Helicopter Wildlife Netting Accidents
Helicopter Wildlife Netting Accidents (N338HW, N22TZ, N369TH, C-GTNV, N122CH) In May 2018 the US National Transportation Safety Board (NTSB) published two reports into accidents involving helicopters attempting to carry out wildlife net captures. UPDATE 11 July 2019: Another netting accident report is published. UPDATE 8 November 2019: …and another. UPDATE 13 February 2020: …and again; the fifth accident in just 18 months. 1) Tail Rotor Strike, N338HW On 12 February 2018, Hughes (later MD) 369D N338HW of Helicopter Wildlife Services was manoeuvring at a low altitude in an attempt to net an elk near Heber City, Utah. According to the NTSB report: When the helicopter was approximately above the elk, his attention was immediately focused forward due to a small rise in terrain. He pitched the helicopter’s nose up, and the helicopter started to shake and spin. Subsequently, the helicopter struck the ground, the right skid broke, and the helicopter came to rest on its right side. Postaccident examination revealed that the tail rotor had struck the elk when the pilot pitched the helicopter’s nose up. The helicopter sustained substantial damage to the tailboom and rotor [sic]. The two persons on board were uninjured. NTSB do not comment on the fate of the elk, but other sources state its injuries were terminal. The NTSB probable cause was: The pilot’s failure to maintain clearance from an elk while maneuvering at a low altitude. Successful elk captures to fit radio collars in New Mexico: 2) Self Inflicted Main Rotor Damage, N22TZ A few months earlier, on 26 October 2017 in La Paloma, Texas, Airbus Helicopters EC130T2 N22TZ of Richardson Aviation was manoeuvring at low altitude with two net gunners located on the left and right in the aft cabin according to the NTSB report. The pilot reported that he entered a left bank to pursue a deer. The deer was located “between our 8 and 9 o’clock position, and the net gunner made the net shot at the deer.” The pilot observed the net miss the deer and simultaneously heard an unusual “whooshing noise” coming from the helicopter. He made a precautionary landing, and during the shutdown, he noticed what he described as an unusual discoloration of the main rotor disc. Examination of the main rotor blades revealed that one of the blades had a large hole in it, about 5 ft from the blade tip. The net that was fired at the deer was recovered and was found to be missing one of the weights that are normally attached to the net’s corners. The NTSB probable cause was: The separation of a weight from the gunner’s net, which struck the helicopter’s main rotor blade during flight. UPDATE 11 July 2019: 3) Self Inflicted Tail Rotor Damage, N369TH On 27 January 2018, Hughes 369D N369TH, operated by Hells Canyon Helicopters (seemingly on contract to the Washington Department of Fish and Wildlife) crashed NW of Pomeroy, Washington. One person died and two were seriously injured. According to the NTSB safety investigation report (and on-site supplement): The purpose of the flight was to capture and collar mule deer for tracking. The flight was operated with three crew members: a pilot, a gunner, and a mugger. The pilot sits in the front left seat, the gunner sits in the rear left seat and shoots nets from a net gun in order to capture deer, and the mugger sits in the front right seat and exits the helicopter...
