the accident helicopter. According to the NTSB, the TGB had a main input seal replaced before the painting at Heliponents Inc in Mesa. The FAA requested the detailed work order from the repair station, but those records were no longer available. Then in January 2019… …the helicopter was painted and photographs that were taken during this process indicated that the tail boom, tail rotor gearbox, and tail rotor assembly remained installed during the painting process. In addition, the tail rotor assembly and tail rotor gearbox were masked. Therefore, the paint found on the contact mounting surfaces was likely applied during the gearbox installation in 2012. Th NTSB go on to explain that 39 flying hours earlier… …in April 2019, the tail rotor gearbox was removed from the vertical stabilizer for a corrosion inspection; no defects were noted in the maintenance logs. A retorque and/or torque stabilization check was not completed after the gearbox was installed, nor was it required to be according to applicable technical manuals. A re-torque was included in the Maintenance Manual for the Bell 205, the original new...
read moreReview of “The impact of human factors on pilots’ safety behavior in offshore aviation – Brazil”
Review of: “The impact of human factors on pilots’ safety behavior in offshore aviation companies: A Brazilian case” (Dario Sant’Anna and Adriana Hilal of COPPEAD Graduate School of Business, Federal University of Rio de Janeiro in Safety Science 140 (2021)) Safety Science is the premier peer-reviewed safety journal. In August 2021 they published a paper on safety in the Brazilian offshore helicopter industry. In this article we summarise the context, methodology and key findings and then discuss the implications. Context Brazil’s offshore oil and gas exploration has driven one of the bigger offshore helicopter operation sectors. The main customer of these helicopters is state oil company Petrobras (described as the ‘Main Contractor’ in the paper). This IOGP member company has a dominant market position, contracting 80-90% of all offshore helicopter operations in Brazil. The authors say that there are three big helicopter operators “accounting for more than 85% of the entire sector” and a couple of smaller operators. Pilots typically work a roster with 15 consecutive days on duty for 12 hours per day and almost 8 hours flying each day according to the authors. Exploration of the deepwater ‘pre-salt region‘ had created a lot of oil and gas industry excitement and the potential was so huge that Brazil has started to open the sector to foreign investors operating offshore fields. It was predicted Brazil was heading for a fleet of 200 offshore helicopters in 2020, with particular growth in heavy helicopters for the long-range deepwater fields. The collapse in the oil price in Q3 2014 however had a catastrophic affect on the offshore helicopter sector in Brazil. The fleet declined from 100 helicopters to 70 in 2016, with a number of contracts terminated in 2015. One helicopter operator is reported to have made almost one third of their pilots redundant. New contracts also tended to be shorter two years rather than five. In 2020 Petrobras is reported to have used a reverse auction process to drive down prices. The authors also note that from 2014 onwards the company had been the centre of a major corruption inquiry (‘Operation Car Wash‘), which affected its own capital expenditure and may have further discouraged foreign investment in the oil and gas sector. Privatisation of Petrobas is now being considered. The last fatal offshore accident in Brazil occurred on 16 March 2022. Research Question and Methodology The authors state that the questions their paper was to address were: What are the main human factors that affect pilots’ safety behavior in offshore operations? How can offshore aviation companies manage to mitigate the adverse impacts of those human factors on their pilots’ safety behavior? The research was qualitative and based on transcribing structured one-to-one interviews of offshore pilots typically lasting 1.75 hours. This approach does ensure feedback is gathered from frontline personnel but such qualitative data will be of perception, opinions and more anecdotal facts. Some refer to such studies as being focused on ‘Thick Data‘ rather than ‘Big Data‘ from a more quantitative study. Both types of studies of course have their place. The authors explain that… Interviewees were encouraged to support their statements with examples, and the interviewer asked follow-up questions. The two authors then independently coded the interview feedback and collated their results into themes. Then, in a deductive way, evidence was gathered so as to support the themes and interpretations. Finally, the findings were compared to what...
