Wrong Engine Shutdown Crash: But You Won’t Guess Which!
Wrong Engine Shutdown Crash: But You Won’t Guess Which! A British airliner, an engine problem and the crew inadvertently shutting down the wrong engine, crashing close to the airfield. Kegworth in 1989 right? Well sorry for the click-bait title but that is not this human factors case study, which predates that accident by almost exactly 20 years. BUA BAC One-Eleven G-ASJJ 14 January 1969: The Accident Flight On the evening of 14 January 1969, British United Airways (BUA) BAC One-Eleven, G-ASJJ was due to depart Milan Linate bound for London Gatwick. According to the Italian investigation report (published in English as CAP347 and in ICAO Circular 118-AN/88) the aircraft had been due to have landed in Genoa. However, due to bad weather it had been forced to divert to Milan Linate, landing at 14:30. The crew, who had also flown a Gatwick-Rotterdam-Gatwick service earlier in the day, were been forced to wait 5 hours for the outbound passengers to arrive by coach from Genoa. They had been on duty since c 06:30 local time (c 05:30 UK time), i.e. 14 hours when the passengers arrived. There were three flight deck crew, all experienced Captains: Captain A occupied the left-hand seat as ‘pilot-in-charge‘ (who had 10973 flying hours in total and 497 hours on type). Captain B was in the right hand seat as co-pilot (12135 hours total, 33 hours on type). Captain C, a Training Captain, was in the centre supernumerary seat as ‘pilot-in-command‘, ultimately responsible for the safe operation of the aircraft (13360 hours total, 2153 hours on type). There was no requirement in the UK Air Navigation Order for the commander to be seated at the controls. The investigators note: Before leaving Gatwick Captain A briefed Captain B concerning the co-pilot duties assigned to him. Although Captain C, as pilot-in-command, did not himself formally brief Captains A and B there was no doubt that they were aware of their respective tasks. At 2018 hours, after clearance from Linate ATC, the engines were started and engine anti-icing selected “ON”. There was a considerable layer of snow along the sides of the taxiways and runway, but they themselves were clear… V1 and Vr had been calculated as 117 kt and V2 at 127 kt with the chosen 18° flap setting. The aircraft was cleared for take-off at 20:31 hours. V1 and Vr were called and the aircraft was rotated into the initial climbing attitude. Immediately after…a dull noise was distinctly heard by all the crew members. This noise was variously described by them as: “not like a rifle shot, not like the slamming of a door or something falling in the aircraft but more like someone kicking the fuselage with very heavy boots, an expansive noise covering a very definite time span with a dull non-metallic thud”. The bang was immediately associated by the crew with the engines. After looking at the TOT gauges, and observing that No. 1 engine was indicating a temperature 20°C higher than that of No. 2 engine, Captain C said: “I think it’s number one” or words to that effect, and after a brief pause “throttle it”. On receipt of Captain C’s comment Captain A closed the power lever of No. 1 engine. During or just after the explosion, he had completed the rotation manoeuvre and the aircraft was climbing at 12º of pitch with reference to the flight director. As a precaution, after closing No. 1 power...
