Inadvertent Fire Bottle Discharge During Maintenance
Inadvertent Fire Bottle Discharge During Maintenance The CHIRP Charitable Trust, who run the UK’s Confidential Human Factors Incident Reporting Programme, has reported on an inadvertent fire bottle discharge incident during maintenance in their Air Transport FEEDBACK Issue 113. The Aircraft was on a heavy maintenance input and several teams were busy working in the flight deck area. Three tasks were being worked simultaneously. Two engineers were assigned to the task of checking the APU [Auxiliary Power Unit] fire bottle squib circuit test. Engineer A, who was in the flight deck, believed that engineer B had disconnected the squib and was set-up to perform the check. Engineer A pulled the fire handle and fired the APU fire bottle which discharged. Engineer B indicated that he did not have the task sheet available as Engineer A had them, despite the fact that one was working in the flight deck the other was at the tail area. There were six people on the intercom system and the flight deck was very busy with a number of activities taking place simultaneously, this resulted in avoidable distractions and poor communication. CHIRP provide the following analysis: Distractions – The engineer lost his train of thought at important stages of the work due to numerous people on the intercom system. Organisational Factors – The company identified that the method of operation (when performing function checks at the end of the check) was not an isolated one and that there was some degree of this being the accepted norm. CHIRP go on to comment: This event highlights some routine HF [Human Factors] related problems. As well as looking at the individual HF errors, the organisation involved has taken steps to ensure there is a more co-ordinated approach to carrying out checks and functions. This applies particularly at busy times – typically towards the end of the maintenance input. While this is an easy mistake to make, it can serve as a lesson to ensure we have put processes and communications in place when carrying out function checks. Safety Resources Aerossurance has previously written about Professor James Reason’s 12 Principles of Error Management. UPDATE 8 April 2020: NTSB Confirms United Airlines Maintenance Error After 12 Years The UK CAA has issued this infographic on distractions: For support on maintenance human factors, preventing maintenance errors and improving maintenance performance you can trust, contact aviation consultancy Aerossurance: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest updates. ...
read moreSea State Forecasting – CHIRP
Sea State Forecasting – CHIRP The CHIRP Charitable Trust, who run the UK’s Confidential Human Factors Incident Reporting Programme, today published Air Transport FEEDBACK Issue 113. This included discussion of a report on sea state forecasting in the North Sea. The original report submitted to CHIRP was: Post CAP 1145 [Safety Review Of Offshore Public Transport Helicopter Operations], a sea state limit has been placed stopping CAT [Commercial Air Transport] operations overseas greater than sea state 6, or 6 metres. We reported for duty one hour before flight as requested. There were no managers present despite the knowledge that the weather (sea state) was due to deteriorate during the afternoon. The Met Office website 12:00Z forecast for the sea off the Aberdeen coast showed a maximum wave height of 4.5 metres, the 18:00Z forecast for the sea off the Aberdeen coast showed a maximum wave height of 6.5 metres over the majority of the UK North Sea as far as The Shetland Isles. One of us contacted the Met Office for clarification of the forecast wave height and was told the sea off the coast of Aberdeen would have waves in excess of 6 metres between 14:00Z and 15:00Z. There was a request made for the hourly forecast charts to be faxed to us so we would have the evidence at hand if management challenged us on our decision to stop flying, but they were not willing to send us the information, only give a verbal brief. Crews elected not to depart on flights that would require a return overseas greater than 6 meters. Management accepted crew’s decision when briefed later. Lessons Learned: Crews should not have to rely on verbal conversations with forecasters and hourly forecast should be made available on the Met Office website. It is noticeable, and very encouraging, that while the reporter was concerned that they would need strong evidence to back any decision not to fly, that the management did accept that decision without the hourly data they had requested. CHIRP commented: The Met Office provides forecasts of Significant Wave Height on a briefing system used by offshore helicopter operators called OHWeb. Operators are required to base their planning and operating decisions on the Wave Height forecasts on OHWeb. Since the report to CHIRP was received, the time steps for the forecasts on OHWeb have been increased from 6-hourly to 3-hourly to improve the fidelity and availability of the forecasts. Although the Met Office generate the product in hourly time steps, it was decided that the provision of hourly reports would not be appropriate because they could represent a potential source of pressure on pilots. With hourly forecasts, it could be that some pilots would feel compelled to ‘design’ the flight route around areas of high sea state using successive short term sea state forecasts. Moreover, with high sea states some pilots could have a tendency to await the next forecast with the mission on hold instead of cancelling it, taking a ‘rest’ break, and replanning it thoroughly. Despite the introduction of 3–hourly forecasts there remains the potential for actual sea states to be higher than those forecast; when this occurs the N Sea operators confer over the source, number and reliability of the reports before making a collective decision to operate, postpone or cancel flights....
