Wake Turbulence Diamond DA62 Accident in Dubai
Wake Turbulence Diamond DA62 Accident in Dubai (G-MDME of Flight Calibration Services) UPDATED 1 June 2020 with Final Report On 20 June 2019 the the Air Accident Investigation Sector (AAIS) of the UAE General Civil Aviation Authority (GCAA) released their preliminary report into the loss on 16 May 2019 of Diamond DA62 G-MDME of Flight Calibration Services Ltd (FCSL) at Dubai International Airport. The aircraft, with 4 persons on board, was flying approaches to runway 30L as part of a ground lighting calibration linked to runway refurbishment. Dubai has two parallel runways, 12R/30L and 12L/30R. The distance between the runway centerlines is approximately 380 meters. These flights were conducted under visual flight rules (VFR), with air traffic communicating with the DA62 on a separate frequency. The investigators say that: The prevailing meteorological conditions at the time of the Accident were fine with ceiling and visibility ok (CAVOK). Low level winds were recorded at 1,000 ft with a speed of 6 kt from 020 degrees, and a speed of 11 kt from 010 degrees at 1,500 ft. Sunset on 16 May 2019 in Dubai was at 1857 At 1929, the Aircraft entered the final to runway 30L for the tenth approach, following a Thai Airways Airbus A350-900, which was flying the approach to the parallel runway 30R. The Airbus was approximately 3.7 nautical miles (nm) ahead of the DA62. When the DA62 levelled off after turning onto final at an altitude of approximately 1,100 feet (ft) and at an airspeed of approximately 130 knots (kt), it rolled slightly but was recovered after nine seconds. Seven seconds later, the [DA62] abruptly rolled to the left until it became inverted and it then entered a steep dive. The aircraft impacted the ground approximately 3.5 nm from the runway 30L threshold. …the Aircraft impacted the ground at an elevation of approximately 130 ft while travelling at high speed in the direction opposite to the direction of flight, on a heading of approximately 100 degrees. All four persons onboard the Aircraft sustained fatal injuries…[and]…the aircraft was destroyed by impact forces and the subsequent fire. The Safety Investigation The 406 MHz Emergency Locator Transmitter (ELT) installation was damaged in the impact, with the antenna and electrical cables severed from the unit. Consequently, no signals were detected from it. Aircraft of the size of the 7 seat DA62 are not required to be fitted with Cockpit Voice Recorder (CVR) or Flight Data Recorder (FDR). The investigators state that at a meeting with the airport before the calibration flights commenced, it was agreed that: The DA62 would apply own separation to other arriving aircraft to the parallel runway 30R while operating under VFR, which meant that ATC would not be responsible for providing wake turbulence separation. The investigators reviewed the airport radar data: Observations of previous approaches during the same calibration flight indicated that the DA62 consistently followed preceding traffic on approach to the parallel runway 30R at distances which were below the specified minimum separation, and less than the distances discussed during the pre-departure meeting. The radar monitor recording indicated that there was an air traffic control (ATC) inconsistency in advising the DA62 of the expected occurrence of hazards caused by wake turbulence from traffic on approach to the parallel runway 30R. Based on these observations, the Investigation believes that there is sufficient reason to...
