EC135 Main Rotor Actuator Tie-Bar Failure
Police Airbus EC135T1 Main Rotor Actuator Tie-Bar Failure (VP-CPS, Cayman Islands) On 26 February 2019 Airbus Helicopters EC135T1 VP-CPS of the Royal Cayman Islands Police Service (RCIPS) was damaged on take off at Owen Roberts International Airport, in the Caribbean Cayman Islands. The RCIPS Air Operations Unit (AOU) was formed in March 2010 with VP-CPS, a 1999 EC135 that had previously served with the East Midlands Air Support Unit as G-EMAS. VP-CPS was withdrawn from service after the accident. RCIPS now have two H145s. The Accident Flight The UK Air Accidents Investigation Branch (AAIB) describe in their safety investigation report that at the start of a combined training and search flight… …the pilot lifted the helicopter to a height of approximately 4 feet…and felt the cyclic control stick shake and then a strong rearwards force, which he was unable to overcome. The pilot immediately lowered the collective lever, landing heavily, and moved both throttle twist grips to idle, switched off the engines and applied the rotor brake. A maintenance team arrived at the helicopter and found damage to the landing gear, tail boom, Fenestron shroud and the transmission deck. The Safety Investigation The main rotor swashplate is moved in the lateral, longitudinal and collective axes by three hydraulic actuators and together they comprise the Main Rotor Actuator (MRA). Further investigation revealed that the tie bar of the longitudinal axis actuator had broken near the fork end. Inside each individual actuator are two axial pistons, one per hydraulic system, which are linked with a tie bar. This bar is manufactured from passivated, high-strength, corrosion-resistant steel, and attached to a fork end which connects to the swashplate linkage. Tension loads from the pistons are transferred to the fork end by the tension ring segments and compressive loads are transferred through the compression ring segments. Sealant is applied to the centre bore of the fork end to prevent moisture ingress into the upper piston through the tension ring segments. To enable actuator replacement without swashplate linkage adjustment, the length of the actuator is controlled to +/- 0.1 mm by selection and fitment of a pair of compression ring segments with the appropriate length. The MRA was removed from for examination. The overall external condition was typical for the equipment, which had completed 18 years in service and 6,561 flying hours. The lateral and longitudinal axis tie bars had been replaced in 2005 after 576 flying hours, due to damaged threads. The tie bar of the longitudinal axis actuator had fractured approximately 30 mm from the end attached to the fork fitting, where the cross-section changes for an ‘O-ring’ seal. Analysis of the material found adjacent to the fracture on the tie bar revealed a high sodium and chlorine content, amongst other chemical elements, with similar deposits found on the other actuator tie bars. There was evidence of the same material on the part of the fork end located within the upper piston. The failed tie bar was removed from the actuator and the fracture surfaces were examined using Scanning Electron Microscopy with semi-quantitative Energy Dispersive X-ray (SEM‑EDX) spectroscopy. On the surface of the tie bar local to the fracture there was evidence of pitting corrosion, with several pits extending into the material [1]. On the fracture surface there was evidence of intercrystalline corrosion with crack propagation covering approximately ¾ of the fracture surface...