read moreUS Fatal Night HEMS Accident: Self-Induced Pressure & Inadequate Oversight
US Fatal Night HEMS Accident: Self-Induced Pressure & Inadequate Oversight The US National Transportation Safety Board (NTSB) has determined (24 May 2018) the probable cause of a 2016 fatal helicopter emergency medical service (HEMS) accident to be: The pilot’s decision to perform visual flight rules flight into night instrument meteorological conditions, which resulted in loss of control due to spatial disorientation. Contributing to the accident was the pilot’s self-induced pressure to complete the mission despite the weather conditions and the operator’s inadequate oversight of the flight by its operational control center. The Accident Flight Airbus Helicopter AS350B2, air ambulance helicopter N911GF, operated by Metro Aviation as ‘Life Flight 2’ for Haynes Life Flight, was based at the Troy Regional Medical Center, Alabama. It had departed Troy at 23:26 Local Time 25 March 2016 to attend a motor vehicle accident outside Goodman, near Enterprise, Alabama. Witnesses indicated that fog, mist, and reduced visibility existed at the site at the time of the helicopter’s arrival to collect the casualty from a farmers field. The casualty was described by ground personnel as “bleeding from head; groggy at times; in and out of consciousness; right femur fracture”. At 00:17 Local Time 26 March 2016, the helicopter departed, destined for Baptist Medical Center Heliport, Montgomery. On board was the single pilot, two medical personnel and the casualty. There was “slight drizzle” around the time and although there was no ground fog according to one witness “there may have been fog above the trees”. Another witness stated there was “a heavy mist” and the ceiling was “very low, maybe 100 foot.” Another stated that “the fog was mixed with rain” and was “kind of pretty thick.” The NTSB say: Review of radar data provided by the US Army from the approach control radar site at Cairns Army Airfield, Fort Rucker, about 13 nm east, indicated that, the helicopter was first identified on radar after takeoff at 0017:35. The helicopter was in a shallow left turn and climbing to 1,000 ft above mean sea level. At 0018:04, the rate of turn began to increase and continued to increase over the next 4 seconds when the helicopter reached a peak altitude of 1,100 ft. The helicopter remained at this altitude and continued the left turn until 0018:28 when the helicopter began a rapid descent. Five seconds later, radar indicated that helicopter had descended through 600 ft. Moments later, the helicopter descended below the floor of the radar coverage area, and radar contact was lost. According to [the Haynes Ambulance Communication Center] HCC, the helicopter’s on-board Skyconnect satellite tracking system updated every 3 minutes, and the pilot was supposed to contact them every 15 minutes. A search was initiated when the pilot did not check in with the communications center as required… About 0700…search parties began to smell what they believed was jet fuel and eventually located the wreckage in a swampy, heavily wooded area. The helicopter had struck trees only about ½ mile north of the motor vehicle accident site. The cause of death for all four occupants was “multiple blunt force injuries”. Local news video The Helicopter Configuration The NTSB say: Although the helicopter was not certificated for flight in IMC, it had sufficient instrumentation to operate in the event of an inadvertent encounter with IMC and was equipped with a helicopter terrain avoidance warning system, a night vision imaging system which...
read moreToo Rushed to Check: Misrigged Flying Controls
Too Rushed to Check: Misrigged Flying Controls If you had spent 2 years rebuilding a classic 1947 Piper PA-12 you’d make the time to check the rigging of the flying controls before first flight, right? Sadly, the 25,000 hour pilot in this fatal case study was in a rush… Accident Flight On 8 April 2017 PA-12 N3280M was being readied at Orlando Sanford International Airport, Florida for its first flight since a restoration that included replacement of the wing and fuselage fabric, flight control cables and electrical wiring. The US National Transportation Safety Board (NTSB) report that: Although the mechanic who had worked on the airplane with the pilot wanted the pilot to do a high-speed taxi test before flight, the pilot wanted to “hurry up” and test fly the airplane as he had a friend visiting and wanted to take him flying in the airplane. Multiple witnesses stated that the airplane accelerated normally, lifted off, and immediately pitched up to a near vertical attitude. One witness stated, “it was like someone took the control yoke full aft.” The witnesses reported that the airplane reached an altitude of about 100 ft, stalled, rolled to the right, and descended in a nose-down attitude to impact on the right side of runway 27L. A postimpact fire ensued that was extinguished by aircraft rescue and firefighting personnel on the airport. The pilot died in the accident. The cause of death was recorded as due to “thermal and blunt force injuries”. Safety Investigation Examination of the wreckage revealed crush damage to the nose and the leading edges of the wings that was consistent with a nearly vertical nose-down