read moreA Failure in Propeller Design and Certification Resulted in the Loss of an EMB-120 in 1991
A Failure in Propeller Design and Certification Resulted in the Loss of an EMB-120 in 1991 On 5 April 1991 Atlantic Southeast Airlines (ASA) Embraer EMB-120 Brasilia N270AS left Atlanta, Georgia at 13:47 Local Time for Brunswick, Georgia as Delta Connection Flight 2311. At 1448:13 the aircraft was cleared for a visual approach to Glynco Jetport in Brunswick, Georgia. The crew acknowledged the clearance and then made a routine call on the company frequency. There was no indication of any problems. Witnesses reported that all appeared normal as the aircraft entered a 180º turn from the base leg with about a 20º bank angle and a gradual descent rate. As the aircraft completed the turn it was seen to pitch up about 5º then roll left. It continued to roll to approximately 90º bank angle and pitched nose down. Witnesses reported a loud squeal or whine just prior to impact just over 1.5 nm from the threshold. All 23 occupants were killed. There was a greater than normal media interest in this accident because among the passengers who died were Texas Senator John Tower, his daughter Marian and NASA astronaut Manley “Sonny” Carter. The Investigation In their final report the US National Transportation Safety Board (NTSB) concluded that the sound witnesses heard would be consistent with the sound of a propeller over-speed. The aircraft was not equipped with either a flight data recorder (FDR) or a cockpit voice recorded (CVR). These were not regulatory requirements at the time. After examination of the wreckage they concluded an uncommanded propeller pitch change had occurred on the number 1 (i.e. left hand) Hamilton Standard 14RF-9 propeller. Examinations of the left propeller components indicated a propeller blade angle of about 3º at impact. This position was based upon the position of the pitchlock acme screw. The left [Propeller Control Unit] PCU ballscrew position indicated that the PCU had commanded a blade angle of 79.2º. The discrepancy [in angle] is a strong indication that a disconnect between these two components occurred prior to impact and that the left propeller had achieved an uncommanded blade angle below the normal flight range. This propeller entered a low-pitch mode, giving extremely high drag, and leading to a loss of control. The propeller control system failure was due to the disengagement of the 36 inch (915mm) long oil transfer tube spline and the quill spline. Once disengaged, the propeller was free to change independent of PCU control. This disengagement occured after the harder, rougher surface of the titanium nitrided transfer tube acted “like a file”, causing abnormal wear on the softer quill spline. The failure on N270AS occurred within 800 hours of service. The first ever in-service anomalies with quills had been discovered only weeks before. Two were returned for examination after operators were unable to perform the routine feather/unfeather ground check. The first worn quill was discovered in January 1991, the second in mid-February 1991. Containment After this discovery, Hamilton Standard issued an Alert Service Bulletin that included a description of ranges of acceptable transfer tube surface characteristics. These could fortuitously be readily identified by surface colour: The spline surface of the titanium-nitrided transfer tube used on N270AS had a “bright gold” or “shiny” finish and such tubes were not acceptable for continued use. Certification of that Modification The titanium nitrided transfer tube had been introduced as a minor modification, replacing the original nitrided transfer tube after a series of testing. ...
read moreTree Top Autorotation for B206L1 After Loose Fuel Line B-Nut Leaks
Tree Top Autorotation for B206L1 After Loose Fuel Line B-Nut Leaks On 2 April 2018 the privately owned Bell 206L-1 D-HHNC lost engine power during its initial climb from Uetersen/Heist Airfield and consequently the pilot initiated an autorotation. According to the German BFU safety investigation report, realising he would not be able to reach the airfield and would likely land in trees, he… …flared the helicopter, pulled the pitch fully and in the last moment yawed consciously by about 180°, because he did not want hitting the trees in a forward direction. Then the helicopter had fallen from only a few meters vertically into the trees. Hanging in the trees he had closed the twist grip and actuated the fuel-cut-off switch. The helicopter was substantially damaged. The pilot was uninjured. During examination of the wreckage the BFU powered up the fuel pumps. Leakage occurred at the B-nut screw fitting at the fuel pipe from the fuel filter to the Rolls-Royce 250 engine fuel pump. The screw fitting was found to be only hand-tight. On 7 April 2018 the BFU examined the engine together with an expert from the engine manufacturer. No external damages, which could have been considered to be the cause for the engine failure, were determined. N1 and N2 power trains could be rotated. The expert noticed individual screw fittings and maintenance actions, which were uncommon. In addition, almost no screw fitting at the engine showed any torque seal or lacquer. Often times only residue of old markings was visible. Up until May 2017 the helicopter had been registered in the USA [as N3199P] and maintained in accordance with requirements of the Federal Aviation Administration (FAA). On 31 March 2017 the last annual inspection of the helicopter