read moreBe Careful If You Step Outside!: Unoccupied Rotors Running AS350 Takes Off
Be Careful If You Step Outside!: Unoccupied Rotors Running AS350B3 YR-DEX Takes Off The Romanian Civil Aviation Safety Investigation and Analysis Authority (AIAS) has issued their safety investigation report into an accident involving Airbus Helicopters AS350B3 YR-DEX on 29 November 2017. The aircraft, operated by Dunca Expeditii, had landed near an inoperative chairlift on a ski slope in the Mount Mic Tourist Complex, Caras-Severin County. AIAS explain that: After the helicopter was landed and the engine was stopped, the pilot placed some materials in two of the three cargo compartments of the helicopter and got into the cockpit with the intention to take off. After starting the engine, he put the twist grip into the “FLIGHT” position, at which time he noticed on the warning panel that the “DOOR” indication light was activated. At this point, without securing the collective lever, with friction applied to the cyclic and with the twist grip in “FLIGHT” position, the pilot got off to check the cargo compartment doors, starting from the right side. When he came to check the cargo compartment door on the left, the wind increased in intensity, at which point the helicopter took-off forward and banked to the right with an angle of approximately 20 degrees. This diagonal, height gaining lift-off resulted in the impact of the main rotor blades with the chairlift cable, at a distance of approximately 37 meters and at a height above the ground about 5 meters from the pilot’s take-off point in the direction of flight. The helicopter impacted the ground on its left side, with the tail boom detaching about three quarters of the circumference, the helicopter canopy being destroyed. It appears the pilot was uninjured. Previous Accidents AIAS list various accidents involving rotors running AS350s: AS350B2 SN2684 F-OGUZ Guyana 17/07/2000 (no other details available) AS350B3 SN3209 HB-ZBN Switzerland 09/10/2001 (head injury after the pilot disemarked) AS350B2 SN2345 OE-XRR Austria 01/09/2009 (rolled over) AS350B2 SN4419 ZK-IMS New Zealand 06/05/2010 (rolled over while pilot checking baggage bay) AS350BA SN2473 ZK-HBD New Zealand 23/09/2010 (rolled over while pilot arranging load) AS350BA SN1132 ZK-HKU New Zealand 09/08/2012 (not relevant as accident happened after the subsequent departure: Regulator Missed the Chance to Intervene Before Fatal Tour Accident say TAIC) AS350B3e SN7718 N840PA USA 18/05/2014 (rolled over onto pilot as he was relieving himself) AIAS Safety Analysis The Investigation Commission tried to determine the helicopter dynamics taking into account the pilot’s statement, namely: The pilot outside the helicopter, on the left-hand side The twist grip on the collective in the “FLIGHT” position The collective not secured Friction applied to the cyclic. When friction is not applied to the collective and this is not secured, due to engine helicopter vibrations, the collective can change its position. The result is the change of the main rotor blades pitch and the increase of the load, thus the helicopter is lifting off. If the position of the cyclic is not altered from the one that it has on the ground, during the lifting from the ground, the helicopter will tend to move in the direction of its position. Also, if the right pedal is not actuated to counteract the reactive torque of the main rotor, the helicopter will rotate about its vertical axis to the left. In conclusion, in the case of an uncommand lift off, the helicopter dynamics would be the following: the...
read moreB1900D Window Blowout
B1900D Window Blowout On 22 October 2018 Federal Airlines Beechcraft B1900D ZS-PHX was in cruise at 20000ft when it suffered an explosive decompression. The aircraft made a safe landing, without injury to the 13 occupants. According to the South African CAA safety investigation report, the decompression was due to the failure of the third cabin window on the right-hand side of the fuselage. This window was installed in January 2007, approximately 6,000 flying hours earlier. The first two cabin windows on each side of the B1900 are a two-pane. The rest are single-pane windows with a life of 43,600 flight hours or 61,700 pressure cycles. Laboratory examination revealed that cracking propagated from the outside surface in the centre of the window. The B1900D Aircraft Flight Manual states: …do not operate the engines with the propellers feathered except during external power starts and propeller feather checks, except that the propellers may be operated in feather at temperatures not to exceed +5°C for a maximum of 3 minutes for the purpose of airframe de-icing. Beechcraft B1900 Airliner Communiqué no. 30 (issued in December 1993) states: After a fleet inspection, 8 other windows were rejected in the operator’s fleet. The SACAA safety message was that: It is imperative that operators abide by the B1900 communiqué no. 30 during ground operations to avoid excessively heating the cabin windows. Safety Resources Our past B1900 safety articles include: B1900D Emergency Landing: Maintenance Standards & Practices Incorrectly Rigged B1900D Charlotte, NC, 8 January 2003: 21 Fatalities Crossed Cables: Colgan Air B1900D N240CJ Maintenance Error B1900C PSM+ICR Accident in Pakistan 2010 Distracted B1900C Wheels Up Landing in the Bahamas Operator & FAA Shortcomings in Alaskan B1900 Accident Alaska B1900C Accident – Contributory ATC Errors UPDATE 3 June 2020: Beechcraft 1900C Landing Gear Collapse at San Antonio, TX 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 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 Webmaster Portal...
