SAR Helicopter Loss of Control at Night: ATSB Report
SAR Helicopter Loss of Control at Night: ATSB Report (Careflight AW139 VH-YHF near Darwin, NT) On 13 May 2018 Leonardo Helicopters AW139 VH-YHF of HEMS operator Careflight, while descending during a nighttime search, the aircraft entered a degraded visual environment, developed a high rate of descent, an autohover mode was inappropriately selected and came within 31 ft of impacting the ground. The aircraft was also then flown on for one more flight after the related 159.5% over-torque. We look at the Australian Transport Safety Bureau (ATSB) safety investigation report issued 16 April 2020. The SAR Tasking, Aircraft Equipment and Preparations On the evening of 13 May 2018 the Australian Maritime Safety Authority (AMSA) Rescue Coordination Centre (RCC) tasked the crew of VH-YHF, to locate an active Emergency Position-Indicating Radio Beacon (EPIRB) 21 nm north-east of Darwin International Airport, Northern Territory in the vicinity of a waterway called Salt Water Arm, popular with recreational anglers. The aircraft was operated single pilot (front right seat), an ‘ Aircrew Officer (ACO)’, a dual qualified winch op and winchman (right hand cabin doorway) and a ‘Flight Nurse’ (rear of the cabin), who was “not expected to be involved in the operation of the aircraft in flight”. The Pilot and ACO were equipped with AN/AVS-9 green phosphor Night Vision Goggles (NVGs). The ATSB explain that the rest of the Night Vision Imaging System (NVIS): • NVG-compatible cockpit lighting • NVG-compatible cabin lighting • 2 x 450 W incandescent forward facing steerable search lights • 1 x 450 W incandescent steerable search light by winch • White flood lights at the front and back of the aircraft. The operator required the use of NVIS for all visual flight rules (VFR) flights at night. The Civil Aviation Safety Authority (CASA) provided the Operator with an exemption to Supplement 60 of the AW139 rotorcraft flight manual. The exemption allowed the ACO to operate from the rear cabin of the aircraft during flight below 300ft and for landing at unimproved sites. The Operator listed the responsibilities of an ACO in their operations manual as “Under direction of the pilot assist with the operation of all aircraft equipment and systems during the conduct of VFR, NVG and IFR operations” and “operate the winch, dispatch, and recovery of personnel and assist the pilot in maintaining clearance from obstacles by lookout and reporting over the intercom”. The ACO was expected to work from both cockpit and cabin. CASA’s position was that “they supported the role of the ACO in the front left seat” and “preferred operators to land” for the ACO to transfer positions, but ‘climb-throughs’ did occur. The operator seems to have recognised this risky manoeuvre was unusual as everyone had to be reported. ATSB state that the crew believed the tasking would “most likely” need use of the hoist, and so with a nearby search area with limited landing opportunities the ACO was in the cabin. ATSB note that: The helicopter’s autopilot was a 4-axis system with enhanced 3-cue flight director (FD). The FD is capable of controlling the helicopter’s movement in the pitch, roll, yaw, and vertical axis. The installed version of the FD had auto-hover functionality (HOV) mode, yet did not offer SAR modes that can mark, return, and transition down to a selected target. Engaging the system instructs the autopilot to make control inputs to bring...
