Fatal Snowy Powerline Inspection Flight
Fatal Snowy Power Line Inspection Flight (H369HM, N4QX) A Hughes (later MD) 369HM N4QX, operated by Vista One Inc, impacted terrain near Perrysburg, Ohio on 15 January 2018, 72 minutes into a power line aerial observation flight. Both occupants, pilot and observer, were fatally injured. Police photographs at the accident scene further showed falling snow and flat light / white out conditions. Local TV news report (VIDEO). The Operational Tasking US National Transportation Safety Board (NTSB) say in their safety investigation report that Vista One holds a Part 133 Rotorcraft External Load certificate and conducts power line inspections under Part 91. The accident flight was the first leg of inspections of the Toledo Edison power grid from Bowling Green, Ohio to the Indiana/Ohio border over the following 4 weeks. Vista One’s power line inspection flights involved the helicopter flying along the line, circling each tower then continuing along the line. Vista One’s owner explained that: It was the responsibility of the crew member [the inspector sat in the rear on the right hand side], using binoculars and a camera, to inspect the towers and lines for the security of cotter keys, nuts, bolts, and so on. The pilot would position the helicopter skids above the static line, about 20 ft, during these flights. …it was typical for the helicopter to cover between 2 and 3 miles in an hour. In the accident report form, the owner stated that it was not normal to inspect the lines in snow and blowing snow due to the poor visibility and wind gusts. Toledo Edison is part of FirstEnergy, a company with a c$25 billion market capitalisation and annual revenues of c$11 billion. Safety Investigation Vista One told the NTSB that the pilot had departed from the company base at the Wayne County Airport, Wooster, Ohio, earlier that morning to pick up a power line inspector at Wood County Airport, Bowling Green, Ohio. The inspector had driven from his home in West Virginia. The pilot refuelled the helicopter during their 63 minute stop there. Security video showed the helicopter on the ramp in falling snow throughout this period. Witnesses described the snowfall as “moderate” at the time of departure. No explanation of why the flight was conducted in such conditions was forthcoming from Vista One or discussion by the NTSB of their operational control or flight following. The National Weather Service (NWS) forecast sub-zero air temperatures, east-southeast wind of 5 to 10 knots, overcast sky cover and light snow. In their safety investigation report the NTSB report the low-time pilot had logged just over 1,200 hours in helicopters, around 200 hours in the MD369. The pilot had logged less than 100 hours of simulated instrument flight time and no flight time in actual instrument conditions. The last simulated instrument flight (0.4 hours dual received) was conducted in September 2015 in a Robinson R44. The pilot had started work for Vista One in September 2017, so significantly this was his first winter with them, and had flown just over 300 hours for the company. Of note is that… …the company did not provide any training records for the pilot. The owner recalled conducting a training flight with the pilot the week before the accident but did not provide any specifics for that flight. The owner mentioned that the pilot had difficulty recalling how to clear the GPS track…. He also stated that the...