flight path at the time of impact. Further examination of the wreckage revealed that the airplane’s elevator control cables were misrigged, such that they were attached to the incorrect (opposite) locations on the upper and lower ends of the elevator control horn, resulting in a reversal of elevator control inputs. The NTSB comment that: If the pilot had checked the elevator for correct motion during the preflight inspection and before takeoff check, he likely would have discovered that it was misrigged, and the accident would have been avoided. The NTSB disappointingly do not discuss the circumstances of the maintenance, however we note that an independent inspection of the flying controls after reconnection, which would have highlighted the error, is not required by Federal Aviation Regulations. NTSB Probable Cause The incorrect rigging of the elevator control cables, which resulted in a reversal of elevator control inputs applied by the pilot during the takeoff, an excessive nose-high pitch, and subsequent aerodynamic stall after takeoff. Also causal was the inadequate post-maintenance inspection and the pilot’s inadequate preflight inspection and before takeoff check, which failed to detect the misrigging. Safety Lessons The NTSB observe that: During preflight inspection of a PA-12 (before engine start), a pilot can see the elevator’s corresponding movements when the control stick is manipulated (either when standing by the open cockpit door or when seated in the front seat); likewise, a pilot standing on the ground and manipulating the elevator by hand can look forward and see the corresponding control stick movement. During a before takeoff check of the PA-12, a pilot can view the elevator from the pilot seat by turning around and looking back. Maintenance personnel should first...
read moreNTSB Comes Out For Gun Control
NTSB Comes Out For Gun Control With Trump in the White House its major news when a Federal agency comes out for gun control…if only to avoid fouling flight controls rather than more innocent fatalities. The Accident Flight The pilot of Robinson R22 helicopter N843SH was taking a passenger up for the pilot’s third “hog hunt” flight in Wadsworth, TX on 13 February 2018. As they reached a height of about 40 to 50 ft above ground “the passenger’s gun [butt] became lodged in the cyclic control”. According to an NTSB report, the pilot: …instructed the passenger to move his gun multiple times, but the passenger “seized up and panicked.” The helicopter impacted the ground, and the fuselage and empennage sustained substantial [sic – see photo] damage. The passenger received minor injuries and the pilot was unharmed. The pilot reported that it was the second hunt with the passenger and that he had provided a safety briefing before the accident flight. He added that, during the safety briefing, he discussed gun safety, when and where to shoot, and instructions on avoiding areas with the flight controls. He added that, as a safety recommendation, he will conduct a more thorough safety briefing, including an on-ground, engine-off cockpit simulation and a lesson on firearm safety. He [now also] allows each passenger to sit in the helicopter, prior to flight, to allow them to get a feel for the cockpit size and how to maneuver with their gun NTSB Probable Cause The passenger’s gun becoming lodged in the flight controls during takeoff and his failure to remove it, which resulted in impact with terrain. Our Safety Message FOD in the cockpit can be deadly. Our Sporting* Message If you want to hunt hog, its more sporting and skilful to be on foot or, hey even, horseback… At least that day it was Hogs 1 – Heli Hunters 0 Other Odd Robinson Accidents The “Hold My Beer” Helicopter Accident Hazardous Hangar Hovertaxy Other Occasions When Flight Crew Briefs of Non-Aviators Proved Ineffective Unexpected Load: AS350B3 USL / External Cargo Accident in Norway Unexpected Load: B407 USL / External Cargo Accident in PNG Tool Bag Takes Out Tail Rotor: Fatal AS350B2 Accident, Tweed, ON * according to one source: Of the estimated 4 to 5 million feral hogs in the United States, approximately 2 million call Texas home. Feral hogs can be found in approximately 230 of our 254 counties and cause an estimated $52 million of damage to Texas agricultural enterprises each year. Hence hunting is authorised to control the population, even from hot air balloons… If you think this agricultural helicopter use is extreme, well there is HeliTorch for controlled burn woodland management… A nice reminder to military certification colleagues that civil helicopter usage is not always that sedate. UK registered Super Pumas were once on call to ignite oil slicks in the Far East with HeliTorch. UPDATE 3 June 2018: Helicopter Wildlife Netting Accidents In May 2018 the NTSB published two reports into accidents involving helicopters attempting to carry out wildlife net captures. UPDATE 5 February 2021: Inexperienced IIMC over Chesapeake Bay: Reduced Visual References Require Vigilance Aerossurance is pleased to sponsor the 9th European Society of Air Safety Investigators (ESASI) Regional Seminar in Riga, Latvia 23 and 24 May 2018. Aerossurance has extensive air safety, operations, airworthiness, human factors, aviation regulation and safety analysis experience. ...