read moreJest11 is Dead: Hawker Hunter Downed by F-35A Jet Wash
Jest11 is Dead: ATAC Hawker Hunter F Mk 58 N338AX Downed by USAF F-35A Jet Wash On 22 August 2017 Hawker Hunter F Mk 58 N338AX, operated by Airborne Tactical Advantage Company (ATAC) under contract to the US Navy as a Public Aircraft, was destroyed when it impacted open water about 80 nm southwest of San Diego, California. It was one of a pair of Hunters supporting an exercise with aircraft carrier USS Theodore Roosevelt and two USAF Lockheed Martin F-35As. The pilot ejected using a Martin Baker Mk3 ejection seat and received only minor injuries. The US National Transportation Safety Board (NTSB) say in their safety investigation report, published 13 April 2020, that: While flying at 14,000 ft mean sea level (msl), one of the F-35s flew alongside and about 1,500 ft from the accident pilot’s right wing. Moments later, the F-35 accelerated ahead of the [Hunter] pilot and crossed in front of his flight path from the accident pilot’s right side to his left side. The pilot attempted to follow the F-35, but the airplane then initiated a right turn and passed in front of the pilot’s flight path again, this time to the right. As the pilot started to turn right to follow the F-35, he heard a “thump”, which he dismissed as jet wash. He continued his maneuver and rotated to the right into an approximate 60° angle of bank and began to apply back pressure, but the airplane immediately rolled into a left bank, at which time the F-35 disappeared from his view. Critically: The pilot briefly terminated the left-hand roll by applying right aileron but was unable to move the flight controls more than one inch to the right of its center position. He remarked that the right aileron flight control movement felt “jammed” as he can normally move the flight controls to his right knee. The airplane then entered an approximate 35° nose down attitude, at which time the pilot applied back pressure on the flight controls, but the airplane repeated its previous movement and entered a left-hand roll. After about 2 full 360° rotations, the pilot stopped the movement with some right aileron, but the flight controls still would not advance to the right more than one inch beyond its center position. As he was passing through 4,000 ft mean sea level, the pilot notified his wingman that he was ejecting. He did not observe any unusual sounds or harmonics from the engine during the accident flight. The airplane impacted open water about 2 nm from its final radar data point. ATAC reported that the debris field was comprised of an oil slick, and no physical remnants of the aircraft. The airplane wreckage was not recovered. Radar data was provided by the Southern California Offshore Range (SCORE) at Naval Air Station North Island, California. The F-35’s relayed altimeter data at a 1 hz sampling rate along with its geographic positioning system (GPS) data. Large Area Tracking Range (LATR) pods were mounted to both [Hunter] Mk 58s, which reported multiple parameters, including position and altimeter data. The radar displayed data points for “Jest11” (the accident airplane) and “Jest12” (the accident pilot’s wingman). The radar data for Jest11 and Jest12 began at 1530:00 at a radar altitude of about 15,800 ft. Both airplanes turned to a southern heading at 1534:42,...
read moreInadequately Secured Pallets Penetrate the Rear Pressure Bulkhead of a Cargo B737
Inadequately Secured Pallets Penetrate the Rear Pressure Bulkhead of a Cargo Boeing 737 (Aloha, B737-300, N301KH) On 16 October 2014 Aloha Air Cargo Boeing 737-330, N301KH flew a cargo to Lanai Airport (LNY), Lanai City, Hawaii. The aircraft was turned around but shortly after rotation on the return flight the aircraft experienced a load shift that caused substantial damage to the aft pressure bulkhead, preventing pressurisation. the aircraft landed safely with no injuries to the three occupants. The Accident Flight The US National Transportation Safety Board (NTSB) explain in their safety investigation report issued on 6 April 2020 (nearly 5.5 years later): Aloha Air Cargo was chartered, by Hawaii Island Air, to fly round trip from [Daniel K Inouye International Airport (HNL), Honolulu, Hawaii] to LNY to deliver lumber for an impeding hurricane. LNY was not a station Aloha Air Cargo normally flew to, nor did they have employees there. The decision was made to limit the number of Additional Crew Members (ACMs) due to concerns about the return flight’s weight and balance. With the choice of taking the load planner or the mechanic, Aloha Air Cargo made the decision to take the mechanic, which was against the company loading procedures since the mechanic was not trained on cargo securing nor were there any approved personnel at the destination to assist with loading and securing the empty pallets. Aloha Air Cargo used various unit load devices (ULDs) in its freighter operation. The LD7 cargo pallet “cookie sheets” consisted of a single skinned pallet with four edge rails, four corner castings and a center sheet section. Since the load planner would not be making the flight, he discussed with the mechanic on how to load the empty pallets for the return flight, which was to load and lock each empty pallet in their original loaded location. The aircraft landed at LNY and the lumber was safely offloaded. The investigators explain that: …while in LNY, Aloha Air Cargo dispatch recommended that all the pallets be placed in position 9 due to concerns about weight and balance. The decision was made to secure the stacked pallets with a cargo strap… The NTSB note this “was insufficient to keep the pallets from moving”. The mechanic, first officer (FO), and Island Air employees helped to load the aircraft and verified that the locks were up and locked in all positions. There were a total of 8 empty pallet cookie sheets. Of these sheets 7 were strapped down and secured to the 8th sheet. The 8th sheet was then locked down in position 9 (the aircraft was equipped with 9 cargo positions on the main deck with the ninth position being the most aft and turned lengthwise). This was done per dispatch’s request for center of gravity (CG) consideration… On rotation the load came loose. Post event examination revealed that the aft pressure bulkhead had substantial damage, left aft (L2) door panel was damaged, and the right hand forward and aft pop up locking mechanism “claws” were detached/torn from their seat tracks. The first indication of a problem to the crew was…. …upon reaching 10,000 ft. the altitude alert horn came on so the crew leveled at 10,000 ft. No emergency was declared. The aircraft landed uneventfully. Upon arrival the flight crew notified dispatch of the pressurization issue [and] made a...