read moreHeliOffshore 2022 Conference Review
HeliOffshore 2022 Conference Review After two years of virtual events, over 140 delegates from HeliOffshore’s international membership gathered in Cascais, outside of Lisbon, 23-24 April 2022 for the association’s annual conference. Aerossurance, as a committed HeliOffshore member, has attended all six in-person HeliOffshore conferences. HeliOffshore, founded in 2014, is the global collaborative safety association for the offshore helicopter industry. This year’s theme was “a safe and sustainable transition to 2040”. Offshore Helicopter Safety Performance Among the good news was that the industry has seen a significant positive improvement in safety performance in recent years (the subject of HeliOffshore’s eagerly awaited fourth safety performance report due out shortly). There have however been two fatal accidents in the offshore community in 2022 (one in the US and one in Brazil, with 3 fatalities in total). Safety Learning As part of a commitment to moving collaborative safety learning to a new level, two operators did a joint briefing on an lessons learning exercise they had done with HeliOffshore after one non-fatal accident and one serious incident in two different regions of the world that both involved approaches to helidecks at night. Further enhancements are also underway to the HeliOffshore Safety Intelligence Programme (HSIP), including a programme of proactive aggregated flight data analysis on the Sikorsky S-92A fleet. Safety Culture and Human Performance Sessions over both days discussed overlapping themes of sustainable safety culture and enabling human performance. This included mention of some particularly interesting research into “the re-design of the Just Culture process in an international energy company“. This excellent research, published in 2018, had already caught Aerossurance’s attention as a rare, peer reviewed, study that assessed how the implementation of Just Culture procedures were actually working in an organisation (looking at 353 cases). Spoiler alert: the procedures based on the original logic of James Reason were being routinely misapplied and the research went on to discuss how this was corrected. Such misapplication is something we commonly see in the aviation sector, with the process (often based on proprietary flowcharts) actually increases the focus on the capability (or not) of individuals rather than on driving system improvements. Safety Leadership An inspirational high point was a presentation by John Amaechi OBE, the psychologist, former former professional basketball player and author of The Promises of Giants (discussed in this VIDEO). He described a concept of ‘step theory’, namely that in life, everything you do is either a step closer to your vision or a step away from it and the direction you take is your choice. Amaechi advocates developing introspection, interpersonal and organisational abilities in order to enhance leadership skills and sharing ideas before you are ready (trusting your collaborators to contribute to refining the ideas). As he has explained in interviews: Leadership is not a title or role. It’s a promise of a kind of experience. It says if I only have the power to influence these two people, I will wield that wisely and well. After that presentation, HeliOffshore announced a new safety leadership bursary. Aerossurance immediately committed to co-funding that excellent initiative, more details of which will be announced later this year. Next Generation of People & Helicopters and the Rise of Renewables A number of participants commented on the need to thinking about developing the next generation of professionals in our community. Others highlighted that the average age of the offshore fleet is increasing due to the minimal number of new aircraft purchased in recent years (especially in...
read moreLoose Clothing Downs Marijuana Survey Helicopter
Loose Clothing Downs Marijuana Survey Helicopter (B206L3 N27TK) On 28 October 2021, Bell 206L3 N27TK, operated by Helico Sonoma, suffered substantial damage and made a forced landing during an aerial survey flight over illegal marijuana crops near Covelo, Mendocino County, Northern California. According to documents in the US National Transportation Safety Board (NTSB) public docket the Mendocino County Sheriffs Office had chartered the aircraft “explicitly to conduct aerial photography/film operations utilizing reporters from USA Today“. Indeed the newspaper published a feature in December 2021: Marijuana wars: Violent Mexican drug cartels turn Northern California into ‘The Wild West’: Lured by America’s push toward legalized cannabis, cartels have abandoned many decades-old marijuana farms in Mexico, moving their operations to Northern California where they can blend in seamlessly alongside legitimate grows… Mendocino, Humboldt and Trinity counties are known as the Emerald Triangle or Emerald Counties, a region that produces a significant portion of cannabis consumed in the U.S. through legal and illegal grows. Alderpoint, near the epicenter, is known as “Murder Mountain“…due to the prevalence of missing persons cases and shootings. During recent years, violence has intensified in Covelo, a remote valley town in Mendocino surrounded by mountains. The pilot, who was 29 with 1701 hours of flying experience (87 on type), described how: A standard weather briefing was gathered from my Foreflight account, and a company