Freewheel Jerk on an SA330J Puma at Sea: Oil Analysis Opportunity
Freewheel Jerk on an SA330J Puma at Sea: Oil Analysis Opportunity (Erickson Helicopters Airbus SA330J N339EV) On 26 January 2018 Airbus Helicopters SA330J N339EV, operated by Erickson Helicopters, sustained substantial damage during a fresh water engine rinse aboard the replenishment vessel USNS Wally Schirra underway in the Pacific. The helicopter was operating under Part 133 (external load) and had been shuttling supplies, known as VERTREP, to other naval vessels in the area. The US National Transportation Safety Board (NTSB) explain in their safety investigation report (issued 3 June 2020) that… …after landing the helicopter on the deck of the ship, power was increased on the No. 2 engine, while the No. 1 engine was reduced to ground idle in preparation for a freshwater rinse of the engines to prevent corrosion. Once the engines were configured, the pilot saw the lead mechanic squeeze the trigger on the wand, and then there was a rumbling sound followed by a rough shudder through the airframe. He then looked back at the cockpit instruments and everything looked normal for the condition the controls were in at the time. About that time, there was another shudder through the airframe, and he heard a change in the tone of the engine and gear box noise. He saw that the rotor speed had started to rise, and the gas generator speed of the No. 2 engine had also started to increase. He shut down the engines. The Tail Rotor Drive Shaft (TRDS) was found to have sheared, disconnecting the Main Gear Box from the Tail Rotor. Safety Investigation Examination of the MGB right freewheel assembly revealed that the small roller bearings were dislocated, the bearing cage was fragmented, and both tabs of the shur-lok washer showed signs of deformation with visible impact damage. Damage to these tabs is consistent with a sudden engagement of the bearing, resulting in an instantaneous spike in torque, known as freewheel jerk. During the transition of the No. 2 engine from the idle position to the flight position, the condition of the freewheel small roller bearings likely prevented the freewheel cage from maintaining the large freewheel rollers on the ramp due to the effect of the freewheel spring. This situation is unstable until an “imbalance” modifies it and suddenly causes the cage and the freewheel rollers to rise on the ramp, imparting a torque spike into the rotor drive system. NTSB say that oil analysis had the potential for early detection of the freewheel unit failure mode: The maintenance manual for the SA330 helicopter requires the oil analysis be performed every 150 hours for the main gear box and every 50 hours for the intermediate gear box. Laboratory results were obtained from the two prior oil samples. The two samples taken were 88.4 hours and 2 years apart [indicating very low utilisation or a period of storage]. The first, dated February 13, 2016 listed Fe at 3.3 parts per million. The second sample, taken in November of 2017 [albeit prior to the 150 hour interval] was misplaced by the operator and not found until after the accident. When it was sent for analysis on February 4, 2018, Fe was detected at 14.7 parts per million. …had both of these samples been analyzed at the time of the inspection, it is likely the operator would have been able to detect the increase in metal before the bearing wear became severe enough to cause the jerk. Oddly while the NTSB laboratory documented an examination of the TRDS, the FWU wasn’t examined. Safety Action After the accident, the operator implemented an internal requirement for oil...
