Helicopter External Sling Load Operation Occurrences in New Zealand
HESLO (Under Slung Load) Occurrences in New Zealand Data issued by the NZ Helicopter Association and NZ CAA show a rising trend in reported occurrences in NZ relating to external load operations and equipment. Around 60% of the reports relate to HESLO equipment or its rigging and about 35% relate to operations with a load. The report mentions UK CAA CAP426 Helicopter External Load Operations from 2006 as a safety resource. CASA issued Airworthiness Bulletin 25-006 “to notify operators and maintainers of additional safety information and current design standards for cargo hooks installed in helicopters”. It discusses phenomena such as Dynamic Rollout (or Ring Reversal), Jammed Loads / Hooks, Uncommanded Release / Inadvertent Cargo Hook Opening etc. Other Safety Resources Keep Your Eyes on the Hook! Underslung External Load Safety EC120 Underslung Load Accident 26 September 2013 – Report Unexpected Load: AS350B3 USL / External Cargo Accident in Norway Unexpected Load: B407 USL / External Cargo Accident in PNG Load Lost Due to Misrigged Under Slung Load Control Cable Fallacy of ‘Training Out’ Error: Japanese AS332L1 Dropped Load UPDATE 28 June 2020: Maintenance Issues in Fire-Fighting S-61A Accident Also: the UK AAIB report on a fatal accident to AS350B2 G-PLMH during HESLO with a boat at Loch Scadavay, Western Isles, Scotland, 13 June 2018, was issued in July 2019. Aerossurance has extensive air safety, operations, HESLO, 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 moreFatal Taiwanese Night SAR Mission
Fatal Taiwanese Night SAR Hoist Mission (NASC AS365N3 NA-106) On 5 December 2018, a National Airborne Service Corps (NASC) Airbus Helicopters AS365N3 Dauphin NA-106, was carrying out a Search and Rescue (SAR) mission to hoist aboard an injured sailor from the bulk carrier W-STAR about 11 nm west of the Peng-Jia Islet when a winchman and patient were both fatally injured (in NASC’s second fatal hoisting accident in 31 days). Taiwan Transportation Safety Board (TTSB), which recently replaced the Aviation Safety Council (ASC) of Taiwan, issued their safety investigation report on 19 November 2019 (only available in full in Chinese). History of the Flight The flight was tasked in daylight. Sunset was 17:03, and civil twilight ended at 17:27. The winchman was lowered to pick up the casualty at around 17:45. While hoisting, the helicopter, which was not equipped with an autohover capability and so unsuitable for might hoisting, started to climb and accelerate. The hoist cable however snagged on the right landing gear. The photographs in the report do not show any hoist cable guard modifications. The flight crew decided to reduce speed and descend. They tried to hover over the sea and dipping the personnel on the hoist into the water to release the tension. The helicopter then continued to fly away from the ship. The TTSB say the crew was unable to maintain visual contact with the hoist and sea surface due to the low ambient light. The helicopter descended and then climbed twice without noticeable hovering operations over the sea. TTSB determined that the personnel on the hoist hit the water twice at a ground speed of 67 to 45 knots and then 37 to 17 knots in the red zone below). The winchman… …suffered from shock and lapsed into a coma while being pulled into the cabin. …organ injuries and serious fractures were also observed, indicating the presence of intense impact force when dipping into the water. Cable damage was found in several places on the fuselage. TTSB Analysis The tasking came about 1 hour before the end of evening twilight, but… …attempts to abort the mission did not succeed since the crew did not effectively evaluate and communicate the approach of the end of evening twilight and the possible unexpected situation beforehand. In addition, the flight crew unable to contact the on-boarded coast guard by radio, thus continued the hoist operation after the end of evening twilight and increased the risks of mission. There were neither written restriction served to limit the AS365N helicopter conducting SAR during the night, nor requirement to ask the flight crew abort sea hoist operation after the end of evening twilight… This… …led to the flight crew’s attempts to keep on trying the sea hoist operation…because of a sense of duty and commitment…and increased the risks of mission. TTSB say: NASC did not specify reasonable operation time prior to the end of evening twilight for those aircraft [that were daytime only capable] and did not develop a mechanism of risk control that authorises its command centre to deploy appropriate aircraft from other regions or hand over to the Taipei Rescue Coordination Centre for reinforcement. As the helicopter arrived target area and the winchman was lowered on deck, the preparations on board for hoist operation were not ready yet with the patient still inside the cabin, caused the delays and extended the operation time. TTSB Safety Recommendations To National Airborne Service Corps, Ministry of the Interior: Review aircraft dispatch related rules for explicitly defining written...