flight plan was filed. Three passengers were to be picked up at Ukiah Municipal Airport (KUKI). The pilot landed at 11:10 Local Time, briefed the passengers and they departed ay 11:40. The briefing included use of doors, headsets, emergency exits, smoking prohibitions, and hazards associated with doors-off operations. I specifically discussed that no loose articles in the cabin are authorization [sic] at any time, and each passenger verbally acknowledged the briefing. I personally inspected the cabin area and determined there were no loose items/articles of clothing that presented hazard to the flight. Only the photographer’s camera gear was present in the cabin, which was physically secured to ensure that it would remain in the aircraft. At 12:00, approximately 9 nm SE of Covelo… I heard the aft-right passenger gasp over the ICS [intercom] and exclaim that she “lost her jacket out the door”. Simultaneously with the gasp I felt something impact the aircraft. I became immediately aware of the potential danger and proceeded to assess the situation. I test the anti-torque pedals which responded normally. I then checked the fore-aft cyclic control to ensure freedom of movement. I experienced an increased amount of control forces associated with resistance against the elevator located on the trailing edge of the horizontal stabilizer. I immediately realized that the jacket had become lodged on the horizontal stabilizer, and therefore was placing the tail-rotor at risk of FOD ingestion. I then made the decision to make a precautionary landing at a gravel bar which was located within autorotative gliding distance at the aircraft’s 3 o’clock. I informed the passengers of the situation, made a distress call on the local CTAF, 122.8, and cautiously flew the aircraft in a circular right hand turn in order to descend and maneuver into the wind. I was deeply concerned the tail-rotor would fail at any moment and maintained an appropriate autorotative airspeed until about 200 agl. I reduced speed and altitude, terminating to a very gentle flare at 5 ft agl decelerating...
read moreUS Air Ambulance Helicopter Hospital Heliport Tail Strike
US Air Ambulance Helicopter Hospital Heliport Tail Strike (Arkansas Children’s Hospital Sikorsky S-76D N761AF) The US National Transportation Safety Board (NTSB) has recently (19 April 2022) opened the public docket on an accident that occurred to Sikorsky S-76D air ambulance N761AF of Arkansas Children’s Hospital on 12 March 2022 at Texarkana, Texas The helicopter was substantial damaged in a tail rotor strike while landing at dusk on an elevated helipad at the Wadley Regional Medical Center (64XS). The helicopter was inbound to do a patient transfer from the medical centre. This was the pilot’s first flight of the day, having come on duty slightly ahead of schedule at 17:08. The pilot was aged 54 with 3,212 flying hours in total, 174 on type. Two medical personnel were also on board. Their seating positions were not noted in the accident report form. The pilot had not been to 64XS before and examined information on an app on an iPad to gain familiarity with the site when en route. Crucially, the data currently in the public docket does not explain the level of detail available in this app. The pilot reported setting a waypoint 3 miles from the hospital “to establish a descent and deceleration point prior to the landing point to make a smooth transition from cruise flight to landing”. At the near-by Texarkana airport wind was reported as 11 knots, 160° and visibility 10 miles. He explained: Prior to reaching the 3-mile waypoint, I started slowing to 80 KIAS, and initiated a descent to 1500 ‘ MR. I made a call to Texarkana Tower that the hospital was in sight. I told the flight crew that we were about 3 minutes inbound. Upon reaching 80 knots, I lowered the gear and turned on the landing lights and search light. I slowed to approximately 60 knots, and descended to about 1000’. My course inbound…was originally 225 degrees. At about 25-30′ AGL on a very slow approach to the pad [at 18:30], I felt/heard a “thump” in the pedals and immediately the aircraft began to vibrate. We assume “25-30′ AGL” actually means a height of 25-30 feet above the helipad, which is a 50 ft square helipad (so slightly sub 1-D sized for an S-76D whose D-value = 52.5 ft) on the roof of a fourth storey building. The TR GBOX CHIP/TR OIL TEMP HIGH light illuminated and the aircraft yawed to the right. The pilot says: I instinctively lowered the collective and flew to the pad. At almost the point of landing, I pulled the collective for cushion, and the aircraft yawed right about 60 degrees as we settled on the pad. The helicopter was safely shut down without injury. The public docket images indicate the tail rotor struck a building that was an obstacle very close to the helicopter landing area. Examination of imagery suggest the helicopter passed very close to a structure sited to the north east as well as directly over a structure containing a lift shaft that was at c 10 ft above the helipad surface and c 25 ft from the deck edge. The aircraft pitch angle will also have needed to be relatively high too. Our Observations One of the key indicators of whether a safety investigation is competently and thoroughly conducted is whether the focus falls on the person closest to the accident or whether systemic issues are examined. A public inquiry chaired by Anthony Hidden QC investigated...