read moreVisual Illusions, a Non Standard Approach and Cockpit Gradient: Business Jet Accident at Aarhus
Visual Illusions, a Non Standard Approach and Cockpit Gradient: Business Jet Accident at Aarhus (Aerowest C560XLS+ D-CAWM) On 5 August 2019 business jet Cessna 560 XLS+ D-CAWM of Aerowest. inbound from Oslo, was destroyed landing at Aarhus (EKAH). The 3 crew and 7 passengers were able to evacuate without injury. The Accident Flight The Accident Investigation Board Denmark (AIBD) explain in their safety investigation report (issued 10 June 2020) that: The commander was the pilot flying, and the first officer was the pilot monitoring. The commander was an experienced pilot and highly ranked at the operator. [This was the] first officer’s first job as a commercial pilot. As a consequence of the [first officer’s] latest OPC [Operator Proficiency Check] grading, the Head of Training & Standards restricted the first officer to fly only with supervision commanders. An on-board cabin crewmember was not a formal requirement for this aircraft type. The cabin crewmember had not received specific aircraft type training (not required) and was not formally responsible for on-board cabin flight safety The accident occurred in dark night under Instrument Meteorological Conditions (IMC). The forecasted weather conditions at EKAH were generally consistent with the actual weather reports…. Fog could be expected and was present at EKAH. However, on initial radio contact with Aarhus Tower, the first officer perceived, noted, and read back to the commander the meteorological visibility to be 2500 m instead of the reported 250 m. AIBD suggest this may have created a false perception that the visibility was better than it actually was. Aarhus Tower had also stated that… Runway Visual Range (RVR) at landing to be 900 m, 750 m, and 400 m in fog patches. The commander made an approach briefing for the Instrument Landing System (ILS) for runway 10R including a summary of SOP in case of a missed approach. The flight crew performed the approach checklist [and] discussed the weather situation at EKAH with expected shallow fog and fog patches at landing. The commander informed the first officer that the intention was to touch down at the beginning of the runway. In order to avoid entering fog patches during the landing roll, the commander planned flying one dot below the GS [Glide Slope], performing a towed approach, and touching down on the threshold. However, the commander did not communicate this plan of action to the first officer. The aircraft started descending below the GS for runway 10R. The first officer asked the commander whether to cancel potential Enhanced Ground Proximity Warning System (EGPWS) GS warnings. The commander confirmed. The aircraft aural alert warning system announced passing 500 feet RH. The recorded computed airspeed was 125 kt, the recorded vertical speed was approximately 700 ft/minute, and the GS deviation approached one dot below the GS. The commander noted the PAPI indicating the aircraft flying below the GS (one white and three red lights). The first officer called “Approaching minimum”. Shortly after, the aircraft aural alert warning system announced “Minimums Minimums”. The FDR recorded a beginning thrust reduction towards flight idle and a full scale GS deviation (flying below). The commander called “Continue”. The commander had visual contact with the approach and runway lighting system. It was the perception of the first officer that the commander had sufficient visual cues to continue the approach and landing. The first officer as pilot monitoring neither made callouts on altitude nor deviation from GS. The commander noticed passing a white crossbar,...
read moreB767 Fire and Uncommanded Evacuation After Lockwire Omitted
B767 Fire and Uncommanded Evacuation After Lockwire Omitted (Dynamic B767-200 N251MY at Fort Lauderdale, FL) On 29 October 2015 Dynamic International Airways Boeing 767-200ER N251MY, powered by Pratt & Whitney JT9D-7R4E4 engines, experienced a fuel leak and fire on the ground at the Fort Lauderdale-Hollywood International Airport, Florida (FLL). One of the 100 passengers received serious injuries from jet blast, 21 minor injuries and the aircraft sustained substantial damage. The Accident The US National Transportation Safety Board (NTSB) explain in their safety investigation report (issued 8 June 2020): A significant fuel leak and subsequent fire occurred in the left engine strut and nacelle during taxi… The flight crew promptly shut down the left engine using the fire handle, and requested fire equipment. The “A” flight attendant activated the emergency signaling system…to notify the flight deck and other crewmembers of an emergency. The chime was audible in the CVR recording, but the flight crew did not respond via interphone. There was no indication on the CVR of an evacuation checklist or communication between the cabin and flight deck. As the airplane stopped on the taxiway, passengers saw the fire and insisted that the cabin crew initiate an evacuation. One passenger opened an overwing exit on his own, and the slide did not deploy. The cabin crew initiated the evacuation without coordination with the flight crew. After the evacuation had already begun, the flight crew advised over the PA to evacuate out the right side of the airplane. The flight crew did not immediately