read moreAAR Bell 214ST Accident in Afghanistan in 2012: NTSB Report
AAR Bell 214ST N5748M Accident in Afghanistan in 2012: NTSB Report On 16 January 2012, Bell 214ST N5748M, crashed 7 miles south of Camp Bastion in Helmand province, Afghanistan, killing the crew of three. The helicopter was operated as a Part 135 flight by AAR Airlift Group under contract to the Department of Defense (DOD) Air Mobility Command (AMC), the air component of the US Transportation Command). The Accident Flight The helicopter, call sign ‘Slingshot 72’, was transporting military personnel between coalition bases with another 214ST (N391AL, ‘Slingshot 71’). About 1040, both helicopters departed Camp Bastion after a rotors running turnaround for Shindand Air Base on their third sector of the day. The only passengers were on Slingshot 71. They climbed to a cruising altitude of 800 – 1,000 ft. Slingshot 72 was the lead helicopter, with Slingshot 71 trailing by about ¼ to ½ mile. The US National Transportation Safety Board (NTSB), who were delegated the investigation by the Afghan Ministry of Transport and Civil Aviation, say in their safety investigation report: The SIC of Slingshot 71, who was the pilot flying, saw Slingshot 72 enter a “sharp” bank to the right; he estimated that the bank was about 70º to 80º. The SIC then saw Slingshot 72 begin to “come apart.” …he flew Slingshot 71 to the left to avoid the large amount of debris coming from Slingshot 72, which included large pieces of structure. The SIC reported that the tailboom of Slingshot 72 began to “separate and fold” and estimated that about two-thirds of the tailboom came off the helicopter. The SIC then saw Slingshot 72 pitch down about 75º to 80º, impact the ground, and burst into flames. The PIC of Slingshot 71, who was the pilot monitoring, stated that, after making a radio frequency change, he looked up and saw Slingshot 72 in a “steep pitch down.” The PIC stated that “nothing seemed wrong” with Slingshot 72 when he had looked down to make the radio frequency change. [H]e saw structure starting to come off Slingshot 72 and that the debris looked similar to “confetti.” The PIC noticed that the tailboom of Slingshot 72 appeared to be folded under the helicopter and stated that he could see the “zinc’ color of the inside of the tailboom. Afterward, the PIC observed Slingshot 72 descend “straight down,” impact the ground, and burst into flames. The PIC reported that the flight crew of Slingshot 72 made no radio transmissions indicating any problems. After US forces reached the area and secured the accident site, Slingshot 71 departed the area and landed uneventfully at Camp Bastion. The Slingshot 72 wreckage was then recovered and moved to a secure location at Camp Bastion. NTSB Safety Investigation The accident site consisted of a primary impact area and a scattered debris field, which measured about 1,575 feet north-south by 656 feet east-west. The primary impact area consisted of the main fuselage, which had been fully consumed by the postcrash fire. The forward tailboom section was found separated from the main fuselage about 49 feet north of the primary impact area, and the aft tailboom section (containing the vertical stabilizer and tail rotor) was found about 279 feet north of the primary impact area. The main debris field was located south of the primary impact area (distance unknown) and...