read moreLuftwaffe VVIP Global 5000 Written Off After Flying Control Assembly Error
Luftwaffe VVIP Global 5000 14+01 Written Off After Flying Control Assembly Error On 16 April 2019 Luftwaffe VVIP Bombardier BD-700-1A11 Global 5000 14+01 departed Berlin-Schönefeld (BER) for Cologne-Bonn (CGN) on its first flight after having undergone heavy maintenance by Lufthansa Bombardier Aviation Services (LBAS). The aircraft climbed to c 21000 ft but suffered flight control problems. The aircraft returned to Berlin-Schönefeld but suffered severe roll instability and the both wing tips reportedly struck the runway. Some reports suggest the aircraft was exposed to 5g manoeuvres. The aircraft has now been assessed as write off due to the damage sustained. In December 2019 the Luftwaffe said that: As part of the work, a component of the flight control system was replaced. An error in the setting of so-called signal transducers in conjunction with a lack of care in the function verification resulted in a malfunction in the flight control. Other reports suggest a torque tube assembly was misassembled. VIDEO UPDATE 9 October 2020: Transport Canada have issued Airworthiness Directive CF-2020-35: Flight Controls – Roll Control Input-Modules (RCIMs) Incorrect Installation which states: There are several in-service reports of a single RCIM being installed incorrectly, and one report of both RCIMs being installed incorrectly. An investigation has determined that it is physically possible for an RCIM to be installed and zeroed 180 degrees from its intended (design) installation orientation. If both RCIMs are installed incorrectly in the same manner, a misrigging condition occurs causing the multi-function spoilers (MFSs) to deploy opposite to the roll command. Misrigging of the MFS in this manner could lead to loss of control of the aeroplane. To reduce the likelihood of incorrect RCIM installation during maintenance, the Aircraft Maintenance Manual (AMM) has been revised with improved RCIM installation and adjustment tasks. These improved tasks provide additional guidance to ensure proper orientation of the RCIM. A new AMM functional test task was introduced to improve the robustness of post-maintenance checks to confirm proper installation of the RCIMs. This AD requires the use of these latest AMM procedures when performing maintenance involving one or both RCIMs. It is not clear if this AD is relevant to the Berlin-Schönefeld incident. UPDATE 20 October 2022: It has been brought to our attention that a summary of the Directorate of Aviation Safety Bundeswehr (DASBw) report has been made public and confirms the involvement of the MFS and RCIMs. Their findings were: Based upon the design of the system, the possibility exists, that an improperly installed and adjusted element of the FCS can pass an operational test, without generating a failure message. The maintenance company performed routine maintenance. During the course of the routine maintenance a malfunction of an element of the FCS was determined which required troubleshooting. In the completion of the troubleshooting and operational checks, the abnormal operation of the MFS was not recognized. The aircraft was deemed “ready for flight” and transferred to the flight crew. Prior to takeoff, while completing the flight control checks on the ground, the AC did not recognize the abnormal operation of the MFS. Shortly after takeoff, the crew recognized a problem in the flight controls and decided to return to Berlin-Schönefeld for landing. While flying with under the command of the autopilot, while attempting a left hand turn, the aircraft rolled towards the right and entered a steep uncommanded dive. The aircraft was recovered and brought...