shut down the right engine and an evacuating passenger ran behind the engine [about 11 seconds after the aircraft was stopped] and was blown to the pavement resulting in serious injuries. The lack of coordination between the flight crew and cabin crew resulted in the evacuation initiating while the right engine was still running. About 35 seconds later, the number 2 engine was shut down. About 54 seconds after the airplane stopped, an airport authority official arrived, and repositioned the 2R slide. About one minute later, airport firefighting vehicles arrived and began extinguishing the fire. https://youtu.be/9K3HDfhgdXo The Safety Investigation During a visual examination of the left engine and strut, a fuel coupling assembly was found separated with the coupling body pushed aft on a main fuel supply line. There were indications of fuel leakage at the flange interface of the fuel supply lines where the coupling had separated including discoloration from fluid pooling in the strut compartments and streaking down the left engine cowling. There was no safety lockwire present on either the body or nut side of the fuel coupling as required in the Boeing aircraft maintenance manual (AMM), and no broken lockwire was recovered in the surrounding strut compartments. A material examination of the fuel supply lines and coupling components verified that the parts met dimensional drawing specifications and were free of defects or damage that would have affected normal operation. In 2012, the airplane was placed in storage until 2015 when it was taken out of storage and prepared for leasing to Dynamic. A Boeing Service Letter recommending replacement of fuel line flexible coupling (Wiggins coupling) retainer components was issued on March 14, 2000. Maintenance records of the accident airplane indicate the last time this service was performed was by Kalitta Air LLC on October 12, 2012 just prior to going into...
read moreFatal Falcon 50 Accident: Unairworthy with Unqualified Crew
Fatal Falcon 50 Runway Excursion Accident: Unairworthy with Unqualified Crew On 27 September 2018 Dassault Falcon 50 N114TD, operated by Air America Flight Services on a Part 135 on-demand air taxi flight, was destroyed in a runway excursion at Greenville Downtown Airport (GMU), South Carolina. The two pilots were fatally injured. The two passengers were seriously injured. The Accident Flight The US National Transportation Safety Board (NTSB) explain in their safety investigation report (issued 3 June 2020) that: The Dassault Falcon 50 is a midsize long-range business jet. According to the cockpit voice recorder (CVR), during the approach to GMU, the flight crew had difficulties understanding the navigation fixes that air traffic control had provided. The CVR also showed that the flight crew did not use any prelanding checklist or discuss that no braking was available with the brake system in the “#1-ON” position (the pilot was the copilot for the previous four flights in the airplane, during which this condition was present). The “#1-ON” position of the switch selected normal braking utilizing system 1, and provided antiskid protection, while the “2-OFF” position selected emergency braking and did not provide antiskid. According to the pilot who conducted four flights in the airplane before the accident flight, upon application of the brakes with the brake switch in the “#1-ON” position, braking was normal at low speeds (estimated to be 15-20 knots) but at faster speeds, no braking was available. Braking was restored when the brake switch was placed in the “#2-OFF” position. This pilot [who who commanded the four flights prior] stated that he reported the brake system failure to the company’s Director of Maintenance after the first two flights (in late August and early September 2018) and indicated his belief that the source of the problem was the antiskid system. In interview with the Director of Maintenance, the son of the accident co-pilot, denied that he had been told. He also stated there were no defects deferred on the aircraft and the NTSB found no maintenance records indicating a brake system issue. However: Next to the switch, a green sticker was affixed to the panel with the label “ATA # 32-5 “INOP” DATE: 9/27/18”. The NTSB go on: At 1345:34, the CVR recorded the sound of the airplane touching down. At 1345:38, the pilot stated that the brakes were not operating. He and the copilot commented about the lack of brakes several more times before the airplane went over an embankment and came to a stop. Air traffic controllers at GMU reported that the airplane touched down “normally” at a standard touchdown point on the runway. They saw the airplane’s thrust reverser deploy and watched as the airplane continued down the runway without decelerating. An airport security video captured the airplane’s touchdown and showed that the thrust reverser and the airbrakes were deployed. The video [below as stills with time in lower left corner] also showed the airplane as it continued to the end of the runway and went over the embankment. A second video: [The aircraft had] departed the left edge of the runway [19] near the departure end, traveled across the flat grassy area at the end of the runway, continued down a 50-foot embankment, and came to rest on the airport perimeter road about 425 ft from the runway. The wreckage was oriented on a heading...