read moreNorwegian HEMS Landing Wirestrike
Norwegian HEMS Landing Wirestrike (Norsk Luftambulanse EC135P2+ LN-OOI) On 14 January 2013, a HEMS / air ambulance Airbus Helicopters EC135P2+, LN-OOI of Norsk Luftambulanse, crashed near an entrance to Sønsterud tunnel in Hole municipality, Buskerud County, Norway. The pilot and a doctor on board were killed. The HEMS Crew Member (HCM) survived with serious injuries. History of the Accident Flight According to the Accident Investigation Board Norway (AIBN) investigation report (issued in June 2015), the helicopter and its crew were on standby at Lørenskog, Oslo when a call was received to attend an overturned lorry 21 nm away near Sollihøgda on the E16. The aircraft was airborne 9 minutes after the ambulance control took the 112 call. The Aircraft Commander was in the front right seat, the HCM in the front left seat and a physician, as a medical passenger, in the right-hand cabin seat. En-route, the physician received the accident site coordinates via the fleet management system LOCUS used by the emergency medical communication centre. The HCM set a course for position 595950N 0101810E in the helicopter’s digital map system ([EuroAvioincs] EURONAV [5]) and the course to the traffic accident site was displayed on the cockpit multi-function display. The crew were “very familiar” with the destination but the HCM “followed the procedures regardless and zoomed in on the possible landing site on the moving map display”. He noticed an adjacent powerline. The pilot acknowledged it and the doctor was also informed for situational awareness. They tried calling the emergency services on site at the road accident (on Channel 33 – VHF ‘Medical’)) without success. The aircraft was also fitted with radios for the digital emergency network (TETRA). This was not however in use in that district at the time. The introduction of TETRA elsewhere had been problematic due to weak management of change and crews had become use to often landing without having achieved radio contact with ground units. After a ten-minute flight, the helicopter arrived at the scene of the traffic accident which had occurred between the exits of the Nes and Sønsterud tunnels. The aircraft commander reduced the speed to 50 kt and flew approx. 200 m south of the site, in a south-western direction, at approx. 800 ft. altitude above the ground (1 461 ft. MSL) in order to find a suitable landing area. According to the HCM, they flew relatively fast and high, and were not on particular lookout for any aviation obstacles [and] he and the aircraft commander agreed to land on the road by the southern exit of the Nes tunnel [where there was an emergency lay-by]. A survey of the operator’s employees conducted by AIBN after the accident confirmed this was a reasonable site, considering the obstacles the crew had spotted (a line of streetlights and a coincident low powerline). After passing the landing site, the helicopter continued on a south-western course, at the same time as it descended to 700 ft. (MSL) and made a wide right turn. It then slowly continued towards the landing site in a north-eastern direction. [The operator’s OM-A (Operations Manual Part A General)] does not describe a special procedure for landing in areas where the moving map indicates that there is a power line or other aviation obstacles. OM-A also does not contain a description of how the crew should use their eyes to look for aviation obstacles in the most critical final part of approach and landing. On...
read moreA109E Window Loss Highlights Maintenance Lessons
A109E Window Loss Highlights Maintenance Lessons During a post-maintenance flight over Cornwall on 27 June 2019, of Leonardo A109E, G-ETPI, as the helicopter was accelerated towards 140 kt, there was a loud bang and a sudden increase in wind noise. The window transparency from the left cockpit door had separated. The pilot was able to land the aircraft safely. According to the Air Accidents Investigation Branch (AAIB) in their safety investigation report: The A109E cockpit doors are of a composite construction and include a non-opening single acrylic window transparency…attached to the door by an extruded rubber seal channel. The rubber seal has three separate grooves to accommodate the window, the door frame and a seal filler strip which locks the seal and window in place. The Maintenance Manual requires that a thin layer of adhesive is applied to the seal channel during installation. During the previous maintenance the aircraft had been repainted… …which necessitated the removal and disassembly of all cockpit and cabin doors and windows. These tasks were documented as a single item on a maintenance worksheet, which was signed-off by the certifying engineer on 21 March 2019. Following completion of the helicopter base maintenance and repaint, the doors and windows were reassembled and refitted by an engineer. The worksheet did not record the date on which the task had been completed but indicated that it had been inspected and certified by the certifying engineer on 9 April 2019. During examination of the window aperture afterwards it was not possible to confirm that adhesive had been used. The window and seal were never recovered so could not be examined. The right cockpit door window was removed for inspection and this revealed the correct presence of adhesive in the grooves of the seal. Inspection of the cabin windows confirmed adhesive had been used but “minimal squeeze-out”and so extra adhesive was applied. However: The post-incident inspection and reinstallation of the cockpit door windows was undertaken by the same engineer and certifying engineer who had done the original window installation in April 2019. The maintenance organisation carried out their own investigation, which only started after the post-incident inspection: It identified that the engineer who installed the left cockpit door window had experienced some difficulty fitting the seal filler strip to the seal channel. The engineer had used a soapy solution to insert the filler strip but acknowledged during the investigation that the solution was applied liberally, such that it covered the window and the concentration of soap had been stronger than might normally be used. The C537 adhesive specified in the A109E maintenance manual is a multi-purpose silicone adhesive/sealant which adheres to most surfaces and cures to form a tough flexible rubber. A single 310 ml tube of adhesive was issued to G-ETPI during its original maintenance input. …a similar tube of adhesive with approximately 1 inch of adhesive remaining was found in the hangar. It was determined that this was the originally-issued tube of adhesive and that it had been used during the original and post-incident window installations on G-ETPI. The maintenance organisation considered that, applied in correct quantity, the original and post-incident installation of all the cabin, cockpit and cockpit door windows would have required more adhesive than that which appeared to have been used. It would also have expected to see residual adhesive on the...