read moreNTSB: Ergonomics Explain Main Rotor Loss During Flight Test
NTSB: Ergonomics Explain Main Rotor Loss During Flight Test (Bell 206B N61PH) On 16 April 2019 Bell 206B N61PH of Van Horn Aviation was destroyed during a test flight evaluating developmental main rotor blades near Fort McDowell, Arizona. Both occupants were killed. The US National Transportation Safety Board (NTSB) issued their safety investigation report on 6 April 2022. The Accident Flight The NTSB explain the flight was being conducted as a Part 91 test flight and the aircraft was in the Experimental (Special) category. The helicopter was modified to have Van Horn Aviation’s 20635000-501 main rotor blades. These were constructed using carbon fibre/epoxy pre-preg woven fabric and unidirectional tape. The pilot was aged 52, held a Commercial Pilots Licence and had 1200 hours flying experience according to the NTSB. He was accompanied by a 28 year old engineer who had a Private Pilots Licence. Neither the NTSB report nor the public docket mention either having any flight test qualifications. The helicopter made the first test flight of the day between 05:45 and 06:20. After 100 lb of ballast was loaded, it departed again at 06:32 for a flight that was to consist of… …multiple autorotations at maximum gross weight, entered following a 1-second delay after a simulated loss of engine power. The operator reported that the [pilot] would perform all the flight maneuvers and the flight test engineer would perform several tasks during the test flight, which included holding a 17-inch, 7.72-lb [3.5 kg] engineering laptop with his left hand above the cyclic control while simultaneously using and stowing a clipboard and pencil to manage data collection. Flight cards are prepared for each test flight and listed the maneuvers to be performed during the flight. The accident flight was to be the last test flight of the main rotor blades before their certification process. Cyclic controls were installed at both seat positions, reportedly a deviation from procedures according to the operator (although no procedural documents are reproduced or referenced in either the NTSB report or the public docket). A review of the radar data revealed that the accident flight duration was about 34 minutes. The pilot executed multiple turns and descent maneuvers near the area of the accident site. The…final radar-recorded altitude was…about 3,000 ft above ground level (agl). A witness saw the helicopter falling from the sky and saw several other objects descending to the ground before losing sight of it behind trees. NTSB Safety Investigation The examination of the accident site revealed post-crash fire and impact damage consistent with a right side-down, nose-level attitude during ground impact. The main rotor hub assembly, vertical fin stabilizer, tail rotor assembly, tail rotor driveshaft, and forward induction cowl fairing separated from the main wreckage and was found in the debris field. One main rotor blade was found furthest from the main wreckage. The other main rotor blade was found near the main wreckage. The debris field was about 1 mile long and 1,000 ft wide… Damage found was consistent with a mast bumping event. …a phenomenon specific to the 2-bladed teetering or underslung rotor system where the rotor hub flap stops shear the mast. Mast bumping is the result of excessive rotor flapping. No evidence of any prior mechanical malfunctions was found. The NTSB comment on the challenging ergonomics: In order for the engineer to operate the computer or take notes on the clipboard, he would have to hold the computer with one hand while using the other to enter commands or take notes....