read moreB747-400F Tyre Explosion During Inflation
B747-400F Tire Explosion During Inflation The Singapore Transport Safety Investigation Bureau (TSIB) have reported on a tyre explosion on China Airlines Boeing 747-400F freighter B-18719 on 18 October 2018 during a turnaround at Singapore Changi. The aircraft had landed at 0443LT and was scheduled to depart two hours later. During a walk-around inspection, the tyre pressure of the No.11 tyre was found to be low. While the tyre was being inflated with nitrogen, the tyre burst. A tyre pressure gauge that a Technician had placed on the top of the tyre was propelled into the wing body fairing. The technician “felt a blast of cold air to the right side of his face” but was uninjured. The Safety Investigation The Aircraft Maintenance Manual (AMM) contains procedures for both Hot and Cold Tyre Pressure Checks. The cold check is Boeing’s preferred method and the hot check is intended for occasional use only. A cold check can be performed if the tyre has cooled for 2 hours or more. However the cooling time can vary depending on the weather conditions, ambient temperature etc. Boeing considers it acceptable to determine if the tyre has cooled to ambient temperature by touch. TSIB note that this “has an element of subjectivity”. The Licensed Aircraft Engineer (LAE) checked the tyre and believed it had cooled, noting it was raining heavily at the time. After assessing by touch that the tyre was not hot, he tasked Technician A to measure the tyre pressure while he himself went to the cockpit and noted that the brake temperature was indicated as “0” on a scale of 0 to 9 on the wheel synoptic page of the aircraft’s Engine Indicating and Crew Alerting System (EICAS). However, this was not conclusive as: “0” and “9” represented the Cold and Hot ends respectively. “0” corresponded to a brake temperature lying within the range from ambient temperature to 176ºC. Technician A used a manual tyre pressure gauge and determined the tyre pressure was 170 psi. The air operator had set a tyre service pressure of 200 (+5/-0) psi irrespective of the aircraft’s gross weight (which was within the range allowed by the AMM), so there had been a drop of 15% in pressure and so the tyre should have been replaced. It appears the LAE however erroneously calculated the drop from the minimum inflation pressure (185 psi) i.e 8.1%. That percentage allowed the tyre to be re-inflated subject to a tyre pressure checked again 24 hours. The LAE then instructed Technician A, who would be assisted by Technician B, to service No.11 tyre to 200 psi. During the inflation the tyre burst as described above. The examination of the burst tyre by the tyre manufacturer [Bridgestone] suggested that there was a pre-existing ply cord deterioration condition on the tyre and that this condition was consistent with the tyre having been operated under significantly low pressure prior to the incident. Indeed, had the tyre been appropriately serviced, it seemed very unlikely that the tyre pressure could have dropped to 170 psi. The ply cord deterioration was likely accompanied by a slow deflation of the tyre which was somehow not noticed during daily checks of tyre pressure or transit walk-around inspections. The integrity of the tyre was compromised progressively by the ply cord deterioration and it was during this incident that the tyre wall could no longer withstand the internal inflation pressure and...
read moreKing Air 100 Stalls on Take Off After Exposed to 14 Minutes of Snowfall: No De-Icing Applied
King Air 100 Stalls on Take Off After Exposed to 14 Minutes of Snowfall: No De-Icing Applied (Island Air Express, C-GIAE) On 23 February 2018, an Island Express Air, Beechcraft King Air B100, C-GIAE, departed Abbotsford, British Columbia on a day Instrument Flight Rules (IFR) flight to San Bernardino, California with a single pilot (the owner of the operator) and 9 passengers. According to the Transportation Safety Board of Canada (TSB) safety investigation report (issued 14 August 2019) snow had been falling during the flight planning and the aircraft had been kept within a hangar to protect it from the snow. TSB explain that: The pilot and passengers boarded the aircraft and, at 1150, the hangar door was opened and the aircraft was towed outside. At 1154, both engines were running. No de‑icing or anti-icing fluid was applied to the aircraft. At 1159, the pilot informed the controller that the aircraft was holding short for Runway 07. While the aircraft was waiting for takeoff clearance, no contamination was observed adhering to the wings. Two minutes later…the occurrence aircraft was cleared for takeoff. …the amount of snow estimated to have fallen on the aircraft from the time it exited the hangar until it entered the runway was about 4 to 5 mm. At 1203, the aircraft taxied onto the snow-covered Runway 07 and continued with an immediate takeoff. Approximately 4 to 5 seconds after takeoff, the pilot selected the landing gear control to the up position. As the gear retracted, the aircraft rolled approximately 30° to the left. To correct the uncommanded left bank, the pilot applied right aileron, and the aircraft returned to a near wings-level attitude. In order to make an immediate off-field emergency landing, the pilot retarded the power levers and then applied forward pressure on the control column to land the aircraft. The aircraft struck terrain between Runway 07 and Taxiway C. The aircraft slid across the snow-covered ground for approximately 760 feet before coming to rest in a raspberry patch located on the airport property. Five passengers and the pilot were seriously injured. The other 4 passengers received minor injuries. Both occupants of the crew seats received serious head injuries (i.e., facial fractures and lacerations) and compression injuries (i.e., spinal fractures). The passenger seated in the right-hand crew seat was rendered unconscious and had to be carried out of the aircraft. The passengers seated in the cabin received a variety of injuries… Two of the adult passengers seated in the cabin had compression injuries and spinal fractures. Otherwise, the injuries received by the adults and children seated in the cabin were the result of being hit by loose articles, detached seats, and other passengers. Safety Investigation: Flightpath and Icing The flight path was reconstructed as follows: It is likely the aircraft stalled during the initial climb after the aircraft lost the benefit ground effect. The aircraft was equipped with an ice protection systems and it had been activated. Type I de-icing fluid was available but not used. Type I fluids do not however offer any significant anti-icing holdover protection and so are commonly used as part of a two-step de/anti-icing procedure when the final application of a Type II or Type IV fluid provides the required hold-over time. According to the aviation weather report current at the time of the occurrence, the aircraft departed in moderate snowfall. However, according to internationally recognized de-icing and...