read moreRunway Excursion Exposes Safety Management Issues
Runway Excursion Exposes Safety Management Issues On 7 January 2019 RAF-AVIA Saab 340B YL-RAF, positioning from the airline’s base at Riga in Latvia veered off the runway during the landing roll at Savonlinna Airport in Finland. The Accident Flight The Finnish Safety Investigation Authority (SIAF, the Onnettomuustutkintakeskus) explain in their safety investigation report that: The runway had been cleared of snow but the clearance had to be repeated to achieve better runway friction. The aircraft had to wait for the landing in the holding pattern, and the landing was delayed. At the time of the landing it was dark, a crosswind was blowing, it was snowing and the runway was slippery. The approach proceeded normally until the aircraft passed the threshold. At the final phase of the landing the aircraft floated close to the surface for 6–7 seconds before touchdown, following which the touchdown point moved farther down the runway than normally. Extra airspeed after the threshold partly contributed to this. The captain steered the aircraft toward the ground at a fairly high vertical speed. At that time the aircraft was already over the snowbank at the edge of the cleared area of the runway. Despite the pilot’s corrective control actions the aircraft veered off the runway into the snowbank. The flight crew comprised of two pilots and a ground engineer. Nobody was injured but the aircraft suffered significant damage. They comment that: At no time did the pilots consider aborting the approach or landing, i.e. going around. The airline’s operational manuals (OM-A and OM-B) were inconsistent concerning maximum crosswind components. According to the Operations Manual (OM-A) the crosswind limits given by the Aircraft Operations Manual (OM-B) must be followed during landing. However, the OM-A also says that if the estimated runway friction is poor, crosswind landings are prohibited. In other words, then the crosswind component should be zero knots. In this occurrence the AFIS officer informed the pilots that the runway friction was poor. The instructions were difficult to follow in practice. The investigation was hampered because: The Cockpit Voice Recorder had not recorded anything from the flight in question, and the earlier recordings that were retrieved from its memory were of extremely poor quality. The recording quality of the FDR, when compared to modern recorders, was poor. The magnetic tape of the FDR was worn, which caused defects in the recording. The SIAF describe a phenomena where: When snow is blowing sideways, a pilot may see an illusion when approaching the runway where the aircraft’s track is deviating from the intended track or the runway bearing. The illusion is stronger at nighttime when the aircraft’s landing lights are on. The Contractual Arrangement, Due Diligence, Safety Management and Regulation The airline had a contract from Finnish ground handling and logistics company Maavoima who had won the tender for the subsidised Helsinki–Savonlinna public service obligation route in April 2017. The contract was awarded by the Finnish Transport Agency to the lowest bidder. The FTA had stipulated no safety requirements beyond the requirements that the air operator hold a regulatory approval for fear that safety requirements would be seen as ‘anti-competitive’. SIAF highlight that the lack of additional safety requirements was the FTA’s choice. Furthermore, as prime contractor… …Maavoima relied on the fact that air operator certificates and operating licences ensure that the air operator acts in a...