read moreDash 8 Q400 Return to Base After Pitot System Contaminated By Unapproved Test Kit Lubricant
Dash 8 Q400 Return to Base After Pitot System Contaminated By Unapproved Test Kit Lubricant (Flybe G-JECR) On 15 November 2018, Flybe DHC Dash 8 Q400 G-JECR returned to Exeter, shortly after departing for Paris Charles de Gaulle when the pilots received an intermittent ALT MISMATCH message during the climb. The UK Air Accidents Investigation Branch (AAIB) investigation revealed a difference between ‘work as imagined’ and ‘work as done’ in testing the pitot static system. In their safety investigation report the AAIB comment: ‘Work as done’ according to the Shorrock concept [discussed below] is the actual activity taken to complete the task and may occur in an environment that is subject to a variety of constraints, challenges and demands that are not ‘imagined’ or ‘disclosed’. The work done may be the product of adaptations to overcome these which, although intended to achieve the objective, may result in unintended consequences. History of the Incident Flight …the aircraft had been undergoing a standard maintenance check at the operator’s maintenance facility at Exeter Airport. This activity included cleaning and leak checks of the pitot static system. The aircraft was released for service on the morning of 15 November 2018. AAIB say that: Analysis of flight data for the incident flight indicated that shortly after takeoff the altitude from Air Data Unit 1 (ADU1) under-read the altitude from Air Data Unit 2 (ADU2) by about 50 to 60 ft, but as the aircraft climbed the altitude difference varied between 20 and 70 ft. During this same period the airspeed from the ADU1 under-read the airspeed from the ADU2 by about 3 kt. When the aircraft levelled off at FL190, the altitude from ADU1 under-read the altitude from ADU2 by about 140 ft, and the difference between the ADU1 and ADU2 airspeeds remained at approximately 3 kt. The cruise airspeed was then reduced from about 230 to 190 kt, at which point the ADU1 and ADU2 altitude difference reduced to about 100 ft. As the aircraft descended for the approach, the altitude difference between ADU1 and ADU2 reduced to about 20 ft and the airspeed difference increased briefly to 5 kt. A review of previous flights of G-JECR, and data from other aircraft of the same type, indicated that during the climb it was normal to see a difference in altitude between ADU1 and ADU2 of 20 to 30 ft. This then reduced to less than a few feet in the cruise and to an average of about 5 ft during the approach. The difference between ADU1 and ADU2 airspeed during the climb and cruise was about 1 kt and during the approach, this could increase to about 3 kt. The Pitot Static System Design AAIB explain that: There are two primary pitot static probes located on the left and right side of the nose fuselage, linked to ADU1 and ADU2 respectively, and a third pitot static probe on the right side of the nose fuselage linked to the standby instruments. Pitot, or total pressure, is measured by the forward-facing hole, and static pressure by four 1.5 mm diameter holes on the side of the probe. The two primary pitot pressures (T1 and T2) are fed directly to the respective ADU, whereas the static pressures from the two static holes from each primary probe are averaged (S1 and S2) and fed to each ADU to minimise any...
read moreFall From Stretcher During Taiwanese SAR Mission
Fall From Stretcher During Taiwanese SAR Mission (NASC AS365N2 NA-104) On 4 November 2018, a National Airborne Service Corps (NASC) Airbus Helicopters AS365N2 Dauphin NA-104, took off from Kaohsiung International Airport at 1715 Local Time. It was to do a Search and Rescue (SAR) tasking to hoist an unconscious patient from a cargo ship c 2.5 nm offshore. At about 1726, while hoisting, the patient fell from stretcher into the sea. They were recovered but pronounced dead on landing. Taiwan Transportation Safety Board (TTSB), which recently replaced the Aviation Safety Council (ASC) of Taiwan, issued their safety investigation report on 31 October 2019 (only available in full in Chinese). On arrival at the ship the patient was found to be conscious, but not speaking. The hoisting commenced from the vessel’s superstructure at an altitude of 150 ft ASL. The TTSB explain that during the hoisting the casualty started to wave their arms and the stretcher started to spin. Stills from the hoist video suggest that the aircraft was ascending during the hoist sequence and as the patient waved their arms the stretcher tilted and the patient started to slip head first from the stretcher. It appears that the aircraft was carrying strops and a rescue basket but not the stainless steel, foldable SAR stretcher that NASC had available at their base. The stretcher used was one supplied by the ship and images seems to indicated that the patient’s head was elevated on a white pillow positioned on the raised edge of the stretcher, potentially positioned their centre of gravity towards the head of the stretcher (as well as a FOD risk). There may also have been time pressures as the AS365N2 was not equipped with autohover and nighttime was closing in. No safety recommendations were made. NASC suffered another fatal hoisting accident shortly after. We’ll publish a summary of that in December. Safety Resources The European Safety Promotion Network Rotorcraft (ESPN-R) has a general helicopter safety discussion group on LinkedIn and a Hoist Operation Safety Promotion LinkedIn