and the engine was documented at a total operating time of 13,591.1 hours. The maintenance documentation did not show when and during which maintenance procedure the screw fitting of the fuel pipe on the fuel filter had last been loosened. At the time of the accident, the helicopter had a total of about 13,632 operating hours. Safety Resources Aerossurance has also previously written these pertinent articles: Professor James Reason’s 12 Principles of Error Management Loose B-Nut: Accident During EC130B4 Maintenance Check Flight B-Nuts were also involved in a $62.4mn fire on a USAF RC-135V Rivet Joint reconnaissance aircraft on 30 April 2015. We discuss that accident in our article: USAF RC-135V Rivet Joint Oxygen Fire Fatal S-61N Dual Power Loss During Post Maintenance Check Flight AS350B2 Accident After Vibration from Unrecorded Maintenance Maintenance Misdiagnosis Precursor to Tail Rotor Control Failure Fire After O-Ring Nipped on Installation Coking Causes Power Loss: Australian AS350BA UPDATE 24 May 2019: Loose Engine B-Nut Triggers Fatal Forced Landing UPDATE 2 January 2020: EC130B4 Destroyed After Ice Ingestion – Engine Intake Left Uncovered UPDATE 9 October: 2020: Latent Engine Defect Downs R44: NR Dropped to Zero During Autorotation UPDATE 27 July 2023: B407 Damaged During Autorotation Training UPDATE 25 May 2025: CHC Sikorsky S-92A Seat Slide Surprise(s) In 2012 the FAA Safety Team (FAASTeam) published a notice on B-Nuts: No matter how simple this component is, it requires a specific “torque” to keep it reliable in maintaining plumbing system integrity. You may have seen a maintenance record entry where the sign-off stated, “Tightened B nut.” Does this mean it was tightened enough to stop a leak, or was it tightened to a specific...
read moreContaminated Oxygen on ‘Air Force One’
Contaminated Oxygen on ‘Air Force One’ In April 2016 Boeing maintenance technicians contaminated the oxygen system of 92-9000, a USAF Boeing VC-25A, one of two converted B747-200Bs flown by the 89th Airlift Wing at Joint Base Andrews, Maryland as Presidential transports (using the call sign Air Force One, only when the President is on board). The damage, done at a Boeing facility at Port San Antonio, Kelly Field, Texas, was spotted before any Presidential flying. It cost $4 million to rectify, making this a Class A mishap in the US DoD classification system. The Incident To minimise the risk of fire the VC-25A Aircraft Maintenance Manual (AMM) requires all tools and components used on the oxygen systems to be ‘oxygen clean’. As the UK CAA note: All oxygen system equipment must be kept absolutely free from traces of oil, grease or flux, as these substances will ignite spontaneously in contact with pressurised oxygen. When a form of lubricant is necessary (e.g. because of a binding thread) the approved or recommended lubricant must be used. Lubricant should be used sparingly to ensure that it does not enter the oxygen system. Investigators say three Boeing technicians had used a contaminated regulator, tools and other components during leak checks conducted as part of a scheduled inspection 1-10 April 2016. One technician gave another one items they initially claimed were ‘oxygen-clean’. But the second technician subsequently became aware this was incorrect. When challenged. the first technician allegedly said: Here [is] some cleaning fluid. Do with it what you want. Use it if you want, but I don’t know anything about it. The fluid could have been used successfully to decontaminate the items, but investigators found none of the three technicians involved in the leak check were actually trained in the appropriate cleaning technique. The second and third technicians attempted to clean the items but subsequently both the passenger and medical oxygen system became contaminated. The Analysis Fatigue and pressure were factors that potentially contributed. Investigators found that maintenance at the Boeing depot had fallen behind schedule and in December 2015 workers had been put on mandatory 12-hour shifts beginning. The three personnel involved has been working six or seven days each week. This strongly suggests they will have been fatigued. We have discussed fatigue previously, looking at a number of case studies: Maintenance Personnel Fatigue and Alertness The investigators also noted that when Boeing has previously relocated maintenance to Texas from Wichita, Kansas, 172 personnel at the new facility would not meet a USAF 5 years experience requirements. Boeing successfully applied for waivers based on their assessment this was low risk. The technicians had under gone training in oxygen safety, in one case just 3 weeks earlier. Investigators comment that they “either did not absorb or retain the information”. The problem on the VC-25A was identified when a non-oxygen clean regulator was found connected and testing confirmed the systems were contaminated. Boeing paid for the rectification of the damage. The San Antonio site is now starting work converting 747-8 N894BA as the first VC-25B to replace the now dated VC-25As. The aircraft was ferried there on 27 March 2019. Boeing quality, albeit in production, remains topical: US Air Force forces Boeing to make changes after problems with KC-46 Pegasus production and Boeing Has ‘Severe Situation’ After Parts Left in Tankers, Says Top USAF Buyer The company has also declared this Friday [15 March 2019] to be “FOD Amnesty Day,” according to an internal company email reviewed by Defense One. The email, which does...