read morePremature A319 Evacuation With Engines Running
Premature A319 Evacuation With Engines Running On 3 August 2018 CSA Czech Airlines Airbus A319-112 OK-PET was about to depart Helsinki-Vantaa Airport with 135 passengers and 5 crew on board. The Finnish Safety Investigation Authority (SIAF, the Onnettomuustutkintakeskus) describe in their investigation report that: As the aircraft was taxiing towards the runway, passengers and cabin attendants detected smoke inside the cabin. The purser reported this to the captain by interphone, who then stopped the aircraft on the taxiway. The situation surprised [the flight crew] because there was no smoke on the flight deck, nor had the aircraft’s systems generated any notifications. The Captain believed the smoke originated from the cargo compartment. A moment later the purser asked the captain for permission to evacuate the aircraft. …the captain tried to act quickly and failed to complete the procedures in the order of the evacuation checklist. For example: …the captain activated the evacuation signal even though the engines were still running. The cabin crew initiated the evacuation. Furthermore: The captain did not make an evacuation announcement and, therefore, not everyone recognised what the evacuation signal meant. Some passengers thought that it was a normal deplaning. During the evacuation some passengers rushed past slower-moving passengers and children were trampled over. Also, the carry-on luggage that some passengers took along slowed down the evacuation. The evacuation was done using emergency slides at four cabin doors. In the beginning of the evacuation the engines were still running, which put the first passengers who deplaned through the front doors in danger of being ingested into a running engine. It was not possible to use the emergency slides at the rear doors while the engines were still running. During the evacuation 26 passengers sustained minor injuries. Their injuries were mild, caused by the congestion in the aisle and from using the emergency slides. Since the passengers were not gathered together, most of them remained in the vicinity of the aircraft. Some of them ran onto the grassy area between the aircraft and RWY 15/33. At this stage, when no-one was controlling them, they could have entered the active runway. The shift supervisor of airport rescue service, upon arrival [after c 8 minutes], took control of the passengers and told them to gather at a safe area. Air navigation service provider ANS Finland stated that “while, in theory, it was possible for the passengers to enter runway 15, it was highly unlikely because of the difficult terrain and the physical distance”. Safety Investigation Investigators found the origin of the smoke was a seized Air Cycle Machine (ACM) bearing. The ACM is part of the aircraft’s air conditioning system. When the unit failed, it generated smoke which was ducted through the air conditioning system into the cabin. The running time on the piece of equipment was 28067 hours, including 14047 starts. The ACM bearing and the subsequent generation of smoke has occurred before in the A320 family fleet. For example: UK AAIB investigation into a smoke event to EasyJet A319-111, G-EZIM at Isle of Man Airport, 31 March 2017. Safety Analysis and Conclusions SIAF developed an AcciMap that summarises their analysis: The SIAF conclusions were: In training the captain issues the command to evacuate and, therefore, evacuation initiated by the cabin crew had not been practiced. Conclusion: Evacuations initiated by the cabin crew are not normally practiced in commercial air...
read moreRegulator Missed the Chance to Intervene Before Fatal Tour Accident say TAIC
Regulator Missed the Chance to Intervene Before Fatal Tour Accident say TAIC On 21 November 2015 Airbus Helicopters AS350BA ZK-HKU, of Fox and Franz Heli Services. was conducting scenic flights out of the operator’s base near Fox Glacier town. Heavy rain had caused the cancellation or postponement of several flights, but after a shorter flight to the lower part of Fox Glacier (also known as Te Moeka o Tuawe) the 28 year old pilot decided that the weather had improved enough to conduct a flight to the head of the Fox Glacier valley. At 0945 the helicopter departed for a 20-minute flight with seven people on board (the pilot, two Australian tourists and 4 from the UK) . The flight was reported overdue at 1015. The wreckage was subsequently located on the glacier just below Chancellor Shelf (which is about 5,600 feet above sea level). There were no survivors. The helicopter was destroyed. The New Zealand Transport Accident Investigation Commission (TAIC) say in their accident report that physical evidence indicated that “the helicopter hit the ice in a relatively level attitude with a very high rate of descent” and “relatively high forward speed”. There were indications that main rotor speed hap drooped. The helicopter was not equipped with the instruments necessary for safe flight in low or no visibility, and the pilot was not trained for instrument flying. Passenger photos and a webcam at the company base showed the flight had departed Fox Glacier town in light rain and overcast conditions, with some low cloud. The flight encountered heavy rain later on. Approaching Chancellor Shelf there was low cloud just above with some cloud spilling down the mountain. The helicopter had landed on Chancellor Shelf and the passengers had got out to walk in the snow. It was snowing at the time and cloud was coming and going in the general area. The lower valley was partly visible in one view, which suggested a visibility greater than the minimum 1,500 m required for visual flight rules. In other directions the flat light allowed little or no distinction between the surface and the cloud. There was no recorded evidence of the helicopter’s flight path after it departed Chancellor Shelf…unusual for tourists on a scenic flight. It suggests that the visual conditions might not have been ideal for photography. The aircraft took off from Chancellor Shelf at an estimated 47 kg over weight, having departed the operator’s base 65 kg overweight. In addition: The tail rotor hydraulic servo was due for overhaul at 13,741 airframe hours. On 24 April 2015 the contracted maintenance organisation had extended the servo replacement to 13,921 hours [i.e. by 160 hours], as allowed by the Civil Aviation Rules and the approved maintenance programme. The helicopter had accrued 13,959 flight hours as at 19 November 2015… [so] the servo had remained in service for 38 hours beyond…the maximum flight hours permitted before overhaul… TAIC note that these facts were unlikely to have been factors in the accident. The overweight operation and component over run might suggest weaknesses in the operator’s organisation however. The Operator’s Organisation Formed in 1986, the Alpine Adventures company owned by JP Scott (also trading as Fox and Franz Heli Services, Tekapo Helicopters and Makarora Helicopters) had “a fleet of 13 helicopters and employed nine full-time pilots, four part-time pilots and 24 ground staff.” At the time of this accident the operator had one of the...