read moreFish Spotting Helicopter Strikes ‘Glassy’ Sea
Fish Spotting Helicopter Strikes ‘Glassy’ Sea (VSC H369D N8648F, from Tuna Boat Jib Yu 868 off Nauru in the Pacific) On the morning of 5 July 2018 MD Helicopters (Hughes) 369D helicopter N8648F of Vertol Systems Company (VSC) impacted the Pacific Ocean near Nauru in Micronesia. This occurred about 30 seconds after takeoff from a Taiwanese-registered fishing vessel, Jib Yu 868, a 70 m tuna purse seiner of the Chern Lung Fishery. The US pilot and the Taiwanese fish-spotter received fatal injuries. The US National Transportation Safety Board (NTSB) explain in their safety investigation report (dated 19 May 2020) that: The pilot and the turbine-powered, float-equipped helicopter were stationed on the ship, and a Taiwanese observer provided fish-spotting services. VSC leased helicopters and pilots to multiple companies, including foreign fishing companies operating in the southern and western Pacific Ocean. VSC had a logistics and maintenance base on Majuro (in the south Pacific Ocean) to facilitate these operations. Helicopters and pilots under contract were stationed on fishing ships, but no helicopter maintenance personnel were stationed on the ships. VSC would provide ship-board maintenance and maintenance personnel on a temporary, as-required basis. According to the available evidence, no VSC maintenance personnel were aboard the fishing ship during the days before or on the day of the accident. The Accident Flight Most of the brief flight was captured by a shipboard surveillance camera. The camera faced forward, with a field of view that included the helicopter on the landing platform, as well as the ocean surface forward of and on both sides of the ship. The ocean surface appeared glassy, with only slight swells and no waves. Glassy water make it difficult to judge an aircraft’s height above the water. We discussed this in: Austrian Police EC135P2+ Impacted Glassy Lake, which was similar to accident that occurred in New Zealand to Hughes 369 ZK-HXZ in 2012 (discussed in an NZCAA accident report). The helicopter lifted off and immediately entered a right descending turn, flying out of view on the right side of the image. Several seconds [actually about 12 seconds] later, the helicopter re-entered the field of view via the upper right image frame. The helicopter was traveling nearly horizontal from right to left at an altitude that was sufficiently low for visible ripples to form on the water surface behind the helicopter. The helicopter struck the water, overturned, and remained afloat inverted. Skiff boats responded to the accident location within minutes, and both helicopter occupants, who were still strapped into their seats [which has 4 point harnesses], were recovered but unable to be resuscitated. VIDEO: available on the Aerossurance LinkedIn news feed. According to the CCTV video footage timestamp the impact occurred c30 seconds after takeoff (not 20 seconds as stated by the NTSB). The helicopter was destroyed by impact forces and salt water immersion. …examination of the helicopter revealed no evidence of any mechanical anomalies that would have prevented continued flight… Two days earlier the helicopter, parked outside on the ship’s helideck, was exposed to a significant storm. Subsequently, the pilot had difficulty starting the engine. However, the NTSB do not believe this was relevant to the accident. The autopsy report [on the pilot] concluded that there was no significant natural disease or trauma, and that the pilot’s cause of death was “probable drowning.” No details are recorded of the fish-spotter’s cause of death but it was noted he also...