read moreUSAF T-38C Downed by Bird Strike
USAF T-38C Downed by Bird Strike On 17 August 2018, Northrop Grumman T-38C Talon 68-8206 of the USAF 71st Flying Training Wing, crashed in a field approximately 62 miles west of its base at Vance AFB, Oklahoma. The jet trainer was the lead of a two ship formation performing low-level training. The USAF Accident Investigation Board report, released 20 March 2019, explains that: While flying at approximately 1,000-1,500 feet above the ground and looking over his left wing at his wingman, the [pilot of the T-38C] heard a loud noise on the right side of the aircraft. The pilot, an instructor and the sole occupant, then heard an audible fire warning, saw the right (number 2)engine fire light and detected indications of right-hand flight control hydraulic and right generator failures. While initiating a climb away from the low-level route, the [pilot] experienced a degradation in aircraft controllability and his wingman reported seeing a visible fire…. The [pilot] successfully ejected from the aircraft, sustaining minor injuries. The aircraft was approximately 3,000 feet AGL, 195 knots, 10 degrees nose low, and with a descent rate of 3,500 feet per minute [with] approximately 60 degrees of right bank at the time of ejection. The T-38C, valued at $11mn, was destroyed. The investigation found the aircraft had ingested a Swainson’s Hawk, typically 0.9 kg (32 oz), into the number 2 engine. The bird was identified by experts at the Smithsonian Institute. Investigators say: This bird strike caused the catastrophic loss of the engine and a fire in the forward engine bay. The fire melted through the aircraft skin, exposing the Flight Control and Utility Hydraulic Systems’ flexible hydraulic pressure and return lines to extreme heat, causing the degradation, and ultimate loss, of aircraft controllability. However, the fire and loss of flight control authority necessitated ejection… Safety Resources We have previously written: USAF HH-60G Downed by Geese in Norfolk, 7 January 2014 Swedish Military NOE Helicopter Bird Strike: During a low-level night two-ship training flight a Swedish Armed Forces Agusta 109LUH collided with a large bird. Safety Lessons from a Fatal Helicopter Bird Strike: A fatal accident occurred on 4 Jan 2009 involving Sikorsky S-76C++ N748P of PHI that highlighted a range safety lessons. We also discuss current activity on enhancing bird strike requirements. Power of Prediction: Foresight and Flocking Birds looks at how a double engine loss due to striking Canada Geese had been predicted 8 years before the US Airways Flight 1549 ditching in the Hudson (which was just days after the Louisiana helicopter accident). NTSB Recommendations on JT15D Failure to Meet Certification Bird Strike Requirements Final Report Issued on 2008 Bird Strike Accident in Rome USMC CH-53E Readiness Crisis and Mid Air Collision Catastrophe RCAF Production Pressures Compromised Culture Investigation into F-22A Take Off Accident Highlights a Cultural Issue AC-130J Prototype Written-Off After Flight Test LOC-I Overstress C-130J Control Restriction Accident, Jalalabad Korean T-50 Accident at Singapore Airshow UPDATE 30 March 2019: Contaminated Oxygen on ‘Air Force One’ Poor standards at a Boeing maintenance facility resulted in contamination of two oxygen systems on a USAF Presidential VC-25 (B747). UPDATE 30 October 2019: ‘Crazy’ KC-10 Boom Loss: Informal Maintenance Shift Handovers and Skipped Tasks UPDATE 7 November 2020: Deadly Dusk Air Ambulance Bird Strike UPDATE 30 December 2020: AS350B3/H125 Bird Strike with Red Kite UPDATE 23 March 2022: Big Bustard Busts Blade: Propeller Blade Failure After Bird Strike About 8% US military of all Class A, B and C aviation mishaps from fiscal 2011 through 2017 resulted from wildlife...