read moreERJ175 NLG Uplock Spring Production Defect
ERJ175 NLG Uplock Spring Production Defect On 4 December 2016 Embraer ERJ170-200LR (ERJ175) N161SY, operated by SkyWest Airlines for United Express, experienced a Nose Landing Gear (NLG) collapse during rollout when landing at the San Antonio (KSAT), Texas. History of the Incident Flight The US National Transportation Safety Board (NTSB) report that: …after departure from the George Bush Intercontinental Airport (KIAH), Houston, Texas the crew heard a loud “thud/pop” just aft of the flight deck. Because no warnings or indications were displayed on the flight deck, the crew decided to proceed to [their destination, Monterrey (MMTY) Mexico]. When the landing gear was extended on approach, the crew received warning indications regarding the landing gear position and a “LDG GEAR LEVER DISAGREE” message. The crew declared a missed approach, retracted the landing gear per the quick reference handbook (QRH) procedures, and elected to divert to KSAT. Upon entering US airspace, the crew declared an emergency and performed a flyby of the control tower to verify landing gear position. The tower confirmed that the gear appeared to be in the down position. After touchdown on runway 4, during the landing rollout the nose gear retracted, without command, as the aircraft slowed to a stop. The crew and passengers evacuated the aircraft from the aft cabin doors via the evacuation slides. One minor [evacuation] injury was reported by a passenger…. The airplane sustained minor damage. Safety Investigation The NLG downlock springs were removed and shipped to the NTSB Materials lab…The right NLG downlock spring was received intact. The left NLG downlock spring was received in two separate pieces. The NLG downlock spring separated in the ninth coil from the lower end due to progressive crack formation. No evidence of overstress was observed. During a visual inspection, external surfaces of the downlock spring wire had small openings, which resulted in surface roughness measurements that were above the allowable limit set by Embraer. Cross-sections prepared through multiple downlock spring coils along the length of the spring showed intergranular cracking at the openings. The openings and cracking were associated with white etching microstructure of the wire that was consistent with retained austenite, while the base material of the coils had microstructure consistent with martensite, as specified. The amount of retained austenite in a circumferential surface layer of the downlock spring coils was above the allowable limit specified by Embraer per AMS 5678. Two spring pieces (an end segment and a ring segment) were documented using radiographic images. The computed tomography (CT) slice images were examined, processed, and analyzed by the NTSB to evaluate the components. The results of the CT imaging were inconclusive in locating crack location in the spring segments. The manufacturer provided information to the NTSB regarding additional NLG and MLG downlock springs that failed during operations. The spring from this incident was the only one which resulted in an uncommanded gear retraction on landing. Manufacturing records for the incident spring were reviewed and compared with other events. The manufacturer identified a suspect batch of raw material for the springs, common to multiple events and springs with higher than allowable amounts of retained austenite. The aircraft manufacturer performed multiple quality audits throughout the supply chain for the spring manufacturing process and shared the results with the investigative team. NTSB Probable Cause A failure of the nose landing gear...