read more“Delivering Our Priorities”: HeliOffshore 2018 Conference Report
HeliOffshore Conference 2018 Report: “Delivering Our Priorities” The offshore helicopter safety association, HeliOffshore held its fourth conference and AGM in Baveno, Italy 5-6 May 2018. The focus was on ‘Delivering Our Priorities’ for improved offshore helicopter safety. Being close to Leonardo‘s sites just north of Milan, the Italian manufacturer arranged a formation fly-past at the start of the conference of an AW169, AW139 and AW189. The conference was attended by a record 203 industry leaders from operators, helicopter manufacturers, oil and gas companies, regulators, suppliers and service providers (including, for the fourth year, Aerossurance). Day 1 HeliOffshore chairman Bill Chiles explained: We are ordinary people who can help our team members to achieve extraordinary results. There is no more noble cause than for all of us to work together to save lives. We do this because it is right – it’s a fundamental human obligation to make sure all our passengers and crews return home safely every day. You can view the conference introduction presentation here. In a keynote presentation Richard Noble discussed delivering breakthrough performance. Noble was holder of the land speed record between 1983 and 1997, when his lead the Thrust SSC team that achieved the first supersonic land speed record (and a then record 59 million webpage hits in 1997). His current project, the Bristol built Bloodhound SSC car is powered by one EJ200 reheated turbofan from a Typhoon figther, three Nammo high test peroxide (HTP) rocket motors and a 550bhp Jaguar Supercharged V8 engine (just to power the HTP turbopump). It is designed to achieve 1,000 mph on the Hakskeen Pan in South Africa. Noble is an advocate of the Wisdom of Crowds and the project is to put over 30Gb of telemetry data online for collaborative analysis. Fawaz Bitar, chairman of the IOGP Management Committee and BP’s Head of Global Operations – Upstream, also emphasised the need for stakeholders to collaborate on safety in his presentation. He indicated that IOGP would be ready to invest in safety initiatives, echoing Chiles’ comments: It’s personal: in BP alone 2,500 passengers are transported each day by helicopter and fixed wing aircraft. People’s lives depend on aviation safety. In a decade, the oil and gas industry has halved fatalities and our mission is now to eliminate all loss of life. This is no longer a vision. It is an expectation. https://youtu.be/c36dvL038ZA Day 1 continued with panel sessions on safety collaboration and delivering results. You can view the Next Steps in Safety Collaboration presentation here. You can view the Delivering Results presentation here. https://www.youtube.com/watch?v=Ll9_tCt-5cc&feature=youtu.be Terry McVenes of Boeing commented: You’re on the right track. It’s taken collaboration and communication and a working together spirit that wasn’t easy at the beginning. (In the fixed wing industry) we also had different constituents and perspectives. Trust was a big issue to work through. It is such a precious thing. General Tan Sri Muhammed Ismail Jamaluddin, CEO of, Weststar Aviation said: It’s the leadership in the company that needs to push safety projects to the top. Trust and leadership are things Aerossurance has discussed before: Leadership and Trust In a joint presentation, Airbus Helicopters and Sikorsky explained how a proven stage gate review processes will now be applied to HeliOffshore projects. This provides increased clarity on progress and implementation responsibilities. Day 2 The main themes on day 2 were the workstreams: Safety Intelligence Operational Effectiveness System Reliability and Resilience In Safety Intelligence, there was a major emphasis on all...