read moreMaintenance Misdiagnosis Precursor to EC135T2 Tail Rotor Control Failure
Maintenance Misdiagnosis Precursor to EC135T2 TRCF in Japan On 9 December 2007 Eurocopter EC135T2 JA31NH, operated by All Nippon Helicopter, took off from Tokyo Heliport for a ferry flight to Shizuoka Heliport. The helicopter crashed on approach after a loss of tail rotor (fenestron) control. The pilot died and a mechanic onboard was seriously injured. Investigators from the Japan Transport Safety Board (JTSB) determined that following the propagation of a fatigue crack, the tail rotor (TR) control rod had ruptured at the threaded connection to the yaw actuator during the flight and this made the tail rotor uncontrollable. As the helicopter decelerating, the fuselage started to rotate, possibly after power was increased for a go-around, and the aircraft lost height and impacted the ground. The investigators comment in their safety investigation report that: …it is considered highly probable that the captain did not perform an emergency procedure for the tail rotor failure conditions, as provided in the flight manual. It is considered probable that his failure to perform such an operation reflected the absence of a syllabus for tail rotor failure in the periodic training for the captain. The investigators note that: The maintenance manual provides that the periodical inspection of the TR control, including that of the ball pivot, must be performed every 800 flight hours or every three years, whichever occurs first. A periodical check for the Aircraft was performed by the Maintenance Service Company on March 9, 2006, 368 h 25 min in flight time before the occurrence of the accident. But there was no looseness in the threaded area of the Rod. There was no abnormality with the ball pivot, either. However: After the accident, it was found that the ball pivot had become stiff in the sliding surface due to corrosion. It is considered highly probable that the unusual feeling in the anti-torque pedal movement, which had been reported by several pilots, was caused by the stiffening of the ball pivot… The investigation revealed that troubleshooting was performed on 20 October 2007, 45:35 flying hours before the accident, but this: …was not performed in accordance with the trouble shooting procedure provided in the English written maintenance manual of the aircraft manufacturer. As a result, the inspection of the ball pivot was not performed and its stiffening was not found. In addition, the fact that the joint of the tail rotor control rod and the yaw actuator has a left-handed thread is provided in the English written maintenance manual of the aircraft manufacturer, but it is considered somewhat likely that the mechanic involved in this case, while intending to tighten the joint, actually turned the joint to the opposite direction to loosen it. The investigators concluded that: Therefore, it is considered highly probable that the threaded area of the Rod had become loose and the ball pivot had stiff sometime after the periodical inspection performed by the Maintenance Service Company and as a result, a crack created in the threaded area of the Rod. They went on: …it is considered highly probable that repetitive bending loads in excess of the fatigue strength had been applied on the Rod due to the loosening of the joint of the Rod and the yaw actuator and the stiffening of the ball pivot as well as a resonance phenomenon following the stiffening. As to the stiffening of the...