group. Tail Rotor Pitch Control Loss During Hoisting: Fatal NASC AS365N3 hoisting accident Hoist Assembly Errors: SAR Personnel Dropped Into Sea: NASC UH-60M hoist failure Taiwan Night Medevac Helicopter Take Off Accident: NASC UH-60M Loss of Control In-flight, high descent rate and water impact Fatal Fall From B429 During Helicopter Hoist Training Marine Pilot Transfer Winching Accident Swedish Special Forces SPIES and Military SMS USAF UH-1H Helicopter Hoist Training Accident: equipment snagged on obstacle UPDATE 14 December 2019: Fatal Taiwanese Night SAR Hoist Mission (NASC AS365N3 NA-106) UPDATE 27 December 2019: Fatal Powerline Human External Cargo Flight UPDATE 19 April 2020: SAR Helicopter Loss of Control at Night: ATSB Report UPDATE 2 May 2020: Sécurité Civile EC145 SAR Wirestrike UPDATE 11 May 2020: European Search and Rescue (SAR) Competition Bonanza UPDATE 20 March 2021: SAR AW139 Dropped Object: Attachment of New Hook Weight UPDATE 15 May 2021: Military SAR H225M Caracal Double Hoist Fatality Accident UPDATE 27 November 2021: TCM’s Fall from SAR AW139 Doorway While Commencing Night Hoist Training UPDATE 19 February 2022: SAR Hoist Cable Snag and Facture, Followed By Release of an Unserviceable Aircraft UPDATE 26 November 2022: Guarding Against a Hoist Cable Cut SAR Consultancy: Procurement, Tenders, Contacts and In-Service Assurance and Aviation Advice In September 2017 one European Coast Guard selected Aerossurance to be their new aviation consultants after a competitive tender with 7 bidders. In July 2018 Aerossurance started work supporting a second European Coast Guard with a procurement project. The Aerossurance team is and has...
read moreAustrian Police EC135P2+ Impacted Glassy Lake
Austrian Police EC135P2+ Impacted Glassy Lake After nearly 8 years and 8 months Austrian accident investigators from the Sicherheitsuntersuchungsstelle des Bundes (SUB) have released their report into Interior Ministry Airbus Helicopters EC135P2+ police helicopter, OE-BXF, that impacted Lake Achensee on the morning of 30 March 2011. All 4 occupants were killed. The helicopter arrived in the vicinity of the village of Achenkirch, north of the lake, just over 30 minutes after departure from Innsbruck. The weather was good and winds were calm. It made a 270º turn in the eastern area of the village before flying south west towards the Christlum Achenkirch Achensee ski resort. The helicopter was at this time approximately of 250 to 500 ft AGL. The helicopter then flew to the south, manoeuvred hard, descended and crossed over the shore of the lake at a ground speed of c 134 kts. The helicopter impacted the lake shortly after. The helicopter was equipped with neither an FDR nor CVR but the EURONAV mission system and aircraft Usage Monitoring System (UMS) were downloaded. In addition, the innovative Immersive Witness Interview application from IWI was used to collate and plot the observations of three witness. This was especially valuable in reconstructing the last 9 seconds of the flight for which data was missing (although in fact the witness data was analysed by IWI even before any data had even been recovered from the aircraft). IWI also used virtual-reality technology, including laser scanned terrain (128 million points), 0.25 m resolution imagery, cockpit instrumentation imagery and weather effects modelling (including water mirror effects) to provide investigators with other insights. The investigation concluded the pilot misjudged height when flying low over the glassy surface of the lake. An IWI reconstruction shows the likely reflections on the lake’s surface. No operational reason was determined for the low flying. It does not appear the RADALT was referred to and procedures did not require its use. Safety Resources We have previously written about other accidents where IWI has proved valuable: For Rotors Grease is the Word A similar accident occurred in New Zealand to Hughes 369 ZK-HXZ in 2012 (discussed in an NZCAA accident report). The FAA Seaplane, Skiplane, and Float/Ski Equipped Helicopter Operations Manual (FAA-H-8083-23) says: Flat, calm, glassy water certainly looks inviting and may give the pilot a false sense of safety.…Unfortunately…the visual…characteristics of glassy water hold potential hazards for complacent pilots. Consequently, this surface condition is frequently more dangerous than it appears.… The visual aspects of glassy water make it difficult to judge…height above the water. The lack of surface features can make accurate depth perception very difficult, even for experienced…pilots. Without adequate knowledge of the…height above the surface, the pilot may…fly into the water at relatively high speed.… Besides the lack of surface features, the smooth, reflecting surface can lead to confusing illusions. You may also be interested in: EC135P2 Spatial Disorientation Accident EC135P2+ Loss of NR Control During N2 Adjustment Flight US HEMS EC135P1 Dual Engine Failure: 7 July 2018 Misassembled Anti-Torque Pedals Cause EC135P1 Accident AAIB Report on Glasgow Police EC135T2+ Clutha Helicopter Accident Maintenance Misdiagnosis Precursor to EC135T2 Tail Rotor Control Failure Accident Report: Fatal Police Helicopter Double Engine Flameout Over City Centre US Police Helicopter Night CFIT: Is Your Journey Really Necessary? HEMS S-76C Night Approach LOC-I Incident UPDATE 5 March 2020: HEMS AW109S Collided With Radio Mast During Night Flight UPDATE 2 May 2020: Sécurité Civile EC145 SAR Wirestrike UPDATE 6 June...