read moreDrone Operation Injury
Drone Operation Injury (DJI Phantom 4 UAS at Virginia Tech) On 14 August 2018 a DJI Phantom 4 Unmanned Air System (UAS) / drone flight was planned as demonstration for students of the Virginia Tech (VT) College of Natural Resources and Environment under the provisions of 14 Code of Federal Regulations (CFR) Part 107. The Accident Flight The Phantom 4 is a 1.4 kg quad-copter. The VT Conservation Management Institute (CMI) has two UAS pilots and focuses on natural resource related UAS uses (e.g. habitat mapping, wildlife monitoring and woodland burn monitoring). The US National Transportation Safety Board (NTSB) report that: The Mountain Lake Biological Station was University of Virginia property. The CMI chief pilot explained that they had been conducting demos there for 3 years with departmental approval and the Station management. It was not specified what the clearance entailed, and there were no records of any flight operations clearances or requests for the Biological Station site. The drone pilot held a Federal Aviation Administration (FAA) Part 107 Remote Pilot Certificate and had logged a total of 3.7 hours as Remote Pilot in Command (RPIC), most of which was on the senseFly eBee fixed-wing drone and the 3D Robotics (3DR) Solo quadcopter. He had logged 8 minutes RPIC on the Phantom 4 but reported about 2 hours of experience with it as a hobbyist. His training on the Phantom 4 consisted of performing some basic maneuvers at a practice field using various DJI GO 4 functions, and practicing using the DroneDeploy flight control app. While CMI could furnish the NTSB with an Operating Guide and Checklists for the eBee and Solo, significantly it did not have these for the Phantom 4. On the day of the incident, the pilot conducted a mapping flight prior to the demo. The pilot reported that, during the mapping flight, he attempted an automatic landing but the drone “missed its homepoint,” and the Director of CMI hand-caught the drone. The pilot reported that he “used the manual shutdown procedure, which worked correctly.” According to the pilot, the demonstration was intended to consist of a short, automated flight over a pond using the DroneDeploy control application (app) to show how mapping surveys were conducted, followed by a manual flight to view wildlife in the pond…at the Mountain Lake Biological Station, Blacksburg, Virginia. The six students who were observing the demo flight were located less than 10 feet from the pilot. There was no visual observer or other assistant to the pilot for this flight. He started the demo in manual flight mode, and took off from a plastic picnic table on the berm of the pond. The pilot reported that he was controlling the aircraft via a Samsung Galaxy J7 smartphone using the DJI GO 4 app and that he normally conducted mapping flights using the DroneDeploy app. All obstacle avoidance and vision positioning systems were turned on. He reported the flight was normal, although the wind picked up a little bit during the flight. He flew the drone back to the picnic table for landing but reported that it would not touch down onto the table. The pilot reported that he made numerous attempts to land and attempted “the shutdown procedure,” but the drone flew off to the side. He then reported that he climbed the drone back up and attempted an automatic landing and a landing in the grass, again using the “shutdown procedure,”...