read moreEC130B4 Destroyed After Ice Ingestion – Engine Intake Left Uncovered
Airbus EC130B4 Destroyed After Ice Ingestion – Engine Intake Left Uncovered (Air Methods, N334AM) On 2 January 2013, Eurocopter EC130B4 HEMS air ambulance helicopter N334AM, operated by Air Methods, experienced a hard landing following a loss of power from its Turbomeca Arriel 2B1 turboshaft engine near Seminole, Oklahoma. The pilot and three medical crew members were all seriously injured. The US National Transportation Safety Board (NTSB) say in their final report, that according to the pilot, the crew… …received a standby call for a response to an accident scene. The pilot checked weather for the flight. He went and removed the helicopter inlet cover and the flight was requested to launch. The pilot performed a walk around inspection of the helicopter and started the helicopter normally. Shortly after takeoff, while climbing through 1,600 and 1,700 feet mean sea level (msl), the pilot heard a sound like something had struck the helicopter and the engine stopped producing power. The pilot had limited recollection of the next events but recalled that while performing an autorotation, he made a right turn to an open field. While maneuvering to land to the field he saw a previously undetected barbed wire fence. The pilot maneuvered the helicopter over the fence and [a] crew member reported seeing the sky through the forward windscreen before they impacted the ground. According to the NTSB Airworthiness Group report: The location of the ground scars relative to the final resting position of the aircraft was consistent with a clockwise rotation of the aircraft of approximately 180 degrees following initial ground impact of the landing skids and the tail skid. A barbed-wire fence was located approximately 16 feet west of the single tail skid ground scar and approximately 54 feet west of the main wreckage. The NTSB explain that: Engine examination revealed that the four axial compressor blades exhibited significant deformation on the outboard tips of their leading edges in the direction opposite of normal rotation consistent with the ingestion of soft body foreign object debris, such as ice. Investigation however revealed that: For 3 days before the accident flight, the helicopter was parked outside without its engine cover installed and was exposed to light drizzle, rain, mist, and fog. The engine inlet cover was installed the day before the accident at an unknown time. The helicopter remained outside and exposed to freezing temperatures throughout the night until 2 hours before the flight. Although the helicopter was maintained in a ready status on the helipad and maintenance personnel performed daily preflight/airworthiness checks, the inlet to the first-stage of the axial compressor was not inspected to ensure that it was free of ice in accordance with the Aircraft Maintenance Manual. The NTSBconclude that: Based on the weather conditions that the helicopter was exposed to during the 3 days before the accident, it is likely that ice formed in the engine air inlet before the flight and that, when the pilot increased the engine power during takeoff, the accumulated ice separated from the inlet and was ingested by the engine and damaged the compressor blades. NTSB Probable Cause The loss of engine power due to ice ingestion. Contributing to the accident was maintenance personnel’s delayed decision to install the helicopter’s engine inlet cover until after the engine had been exposed to moisture and freezing temperatures and their inadequate daily preflight/airworthiness checks, which did not detect the ice formation....
read moreCosta Rican C208B Stalled While Trying To Avoid High Ground
Costa Rican C208B Stalled While Trying To Avoid High Ground (Nature Air TI-BEI) On 31 December 2017, Cessna 208B Grand Caravan TI-BEI, operated by Nature Air, crashed while manoeuvring after takeoff at Islita Airport (MRIA), near Corozalito, Costa Rica. The 2 flight crew and 10 passengers (all 10 US tourists) were fatally injured. There was a post crash fire. The Accident Flight The C208 was the second of a pair of C208Bs transporting hotel guests from MRIA to Juan Santamaría International Airport (MROC), San Jose, where most of the passengers had connecting international airline flights. The US National Transportation Safety Board (NTSB), who were delegated this accident investigation, say in their safety investigation report that: The flight departed a nontower-controlled airport that was in a valley surrounded on all sides by rising terrain, with the exception of the area beyond the departure end of runway 21, which led directly toward the Pacific Ocean. The airport had a single paved runway, runway 3/21, that was about 3,000 ft long and 30 ft wide. The…first airplane departed runway 3…and made an immediate right turn to the east/southeast after takeoff, following a pass in the hills over lower terrain that provided time for the airplane to climb over the mountains. Both a witness and surveillance video footage from the airport indicated that, 15 minutes later, the accident airplane also departed from runway 3 but instead continued on runway heading, then entered a left turn and descended into terrain. Evaluation of the surveillance video was performed using a computer program……groundspeed was estimated to be 68±3 kts shortly after takeoff and the airplane was climbing about 715 ft/minute. Several seconds later, the airplane was descending about 1,510 ft/minute and its groundspeed was 82±4 kts. Its bank angle reached up to 75º right-wing-up at that time; the airplane impacted the ground shortly thereafter. The Pilot’s Operating Handbook (POH) for the airplane listed a gross weight stall speed at 60° bank with 0° and 20° flap settings as 110 kts calibrated airspeed (kcas) and 98 kcas, respectively. NTSB Analysis Although a takeoff from runway 21 afforded the most favorable terrain since the airplane would fly over lower terrain to the ocean, it is possible that a significant enough tailwind existed for runway 21 that the pilots believed the airplane’s maximum tailwind takeoff limitation [10-kt] may be exceeded and chose to depart from runway 3 in the absence of any information regarding the wind velocity. The investigators note that no windsocks were installed at the airfield at the time of the accident. Wind models at 10 meters above ground level indicated that, for the time of the accident, the wind was about 5 knots from the northeast. Performance calculations showed that the airplane would have been able to take off [on runway 21] with up to a 10-kt tailwind, which was the manufacturer limitation for tailwind takeoffs. The witness who saw the accident reported that he spoke with the pilots of both airplanes before the flights departed and that the pilots acknowledged the need to use the eastern pass in order to clear terrain when departing from runway 3. The reason that the flight crew of the accident airplane failed to use this path after takeoff could not be determined. It is likely that, after entering the valley ahead of the...