read moreWhen Screens Go Blank: NTSB on a 787 Display Loss After a Lightning Strike
When Screens Go Blank: NTSB on a 787 Display Loss After a Lightning Strike On 10 October 2014, United Airlines (UA) Boeing 787-824 N26906 was struck by lightning during initial climb, a few minutes into a flight from London Heathrow (LHR) to Houston (IAH). The US National Transportation Safety Board (NTSB) published their final report in April 2018. The Incident Flight The NTSB explain that: The flight crew reported that the aircraft was flying through a “moderate non-CB (cumulonimbus) rain shower” with cloud tops of 10,000 feet mean sea level (msl) at the time of the lightning strike. The Captain stated that: The strike apparently occurred just above the Captain’s forward windshield frame. It was completely unexpected. There were no precursor indications (corona, daylight visible St Elmo’s, perceived static buildup, tingling, etc.), nor were there any notable after effects other than the failures. There were no other discharges visible as we approached the cloud, or after the event. The strike was brilliant, but not blinding; consistent with the close proximity to our eyes. The audible “crack” was very loud, as would be expected by the location, and the Flight Attendants reported hearing a rumble travel through the fuselage back to the door three area immediately after the discharge. The NTSB say that: Based on crew reports and verified with images from the crew and the EAFR [enhanced airborne flight recorder], the flight crew lost the use of three of the five head down displays [HDDs] following a lightning strike. [Additionally] a status message related to a power distribution channel was displayed, and the captain’s forward windshield heat became inoperative. The standby instruments and the heads up displays (HUD) were unaffected by the event. The crew followed published procedures, however the procedures did not contain a checklist related to a partial loss of displays. After the crew elected to follow the “Loss of All Displays Checklist”, none of the affected displays recovered to an operational state. The crew accomplished the abnormal checklist for the window heat. The checklist did not restore the function of the window heat. The 787 cockpit has no thermal circuit breakers (TCB) accessible by the crew. A software function called Circuit Breaker Indication and Control (CBIC) provides indication and control for electronic circuit breakers (ECB) and indications only for TCB’s. The crew made a safe landing back at LHR using the remaining two displays. Maintenance Actions After landing, LHR maintenance performed a lightning inspection and found external nonstructural damage in five locations along the nose which was addressed in accordance with structural repair manual (SRM) allowable damage criteria. A power reset to the aircraft per maintenance manual procedures was accomplished, and the displays and other affected systems returned to normal function. After a review by United maintenance personnel, the aircraft was approved for dispatch and continued the flight to IAH with no further faults noted. Safety Investigation Using data gathers during post-incident near strike lightning and flat plate testing, Boeing Company conducted an analysis of the electrical fields present in the cockpit during a lightning event: The analysis used three current waveforms (“A”, “D” and “H”), from ARP 5412 revision B, which are the same waveforms used during certification testing and analysis of flight deck equipment. The analysis confirmed that under some dynamic lightning conditions, the spark gap device installed in the Window Heat Protection Unit will...