read moreNTSB Report on 2013 S-76A++ Tail Rotor Blade Loss
NTSB Report on 2013 S-76A++ Tail Rotor Blade Loss The US National Transportation Safety Board (NTSB) has reported on a fatal Sikorsky S-76A++ accident to a Gulf Of Mexico offshore helicopter during a post-maintenance check flight of avionics systems. The accident occurred on 15 March 2013 to N574EH, operated by Era Helicopters LLC. The pilot and two mechanics died. After testing the avionics, the pilot allowed the mechanic to fly the helicopter at 1,000 feet above ground level. The mechanic maneuvered the helicopter for about 1 minute and then stated that he was transferring control of the helicopter back to the pilot. Two seconds later, the cockpit voice recorder (CVR) cut off. About 1 minute after the CVR cut off, the pilot made a routine radio call to the tower controller that he was returning to land. Two minutes after this call, the pilot radioed the tower controller and his company’s dispatcher, stating that he had a problem and would be landing off-airport immediately. Several ground witnesses noticed the helicopter as it flew toward the accident site, and it was making an unusual noise, described as grinding, screeching, or whistling. The helicopter impacted with a high vertical descent rate and a postcrash fire ensued. Examination of the helicopter revealed that the main rotor and tail rotor systems had low rotational energy at the time of ground impact. Two of the tail rotor blades (yellow and red) were fractured adjacent to the tail rotor hub. The fracture signatures on the red/yellow tail rotor spar assembly were consistent with the red tail rotor blade spar initially fracturing and the red tail rotor blade departing from the tail rotor. The NTSB say that: The resultant imbalance of the tail rotor fractured the tail gearbox (TGB) output housing studs and most likely tripped the CVR g-switch, which cut off the CVR. UPDATE 17 March 2019: Our diligent readers have correctly highlighted that this NTSB statement about the g-switch is erroneous as it isn’t compatible with the CVR transcript and the earlier discussion of subsequent radio calls to air traffic. The NTSB continue: The yellow tail rotor blade spar fractured due to high centrifugal forces as a result of the imbalance, and the yellow blade departed from the tail rotor; the tail rotor was then rebalanced. The two remaining tail rotor blades continued to provide partial tail rotor anti-torque, and tail rotor drive remained continuous through the TGB. The entirety of the red and yellow blade separation event likely occurred very quickly, with only a momentary bump or vibration at the time of blade separation. As the TGB output housing began to separate from the center housing, the gears likely began going out of mesh, allowing the output bevel gear to eventually contact the TGB center housing. This condition likely resulted in the loud, unusual noise reported by witnesses, as well as a drag force on the tail rotor drive system. As the pilot attempted to land, he likely shut the engines down in conjunction with an autorotative landing. Because the tail rotor drive system and main transmission remained mechanically linked, when the engines were shut down, it is likely that main rotor speed (Nr) degraded due to the compromised TGB. As a result, the helicopter developed a high vertical descent rate until ground impact. The red blade spar fracture...