read moreRemote Landing Site Blade Strike
Remote Landing Site Blade Strike The Accident Investigation Board Norway (AIBN) have released their safety investigation report (available in Norwegian only) into a serious incident to Airbus Helicopters AS350B3 LN-OWE, operated by Nord Helikopter. It occurred 24 February 2018 at Kvamsdal, Masfjorden Municipality, Norway during operations supporting the construction of a new power line. While manoeuvring at a temporary worksite with four persons on board (the pilot, a loadmaster and two passengers), the main rotor blades came in contact with a container that was located next to the landing site. The commander manouvered the helicopter away from the container. There were insignificant vibrations in the helicopter. The helicopter was controllable and therefore the commander decided to return to the departing site one to two minutes flight time away. The AIBN did not concur with that decision. After shutdown, it was found that the outermost part of all three main rotor blades was damaged. None of the persons sustained any injuries. The site layout had changed considerably since the pilot’s last visit there and obstacles had been sited too close. The AIBN believes that…the commander should not have accepted the reduced safety margins, and consequently refrained from landing. 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 moreAS350 Tail Rotor Control Incident, Grand Cayman
AS350 Tail Rotor Control Incident, Grand Cayman An Airbus AS350BA helicopter, VP-CIH, suffered tail rotor control problems during a sightseeing tour flight from Owen Roberts International Airport, Grand Cayman, 30 August 2018. In their safety investigation report the UK Air Accidents Investigation Branch (AAIB) describe how… Whilst descending through 500 ft and turning onto final approach for George Town Aerodrome, the pilot felt that the tail rotor pedals were not producing the correct yaw response, so he aborted the approach and informed ATC he would be returning to Owen Roberts International Airport. On the approach to the latter he tested the directional control, which did not respond correctly, so he informed ATC that he planned to conduct a run-on landing… The pilot carried out a successful run-on landing on Runway 26, having rejected the grass alongside as too soft for a safe run-on landing. None of the 5 persons on board were injured. Safety Investigation During examination of the helicopter it was found that the TGB [tail gearbox] actuating rod (part number 350A27191003) had ruptured at the aft end. [This rupture] was associated with the uncoupling of the steel sleeve inside the external aluminium alloy tube. An anomaly in the internal structure of the material of the rod was identified, along with the presence of cracks in a cold worked area. The manufacturer reported that this was the first such event on the AS350 that they were aware of. Safety Action As a result of these findings, on 20 March 2019 the EASA issued Airworthiness Directive 2019-0060, mandating [sic] dye penetrant crack checks of TGB actuating rods on affected AS350 and AS355 helicopters. Other Safety Resources Engine Failure after Inadvertently Being Put Back into Service Incomplete (and excellent autorotation in mountainous terrain) EC135P2+ Loss of NR Control During N2 Adjustment Flight Dim, Negative Transfer Double Flameout BK117B2 Air Ambulance Flameout: Fuel Transfer Pumps OFF, Caution Lights Invisible in NVG Modified Cockpit AAIB Report on Glasgow Police EC135T2+ Clutha Helicopter Accident US HEMS EC135 Dual Engine Failure: 7 July 2018 Accident Report: Fatal Police Helicopter Double Engine Flameout Over City Centre HF Lessons from an AS365N3+ Gear Up Landing Austrian Police EC135P2+ Impacted Glassy Lake UPDATE 2 January 2020: EC130B4 Destroyed After Ice Ingestion – Engine Intake Left Uncovered UPDATE 27 December 2020: Fire-Fighting AS350 Hydraulics Accident: Dormant Miswiring 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 moreSevere Propeller Vibrations on ATR 72-212A: BEA Report