read moreBusiness Jet Apron Jet Blast Injury
Business Jet Apron Jet Blast Injury (GX N307KP, Augusta, GA) On 16 October 2019 a passenger being escorted across the apron of Augusta Regional Airport (AGS), Augusta, Georgia to a waiting Learjet operated by department store Dillard’s was seriously injured by the jet blast from Bombardier BD-700-1A10 Global Express XRS N307KP that had just started to taxi. The US National Transportation Safety Board (NTSB) issued their safety investigation report on 6 April 2022. According to the injured passenger, she and six other passengers were being escorted by one of their pilots to a Learjet. She stated that she was about 70 ft from the Bombardier when she was knocked over by the jet blast from the engine. The first officer of the Learjet stated that he was walking to the airplane with two passengers, and the five remaining passengers were following behind them. As some of the passengers were about to board the airplane, he heard a loud roar and felt a strong, warm gust. He turned around and saw one of the passengers on the ground. He stated he initially thought the Bombardier only had its auxiliary power unit running and believed the airplane was far enough away. The FO also stated the injured person was briefly unconscious, A second passenger was blow over but only suffered cuts to her knees. The Bombardier aircraft had arrived to drop one passenger off: They shut down the left engine and deplaned the passenger, restarted the left engine, and taxied back to the runway. During the entire stop, the rotating beacon was on and the right engine was operating. The captain stated that he used normal breakaway power to get the airplane out of the parking spot, then taxied at normal speeds. An FAA inspector commented that there was a procedure “for marshalling the transit aircraft in, but not marshalling them out of the ramp”. The NTSB Probable Cause was: The first officer’s failure to maintain a safe distance from a large turbine-powered airplane while escorting passengers, resulting in a passenger encounter with jet blast. Safety Resources You may also find these Aerossurance articles of interest: Fatal ATC Handover: A Business Jet Collides with an Airport Vehicle on Landing Pedestrian Seriously Injured by Air Ambulance Landing at Melbourne Hospital Challenger Damaged in Wind Shear Heavy Landing and Runway Excursion Pilatus PC-12 Collided with Pick-Up Truck During Dusk Take Off Ground Collision Under Pressure: Challenger vs ATV: 1-0 Visual Illusions, a Non Standard Approach and Cockpit Gradient: Business Jet Accident at Aarhus Gulfstream G-IV Take Off Accident & Human Factors Fatal US G-IV Runway Excursion Accident in France – Lessons Execuflight Hawker 700 N237WR Akron Accident: Casual Compliance Unstabilised Approach Accident at Aspen Business Jet Collides With ‘Uncharted’ Obstacle During Go-Around Disorientated Dive into Lake Erie Fatal Falcon 50 Accident: Unairworthy with Unqualified Crew G-III Attempted Takeoff Using Runway Edge Lights as Centerline G200 Leaves Runway in Abuja Due to “Improper” Handling Cockpit Tensions and an Automated CFIT Accident Global 6000 Crosswind Landing Accident – UK AAIB Report BFU Report on Dramatic Challenger Wake Vortex Accident Falcon 7X LOC-I Due To Solder Defect Misfuelling Accidents A320 Rolls Back on Stand: Incomplete Maintenance Procedures and Ground Handling Deviations Runaway Dash 8 Q400 at Aberdeen after Miscommunication Over Chocks A330 Starts to Taxi Before Tug is Clear Jetstar Dispatcher Forced to Run After Distracted Pushback A320 Collided with Two...
read moreHelideck Heave Ho!
Helideck Heave Ho! (CHC/BHS Sikorsky S-76C++ PR-CHI) On 16 February 2014 Sikorsky S-76C++ PR-CHI of CHC‘s Brazilian Helicopter Services was damaged when landing on the bow deck of the drillship Aban Abraham while on charter to Brazilian state oil and gas company Petrobras. According to the Centro de Investigação e Prevenção de Acidentes Aeronáuticos (CENIPA) safety investigation report (finally released 16 November 2021 in Portuguese only) the helicopter had departed Cabo Frio Airport (SBCB) at 07:12 Local Time. It was to route to Aban Abraham NS07 (9PDA), then the Petrobras P-63 FPSO (9PHD), back to the Aban Abraham and then returning to Cabo Frio. Details of the helideck pitch, roll and heave (P/R/H) was not available when the aircraft departed Cabo Frio but were to be radioed by each vessel no later than 20 minutes before landing. During the third sector from P-63 to Aban Abraham the drillship’s radio operator reported the P/R/H was “within the limits for landing”. The data came from the vessel’s Helideck Monitoring System (HMS) and limits had been set that “were known to the [helicopter] crew and [drillship] radio operator”. However, CENIPA do not detail the limits in use in their report. According to CENIPA: …minutes before, there had been variations in P/R/H greater than the maximum permissible for the operation of the aircraft, which were not reported. No document or standard was found that contained instructions for the radio operator about the time interval to be considered when reading the maximum P/R/H values of the helideck on the HMS… Indeed CENIPA state that the HMS also showed “several peaks of heave above the limits” shortly before the landing. However, the CENIPA report unhelpfully includes no HMS or FDR data. The flight crew “performed a direct approach for