read moreHelicopter Throttle Bracket Left Unsecured After Maintenance
Helicopter Throttle Bracket Left Unsecured After Maintenance On 11 August 2014, a Hughes 269C helicopter, N7432F, impacted trees and a river bank in a steep ravine following a partial loss of engine power near Darrington, Washington. The pilot, a 59-year-old airline pilot, was uninjured. The US National Transportation Safety Board (NTSB) report that: The pilot reported that during a flight in the rented helicopter he was descending out of 5,000 ft. As he approached 4,000 ft, he increased collective and noticed that the engine was slowing down; he was unable to recover the engine rpm to a normal range. The helicopter continued to descend until the pilot entered an autorotation. The helicopter impacted a tree about 30 ft high and then came to rest in a small stream. The pilot stated he did not believe the engine ever quit, but the engine would not produce enough power to continue flight. The aircraft was recovered and it was… …found that the throttle mount bracket was hanging by the throttle cable linkage and was not secured to the servo mount studs as it should have been. This would prevent the loss of throttle movement for acceleration. The operator [who leased the aircraft to the pilot] stated that the engine had just been installed into the helicopter 10 flight hours prior to the accident. [It had been removed from another aircraft in their fleet.] We note that no further information is recorded in the NTSB report or public docket on the conduct of the maintenance, limiting the ability to understand the circumstances of any maintenance error and learn. The NTSB determined the probable cause to be: Maintenance personnel’s failure to secure the throttle mount bracket during a recent engine installation, which resulted in the loss of throttle movement and an inability to control engine power. Safety Resources Professor James Reason’s 12 Principles of Error Management Back to the Future: Error Management Critical Maintenance Tasks: EASA Part-M & -145 Change Safety Performance Listening and Learning – AEROSPACE March 2017 Maintenance Human Factors: The Next Generation Airworthiness Matters: Next Generation Maintenance Human Factors Robinson R44 Power Loss: Excessive Lubricant UPDATE 24 June 2018: B1900D Emergency Landing: Maintenance Standards & Practices The TSB report posses many questions on the management and oversight of aircraft maintenance, competency and maintenance standards & practices. We look at opportunities for forward thinking MROs to improve their maintenance standards and practices. UPDATE 25 August 2018: Crossed Cables: Colgan Air B1900D N240CJ Maintenance Error On 26 August 2003 a B1900D crashed on take off after errors during flying control maintenance. We look at the maintenance human factor safety lessons from this and another B1900 accident that year. UPDATE 5 November 2018: The NTSB has published the probable cause of the fatal accident to 269C N204HF in September 2017: Contributing to the accident was the failure of maintenance personnel to properly rig the throttle control tie-rod assembly, which resulted in an in-flight separation of the assembly and rendered control of engine rpm impossible. UPDATE 19 April 2019: FAA Rules Applied: So Misrigged Flying Controls Undetected UPDATE 15 March 2020: R44 Force Lands After Improper Repair Aerossurance worked with the Flight Safety Foundation (FSF) to create a Maintenance Observation Program (MOP) requirement for their contractible BARSOHO offshore helicopter Safety Performance Requirements to help learning about routine maintenance and then to initiate safety improvements: Aerossurance can provide practice guidance and...
read moreAn AW109SP, Overweight VIPs and Crew Stress
An AW109SP, Overweight VIPs and Crew Stress On 15 December 2014 Leonardo AW109SP helicopter A6-FLP, operated by Falcon Aviation Services (FAS), sustained significant damage after taking off overloaded in Abu Dhabi, UAE. This was an unusual accident where the crew were put under considerable stress during a poorly planned and executed VIP flight booking. Flight Preparations The Air Accident Investigation Sector (AAIS) of the UAE General Civil Aviation Authority (GCAA) say in their safety investigation report that: The FAS Sales Department received a phone call at 1613 LT to book a flight which would depart Emirates Palace Hotel at 1715 LT for Al Marmum Farm. The reservation was confirmed at approximately 1658 LT. The departure time was [later] changed to 1730 LT… At the time the flight reservation was booked, no information was provided about the number or weight of the passengers. Later, FAS were told there would be six passengers. The flight was to also be conducted ‘in formation’ with an AW139, operated by a different company. The GCAA do not expand on that requirement. Although the AW109SP is a single pilot helicopter, FAS routinely rosters a Safety Pilot (SP) for night operations. The SP was originally scheduled for another flight but, she was on duty and available to act as SP for the Accident flight. Emirates Palace Hotel Heliport [is] adjacent to the hotel. It was used primarily for the arrival and departure of hotel guests. The heliport was uncontrolled and there was no heliport landing officer (HLO). The passengers arrived at the heliport late and in dramatic fashion: At 1830 LT, approximately 12 vehicles arrived at the heliport with the passengers and a