read moreTroublesome Tiedowns: The Sequel
Troublesome Tiedowns: The Sequel On 2 May 2018, float-equipped Robinson R22 helicopter N923SM of Helicopter Academy LLC was in cruise at 80 knots and 800 ft about half a mile off Panama City Beach, Florida, when it slowly started losing airspeed. The pilot, the sole occupant, pushed the cyclic control forward until he reached the forward stop, but the airspeed continued to decrease and the helicopter began to lose altitude. Another helicopter was flying in formation during this positioning flight and observed N923SM’s speed drop to from 80 to 30 knots in about 15 seconds. The helicopter ultimately impacted the water tail boom first. The helicopter rolled inverted after being struck by waves almost immediately and the pilot clung to the floats until rescued with minor injuries. Safety Investigation The US National Transportation Safety Board (NTSB) say in their safety investigation report: Postaccident examination of the helicopter revealed that the main rotor blades were deformed, the fuselage was substantially damaged, and the tail boom was partially separated. Further, the ropes used to tie down the helicopter’s main rotor blades were found wrapped around the rotor head swashplate and pitch control rods. They explain that: Before the flight, the pilot conducted a preflight inspection of the helicopter, which would have included removing the rotor blade tie-down ropes and associated socks that cover the rotor blade tips and storing them under the cockpit seat. However, because the ropes were found wrapped around the swashplate and pitch control rods, it is likely that the tie-down ropes were not properly removed and secured and, at some point during the flight, became entangled with the swashplate and pitch control rods, which prevented the pilot from being able to effectively control the pitch of the helicopter. There are no written procedures for tie down ropes and storage procedures. Its taught verbally. …the pilot removed the tie down ropes and thought he placed them under the left cockpit seat storage container. He was not distracted and does not remember placing the tie downs anywhere else. The flight was without doors, so any loose items could have departed the aircraft. …the pilot held a commercial pilot certificate with a rating for rotorcraft-helicopter as well as a flight instructor certificate with a rating for rotorcraft-helicopter. The pilot reported 467.7 total hours of flight experience [all in the R22]. NTSB Probable Cause The pilot’s failure to properly remove and secure the tie-down ropes during the preflight inspection, which resulted in the ropes becoming entangled in the rotor head swashplate and pitch control rods during flight and the subsequent loss of pitch control. Safety Resources We have previously discussed Troublesome Tiedowns: On 21 October 2015 Bell 206B N1060C attempted a take-off from Fishing Vessel Majestic Sun off Christmas Island, Kiribati in the Pacific for a fish spotting flight, but a tie down remained attached. On 30 October 2015, N420PH, a Bell 407 of PHI, lost most of one rotor blade in an accident on an offshore installation in the Gulf of Mexico. We have also discussed debris being lost from aircraft: Tool Bag Takes Out Tail Rotor: Fatal AS350B2 Accident, Tweed, ON The adequacy of pre-flight inspections was a factor in these previous occurrences we have discussed: When Habits Kill – Canadian MD500 Accident EC120 Forgotten Walkaround Fuel Exhaustion Causes Emergency Landing Flawed Post-Flight and Pre-Flight Inspections Miss Propeller Damage UPDATE 10 July 2019: Fatal B206L3 Cell Phone Discount Distracted CFIT UPDATE 25 April 2020: Fatal R44 Loss of Control...
read moreWhen Red Bull Gives You More Than Wings…
When Red Bull Gives You More Than Wings… A database of US military aviation accidents and incidents complied by Military Times last year revealed an odd mishap. It resulted in website The War Zone submitting a Freedom of Information Act request. The response detailed how the co-pilot of a US Air Force (USAF) Beechcraft MC-12W Liberty King Air 350 10-006450 had reached for refreshment of a flight out of Hurlburt Field, FL on 5 June 2017 (probably on a training flight for US Special Operations Command [SOCOM]). While still holding the unopened 16oz (454ml) can of Red Bull it… …ruptured spilling fluid onto the center console. While the MCP used his shirt to absorb what he could… He subsequently shut down the mission system power… The crew discussed their options and decided to RTB [return to base]. The cost of this mishap: $113,675 (as 13 avionic Line Replaceable Units [LRUs] had to be replaced), making it a Class C Mishap based on cost. The War Zone comment: The aftermath might have earned them [i.e. the crew] some sort disciplinary action, but Air Force censors redacted the investigating officers’ findings, conclusions, and recommendations. Its odd that these sections were redacted but disciplinary action might well explain that. Its not clear if the USAF did any safety promotion activity after this event or if there was actually any prohibition in carrying and consuming canned drinks on-board. Spilt drinks have caused problems before: Fate is Almost the Hunter: United Airlines Pilot’s Spilt Coffee Helps Trigger False Terrorist Alert UPDATE 12 September 2019: Spilled coffee forces plane to divert over Atlantic (AAIB report) UPDATE 29 January 2020: A350 engine shutdown incidents linked to cockpit drink spills UPDATE 25 April 2020: Airbus develops anti-spill cover to protect A350 centre pedestal (an interim fix) UPDATE 4 September 2020: Airbus redesigns