read moreCessna 208B Caravan Ditching Video, Molokai, Hawaii, 2013
Cessna 208B Caravan Ditching Video, Molokai, Hawaii, 2013 We have previously covered the graphic ditching of Sikorsky S-76C 9M-STE (MSN 760398) of MHS Aviation in the South China Sea on 12 December 2013, and a passenger video of the ditching and rescue. Coincidentally, the day before (but in practice a couple of hours later due to the time difference), another ditching occurred, this time of a Cessna 208B Caravan off Hawaii, filmed by a passenger (Ferdinand Puentes). Sadly one person died in this accident (State Health Director Loretta Fuddy) and three people were seriously injured. The NTSB report that: On December 11, 2013, at 1522 Hawaiian standard time, a Cessna 208B, N687MA, sustained substantial damage following a loss of engine power and ditching into the Pacific Ocean near Kalaupapa, Hawaii. The airline transport pilot and two passengers were seriously injured, one passenger was fatally injured, and five passengers received minor injuries. Makani Kai Air was operating the flight under the provisions of 14 Code of Federal Regulations Part 135. Visual meteorological conditions prevailed for the cross-country flight, which had originated about 2 minutes before the accident. A company flight plan had been filed. The flight departed from the Kalaupapa airport on the island of Molokai, and was en route to Honolulu International airport, on the island of Oahu. The pilot stated that shortly after takeoff, a loud bang was heard and there was a total loss of power. After a short glide, he performed an open ocean ditching. The airplane floated for approximately 25 minutes and then sank. All the passengers put on their life preservers and exited the airplane. US Coast Guard and Maui Fire and Rescue personnel recovered the passengers approximately 80 minutes later. Local press subsequently interviewed the pilot. UPDATE 23 May 2016: The NTSB final report includes: All the passengers and the pilot exited the airplane through the rear right door, and the airplane remained on the water surface for approximately 25 minutes before it sank. One passenger swam to shore, and United States Coast Guard and Maui Fire and Rescue helicopters recovered the pilot and 7 passengers from the water about 80 minutes after the ditching. Several passengers stated that the pilot did not provide a safety briefing before the flight. One passenger stated that the pilot asked how many of the passengers had flown over that morning and then said, “you know the procedures.” The passenger who died before the first responders arrived was found wearing a partially inflated infant life vest. The autopsy of the passenger did not reveal any significant traumatic injuries, and the autopsy report noted that her cause of death was “acute cardiac arrhythmia due to hyperventilation.” Another passenger reported that he also inadvertently used an infant life vest, which he said seemed “small or tight” but “worked fine.” If the pilot had provided a safety briefing, as required by Federal Aviation Administration regulations, to the passengers that included the ditching procedures and location and usage of floatation equipment, the passengers might have been able to find and use the correct size floatation device. The National Transportation Safety Board determines the probable cause(s) of this accident as follows: The loss of engine power due to the fracture of multiple blades on the compressor turbine wheel, which resulted in a ditching. The reason for the blade failures could not be determined due...