read moreBeechcraft 1900C Landing Gear Collapse at San Antonio, TX
Beechcraft B1900C Landing Gear Collapse at San Antonio, TX, 8 May 2020 (Ameriflight, N31704) On 8 May 2020 Ameriflight Beechcraft 1900C N31704 was damaged in an accident at San Antonio, Texas. The aircraft was being flown single pilot as a Part 135 cargo flight. The US National Transportation Safety Board (NTSB) preliminary report states that: …the flight departed the Corpus Christi International Airport (CRP), Corpus Christi, Texas, at 2004 with 631 lbs of cargo and a fuel load of 2,800 lbs. During the initial climb, the captain selected the landing gear handle to the UP position to retract the landing gear. The attempt was unsuccessful, and the captain attempted to cycle the landing gear handle once more yielding the same result. Following the second unsuccessful gear retraction, the captain elected to leave the landing gear handle in the DOWN position and continued to the San Antonio International Airport (SAT), San Antonio, Texas, where more services would be available if needed. The airplane climbed to 8,000 ft mean sea level and cruised below the maximum landing gear extended speed (VLE). Nearing San Antonio, the pilot completed the before landing checklist and noted ‘three greens’ which indicated the landing gear was down and locked. However… As the main landing gear touched down…the left main landing gear collapsed, the red unsafe light in the landing gear handle illuminated…followed by an aural horn indicating the landing gear was now unlocked and unsafe for landing. Simultaneously, the airplane began to dip toward the left, causing the left wing tip to contact the runway [which resulted in] momentum taking the airplane from the runway centerline off the runway and into the grass area several thousand feet from the runway 4 threshold. Once the airplane came to a complete stop, the captain shutdown all power to the airplane and exited through the main entry air stairs. A postaccident damage assessment by the operator revealed that the left main landing gear brace was fractured. The operator reported that the airplane’s weight at the time of the accident was 14,381 lbs (the airplane’s maximum gross weight is 17,120 lbs). UPDATE 30 March 2022: NTSB Final Report & Probable Cause Issued The NTSB final report reveals: …the left main landing gear upper drag leg arm fractured in bending and twisting overload. There was no evidence of preexisting cracking or corrosion. The dimensions of the part were consistent with the drawing and the chemical composition and microstructure were consistent with 7075 aluminum alloy, as required. The mechanical properties were lower, and the electrical conductivity was higher than the requirements for 7075-T6 aluminum alloy. The measured mechanical properties and electrical conductivity did not conform to any standard temper for 7075 aluminum alloy. The NTSB probable cause was determined to be: The failure of the left main landing gear upper drag leg arm due to substandard mechanical properties, which resulted in a collapse of the landing gear upon landing. Safety Resources Our past B1900, B99 and King Air safety articles include: B1900D Emergency Landing: Maintenance Standards & Practices Beech 99A MLG Collapse Incorrectly Rigged B1900D Charlotte, NC, 8 January 2003: 21 Fatalities Crossed Cables: Colgan Air B1900D N240CJ Maintenance Error B1900C PSM+ICR Accident in Pakistan 2010 Distracted B1900C Wheels Up Landing in the Bahamas Operator & FAA Shortcomings in Alaskan B1900 Accident Alaska B1900C Accident – Contributory ATC Errors B1900D Window Blowout King Air...