read moreBear Paws Claw Reindeer Herding Bell 206
Bear Paws Claw Reindeer Herding Bell 206 (SE-HPM) A single pilot was conducting reindeer herding using Bell 206L1 SE-HPM for Alpine Helicopter Sweden in the Alajaure National Park, 30 nm north of Kiruna on 8 October 2019. The helicopter was equipped with ‘bear paws‘ to allow landing on soft surfaces. The pilot needed land to pick up a one passenger. According to the Swedish Accident Investigation Board (the Statens Haverikommission [SHK]) in their safety investigation report (issued 16 March 2020): After setting down the helicopter, the pilot felt that it was unsteady due to a turf under the left [skid]. He therefore decided to lift up in order to move the helicopter slightly to the right. In connection with that, he experienced a sudden roll movement to the right. Although the collective pitch lever was lowered immediately, the helicopter continued to roll to the right with the main rotor hitting the ground and the helicopter resting on the right side. The damage were extensive but the pilot was uninjured. During the site investigation it was found that the bear paw plate on the right skid had been turned slightly clockwise. Marks were found in the turf indicating that the plate had dug in. When the bear paw installation was examined more closely, the investigation team found that the plate was mounted so that it could be forced to rotate about 20 degrees clockwise and about 80 degrees counterclockwise from its normal position. The SHK say that: When lifting from soft marshland, it can be difficult to determine if the landing gear is stuck on an obstacle or if it has “sucked” into the wet marshland… When operating from uneven ground, it is important that toch down and lifting are done slowly and carefully in order to detect any obstacles and tendency to roll. They also asked Transport Canada “to initiate a discussion with the manufacturer of the plates, Dart Aerospace, about the possibility of a more secure installation of the plates”. SHK Conclusion The investigator concluded this was a dynamic rollover: The accident was caused by the plate mounted on the right rear part of the helicopter’s landing gear getting stuck in a turf under the helicopter in connection with hovering, and by the pilot not being able to stop the roll tendency. Safety Resources This EHEST leaflet covers the following subjects: – Degraded Visual Environment (DVE), – Vortex Ring State (VRS), – Loss of Tail Rotor Effectiveness (LTE), – Static & Dynamic Rollover, and – Pre-flight planning Checklist. Be Careful If You Step Outside!: Unoccupied Rotors Running AS350 Takes Off US Police Helicopter Night CFIT: Is Your Journey Really Necessary? When Habits Kill – Canadian MD500 Accident UPDATE 16 May 2020: AS350B3 Dynamic Rollover When Headset Cord Snags Unguarded Collective UPDATE 16 May 2020: AS350B3 Rolls Over: Pilot Caught Out By Engine Control Differences UPDATE 26 July 2020: Impromptu Landing – Unseen Cable Aerossurance has extensive air safety, operations, airworthiness, human factors, aviation regulation and safety analysis experience. For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com Follow us on LinkedIn and on Twitter @Aerossurance for our latest...