read moreUK CAA CAP1145: Update on North Sea Helicopter Safety (CAP1243)
UK CAA CAP1145: Update on North Sea Helicopter Safety (CAP1243) Not long after the fatal loss of Eurocopter AS332L2 G-WNSB 1.5 nm west of Sumburgh Airport, Shetland Islands on 23 August 2013 with 4 fatalities (AAIB Special Bulletin), the UK Civil Aviation Authority (CAA) launched an rapid review on offshore helicopter safety. CAP1145 This CAA Review resulted in the CAP1145 report (‘Safety review of offshore public transport helicopter operations in support of the exploitation of oil and gas’), issued in 20 February 2014. CAP 1243 The CAA have now issued CAP 1243, the Offshore Helicopter Review Progress Report, which provides an update on the 10 months to 31 Dec 2014. In their press release, the CAA highlighted 4 safety improvements introduced since CAP1145 was published: Stopping flights over the most extreme sea conditions (Aerossurance has previously covered the European Aviation Safety Agency (EASA) actions to introduce Airworthiness Directives to make the certified ditching capability clear). Ensuring every passenger on an offshore helicopter flight is equipped with new improved Emergency Breathing System (EBS) ahead of schedule (Aerossurance has previously covered the industry imitative to introduce a Compressed Air – Emergency Breathing System, a technology the CAA had considered and rejected in the 1995 CAP641 Review of Helicopter Offshore Safety & Survival). Standardisation of pilot training, particularly for the use of complex automated systems on helicopters and the associated operating procedures (Aerossurance has previously commented on the Joint Operators Review (JOR) review, the formation of HeliOffshore and on the issues of automation and monitoring). Establishing a new top level group to drive change, the Offshore Helicopter Safety Action Group (OHSAG) that includes unions, industry and the CAA (which Aerossurance has discussed too). House of Commons Transport Committee Additionally the House of Commons Transport Committee have released a more detailed statement by EASA on some of the actions underway. That committee called for a Public Inquiry in its Second Report of Session 2014–15 on Offshore Helicopter Safety (report HC 289), particularly into the effectiveness of the CAA, but its recommendation was dismissed by the Department for Transport (DfT). Aerossurance covered that report and the DfT response previously. SINTEF Helicopter Safety Studies Oddly, one reason for this rejection was that a large, industry funded, study had been conducted previously in Norway by the research institute SINTEF (Helicopter Safety Study 3, issued in 2010). The HSS-3 was the third Norwegian study published over two decades. HSS-1 covered 1966-1990 and HSS-2 1990-1998. The second Norwegian HSS report was issued following the last fatal air accident in Norway (apart from a fatal passenger incident in 2014 previously reported by Aerossurance). That accident, which followed a high speed shaft failure on Eurocopter AS332L1 LN-OPG on 8 Sept 1997 resulted in 12 fatalities. Since that time there have been four fatal accidents in the UK sector: Sikorsky S-76A+ G-BJVX in the Southern North Sea 2001 (Main Rotor Blade failure), with 11 fatalities Eurocopter AS365N G-BLUN in the Irish Sea in 2006 (Controlled Flight Into Terrain / Water at night), with 7 fatalities Eurocopter AS332L2 G-REDL in the Central North Sea in 2009 (MGB epicyclic failure), with 17 fatalities which was also subject to a Scottish Fatal Accident Inquiry Eurocopter AS332L2 G-WNSB on approach to Sumburgh in the Northern North Sea in 2013 (Controlled Flight Into Terrain / Water) with 4 fatalities (the AAIB report is awaited) It should be noted that there is approximately 50% more flying in the UK sector than Norway. CAP491 HARP Report...
read moreThe ‘Automation Problem’ – A Discussion
The ‘Automation Problem’ – A Discussion Automation, or perhaps more correctly the use of automated systems, has become a hot topic in the aviation industry, particularly since the issue of the accident report into the loss of AF447 (issued in July 2012). We review one analysis of the underlying cause and discuss a warning about an emerging threat. Automation Introduction Aerossurance has covered the outcome of investigations into fixed wing accidents such as the Asiana OZ214 B777 Accident at SFO 6 July 2013 and other serious incidents involving Boeing 737s, Embraer ERJ 170s and Airbus A320s. Aerossurance has also discussed a Royal Aeronautical Society Rotorcraft Group conference in July 2014 on the introduction of automation to offshore helicopters, provocatively titled Technology: Friend or Foe?. The use of helicopter automation is only likely to increase (see: Bell 525 Fly-By-Wire Update). We also covered the release of a series Crew Resource Management (CRM) videos from UK Civil Aviation Authority (CAA) including one that reconstructed of an actual incident where autopilot mode confusion during the glidescope capture results in loss of control a breakdown in collective situation awareness. The ‘Automation Problem’: by Captain Ed Pooley The 