read moreFatal Powerline Human External Cargo Flight
Fatal Powerline Human External Cargo (HEC) Flight (Winco H369D N138WH) On 7 November 2017 Hughes 369D helicopter, N138WH operated by Winco Powerline Services under Part 133 regulations, was lifting two electricity utility linesmen on an external cargo long line. as Human External Cargo (HEC). The long line contacting a shield wire suspended between power transmission towers near Sulphur, Louisiana. The long line severed and the two linesmen were fatally injured when they fell around 100 ft to the ground. According to the US National Transportation Safety Board (NTSB) investigation report (issued November 2019): …the purpose of the flight was to install guard ropes between the deenergized 500-kilovolt power transmission lines before the existing braided steel shield wire from the nearby transmission tower was replaced. The east/west power transmission lines, with three sets of bundled conductors (northern, center, and southern), crossed perpendicular over a road. The pilot reported that, following a preflight safety briefing, he and one of the linemen discussed the expected work tasks. The pilot stated that, following their discussion, he brought the helicopter into a hover to allow the linemen to hook onto the external cargo long line. He then repositioned the helicopter to allow the linemen to work on the center conductor bundle. …after the linemen had tied off the guard rope to the center conductor bundle, he repositioned the helicopter to allow work on the northern conductor bundle. The pilot reported that he saw the long line contact the braided steel shield wire as one of the linemen held onto the northern conductor. The long line severed as the pilot turned the helicopter into the wind and attempted to move the linemen away from the northern conductor. The pilot reported that, immediately before the long line severed, he observed one of the linemen tugging at the conductor to reposition the guard rope perpendicular to the conductors. After the long line severed, the pilot returned to the landing zone and made an uneventful landing. The 60-ft long line separated about midspan. The pilot was 71 and had… …had accumulated 25,090 total hours of flight experience, of which 21,063 hours were logged as pilot-in-command and 11,286 hours were flown in Hughes 369 helicopters. The helicopter was operating under Part 133 Class B during the flight according to the operator (i.e. with a jettisonable load). The linesmen were considered as crew, not passengers, during powerline construction operations. The operator reported that: The FAA had approved the helicopter’s hook installation; however, because the flight was conducted under Part 133 Class B, the FAA did not regulate, specify, or approve the long line or the harnesses that was used to hoist the two linemen. In 2018 the FAA issued Safety Alert for Operators (SAFO) 18013 Updated Rotorcraft External Load Attaching Means and Quick Release Devices for Human External Cargo (HEC). This prohibited Part 133 operators from conducting HEC operations with attaching means not certificated to HEC requirements contained in Parts 27 and 29. This specifically related to a Portable Safety Device (PSD), also known as a Belly Band System or emergency anchor, that serves as a backup system to the primary hook, even if the hook kit is not certified for HEC. This affected MD500/Hughes 369 operators in particular. The operator reported that the long line was a 7/16 inch Amsteel Blue synthetic rope made of Dyneema SK-75 synthetic fiber that had...
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