read moreEasyjet A320 Flap / Landing Gear Mis-selections
Easyjet A320 Flap / Landing Gear Mis-selections The UK Air Accidents Investigation Branch (AAIB) have reported on inadvertent flap retraction on departure from Liverpool John Lennon Airport on 24 June 2018, involving Easyjet Airbus A320 G-EZOZ. Incident Flight The crew were on the third sector of the day, from Liverpool to Paris Charles de Gaulle. The takeoff was planned from Runway 27 with Configuration 1+F (leading edge slats extended to 18° and trailing edge flaps extended to 10°) and an aircraft gross weight of 62.6 t. The co-pilot was the Pilot Flying (PF). The AAIB report that: The takeoff roll was normal. …after lift-off the co-pilot called for “gear up”; the commander replied “gear” but inadvertently placed her hand on the flap lever instead of the landing gear lever and selected Flap 0. She realised the error and moved the flap lever back to the Flap 1 position, whereby the slats remained extended but the flaps continued to retract. The co-pilot recalled hearing the commander call “gear” and looking at the gear lever but not seeing the commander’s hand on the lever. However, by this time the flap lever had already been moved and returned. Data from the Quick Access Reorder (QAR) showed that passing 181 ft radalt height at 162 kt, both the flap and slat angles had started to reduce. The slat angle reduced slightly from 18° to 17.2° but then returned to 18°. The flap angle continued to retract to 0°. No movement of the flap lever was recorded. However, flap lever position is only recorded every two seconds, so it is likely that the lever was moved and returned in less than this time. Passing 330 ft radalt the landing gear was selected UP. Climbing through 600 ft radalt, pitch angle was reduced to 10° and the airspeed started to increase. Passing 800 ft radalt, speed had increased to 185 kt and the pitch angle was increased to 15°. Passing 1,350ft radalt the thrust levers were retarded to climb power and the pitch attitude reduced to 10°. Flap 0 was selected passing 1,650 ft as speed increased through 200 kt. By 2,000 ft radalt the slats had fully retracted. The AAIB note that: Both pilots…focused on flying the aircraft. They reduced the pitch attitude to accelerate and, maintaining a positive rate of climb, retracted the landing gear. They considered using TOGA thrust but decided this was not necessary. Throughout the incident the airspeed remained above Vls [the lowest selectable speed]. Once the aircraft was stabilised, the autopilot was engaged and the slats were retracted. The flight was completed without further incident. Discussion The AAIB note that… …neither pilot could identify any reason why the slip had occurred. They were not aware of any distraction and did not report feeling fatigued. The AAIB explain the flap system logic as being as follows: When the flap lever is moved to Position 0 from CONFIG 1+F after takeoff, the flaps and ]leading edge] slats begin retracting at the same time if the airspeed is above 148 kt. …when the airspeed is above 100 kt, moving the flap lever from Position 0 to 1 commands CONFIG 1 rather than CONFIG 1+F, extending the slats but not the flaps. If, after takeoff (and above 100 kt), the flap lever is moved from Position 1 to 0 and then back to 1, the slats and flaps begin to...