landing” and perceived “some more prominent movements of the helideck” once they were below 500 ft. They “considered the possibility of a go-around…about one minute before the occurrence” but decided to continue. Ultimately there was a heave that ‘surprised them”, followed by a second one about 2 seconds later that resulted in an abnormal contact between the helideck and the right main landing gear, which collapsed. The helicopter was shut down and all 12 occupants safely disembarked. The helicopters was subsequently removed as an underslung load by a Kamov Ka-32. CENIPA Analysis Firstly CENIPA state: …the lack of a time interval [defined in regulation] to be considered by the radio operator for reading the P/R/H data on the HMS…in order to determine a safe condition for landing inside operating limits, contributed to the occurrence, as it allowed the crew to proceed to the landing at the helideck with information different from that actually found by the aircraft at the time of landing. While this is a sound systemic focus, the investigators decided with hindsight bias, to use the crew’s candour against them by determining… …the piloting judgment of the crew also contributed to the event, since despite having perceived more relevant movements of the helideck and having been considered a go-around, the pilots decided to proceed with the landing, judging that the conditions were favourable, thus highlighting a deficiency in the assessment of the scenario… This is a classic case of Catch 22 in a safety investigation. A statement that indicated the crew had failed to notice high levels of heave would potentially have resulted in a determination that lack of attention was contributor, while mentioning worsening conditions is judged as a failure to act. Safety Actions...
read moreSAR Seat Slip Smash
SAR Seat Slip Smash (RCAF CH149 Leonardo Cormorant LOC-I) The Royal Canadian Air Force (RCAF) is investigating a Loss of Control – Inflight (LOC-I) accident that occurred to Search and Rescue (SAR) Leonardo CH149 Cormorant (AW101) CH149903 at Gander, NL on 10 March 2022. The SAR helicopter, callsign Outcast 903, of 103 Search and Rescue Squadron, 9 Wing was completing an onshore rear crew focused training flight, the first of two planned for the day at c15:42 Local Time. There were six crew members on board: two pilots, two Flight Engineers and two Search and Rescue Technicians. At the end of the first training mission, the crew conducted hover work in the vicinity of the intersection of Runway 31 and Runway 21. During the final clockwise hover turn sequence, the pilot flying’s seat unexpectedly descended to its lowest position. The aircraft flight vector immediately reversed from a clockwise rotation to an accelerated counter clockwise left yaw about the aircraft mast. As the aircraft continued to yaw left, the attitude of the aircraft became unstable resulting in an increasing right bank attitude. The aircraft rotated through approximately 400° and as the right rolling moment intensified, the right outboard wheel, the horizontal stabilizer assembly located on the right side of the tail section, and main rotor blades impacted the runway. Two of the crew received serious injuries, three minor injuries and one egressed uninjured. The aircraft was significantly damaged on impact with the ground (although AW101s, aka Merlins, have been successfully rebuilt after major accidents [in one case an accident in Afghanistan, followed by being dropped by a US helicopter during the recovery and being dragged into a compound by armoured vehicle!]). The RCAF report their safety investigation is focusing on “materiel and human factors“. We will update this article as they release more information. UPDATE 29 July 2023: The conclusions of the investigation have been published: The investigation determined that a combination of factors, including seat non conformances and the horizontal position that was maladjusted, allowed the seat to be in a false lock condition. When the seat dropped, the loss of outside visual references in combination with the severe vertical vibration resulted in an unrecognized spatial disorientation of the pilot flying. This caused the pilot flying to incorrectly perceive a right yaw and apply full left pedal input; this led to a severe left yaw and contributed to the change in roll attitude that likely rendered the helicopter unrecoverable. Multiple special inspections and aircrew information files were issued to address the seat non-conformances and avoid false lock conditions. Additional preventive measures have been identified to address deficiencies in fire fighting services, egress and tracking of armament as highlighted during this investigation. CBC have gone on to report that: The seat’s lock pins, which lock it in place, were shorter than manufacturing requirements… That could result in the pins not fully engaging with the locking mechanism…which could provide a false sense that the seat is locked. The pins can’t be seen when the seat is installed “meaning there is no opportunity for visual confirmation by the pilot to know the seat is locked in place”. The pilot checked whether the seat was locked before the flight by doing a “wiggle check,” according to the report, moving back and forth to make sure it was locked in place. CBC say that investigators… …also found that the...
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