read moreUnalaska Saab 2000 Fatal Runway Excursion: PenAir N686PA 17 Oct 2019
Unalaska Saab 2000 Fatal Runway Excursion: PenAir N686PA 17 Oct 2019 The US National Transportation Safety Board (NTSB) has issued an investigative update for the 17 October 2019 runway overrun of PenAir Saab 2000 N686PA (Flight 3296) while landing at Tom Madsen Airport (PADU/DUT), Unalaska, Alaska (Port of Dutch Harbor). This was only the second fatal accident involving a US Part 121 passenger airline since 2009. The flight was cleared for the RNAV runway 13 approach into PADU. The aircraft passed through the airport perimeter fence, crossed a road, struck a sign and came to rest on shoreline rocks. Two propeller blades entered the fuselage. Of the 42 persons on board, one passenger was fatally injured and several others sustained injuries. NTSB Safety Investigation The NTSB say that: According to the flight crew, the captain was the flying pilot and the first officer was the pilot monitoring. The first officer stated that he completed the performance calculations during cruise, before beginning descent, and prior to obtaining the weather at DUT. The flight crew indicated that they conducted a go-around during the first approach to runway 13 because they were not stabilized. On the second approach, the flight crew indicated they touched down about 1,000 feet down the runway and the captain initiated reverse thrust and normal wheel-braking. The captain stated that he went to maximum braking around the “80 knot call.” The flight crew reported that they attempted to steer the airplane to the right at the end of the runway to avoid going into the water. The NTSB’s initial feedback from study of the Cockpit Voice Recorder (CVR) was that: Weather was initially reported (by the local weather observer) as winds 210 degrees at 8 knots, gusting to 14 knots, visibility 7 to 10 miles, a ceiling at 4,300ft that was broken, a temperature of 8 degrees Celsius, a dew point of 1 degree Celsius, and an altimeter setting of 29.50 inches Hg. A later transmission from the local weather observer to another aircraft reported the winds were 180 degrees at 7 knots, visibility 8 to 10 miles with showers in the vicinity, and a broken ceiling at 3,900 feet. The aircraft was configured for the approach: flaps 20, gear down. During the approach, the winds were reported as 270 deg at 10 knots. A go-around was executed, and the flight returned for a visual approach to runway 13. During the go-around, the winds were reported as 300 degrees at 8 knots. After the go-around, the winds were reported to be 290 at 16 gust 30 (multiple overlapping radio transmissions occurred at this time). Transmissions between the weather observer and another airplane indicated that winds favored runway 31 but could shift back to runway 13. The aircraft was configured again for the approach: flaps 20, gear down. During the second approach, winds were reported as 300 degrees at 24 knots. The aircraft touched down and the roll out lasted approximately 26 seconds until the aircraft departed the runway. The crew announced, over the PA, an evacuation out the right side of the aircraft and made a radio call for assistance. Press reports indicate that only one emergency exit was opened. The Flight Data Recorder (FDR) was examined: Touchdown occurred with the aircraft travelling at about 129 knots indicated airspeed and 142 knots ground speed. Following touchdown,...