read moreNTSB Confirms United Airlines Maintenance Error After 12 Years
NTSB Confirms United Airlines Maintenance Error After 12 Years (Airbus A320 N442UA at Jackson Hole 2008) On 25 February 2008 United Airlines Airbus A320 N442UA left the right side of Runway 19 during landing at Jackson Hole Airport (JAC), Wyoming. The NTSB determined in 2020(!) this serious incident was due to “inadequate maintenance” during a prior landing gear tachometer installation. This was the third United Airlines tachometer cross-connection maintenance error to emerge between October 2007 and March 2008. Incident Flight The US National Transportation Safety Board (NTSB) reported on 30 March 2020 that… ..the takeoff [from Denver International Airport (DEN), Colorado], climb, cruise and descent to JAC was normal. The captain was the flying pilot. During the approach briefing it was noted that the Mu readings indicated “good” breaking and that if the airplane did not touchdown in the first 2,000 feet of runway, they would perform a go-around. The captain stated that the touchdown was “firm” and the speedbrakes auto-deployed quickly; he believed that the airplane touched down in the first 2,000 feet of runway. The deceleration was normal until the airplane reached about 80 knots and 2,000 feet from the end of the runway when it started to slide. At that time, the captain stated that he applied maximum manual braking and the airplane started to slide toward the right side of the runway. The captain applied maximum left rudder, maximum braking, and reverse thrust as the airplane exited the right side of the end of the runway. The airplane came to rest against snow banks. The first officer said that the engines “flamed out” when they ingested snow. As the flight crew was shutting off the engine fuel levers and were getting out of their seats, they heard a passenger yell “fire” and the passengers began a self-initiated evacuation of the airplane. The 119 passengers and 6 crew members evacuated the aircraft via the emergency slides. One passenger received minor injuries during the evacuation. Examination of the runway revealed distinct rubber transfer marks leading to an area of disturbed snow on the right side of the runway. The Left MLG inboard tire exhibited a large flat spot with a rupture through the aft end from sidewall to sidewall. Maintenance History According to United Airlines, both MLG and the nose landing gear were replaced on the airplane on February 2, 2008 due to approaching overhaul time limits. The left-hand main landing gear was an “enhanced” landing gear and the right-hand landing gear was a standard or “pre-enhanced” landing gear. According to Airbus, the Service Bulletin to retrofit an airplane with the “enhanced” gear required they only be replaced as a set and that installation of a “mixed” configuration would only be approved on a case-by-case basis. United Airlines was unaware that two different types of landing gear were installed on the airplane and there were no records indicating that a request was made to install a “mixed” set of gear on the incident airplane. United Airlines contracted with Hawker Pacific Aerospace to overhaul its A320/A319 landing gears. Review of records and interviews of United and Hawker Pacific personnel revealed…all work was accomplished using United Airlines Joint Documents and Messier-Dowty Component Maintenance Manuals. The wiring harnesses of the landing gear are overhauled at this time and installed into the overhauled Hawker Pacific gear components. During the landing gear installation,...
read moreHEMS AW109S Collided With Radio Mast During Night Flight
HEMS AW109S Collided With Radio Mast During Night Flight (Babcock MCS Portugal I-EITC) On 15 December 2018 Leonardo AW109S I-EITC of Babcock MCS Portugal flew into a radio mast at night near Serra de Santa Justa, Valongo, Portugal. The HEMS air ambulance helicopter was operated under a 5 year, 4 base 24/7 contract for the the National Institute of Medical Emergency (INEM), awarded in June 2018. It was en route, returning from an urgent inter-hospital patient transfer that afternoon. On board were two pilots and two medical passengers. All died in the accident. The Accident Flight In their safety investigation report, issued 6 March 2020, the Portuguese accident investigators GPIAAF (Gabinete de Prevenção e Investigação de Acidentes com Aeronaves e Acidentes Ferroviários / Office for the Prevention and Investigation of Accidents in Civil Aviation and Rail) explain that after the successful inter-hospital transfer the crew initially retired to a coffee shop to wait out the poor local weather (rain and low cloud). The crew made several phone calls related to the weather. Witness testimony was the Commander was comfortable with an IFR diversion and night-stop at Porto International Airport if required. Subsequently the helicopter departed Massarelos heliport, at 18:35 UTC, heading to refuel at Paredes-Baltar heliport before returning to its base at Macedo de Cavaleiros heliport. None of these sites had navigation aids or meteorological data. Although not used, Porto International Airport’s navaids were operational. At 18:38:03, the crew informed the ATC that they will maintain an altitude of 1500 ft to Baltar. According to secondary radar data provided by the air navigation service provider, after take-off, the aircraft proceeded with a direct heading to the Paredes-Baltar heliport, flying at a cruising speed of around 130 kt and at altitudes oscillating between 1400 ft and 1500 ft. At 18:40 the helicopter collided at 371 m (1217 ft) AMSL just 2.2 m (7 ft) from the top of a 66 m (216 ft) guyed steel lattice radio broadcast tower. It was not possible to confirm if this beacon was operating on the accident night. [Note a lower adjacent deactivated mast was unlit.] This tower (marked ‘1’ below) was actually one of 10 obstacles along the ridge line. However only those 200 ft (60 m) above ground level were marked, with only those over 328 ft (100 m) listed in the AIP. The investigation subsequently identified that some of the obstacles were unlit. In relation to emergency response: After the aircraft hit the ground, the Emergency Locator Transmitter (ELT) signal was activated, however, it was not received by the COSPAS/SARSAT satellites, as the system lost the antenna. In accordance with the existing contract for the HEMS service provision…the operator should have installed an aircraft tracking system that would allow the contractor to follow up the performed missions in real time. This system was not installed on the aircraft by the operator or verified by the contract [holder]. Consequently, lacking an accurate fix on the aircraft an extensive search was required. Safety Investigation GPIAAF note that: A risk analysis of the HEMS operation service in Portugal and its limitations was not [produced] by the operator or required by the [customer], especially in the northern part of the country and on the usual routes, where evidence suggests that it is followed a typical low altitude flight profile, in some cases below the minimum altitude values imposed by the regulation, and frequently in adverse weather conditions. The operator, by accepting the...