A350 control panel to resist liquid spillage Its not just drinks: We reported in June 2014 on a Royal Air Force (RAF) A330 Voyager ZZ333, that was involved in a loss of control (LOC-I) incident during a flight to Afghanistan in February 2014. The UK Military Aviation Authority (MAA) issued a preliminary report on 17 March 2014 that said investigators: …found evidence to link the movement of the seat to the movement of the side-stick, in the form of a Digital SLR camera obstruction which was in-front of the Captain’s left arm rest and behind the base of the Captain’s side-stick at the time of the event. Analysis of the camera has confirmed that it was being used in the three minutes leading up to the event. Furthermore, forensic analysis of damage to the body of the camera indicates that it experienced a significant compression against the base of the side-stick, consistent with having been jammed between the arm rest and the side-stick unit. The full Service Inquiry (SI) report has since been published. MC-12W Liberty Background The US Air Force (USAF) MC-12W Liberty programme was started in 2008 to field an immediate Intelligence, Surveillance and Reconnaissance (ISR) capability for Iraq and Afghanistan and went from contract to first combat sortie in just 8 months, by modifying the KA350. These KA350s had the Rockwell Collins Pro Line 21 cockpit avionics system. The MC-12W programme was reportedly named ‘Project Liberty’ “as a homage to the World War II-era Liberty Ship programme” of mass produced merchantmen. The mission systems were integrated by L-3 Communications, with 22,000 man hours needed for each conversion. The first combat mission was undertaken in Iraq on 10 June 2009. The $1 billion MC-12W procurement was intended to...
read moreERJ-190 Flying Control Rigging Error
ERJ-190 Flying Control Rigging Error (UPDATED 25 June 2020 with Final Report) The Portuguese accident investigation agency, GPIAAF, issued a safety investigation update on 31 May 2019 on a serious in-flight loss of control event involving Aruba registered Air Astana Embraer ERJ-190 P4-KCJ that occurred on 11 November 2018, immediately after a C2-Check (1C + 2C + 6 year) at the OGMA facility at the Alverca Air Base, in Poartugal. This was a ferry flight back to Kazakhstan with 6 persons on board, not a maintenance check flight. The aircraft was landed safely but with structural damage sufficient to make this an accident in accordance with ICAO Annex 13. The crew had however encountered considerable difficulty controlling the aircraft, so much so they had debated ditching offshore. However, they regained a degree of control. After two unstabilised approaches, the crew landed runway 19L. The intended runway was 19R, but due to lateral drift they were forced to land on 19L. One passenger fell and suffered a minor injury. https://youtu.be/6n4mQvO4-tE Safety Investigation GPIAAF confirmed that an incorrect aileron control cable system installation had occurred in both wings during the maintenance check conducted in Portugal. GPIAFF note that: By introducing the modification iaw Service Bulletin 190-57-0038 during the maintenance activities, there was no longer the cable routing and separation around rib 21, making it harder to understand the maintenance instructions, with recognized opportunities for improvement in the maintenance actions interpretation. They comment on a problem with fault-finding that: The message “FLT CTRL NO DISPATCH” was generated during the maintenance activities, which in turn originated additional troubleshooting activities by the maintenance service provider, supported by the aircraft manufacturer. These activities, which lasted for 11 days, did not identify the ailerons’ cables reversal, nor was this correlated to the “FLT CTRL NO DISPATCH” message. Its possible, but not confirmed or discussed by GPIAAF, that the 11 days of fruitless fault-finding may have resulted in a delay and pressure to release the aircraft. GPIAFF comment that “deviations to the internal procedures” occurred within the third-party Part-145 maintenance organisation that “led to the error not being detected in the various safety barriers designed” in the process. They do not comment on what deviations occur, why they occurred or crucially how clear and practical those internal procedures were. They do say that the maintenance organisation is making changes. The investigators also suggest that the Type Certificate Holder review their documentation too. They also note that the error “was not identified in the aircraft operational checks (flight controls check) by the operator’s crew.” They add that: Amongst other issues, the safety investigation will look into the aircraft design and functioning, the crew procedures and human factors aspects raised, and will now focus on the maintenance procedures and applied aircraft technical documentation, as well as the human and organizational factors involved in the Part-145 service provider. Final Report (UPDATE 25 June 2020) The GPIAA final report was issued 24 June 2020. The OEM performed assessments on the aircraft primary structure showed exceedance of the limit loads, and according to the structural evaluation that was conducted based on 14CFR and RBAC Part 25 airworthiness requirements §25.305 (a), some degree of detrimental permanent deformation was found on the aircraft. The aircraft was considered beyond economic repair. The OGMA quality system was found to be “well structured and detailed”, however… Relevant gaps were…identified, namely on effective implementation and knowledge of these same procedures and standards by...