read moreUH-1H HESLO Fuel Exhaustion Accident
UH-1H HESLO Fuel Exhaustion Accident Bell UH-1H N4085L, used for Part 133 External Load Operations by Yukon Helicopters, was damaged in a hard landing after being forced to autorotate after fuel exhaustion on 6 June 2019 near Bethel, Alaska. The helicopter sustained substantial damage to the tailboom and transmission mounts and both occupants were injured. According to the National Transportation Safety Board (NTSB) safety investigation report: The chief pilot, who was also the helicopter’s owner, reported that he had refueled the helicopter on uneven terrain before the flight. He filled the tank to the bottom of the filler cap on the left side, which he estimated was about 10 to 15 gallons less than the total fuel capacity of the 210-gallon tank. He estimated that the helicopter burned about 90 gph [gallons per hour]. He added that there were no open mechanical squawks on the helicopter and that he was not aware of any mechanical issues. However, the pilot of the accident reported that,… …before departure, he was told the helicopter was topped off with fuel for the multistop flight. He added that he did not verify the fuel quantity but that, when he departed for the last leg about 60 miles from the destination airport, the fuel gauge showed just below 600 lbs of fuel, and he decided to fly at 120 knots with a tailwind. …after landing, the fuel quantity gauge showed that there was about 225 lbs of fuel remaining and that the 20-minute fuel light, which did not illuminate during the flight, illuminated once on the ground. He estimated that the helicopter’s fuel burn was about 75 to 80 gph. About 3 miles from the destination airport, the engine lost power. A Federal Aviation Administration (FAA) inspector who examined the helicopter reported that… …the fuel quantity gauge had been serviced and calibrated earlier in the year but continued to indicate that fuel was onboard even after the helicopter ran out of fuel. The 20-minute low fuel light appeared to be functioning normally. NTSB Probable Cause The pilot’s improper fuel planning, which resulted in fuel exhaustion and a total loss of engine power, and his improper landing flare during a forced autorotation, which resulted in a hard landing. Contributing to the accident were the inoperative fuel gauge, which was not accurately calibrated, and the pilot’s reliance on the gauge. Safety Resources Survey Aircraft Fatal Accident: Fatigue, Fuel Mismanagement and Prior Concerns Running on Fumes: Fatal Canadian Helicopter Accident UPDATE 28 June 2020: Maintenance Issues in Fire-Fighting S-61A Accident UPDATE 4 July 2020: A Baffled Attitude Fuel Starvation Accident UPDATE 24 April 2021: Unballasted Sling Stings Speedy Squirrel (HESLO in France) UPDATE 26 June 2021: Engine Life Limit Exceedance Caused Logging Helicopter Fatal Accident UPDATE 25 September 2021: Fuel Starvation During Powerline HESLO UPDATE 1 January 2022: Snagged Sling Line Pulled into Main Rotor During HESLO Shutdown Aerossurance has extensive air safety, operations, SAR, HESLO, 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 updates. TRANSLATE with x English Arabic Hebrew Polish Bulgarian Hindi Portuguese Catalan Hmong Daw Romanian Chinese Simplified Hungarian Russian Chinese Traditional Indonesian Slovak Czech Italian Slovenian Danish Japanese Spanish Dutch Klingon Swedish English Korean Thai Estonian Latvian Turkish Finnish Lithuanian Ukrainian French Malay Urdu German Maltese Vietnamese Greek Norwegian Welsh Haitian Creole Persian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing...
read moreTight Cable Tie Nose Gear Jam
Tight Cable Tie Nose Gear Jam (Flybe Dash 8 Q400 G-JEDU) Flybe DHC Dash 8 Q400 G-JEDU made an emergency landing at Belfast International Airport with its Nose Landing Gear (NLG) retracted on 10 November 2017 after cockpit indications showed that the nose landing gear doors had not closed after landing gear retraction. There was an emergency evacuation and two of the 53 passengers sustained minor injuries. Evacuation was complicated as the forward left airstair door was at a shallow angle while the the rear door sill height was large. Safety Investigation In their safety investigation report the UK Air Accidents Investigation Branch (AAIB) state they… …determined that…the forward NLG doors starting to close while the NLG was still in transit to the up position. The NLG tyres contacted the forward doors, causing the NLG to rotate off-centre. Although the NLG subsequently retracted, the forward doors remained open and the tyres became jammed in the NLG bay. This prevented the nose landing gear from extending when subsequently commanded. [After the incident it was found that] the NLG alternate release cable remained jammed despite attempts to pull it using substantial force, however the uplock could be heard releasing when the cable was pulled. A crowbar was used to rotate and centre the NLG, releasing the right tyre from the jammed position; once the gear was centred, it extended under gravity and locked down. During a go-around at Birmingham International Airport on 1 November 2017, G-JEDU’s landing gear failed to retract when selected. A circuit was flown gear down and a safe landing made. Damage was found to the lower