number of security personnel… The cars engaged in extreme manoeuvres and circled the heliport. Many people exited the vehicles and the heliport was surrounded by cars and over 20 people. Having previously flown VIPs, the SP said that this was “the most official and intimidating scene” that she had witnessed. The SP remained outside the Aircraft with the intention of supervising the boarding of the passengers, providing a safety briefing, and ensuring that the passengers were secured in their seats. The boarding of the passengers was conducted by their security personnel… Neither the loadsheet for passenger weights, nor the total number of passengers was available to the crew. The SP was distracted as she tried to ensure that the security personnel did not approach the tail rotor, and she was obstructed by security personnel who appeared to be determined to keep anyone, including the flight crew, away from the VIP passengers. Eventually, the SP was able to shine her torch into the passenger cabin and she noted that there were six [seated] passengers, plus one passenger who was seated on another passenger’s knees, bringing the total number…to seven. This “additional” passenger signalled aggressively to the SP to close the door and he leant over and attempted to close the door himself. It was not possible, due to the activities of the security personnel, to provide a safety briefing, or to confirm that the passengers were secured, prior to takeoff. Meanwhile the AW139 had departed and requested the AW109SP join it so that the formation flight could commence. The SP took her seat and told the Captain that there were 7 passengers on-board. The Captain acknowledged that information but initiated the takeoff immediately. The Accident Flight The AAIS explain that the helicopter took off at 1832 LT:...
read moreNTSB Probable Causes and Bad Apples
NTSB Probable Causes and Bad Apples (and the Bad Apple Index) During an on-line discussion about an Aerossurance post to mark the 20th anniversary of a CFIT accident in Guam, there was criticism that the NTSB ‘Probable Cause‘ was: The captain’s failure to adequately brief and execute the nonprecision approach and the first officer’s and flight engineer’s failure to effectively monitor and cross-check the captain’s execution of the approach. Some contributors rightly felt this simplistically blamed the crew (i.e. taking a ‘bad apple’ ‘old view’ of human error) rather than explained the accident. Others pointed out the accident was 20 years ago and investigators take a more sophisticated approach today. So we decided to look at the full NTSB air accident reports issued since the start of 2016: AAR1601: The Probable Cause was: “the pilot’s conduct…” (see Aircraft accident Embraer EMB-500 Phenom 100 N100EQ) AAR1602: The Probable Cause was: “the captain’s inability” (see Delta MD-88 Accident at La Guardia 5 March 2015) AAR1603: The Probable Cause was: “the flight crew’s mismanagement…” (see Execuflight Hawker 700 N237WR Akron Accident: Casual Compliance) AAR1701‘s Probable Cause, after a lot of debate in the public hearing, was “(1) preflight hydraulic check, which depleted hydraulic pressure… and (2) lack of salient alerting…” but the pilot’s actions were determined to be contributory (see Crashworthiness and a Fiery Frisco US HEMS Accident) AAR1702: The Probable Cause was: “(1) the pilot’s decision to…and (2) the company culture…” (see All Aboard CFIT: Alaskan Sightseeing Fatal Flight) AAR1703: The Probable Cause was: “the pilot’s pattern of poor decision-making…” (see Balloon accident Kubicek BB85Z N2469L) AAR1801: The Probable Cause was: “the failure of the high-pressure turbine (HPT) stage 2 disk…” (see Uncontained CF6-80 Failure: American B767-300 28 Oct 2016) AAR1802: The Probable Cause was: “the flight crew’s decision to continue the VFR flight into deteriorating visibility and their failure to perform an immediate escape maneuver after entry into IMC…” (see Operator & FAA Shortcomings in Alaskan Accident) That’s a 5.5 out of 8 bad apple index (69%) as far as we are concerned! In the NTSB Board debate over the one case (AAR1701) where the Probable Cause was not crew actions (or inactions), Board member Robert Sumwalt, who has recently been sworn in as NTSB Chairman, objected to the original draft Probable Cause saying: This pilot did not do what he was supposed to do. But if we dig deeper — and that’s what really bothers me about the original probable cause is that it is saying that the pilot screwed up… To put the pilot as the primary factor of the probable cause is just wrong, because it points to the last person who made the last mistake. I think we need to dig deeper to get to the root cause of this. So while the concept of Probable Cause is enshrined in US law, perhaps we will see a change of interpretation in future. Certainly the Contributory Factors identified by the NTSB are often better indications of what caused an accident than the official Probable Causes. Note: This is an update of an article originally published on LinkedIn by Aerossurance’s Andy Evans. Tracking the Bad Apple Index UPDATE 7 March 2019: AAR1901: The Probable Cause was: “the jammed condition of the airplane’s right elevator…” However “Contributing to the survivability of the accident was the captain’s timely and appropriate decision to reject the takeoff, the check airman’s disciplined adherence to standard operating procedures….”. If we score this as...