read morePA-34 Electrical Short Melted Rudder Cable
PA-34 Electrical Short Melted Rudder Cable (G-OXFF) Piper PA-34-220T Seneca V G-OXFF of Oxford Aviation Academy was about to enter the runway for takeoff at Oxford Airport on 2 November 2018 when the instructor noticed the rudder pedals felt soft and was “too easy to move”. The student confirmed they did not feel right, so they abandoned the planned flight and returned to the hangar for investigation. Safety Investigation The UK Air Accident Investigation Branch (AAIB) investigation report highlights the need for attention on EWIS (Electrical Wiring Interconnection Systems) of all sizes of aircraft: This Piper Seneca V was fitted with a Garmin 1000 fully integrated cockpit and avionic suite. The system is reliant on electrical power and has a standby battery to keep the system running in the unlikely event of a twin-generator and main battery failure. Inspection of the aircraft revealed the right rudder cable had chafed against the standby battery wiring and shorted to earth. The heat generated by the electrical short had melted through the steel-braided rudder cable. Safety Action This potentially serious risk to airworthiness was brought to the attention of the manufacturer, the CAA, EASA and the FAA. The CAA took immediate steps to inform owners and operators of similarly configured Piper Seneca V aircraft. The manufacturer has subsequently issued a mandatory Service Bulletin (No 1337) which gives instructions to reroute a portion of the emergency power wiring to improve the clearance from the rudder control cables. Safety Resources S-92A Flying Control Restriction on Wiring Loom C-130 Fireball Due to Modification Error UPDATE 1 June 2019: ERJ-190 Flying Control Rigging Error UPDATE 18 November 2020: Embraer ERJ-190 EWIS Production Quality a Factor in Fire UPDATE 27 December 2020: Fire-Fighting AS350 Hydraulics Accident: Dormant Miswiring UPDATE 8 February 2021: RCAF Investigate Defect on Newly Delivered CH-148 Cyclone (S-92) Aerossurance has extensive air safety, operations, airworthiness, human factors, 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 moreLoose Engine B-Nut Triggers Fatal Forced Landing
Loose Engine B-Nut Triggers Fatal Forced Landing On 26 September 2017 Hughes (later MD) 369D SE-JVI was being used for power line inspection on behalf of energy company Vattenfall, by the First European Aviation Company when it suffered a sudden power loss and impact with the ground that killed one occupant History of the Accident Flight The Swedish Accident Investigation Authority, the SHK report that: The helicopter was equipped with a system to measure, photograph and present the status of the power line network and the surrounding terrain by means of advance data processing. The system allows for flying at a higher altitude and greater speed than in traditional power line inspection, where the operator carries out an optical inspection while flying close to the power line at low speed. The systems operator held a CPL-H and rather unusually (for a civil aircraft) was regarded as the aircraft commander and was acting as Pilot Monitoring. Shortly after take-off from Älvsbyn/Högheden Airport [shortly after refuelling after the first sector of the day], at a height of about 80 metres above the ground and a speed of 67 knots, they started to rapidly lose both altitude and speed. Twelve seconds later, the helicopter collided with the ground at the side of a grass field behind a building and near the edge of a forest. The helicopter sustained substantial damage, but no fire broke out. The systems operator was killed and the pilot was seriously injured. Examination of the accident site showed that the helicopter “had a descent angle of approximately 70 degrees, close to zero forward speed and very low rpm in the main rotor and tail rotor, combined with an exceptionally large coning angle of the rotor disk at some point during the sequence”. These findings indicated that the engine stopped supplying power during the flight. The technical investigation showed that a [B-nut] fitting to the gas generator fuel control unit had come loose during the flight…. The relatively low speed and altitude, in combination with a heavily loaded helicopter, meant a briefer autorotation than those practised during training. The Pilot Flying also had just 67 hours on type (though the system operator had 698 hours on type). For this reason, the crew did not reach the landing site without utilising the available rotor rpm at an early stage, which lead to a hard collision with the ground. The high vertical speed of some 2000–2400 feet per minute (10–12 m/s) and low or zero forward speed at the time of the collision means that the helicopter was subjected to forces which exceeded what it was designed [for]. Also of note: …it took 1 hour and 40 minutes before the crashed helicopter was located by the rescue services and medical resources arrived at the scene, despite the helicopter’s ELT starting to transmit at the time of the accident. Investigation Examining the Rolls-Royce 250 engine: …it was discovered that the pipe that supplies reference pressure (the ‘reference pipe’) from the engine compressor to the free turbine regulator and the fuel control unit had come loose from its fitting. The threads of the pipe nut and the fitting were intact, which indicates that these had come apart prior to impact. The investigation noted that another pipe nut in the same pipe system was also loose, but it had not been completely dislodged. The last known maintenance on the...