read moreNASCAR Driver and Pilot Died in Mooney M20C Fuel Starvation FOD Accident
NASCAR Driver Ted Christopher and Pilot Died in Mooney M20C Fuel Starvation FOD Accident (N53CP) On 16 September 2017 Mooney M20C, N53CP was destroyed when it impacted trees near North Branford, Connecticut. The pilot and his passenger, NASCAR driver Ted Christopher, were fatally injured. History of the Accident Flight The 81 year old retired airline pilot departed Francis S. Gabreski Airport (FOK), Westhampton Beach, New York about 1000 for Robertson Field (4B8), Plainville, Connecticut to pick the passenger up for a subsequent return flight to at 1230 FOK where the passenger would be participating in a NASCAR race at the Riverhead Raceway that afternoon. The flights were conducted as private flights under Part 91. The US National Transportation Safety Board (NTSB) explain in their safety investigation report (released in December 2019) that: The pilot [who owned the aircraft] and passenger were friends and had been flying together for over 10 years; they and had flown this route many times according to friends. Review of radar data obtained from the United States Air Force 84th Radar Evaluation Squadron (RADES) revealed radar targets that were coincident with the accident flight. A radar target first appeared about 1242 about 10 miles south of 4B8 and about 1,200 ft mean sea level (msl). A radar track continued south-southeast for about 9 minutes. The airplane remained at altitudes between about 1,200 and 1,600 ft msl (about 900 to 1,300 feet above ground level) until radar contact was lost about 1 mile northwest of the accident site. Several individuals near the accident site reported that they heard the sound of the impact, but there were no witnesses to the accident. Local TV Report NTSB Safety Investigation and Analysis The propeller exhibited signatures consistent with a lack of engine power at the time of impact. The fuel selector was found in the left tank position and the landing gear was extended. There was evidence of fuel in both tanks at the accident site. Examination of the fuel system revealed that air would not pass through the fuel selector valve with the valve selected to the left fuel tank position. The handle was operated by hand and could be moved normally between the settings. Air passed freely through the valve when selected to the right tank position. Disassembly of the fuel selector revealed a piece of red, fibrous material consistent with a shop towel that likely inhibited fuel flow to the engine and resulted in fuel starvation and a total loss of engine power. The rounded mass was about 5/8 inches in length and about 3/8 inches in width. Fibers also covered about 5% of the fuel drain screen. The airplane’s maintenance logs were not found and when the shop towel debris may have been introduced to the fuel system could not be determined. Additionally, a homemade tool constructed of PVC pipe and connection fittings was found in the wreckage that appeared to be designed to manipulate the fuel selector; however, the reason for its fabrication and use during the accident flight could not be determined. The device was broken at its handle. Following the loss of engine power, the pilot may have attempted to switch the fuel selector from the left tank to the right tank and was unable to do so, either due to a failure of his homemade tool or to the inadequate time afforded to...