read moreFatal Wisconsin Wire Strike When Robinson R44 Repositions to Refuel
Fatal Wisconsin Wire Strike When Robinson R44 Repositions to Refuel (N529DW) There is a theory that people let down their guard when the more complex part of a task is complete. On 9 June 2018 the pilot of Robinson R44 helicopter N529DW, operated by MF Helicopters, had just finished a low-level aerial photography flight at a charity boating event (the Four Horsemen Poker Run) along a series of lakes and rivers near Oshkosh, Wisconsin. The US National Transportation Safety Board (NTSB) explain in their safety investigation report that after 90 minutes of photography in the Lake Winnebago area: The pilot landed the helicopter, off-loaded the photographer, and departed to a nearby airport [Wittman Field] to refuel. Witnesses and surveillance video indicated that the helicopter was flying northwest over the river when, about 1/2 mile from the takeoff location, it contacted…a static wire and a fiber optic line, which were the top two lines of an unmarked five-line array that crossed over the Fox River. The lines were about 100 ft above the water and spanned about 640 ft across the river. The tail rotor separated from the helicopter, and the helicopter subsequently impacted the river. VIDEO on LinkedIn. Witness testimony indicate the accident site was only about 500m from the location teh photographer was dropped off. The NTSB report that the photographer commented… …that they had flown over numerous bridges and power lines during the earlier flight and that they had discussed the location of the power lines in reference to the bridges. The pilot had 559.6 total hours of flight experience, all in the R44. The NTSB say: The circumstances of the accident are consistent with the pilot flying at an unnecessarily low altitude and then failing to maintain clearance from the wires while flying at low level. The helicopter was not fitted with any kind of wire strike protection system. The NTSB do not discuss if the wires were marked on aeronautical chartes but it is unlikely they were. Safety Resources We have written on previous wirestrikes: Sécurité Civile EC145 SAR Wirestrike Firefighting Helicopter Wire Strike Helicopter Wirestrike During Powerline Inspection Fatal MD600 Collision With Powerline During Construction Fatal Wire Strike on Take Off from Communications Site Beware Last Minute Changes in Plan UPDATE 26 July 2020: Impromptu Landing – Unseen Cable UPDATE 20 September 2020: Hanging on the Telephone… HEMS Wirestrike UPDATE 5 March 2021: Wire Strike on Unfamiliar Approach Direction to a Familiar Site UPDATE 14 August 2022: Second Time Unlucky: Fatal Greek Wirestrike High-Wire Illusion UPDATE 3 September 2022: Garbage Pilot Becomes Electric Hooker See also: Avoiding Wire Strikes The European Safety Promotion Network – Rotorcraft (ESPN-R) has published this video and guidance with EASA: Also see: UPDATE 6 June 2020: Fish Spotting Helicopter Strikes Glassy Sea UPDATE 23 January 2021: US Air Ambulance Near Miss with Zip Wire and High ROD Impact at High Density Altitude UPDATE 5 February 2021: Inexperienced IIMC over Chesapeake Bay (Guimbal Cabri G2 N572MD): Reduced Visual References Require Vigilance UPDATE 21 December 2021: R44 Unanticipated Yaw Accident During Tailwind Take Off Caught on Video Aerossurance has extensive air safety, operations, SAR, 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 moreTurbine Dromader M18A Downed by Fuel Contamination: Shell Detector Capsules Misused
Turbine Dromader M18A VH-FOS Downed by Fuel Contamination: Shell Detector Capsules Misused in Malaysia On 25 February 2018, Australian registered PZL-Mielec Dromader M18A VH-FOS departed Keratong airstrip in Malaysia to conduct agricultural crop spraying. Systematic Aviation Services (SAS) had wet leased VH-FOS from Dompter Pty Ltd of Victoria, Australia since 2014 for agricultural flying in Malaysia. It had been modified with a Honeywell TPE331-12UHR-702H turboprop in place of the standard radial engine, most likely under an FAA Supplemental Type Certificate (STC). The Air Accident Investigation Bureau of Malaysia (AAIBM) say in their safety investigation report that it refueled three times before departing on its 9th spray run. At the end of that run the pilot noticed the power setting of 55% has dropped to 35%. After attempting to resolve the power loss the pilot decided to make an emergency landing. While descending toward a small patch of shrub the engine totally failed. The pilot dumped the spray agent and flared the aircraft over the shrubby area until it ready to stall then allowed the aircraft to settle on the bushes. The aircraft impacted with the ground cushioned by the shrub. The pilot escaped uninjured but the aircraft was destroyed. The Safety Investigation It had rained heavily the day before. The aircraft was parked under the shade of palm tree as were the fuel drums it was to be refueled from. Sourcing fuel from drum stock increases the risk of fuel contamination. The motorised fuel pump and hose were left covered but on the ground. Fuel sampling were done by the ground handler before each refuelling as to check if there is any contamination of the fuel. Checking of fuel contamination visually from 4 drains were