read moreSurvey Aircraft Fatal Accident: Fatigue, Fuel Mismanagement and Prior Concerns
Survey Aircraft Fatal Accident: Fatigue, Fuel Mismanagement and Prior Concerns (C337A N5382S) On 17 May 2008 Cessna 337A Super Skymaster, N5382S on a marine mammal survey flight, was destroyed when it impacted trees near Eagles Nest Airport, West Creek, New Jersey, during a fuel related diversion. The pilot and one of the three passengers onboard were killed. The US National Transportation Safety Board (NTSB) determined the probable cause to be: The pilot’s departure with insufficient fuel for the planned flight, and his improper in-flight fuel management, which resulted in a total loss of power in both engines due to fuel starvation. Contributing to the accident was the pilot’s fatigue, which was precipitated by his work activities during the days just prior to the accident flight. Concerns had been raised about the pilot and the operation just days before. This fatal accident highlights the importance of doing a proper due diligence and having independent aviation expertise available when contracting for special mission support. A law suit brought by one survivor was settled out of court. Background and Previous Concerns According to the NTSB safety investigation report, the aircraft was operated by Ambroult Aviation, wholly owned by the accident pilot. The aircraft “was one of several owned and operated by the pilot, who flew many of the missions, and conducted most of the maintenance. Most missions were various types of survey flights”. The accident pilot was according to a colleague “very intelligent but disorganized, and not a good businessman”, “struggling to stay financially afloat”, “very paranoid” of FAA inspectors and “reticent to make any distress calls”. A local mechanic reported that the pilot/mechanic’s “maintenance record keeping was poor”. Investigators were unable to located the full set or aircraft technical records. The most recent annual inspection recorded was dated 25 June 2002. The battery for the emergency locator transmitter bore a “replace by” date that was four years prior to the accident. The pilot’s most recent flight review was successfully conducted on 24 February 2008. As he didn’t have his log book with him the certificated flight instructor completed the endorsement on the back of a business card. The pilot’s log books were never found. For this contract: The three passengers were employees of an environmental services company [Geo-Marine] that was contracted [by the State of New Jersey] to conduct aerial surveys of marine mammals [in areas intended for offshore windfarm development]. …the survey area extended approximately 80 miles north-south along the New Jersey shoreline, and extended approximately 20 miles east over the Atlantic Ocean. Each monthly survey consisted of flying 30 numbered course lines, called transects, to cover the entire survey area. The contract between the environmental services company and the State of New Jersey required that the FAA be contacted “to determine flight restrictions in the area” of the survey, and that the survey flights were to be conducted at an altitude of 500 feet. While 14 CFR Part 91.119 permitted operation at altitudes less than 500 feet over open water, a waiver was required for the operator to fly less than 500 feet from any person, vessel, vehicle, or structure. No records of the operator contacting the FAA for flight restrictions were located, and the operator did not contact the FAA for any waivers. Consequently, this reduced the likelihood that the operator’s aircraft, records or personal qualifications would be inspected or reviewed by the FAA. Each...
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