20th issue of Eurocontrol‘s Hindsight magazine focused on automation matters. Among the series of articles and case studies, we particularly recommend an article on The ‘Automation Problem’ by Ed Pooley. Pooley was Head of Safety for a large UK regional airline and is now a consultant and Chief Validation Adviser for SKYbrary. Pooley comments that high levels of automation has had two main effects: Pilots’ Knowledge of both their automated systems and the way they interact with how aircraft fly, however they are controlled, is often insufficient to cope with abnormal events unless these are resolved by straightforward checklist compliance. The extent and nature of the Decision Making which is required to operate a highly automated aeroplane today is quite different from that required to fly most similar-sized aeroplanes thirty years ago. Cockpit monitoring (a topic discussed by Aerossurance in August) and compliance with standard operating procedures are powerful controls that can mitigate risk of a range of accident types. Pooley however contends that these only treat the symptoms of the real automation problem, stating: The focus needs to be placed firmly on effective knowledge-based decision making. Pooley goes on to analyse the Air France AF447 A330 and Asiana OZ214 777 accidents. He also examines two more positive outcomes (the Qantas QF32 A380 and the less well know Cathay Pacific A330 serious incident were both engines started to malfunction after fuel contamination). He concludes, perhaps in places a little controversially: …whilst the way automation is delivered in aircraft design can always be improved, the root of the automation problem we are seeing today does not lie primarily – as many human factors experts will tell you – in system design. Rather, it lies in ensuring that people with the right aptitude and ability are trained as pilots in the first place. And that they are thereafter provided with type and recurrent training which is compatible with a job which now typically has very long periods of automated routine punctured only very rarely by the challenge of something completely) unexpected. Even with the very best selection processes, a successful outcome to any path through training is not a guaranteed one. There is a very heavy responsibility on all aircraft operators to ensure that they do not release pilots...
read moreAerossurance Joins the British Helicopter Association
Aerossurance Joins the British Helicopter Association Aerossurance is pleased to have been accepted as a member of the British Helicopter Association by the BHA Council. The BHA is the non-profit trade organisation that represents the UK’s civil helicopter industry to the Civil Aviation Authority, government departments and international bodies. Its main aim it is to: …promote the safe, efficient and environmentally responsible operation of rotorcraft throughout the UK. The BHA represents UK industry in Europe through its membership of and support for the European Helicopter Association (EHA). From its foundation in 1969, until 2008, the body was known as the British Helicopter Advisory Board (BHAB). Aerossurance is an Aberdeen based aviation consultancy, with extensive experience of helicopter regulation, safety, design, airworthiness and operational matters. Contact us at: enquiries@aerossurance.com ...
read moreDramatic Malaysian S-76C 2013 Ditching Video
Dramatic Malaysian S-76C 2013 Ditching Video Dramatic passenger-shot video footage of a helicopter ditching and rescue off Malaysia has emerged: The Sikorsky S-76C 9M-STE (MSN 760398) of MHS Aviation, chartered by Malaysian oil and gas company Petronas, was on approach to a 3D seismic ship in the South China Sea on 12 December 2013. The 105m long, 9800GRT vessel has a 22m bow mounted helideck, approximately 20m above sea level. She is capable of towing seismic ‘streamers’ of up to 9km in length. The vessel was 86 nm offshore Bintulu, Malaysia. The video footage indicates that the vessel was underway with streamers deployed in light rain and ~1m waves. The helicopter makes a slow approach to the deck into wind and just as it positions ahead of the vessel, with the helideck to the left hand side, the audio indicates an engine power loss. At this point the passenger braces and video is temporarily lost as the aircraft ditches. The soundtrack indicates that water was entering the cabin about 15 seconds after the engine rundown, and the passenger’s submerged lifejacket is briefly glimpsed. The helicopter had 8 people on board (2 crew and 6 passengers). All exited the aircraft. The aircraft floatation system does not seem to have been deployed, and the aircraft appears to be floating, almost submerged on its left hand side. It is understood to have subsequently sunk. While one aircraft liferaft seems to have deployed, it appears all occupants were promptly rescued from the water by fast rescue craft from the ship, which steamed on. Petronas issued a press release that day. The status of the Malaysian accident investigation is not known (see Ministry of Transport website). However, it is known that the Australian