done after each refuelling. Both pilot and ground handler [stated] that there was no trace of water found on each fuel check/drain after the last refuelling. Investigators took a fuel sample from the airframe filter at the crash site. Contamination could be seen. When the sample was tested with water detector capsule, it is confirmed the fuel was contaminated with water. A similar result occurred when the engine fuel control unit filter was checked. The portable fuel pump filter was however found not to have been contaminated. However, this was only tested after 11 days and the investigators suspect any water had since evaporated. The ground handler was using Shell Water Detector Capsules, distributed by ASC (a recognised industry best practice – although disappointingly neither Shell or ASC refer to use on aircraft fuel samples on their websites, as usage shown is based entirely on JIG fuel supply procedures [i.e. to the wing]). However, the method employed was not as recommended. The ground handler was dropping a capsule into the fuel sample and swirling. The correct method is to attach a capsule to a syringe (without a needle), dip in the fuel sample and extract fuel into the syringe through the capsule. If there is water contamination, the colour of the capsule will immediately change. It is not clear if a syringe was available. AAIB Malaysia say: The storage life for unused Shell Water Detector capsule is 9 months from the time of manufacture. The capsules used by the ground handler were manufactured in [September] 2014. As shown in the video this is actually an expiry date and so the capsules were 40 months out of date. While the ground handler had been employed by SAS for many years he had never...
read moreMisted Masks: AAIB A319 Report Reveals Oxygen Mask Lessons
Misted Masks: AAIB A319 Report Reveals Oxygen Mask Lessons (EasyJet G-EZNM) EasyJet Airbus A319-111 G-EZNM was in the cruise at FL290 en route from Newcastle to Bristol on 11 May 2019. The co-pilot was Pilot Flying (PF) and the commander was Pilot Monitoring (PM). The UK Air Accidents Investigation Branch (AAIB) explain in their safety investigation report that: …the co-pilot noticed an acrid burning smell. Upon looking to the rear of the flight deck both crew members observed smoke in front of the flight deck door and rising to shoulder height behind their seats. They donned their oxygen masks, and the commander took control of the aircraft and continued to communicate with ATC; the co-pilot actioned the ‘SMOKE/FUMES/AVNCS [avionics] SMOKE’ checklist in the quick reference handbook (QRH). The commander transmitted MAYDAY to ATC, selected the emergency transponder code, and the crew started an emergency descent… AAIB determined that: The source of the smoke was probably an accumulation of dust in the transformer rectifier unit (TRU). However: About 90 seconds after the pilots donned them, their oxygen masks misted up, obscuring their vision. The co-pilot was able to read the checklist by holding it close to the mask, but could not read his flight instruments. The commander removed his oxygen mask so he could see the flight instruments, having first informed the co-pilot that he would do so and agreeing this was the least risk option [however] it exposed the commander to potentially hazardous fumes. Upon removing his mask the commander noticed the smoke had dissipated. The flight crew prudently decided to divert to Birmingham when they realised that airport was closer. During the descent the crew made an announcement to passengers… After this the smoke became perceptible in the cockpit again. The commander then informed the co-pilot that he felt “a little bit wobbly” but well enough to continue. As his oxygen mask had cleared he refitted it, and it did not mist up again. The aircraft landed safely at Birmingham. Investigating the Oxygen Mask Performance The mask type fitted to G-EZNM was a ‘MF10’ full-face mask-regulator that provides protection during depressurisation and smoke events, while allowing the pilots to communicate with each other. The window has two lenses with an air gap between them. The internal lens has an anti-fogging coating. Pushing the N/100% (N – normal flow) selector into the 100% position, on the regulator control, supplies 100% oxygen (item 3 below). After pushing the N/100% rocker into 100% position, rotating the emergency pressure selector in the direction of the arrow to the emergency position provides 100% oxygen with an overpressure (item 2 below). The overpressure eliminates condensation or fogging of the mask, and prevents smoke, smell or ashes from entering the mask Upon investigation: Both emergency pressure selectors were found not to have been rotated to the EMERGENCY position. The commander was unable to recall if he had selected EMERGENCY. However, if they both had, even for a short period, it is likely the condensation would have been removed, enabling the commander to keep his mask on and breath 100% oxygen during the remainder of the flight. This would probably have improved the physiological condition he reported, which may have been caused by inhaling fumes. Removing the condensation in this way would also have allowed the co-pilot to properly monitor the aircraft’s...