read moreAlaskan AS350 CFIT With Unrestrained Cargo in Cabin
Alaskan Airbus AS350B2 CFIT With Unrestrained Cargo in Cabin (N194EH of ERA Helicopters, 5 May 2016) On 5 May 2016 Airbus Helicopters AS350B2 helicopter N194EH, operated by Era Helicopters, suffered a Controlled Flight Into Terrain (CFIT) while on approach to a remote landing site on the Norris Glacier about 15 miles northeast of Juneau, Alaska. The pilot received serious injuries, and the helicopter sustained substantial damage. It was conducting a Part 91 as a visual flight rules (VFR) internal-cargo company flight. Degraded conditions were reported in the area at the time of the accident. Flight Preparations The US National Transportation Safety Board (NTSB) explain in their safety investigation report (released in November 2019) that: Alaska Heli-Mush Inc, contracted with Era Helicopters to provide helicopter support for the movement of personnel, dogs, and cargo. The purpose of the flight was to transport camp equipment from Era Helicopters’ headquarters in Juneau to a remote dog camp on the Norris Glacier in the Tongass National Forest. Era Helicopters and Alaska Heli-Mush conducted heli-mushing operations for the Alaska tourism industry using a helicopter glacier landing permit issued by the US Forest Service. The pilot conducted a formal flight risk assessment before the flight using Risk Assessment Form ERA A-003. The form had sections addressing crew qualifications, crew currency, duty period, flight profile, environment, and aircraft. The completed flight risk assessment form had a total value of 15, and no sections of the flight risk assessment were exceeded (crew qualifications, crew currency, duty period, flight profile, environment, and aircraft). The flight would have been prohibited if the total value was greater than 32 or any section limit was exceeded. The Era Operations Manual – Part A General Procedures discusses internal cargo carried in passenger compartments and states: “For the purposes of clarity, baggage may be carried in a passenger compartment when properly secured and accompanied by a passenger. Cargo may only be carried in the passenger compartment during cargo only operations. The PIC shall ensure that all cargo, including baggage, on Company aircraft complies with the following: It is carried in an approved cargo rack, bin, or compartment installed in or on the aircraft; It is secured by an approved means.” The operator reported that internal cargo loading is covered in company training and performed by company employees. The operator further reported that the only individuals who have documented cargo training are the pilots, and due to this, all internal cargo loading is supervised and/or approved post-loading by the pilot who has the final authority for airworthiness of the helicopter. The operator configured the helicopter’s cabin to facilitate the transportation of [850lb of] internal cargo. It appears most was carried in the baggage bay. The rear seat assembly was folded up against the cabin wall, and a lidded plastic box that contained a metal heater was placed on the cabin floor behind the pilot’s seat. A single cargo strap was secured to the rear seatbelt attachment points in front of the aft cabin wall and routed over the top of the plastic box from left to right in the cabin. The configuration of the single cargo strap provided lateral restraint; however, no forward restraint was present. The make and model of the single cargo strap, as well as the strap’s maximum load rating, could not be determined. According to cargo paperwork, the box and its...
read moreR44 Force Lands After Improper Repair
Robinson R44 N3254E Force Lands After Improper Repair On 21 July 2017 Robinson R44 II N3254E landed hard during an emergency autorotation in Van Nuys, California. The National Helicopter Service and Engineering Company were operating the R44 on a 1 hour Part 91 revenue sightseeing flight around the Los Angeles area. The pilot sustained minor injuries but the three passengers were seriously injured. Accident Flight The US National Transportation Safety Board (NTSB) say in their safety investigation report that: The pilot reported that the tour was uneventful, and as they approached the airport for landing, he heard an unusual sound. He glanced down at the engine tachometer, and it was higher than normal, indicating above 110%. The pilot began manipulating the engine throttle to reduce power and bring the engine and rotor speeds into alignment, but the rotor RPM began to decay. He was concerned that the engine might overspeed if he adjusted the throttle higher, and presumed that there was likely an unrecoverable failure in the transmission system, so he initiated an autorotation. The pilot stated that at no point during the flight did he receive any instrument panel annunciations or indications of a problem. He did not scan the instrument panel during the descent because his focus was on flying the helicopter and looking for a landing spot. He stated that trees and power poles blocked his landing approach, and he therefore did not have sufficient speed or space to perform an adequate flare, and the helicopter landed hard. He reported that the engine continued to operate during the descent… The helicopter came to rest on a street in a densely populated residential neighbourhood. The landing skids had spread during the impact, and were level with the belly, and the emergency…floats had deployed. The floats had been armed for the flight, and they appeared to have deployed during the hard landing. The entire airframe exhibited buckling damage, and the belly was crushed. The tail rotor gearbox struck a fence, and had partially detached. Both main rotor blades remained attached to the mast, but one was bowed downward and the other was bent slightly upward. The pilot commented that… …although he has trained for emergency events, he was shocked at how quickly everything transpired. NTSB Safety Investigation and Analysis The helicopter was equipped with a “Tourmaster” GPS enabled video recording unit, manufactured by Rugged Video LLC. The unit was typically used by air tour operators to record video, audio, and GPS data for customers as a memento of their flight. Review of onboard video and a spectrographic analysis of the recorded audio revealed that the engine rpm initially decreased but then appeared to be restored a few seconds later while the helicopter slowed. For about the next 40 seconds, the engine continued to operate at the same rpm and the helicopter continued to slow and gradually descend. The engine rpm then quickly decreased, and the helicopter rapidly descended in a manner consistent with the pilot initiating an autorotation. Examination of the helicopter… …did not reveal evidence of any mechanical malfunctions or failures that would have precluded normal operation, and witness signatures indicated that the engine was producing power at the time of ground impact. However, a wire within the right magneto, which provided a signal to both the engine governor and engine tachometer on...