read moreUSAF Tool Trouble: “Near Catastrophic” $25mn E-8C FOD Fuel Tank Rupture
USAF Tool Trouble: “Near Catastrophic” $25mn E-8C FOD Fuel Tank Rupture On 13 March 2009 USAF Northrop Grumman E-8C JSTARS 93-0597 (a heavily modified Boeing 707-300 surveillance aircraft) was in the process of refuelling from a KC-135T tanker according to a USAF Accident Investigation Board. After uplifting around 30,000 lbs of fuel the crew heard a “loud bang throughout the midsection of the aircraft.” Refuelling was paused while the E-8C crew checked for damage. None was identified and fuelling recommenced but “another series of loud noises and vibrations” were “heard and felt throughout the aircraft.” Onboard the KC-135T the boom operator saw fuel streaming from the E-8C. Once alerted the E-8C crew also spotted fuel pouring from “at least two holes in the left wing, just inboard of the number two engine.” The E-8C diverted back to its base at Al Udeid Air Base in Qatar. On inspection, it was found that $25 million worth of damage had occurred when the no 2 main fuel tank had been over pressured and ruptured is a way that was described as “near catastrophic”. Investigators found that a maintenance sub-contractor, FFC, employed by Northrop Grumman, had left a fuel vent test plug in one of the fuel tank’s climb relief vents during Programmed Depot Maintenance (PDM) tank de-seal/re-seal maintenance at the Northrop Grumman Lake Charles Maintenance and Modification Center in Louisiana. The sub-contractor had reportedly failed to follow the USAF Technical Order (TO) procedures when using the plug during base maintenance. “The PDM subcontractor employed ineffective tool control measures,” say investigators. The procedures required tool checks at the start and end of each shift, but there was no evidence the tool was identified as missing. In fact, there were no records of any tools being taken into the fuel tanks, which was not credible considering the work that was completed. The plug was required to be fitted with a red ‘streamer’ but it was found without one too. Due to the relatively short period of time between take-off and aerial refueling, E-8C did not have the opportunity to burn much fuel from the number two fuel tank which would have allowed a secondary dive valve, to open (as occurred during the aerial refuelling when the aircraft deployed to theatre) and provide an alternative means to vent pressure. Other Safety Resources A similar, but unrelated event occurred on USAF Lockheed C-141 Starlifter 61-2778 on 21 September 2001: During preflight inspection a fuel leak was discovered… Maintenance personnel were unable to locate or repair the fuel leak, so they inserted fuel tank vent plugs and pressurized the fuel tank The leak was found and repaired. Once the repair was completed, the fuel systems technician exited the fuel tank but failed to document or request an in-progress inspection, to ensure all tools and materials are removed from the fuel tank; and fuel tank plugs (if used) are extracted from the fuel tank vents. Thus a fuel vent plug was not removed. As the aircraft was being [subsequently] refueled [on the ground], upon reaching approximately 120,000 lbs of jet fuel, the interior left wing fuel tank pressure exceeded wing structural tolerances, as pressure was unable to vent due to the forgotten fuel vent plug. Over-pressurization resulted in catastrophic failure of the left wing structure at the wing root. We previously discussed another E-8 contractor error at Lake Charles: What a Difference a Hole Makes: E-8C JSTARS $7.35 million Radar Mishap FOD in military converted Boeing aircraft remains topical: US Air Force forces Boeing to make changes after...
read moreFatal S-61N Dual Power Loss During Post Maintenance Check Flight
Fatal S-61N Dual Power Loss During Post Maintenance Check Flight On 6 September 2016 Sikorsky S-61N, N805AR (MSN 61717, formerly V8-UDZ of Brunei Shell Petroleum (BSP) from 1974 to 2010), was destroyed during a post-maintenance check flight after experiencing a dual loss of engine power while in a hover near Palm Bay, Florida. The three persons onboard were fatally injured due to “multiple blunt force injuries”. The aircraft was operated AAR, who had acquired the aviation businesses of Xe (formerly Blackwater). The aircraft had flown 40,296.2 flying hours at the time of the accident and an impressively high 107,600 cycles (consistent with the short sectors offshore Brunei). The Accident Flight According to the US National Transportation Safety Board (NTSB) safety investigation report: …the helicopter’s fore/aft pitch servo had recently been removed and replaced. Subsequently, three functional check flights (FCF) were required to be completed. Two FCFs were completed uneventfully the day of the accident, and the crewmembers were conducting the final FCF when the accident