Transport Safety Bureau (ATSB) was requested to provide assistance in the download of the helicopter’s cockpit voice recorder (CVR). In late 2014 ATSB reported that the estimated completion date would be July 2015. UPDATE 4 September 2015: The ATSB website revised that forecast to December 2015. UPDATE 31 December 2015: This was our most popular article in 2015. UPDATE 10 May 2016: The ATSB now forecast July 2016. UPDATE 1 December 2016: The accident report is still awaited and the ATSB now forecast this month (the 3rd anniversary of the accident). UPDATE 30 December 2016: This was our 2nd most popular article in 2016. UPDATE 1 February 2017: The ATSB forecast for issue of the report has slipped to April 2017. UPDATE 13 April 2017: The ATSB say the Malaysian final report has been issued, though it is yet to appear on the Ministry of Transport website. We will monitor for its publication. UPDATE 13 December 2017: Information received by Aerossurance is that disappointingly the ICAO Annex 13 report will not be made public. 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: Helicopter Ditching – EASA Rule Making Team RMT.0120 Update NTSB Report on Bizarre 2012 US S-76B Ditching Newfoundland S-92A Accident US BSEE Helideck A-NPR / Bell 430 Tail Strike NTSB Recommendations on Offshore Gas Venting Helicopter Ditching Limitations Gulf of Mexico Fatal Helicopter Accident (11 Jun 14) Offshore Helicopter Confidence Building – Oil & Gas UK’s 2014 Aviation Seminar Offshore Helicopter Accident Ghana 8 May 2014 & The Importance of Emergency Response UPDATE 24 January 2016: CAP1145 Helicopter Water Impact Survivability Statistics – A Critique UPDATE 20 April 2017: Taiwan AS365N3 Tail Rotor Pitch Control Loss During Hoisting UPDATE 6 August 2018: In-Flight Flying Control...
read moreNew Helicopter Survival Suits in Canada
New Helicopter Survival Suits in Canada Survitec Group design engineer Alice Cannon presented to SAFE Europe symposium in Bristol in March 2014 on the company’s development of a new helicopter passenger survival suit for use in Canada. In November 2014, Gaelle Halliday of oil company Husky Energy presented more information at the first safety conference of the Canada-Newfoundland Labrador Offshore Petroleum Board (C-NLOPB). A competitive tender was initiated in 2012 to replace the previous Nautilus HTS-1 design. That follows an accident to a Cougar Sikorsky S-92A on contract to Husky Energy, off Newfoundland, Canada on 12 March 2009. Of the 18 on-board, 17 people died, although one passenger, Robert Decker, survived. Decker’s core temperature had however dropped to just 28°C when admitted to helicopter 2 hours after. At that temperature unconsciousness and an irregular heart beat, which can result in death, are to be expected. The Canadian Transport Safety Board (TSB) reported on that accident in 2011 and Aerossurance has previously discussed the airworthiness aspects of that accident. The winning Survitec suit features several improvement over the HTS-1. The one major improvement is the use of a permanent neck seal with a hood featuring a secondary face seal. The earlier suit featured only the face seal, and passengers only zipped up for take-off, landings and announced emergencies. This left them vulnerable to sudden emergencies. The upper part of the suit has been changed to yellow for better visibility (yellow is also a less common colour for marine debris than orange). The suit features a light-weight Gore-Tex material used previously of Survitec’s 1000-series suits (launched in 2010). Rather than a separate lifejacket, the suit has a integrated inflatable buoyancy ‘element’. The suit has boots with a ‘less aggressive’ tread and attached gloves. The suit incorporates a compressed air – emergency breathing system (CA-EBS), known as HUEBA (Helicopter Underwater Emergency Breathing Apparatus), introduced after a long gestation after the 2009 S-92A accident. While this was mounted on the right hand side on the first prototypes, this has been moved to the left hand side on productions suits. A Marine Rescue Technologies AU10-HT Personal Locator Beacon (PLB) is also incorporated. As well as transmitting a 121.5 MHz homing signal it broadcasts GPS position to maritime AIS receivers. These suits comply with Canadian Standard CAN/CGSB-65.17-2012 for Helicopter Passenger Transportation Suit Systems. The suits will be rolled out in Nova Scotia in March 2015 and Newfoundland the following month. To support the provision of suits in St Johns, Survitec acquired Newfoundland Marine Safety Systems in Mount Pearl, Newfoundland. Aerossurance has previously reported on: Helicopter Ditching – EASA Rule Making Team RMT.0120 Update UPDATE 17 December 2015: Canadian Coast Guard Helicopter Accident: CFIT, Survivability and More UPDATE 24 January 2016: CAP1145 Helicopter Water Impact Survivability Statistics – A Critique Aerossurance is an Aberdeen based aviation consultancy. For expert advice on helicopter safety, equipment certification / selection and survivability matters, contact: enquiries@aerossurance.com Follow us on LinkedIn for our latest updates....