read moreSurvival Flight Fatal Accident: Air Ambulance Operator’s Poor Safety Culture
Survival Flight Fatal Accident: Air Ambulance Operator’s Poor Safety Culture (B407 N191SF, Ohio) On 29 January 2019, at 0650 local time Bell 407 air ambulance helicopter N191SF, collided with forested rising terrain about 4 miles NE of Zaleski, Ohio. The pilot, flight nurse, and flight paramedic were all fatally injured and the helicopter destroyed. The helicopter was operated by Viking Aviation doing business as Survival Flight (not to be confused with Survival Flight University of Michigan Metro Aviation). The flight departed Mt. Carmel Hospital, Grove City, Ohio at 0628, destined for Holzer Meigs Hospital, Pomeroy, Ohio, about 69 miles SE. The Accident Flight The US National Transportation Safety Board (NTSB) say in their safety investigation report, abstract and 2,600 page public docket that Holzer Meigs Hospital had first contacted MedFlight, another helicopter air ambulance operator, for the patient transport flight at 0601. MedFlight refused the flight due forecast icing and snow. The hospital next contacted HealthNet Aeromedical Services. HealthNet said they would perform a “weather check” and get back to the hospital. After the call with HealthNet, the hospital contacted Survival Flight, a relatively new operator in the area since June 2018, who accepted the flight within 3 minutes (HealthNet subsequently called back to turn down the flight after 6 minutes studying the weather). This is a practice called ‘Helicopter Shopping‘ (see below). According to the Survival Flight Operations Control Specialist (OCS) on duty at the time of the accident at the Survival Flight Operations Control Centre (OCC) in Batesville, Arkansas, the hospital did not mention MedFlight had turned down the flight and there were no entries in a website called weatherturndown.com (see below). They also explained that it was the night shift pilot who had accepted the flight (in just 28 seconds)… …while he was on the phone with that pilot reviewing flight details about 0612, he was told that, due to the upcoming shift change, the day pilot would be taking the flight [they were en route by car and 5 minutes away]. The night shift pilot, who had been awoken by the OCS… …asked the accident pilot while she was driving to the helicopter if she needed anything. He had already briefed the accident pilot concerning the flight request and the accident pilot had told him she already had her helmet and knee-board with her. Twilight would start at 0710 with sunrise at 0739. He asked if she needed the night vision goggles (NVGs) and she told him that she did not. He then notified the medical crew that there was a flight request and proceeded to the helipad to prepare the helicopter. By the time the accident pilot arrived he had the helicopter started and was preparing to program the waypoint information into the navigation system. He handed the accident pilot the pilot phone and she boarded the helicopter. He then returned to the base. It appears no pre-flight risk analysis form was completed (see below). The pilot did have an iPad but the NTSB could not determine if she checked the weather herself. OCC recordings indicated at 0625, the accident pilot contacted the OCS via onboard satellite radio to confirm the destination for the flight. At 0627, the accident pilot again called the OCS, but this time to request the coordinates of Holzer Meigs Hospital. At 0629, the OCS called the accident pilot requesting her flight release information. She...
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