occurred. One of the maneuvers to be performed during the final FCF was rearward flight at a computed airspeed of 20 knots. The crew performed two of these rearward maneuvers during the accident FCF. While the pilot was flying and recovering from the first rearward flight maneuver, unusual sounds were heard, which the flight crew identified as a compressor stall. The pilot then told the maintenance crewmember that they were returning to their home airport; however, after discussing compressor stalls and engine exhaust gas temperatures with the copilot, the pilot changed his mind and told the maintenance crewmember that they were going to try the maneuver again in a different direction relative to the wind (with the wind off the nose). However: While the pilot was recovering from the second rearward flight maneuver, there was a change in background noise, which the maintenance crewmember identified as a compressor stall. About 2 seconds later, there was another change in background noise, consistent with a decay in drivetrain rpm, which was followed by the helicopter descending and impacting the ground. The helicopter came to rest upright [and a] postcrash fire consumed the cockpit and cabin. The tail boom transition section exhibited partial thermal damage, and the tail boom remained intact. The NTSB have published a full Cockpit Voice Recorder (CVR) transcript. Safety Investigation Recent maintenance on N805AR was as follows: The NTSB reviewed a year of Flight Log entries. The entries before the accident were: The aircraft was fitted with a Universal CVR-120. There is no mention of a Health and Usage Monitoring System (HUMS) or Flight Data Recorder (FDR). As the BSP S-61Ns were fitted with Meggitt IHUMS, which integrated HUMS with a CV/FDR, it appears N805AR had been demodified. Although the crew identified the sounds and loss of power as compressor stalls, a sound spectrum study could not characterize the gas generator speed (Ng) behavior, due to overdriven audio on the CVR, to determine the engine anomaly the crew identified as a compressor stall. It is likely that the cause of the overdriven audio is related to an engine anomaly. At the same time the engine anomaly occurred, the sound spectrum revealed Nr quickly decayed due to a dual loss of engine power coupled with a high collective setting. Because main rotor speed (Nr) decayed at the same time the overdriven audio occurred, it is likely both engines lost power nearly...
read moreEverett Introducing S-92A to East Africa
Everett Introducing S-92A to East Africa At HAI‘s HeliExpo 2019 in Atlanta, Everett Aviation signed a lease for their first Sikorsky S-92A from Lobo Leasing. The Tanzanian based operator has put the aircraft, MSN 920140, onto the Kenyan register as 5Y-EXZ. It had pride of place on the Sikorsky stand and is due to arrive in East Africa in mid-April 2019. Simon Everett, CEO of Everett, commented: We’re delighted to be introducing the S-92A… Many regions across sub-Saharan Africa are seeing a tremendous boom in infrastructure and civil engineering projects, and our new S-92A is ideally suited to supporting those missions. This particular helicopter is equipped with a highly versatile utility interior, which can seat up to 19 passengers in standard configuration or mix passengers with stretchers or cargo in a combined configuration. We also see opportunities for the S-92A in the offshore role in our region, and we plan to offer that configuration to our clients soon. 920140 was formerly operated by AAR, who had acquired the aviation businesses of Xe, in Afghanistan in support of US Transportation Command (USTRANSCOM). Sikorsky S-92 Developments Sikorsky has delivered more than 300 S-92A helicopters since entry into service in 2004. Sikorsky say that: In 2018, the fleet flew 175,000 hours, a record for the fleet, contributing to a total of nearly 1.5 million hours flown. Sikorsky launched the planned S-92A+ retro-fit upgrade and the new-production S-92B at the show. Both will feature Phase One of new MATRIX automation technology. This will include Rig Approach 2.0 which will be capable of flying the aircraft to roughly 500m from an offshore installation say Sikorsky. It also introduces, the SuperSearch mode to fly optimised search patterns. The interior will be readily adaptable to SAR and offshore operations. They will also feature the ‘Phase IV’ main gearbox. This is constructed of aluminum rather than magnesium and a different lubrication system. A GE CT7-8A6 engines, as used in the VH-92A Presidential helicopter, are an option, for improved hot-and-high performance. The S-92B variant, to be available in 2022, also will offer a revised cabin entry door, larger cabin windows and titanium side frames. 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...
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