edge of the forward right NLG door and the door seal. The problem could not be replicated during subsequent maintenance. The forward right NLG door and door actuator were replaced and the aircraft returned to service. The AAIB reviewed Flight Data Monitoring (FDM) data and discovered that: …G-JEDU experienced slower than normal NLG retractions (12 seconds) during two sectors on 9 November 2017 and on one sector on 7 November 2017 (20 seconds). Additionally, slower than normal NLG retractions (12 seconds) were noted for the flight on 1 November 2017 where the landing gear failed to retract, and on the previous sector the same day… During a carefully controlled trial after the Belfast occurrence, anomalous inductance values were detected in a NLG up-lock sensor harness (‘NGLK 1’) when jams were reproduced. During removal of the harness it was noticed that there was little slack and a tight bend where it entered the bulhead connector. A computed tomography (CT) scan “identified that one of the two conductors in the NGLK1 harness was fractured…approximately 15 cm above the sensor. In addition, a number of sites which indicated the initiation of possible similar damage were identified”. The AAIB found that: The damage to the harness resulted from a cyclically-driven fatigue failure mechanism, which occurred because the harness had been secured with a non-flexible cable tie which restricted it from flexing during normal nose landing gear operation. However: The aircraft and landing gear manufacturers are aware of other instances of NGLK sensor harness failures in normal operation. During normal retraction, extension and steering operations, the NGLK harnesses are subject to dynamic movement and bending which can result in degradation and breakage of the internal wires. The landing gear manufacturer [had already] initiated a product improvement review...
read more“Shoulda gone around”: B727 Landing with NLG Retracted
“Shoulda gone around”: Kalitta Cargo B727 N720CK Landing with NLG Retracted On 28 January 2019, Kalitta Charters II cargo Boeing 727-2B6 N720CK, landed with its nose gear retracted at Tuscaloosa Regional Airport (TCL), Alabama. The operator is a Part 121 cargo airline based in Ypsilanti, Michigan that conducts just-in-time cargo operations for the automotive industry. They operated a fleet of 5 B727 aircraft and 9 other aircraft. According to the NTSB’s report: …about 12 miles from the airport the captain called for flaps 15 and gear down. After the gear was selected down, the CVR recorded the first officer stating, “yeah it’s down, but [unintelligble] the lights [unintelligble]” The crew reported that they noted a red warning light for the nose gear position, and heard the audible gear warning horn. The CVR recorded the captain queried, “what horn was that?” and the first officer (FO) responded, “[unintelligible] gear warning horn.” Surprisingly: The flight engineer (FE) stated that he recommended that they recycle the gear, the captain declined. The FO stated that he recommended that they go around to troubleshoot, the captain declined. The CVR recorded multiple automated “sink rate, pull up” warnings and the captain responded, “yeah, yeah, I got it.” The FO then queried, “you gonna go around?”, and the captain responded, “ah I’m gonna go… I got, it, I got it.” The captain reportedly stated that the airplane had a history of a microswitch issue, and pressed on the gear handle and light. As the power was reduced to idle, the gear warning horn and the GPWS audible alerts sounded. Curiously: The captain stated in an interview that he asked for the gear to be recycled, and also that he smelled smoke and did not want to delay. Neither the FO, FE, or non-revenue mechanic, reported these items, nor were any of these items audible on the CVR. What is clear however is that: The captain continued the approach and after landing, upon derotation, the forward fuselage contacted the runway and the airplane quickly slid to a stop with the nose gear retracted. After the airplane came to a stop, the captain stated, “it wasn’t down,” and the FO made a radio call to tower. About five seconds later the FO stated, “shoulda gone around,” and the captain responded, “yeah, shoulda.” The crew did not declare an emergency or call for fire / rescue. The NTSB also report that: One day prior to the accident, a different flight crew experienced an indication that the nose landing gear failed to extend. This flight was also landing at TCL, and the crew reported they were high and fast, and that power was near idle, and flaps were in transit when the gear was selected down. After extending the landing gear, the crew received a red warning light for the nose gear. The green nose gear down and lock light was not illuminated. The crew requested delaying vectors and referenced the abnormal checklist for landing gear indications. They attempted to swap out the green down and lock bulb with another bulb but still did not receive the light. The gear was cycled, the red unsafe indication extinguished, and they then received a green down and lock indication for the nose wheel. Significantly: The event was not written up in the maintenance logbook. The Captain [of the previous flight]...
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