read moreWhen Habits Kill – Canadian MD500 Accident
When Habits Kill – Canadian Hughes 500 Helicopter Accident Establishing habits can be effective ways to achieve safe outcomes, by sub-consciously completing routine actions. Examples include automatically fastening harnesses and seat belts or routinely scanning for other traffic. However, sometimes habits can be dangerous, for example when circumstances or equipment change. Just such a case occurred in Canada to an operator supporting the mining industry. The Helicopter Accident The Transportation Safety Board of Canada (TSB) report that on 6 August 2008: The MD Helicopter 369D [aka MD500] (serial number 500715D, registration C-GZIO), operated by Prism Helicopters, was involved in support operations for mining exploration near Alice Arm, British Columbia. The helicopter took off at about 0709 Pacific daylight time for the first flight of the day to a drill site up the Kitsault River valley with one pilot and three passengers on board. As the helicopter departed in a shallow left-climbing turn, it emitted an unusual sound. It reached about 150 feet above ground level, then suddenly banked 90º to the right, and fell to the ground. It broke up on impact with a fallen tree and the main section, with the occupants, fell into the Kitsault River and remained mostly submerged just below the surface. All the occupants suffered fatal injuries on impact. The emergency locator transmitter operated until it was turned off by first responders. There was a small post-crash fire on the river bank that extinguished on its own. Tree damage was consistent with a vertical descent and minimal rotor rpm. The TSB found heavy fabric cover wrapped tightly around the main rotor swashplate and broken pitch change rods). Rotor blade damage was consistent with low rpm at impact. The TSB go on that: The pilot had 38 years of flying experience and had accumulated over 11 000 hours of flight time, with a substantial amount in similar operations. There was an apprentice aircraft maintenance engineer on-site to help with elementary tasks on the helicopter. He would normally look over the helicopter at the end of the day and secure it for the night. This included installing a synthetic heavy material cover (doghouse cover) over the engine intake and around the main rotor control system and tying the main rotor down. He would normally get up in the morning to remove the cover and untie the rotor, among other things. A couple of days before the accident, the pilot suggested that the apprentice need not get up early and that he would prepare the helicopter for the day’s flying. On the last two nights, the apprentice did not tie the rotor down but he installed the cover. TSB explain that: The cover does not have any straps or physical barriers that fall at or below human eye level. Once the pilot gets into the helicopter, there are no visual cues of the cover’s installation. On the morning of the accident, the pilot got up at the usual time, but stayed at the lodge a little longer and arrived at the helipad later than normal. Two of his passengers arrived before him. The pilot was loading their equipment when the third passenger arrived at the helipad. They loaded some more equipment, embarked the helicopter, and departed immediately after. One piece of equipment was left behind. The TSB concluded that the cover was left in place during pre-flight preparations. Consequently the cover damaged the main rotor...
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