read moreA330 Starts to Taxi Before Tug is Clear
A330 Starts to Taxi Before Tug is Clear In the early hours of 9 September 2016 AirAsia X Airbus A330-343X 9M-XXK pushed back from gate D12 at Melbourne Airport, Victoria. The Australian Transport Safety Bureau (ATSB) say in their safety investigation report that: The aircraft maintenance engineer (AME) conducting the pushback was provided by a contracted company, the tug and tug driver were provided by a third company. At 0008, after both engines were started, the AME disconnected the headset and tow bar from both the aircraft and the tug, the AME also removed the bypass pin. The tug driver turned the tug around to allow the AME to attach the tow bar to the rear of the tug. The tug driver then moved the tug and tow bar to a position forward of the aircraft’s right engine and visible to the first officer. The AME then walked to a position in front of the tug, and displayed the bypass pin to the first officer. Sighting the bypass pin was the final item on the flight crew’s after start checklist. The flight crew then contacted ATC and obtained a taxi clearance. At 0009, the first officer confirmed to the captain that the AME and tug were clear, the captain then began to taxi. At this time, the AME was walking towards the left side of the tug, which remained parked forward of the aircraft’s right engine and wing. As the AME walked, they detected the aircraft’s taxi light illuminate and the aircraft begin to move. The AME then ran toward the tug door and alerted the tug driver to the aircraft movement. Video footage of the incident shows the tug driver taking action to avoid a collision with the taxiing aircraft. The ATSB explain that the flight crew procedures included the following steps: After the pushback and engine start sequence is complete, the bypass pin must be sighted. Once taxi clearance is obtained, the flight crew shall ensure both sides of the aircraft are clear prior to taxi The ground handling procedures include the following steps: Once the tow bar is connected to the tow vehicle (after being disconnected from the aircraft), the tow vehicle must move away to an area that is visible to the flight crew. At a suitable and safe distance from the aircraft, (the AME must) hold up the bypass pin to provide visual confirmation that it has been removed to the flight crew and give a ‘thumbs up’ signal indicating ‘clearance to proceed’. Once acknowledged by the flight crew, move away from the aircraft to a safe distance for the aircraft to taxi. The ATSB report that: The tug driver and AME both commented that they expected the aircraft to remain stationary until they had moved clear of the S7 disconnect point boundary. The flight crew commented to the ATSB: Both flight crew interpreted the AME displaying the bypass pin as meaning the tug and AME were clear, and it was safe to commence taxi. The flight crew assumed that ATC providing the taxi clearance meant that ATC had confirmed the tug was clear of the aircraft. The first officer observed the tug and AME to the right of the aircraft and assessed that they were clear of the right engine. The ATSB say that before this incident: In 2015, ATC provider, Airservices...
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