read moreS2000 Runway Excursion at the Start of the Take Off Roll
S2000 Runway Excursion at the Start of the Take Off Roll (SE-LRA at Linköping) On 8 May 2019, Saab 2000 SE-LRA, operating as a transport flight for Saab, suffered a runway excursion at the beginning of the takeoff roll from Linköping/Saab airport, in Sweden. The Swedish Accident Investigation Board (the Statens Haverikommission [SHK]) say in their safety investigation report that: The captain taxied to the runway using the nose wheel steering tiller without any difficulties. After lining up, the crew conducted the daily propeller overspeed test in accordance with the checklist and proceeded directly with the takeoff run. It is clear from the captain’s interview that for some reason they omitted to depress the tiller and activate the nose wheel steering. The result was a quick aircraft yaw to the left. The aircraft left the runway surface with the left main landing gear just before reaching the two diagonal military taxiways, passed one of them and headed back on to the runway where it slowed down and stopped in the middle of the runway. The air traffic controller in the tower noted that the aircraft yawed abruptly to the left but did not see the aircraft actually leaving the runway surface. After the aborted takeoff, the air traffic controller informed the crew of his observations. Damage to a runway edge light was discovered on inspection. SHK Safety Investigation and Analysis Data from the flight data recorders (DFDR and QAR) were available and SHK has analyzed the relevant parameters. However, data from the nose wheel steering angle and brake pressure are not recorded by DFDR/QAR. The nose wheel steering indicated no technical faults before or during the incident. [W]eather and prevailing runway conditions were within the aircraft’s limitations. The dry surface allowed for good friction and aircraft control via nose wheel steering and wheel braking. The take-off was initiated directly from partial power, which resulted in an abrupt course change and provided for only a very limited time to recover before the aircraft left the runway. Contributing was the fact that the nose wheel angle probably was not parallel with the runway heading at brake release. One possible explanation for this could be the aircraft vibrations caused by the propeller test, where both propellers in turn reduce the power momentarily. SHK also note the pilot regularly flew the Bombardier Global 6000 (BD-700) which has a steering hand wheel that does not, unlike on the Saab 2000, need to be pressed to select. SHK Conclusions The direct cause of the runway excursion was a lapse in activating the nose wheel steering tiller during the initial takeoff phase. This led to a delayed correction of the aircraft’s lateral deviation. A contributing factor may have been that the pilot alternated between flying two aircraft types where the nose wheel tiller is used in different ways. No safety recommendations were made. Safety Resources On error management: Professor James Reason’s 12 Principles of Error Management Back to the Future: Error Management …and our review of The Field Guide to Understanding Human Error by Sidney Dekker presented to the Royal Aeronautical Society (RAeS): The Field Guide to Understanding Human Error – A Review Runway Excursion Exposes Safety Management Issues G200 Leaves Runway in Abuja Due to “Improper” Handling CRJ900 Skids Sideways Down Finnish Runway AAIB: Human Factors and the Identification of Saab 2000 Flight Control Malfunctions Twin Otter Nose Wheel Steering Misused...
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