Severe Propeller Vibrations on ATR 72-212A: BEA Report The Bureau d’Enquêtes et d’Analyses (BEA), the French Safety Investigation Authority, released their report in July 2019 (in French, UPDATE 10 Sept 2019: and now also in English) on a series of propeller incidents that occurred due to a vibratory phenomena that was not uncovered in certification testing. Caribbean In Service Event Caribbean Airlines ATR 72-212A 9Y-TTC was operating from Tobago to Port of Spain, Trinidad and Tobago on 4 May 2014. It was at top of descent, 6000 feet and 220 KIAS, with both Hamilton Sundstrand / UTAS 568F-1 propellers at 82% Np, when the flight crew commenced a 1500 fpm descent. The airspeed began to increase and so the crew reduced power. The airspeed did not decrease however. When the aircraft reached 246 KIAS, 4 knots below Vmo (max operating velocity), the crew reduced power to idle. The crew felt strong vibrations which was shortly followed by No 2 Propeller Electronic Control (PEC) warnings. Airspeed did now decrease, so the flight crew increased power slightly and the PEC fault indications disappeared. However, shortly after a No 2 ACW GEN fault message was displayed. After further propeller fluctuations the crew managed to balance the power, albeit at c4.5º difference in blade angles and subsequently made a safe landing. After this flight, the drive shaft of the No 2 engine’s AC generator was found broken and was replaced. Ground runs revealed no abnormalities so the aircraft was released to service. The next flight was normal until loud vibration was reported during taxi after landing when the flight crew moved the power levers from the flight idle to ground idle. Further maintenance fault finding was conducted. When the power levers were positioned in reverse thrust, vibration occurred. After shutdown, blades 1, 2, 5 and 6 of the No 2 propeller were feathered but blades 3 and 4 appeared to remain in the reverse thrust position. Upon disassembly of the No 2 propeller, the trunnion pin of blade 4 and the propeller blade actuator plate were found damaged. The Safety Investigation The BEA investigated this occurrence under the delegation of Trinidad and Tobago. In their report the BEA note that: The circumstances and damage observed were similar to that which had been observed in an investigation into a serious incident on 18 September 2013 in Indonesia, involving an ATR 72-212A registered PK-WFV. An investigation was opened by the Indonesian investigation authority, the NTSC, who issued an immediate safety recommendation to the operator of the aircraft concerning the verification of the condition of the propeller blade trunnion pins and the search for crack indications on part of the fleet. On 30 November 2014, a new similar incident occurred in Sweden to an ATR 72-212A registered SE-MDB, for which an investigation was opened by the Swedish investigation authority, SHK. In fact there was also one other occurrence in 2007 in Spain and three more identified between 2012 and 2014 in Tanzania and Brazil. BEA comment that: In almost all of the [7] cases, the rupture of a trunnion pin of one of the blades and damage to the propeller blade actuator forward plate were observed. They also only involved on No 2 propellers. The BEA noted that as both propellers turn in the same direction, but are located differently relative to the fuselage, they see different aerodynamic loads. Extensive in-flight and ground vibration testing was conducted in 2014 and 2016 on a...
read moreHurried Door Inspection Results in Fall From Aircraft
Hurried Door Inspection Results in Fall From Aircraft On 15 June 2016, Air Europa Embraer ERJ190-200LR EC-LKX, had an aft-door open warning while cruising at 31,000 ft en route to Madrid-Barajas Airport. The crew carried out the relevant procedure and the aircraft landed safely. After disembarking the passengers the flight crew contacted maintenance to inspect the door. While conducting the maintenance, one of the technicians fell from the aircraft, suffering serious injuries. According to the safety investigation report of the Spanish accident investigation agency, the CIAIAC: Two maintenance technicians proceeded to inspect the problem with the aft door while the captain and first officer remained in the cockpit to prepare for the flight to La Coruña, at which time they were called by one of the maintenance technicians to report that his colleague had fallen… The 44 year old male maintenance technician who fell couldn’t recall the events clearly, but did recall that: …a coworker asked him for help, since he had a B1.1 license and is certified on that airplane type, unlike said coworker. So as not to delay the flight, since the airplane was ready for boarding, he interrupted the maintenance activities he was performing on another airplane and went to assist his coworker. His coworker told him that the door was open. To prevent falls when the door is open, the airplane features a safety strap. This strap is more to warn of the danger than to protect against it, since it is not capable of supporting a person. He was also holding on to a safety handle, which also did not keep him from falling. He thought that to identify the fault, he must have opened and closed the door while visually inspecting the sensor from the inside. During the visual inspection, he must have placed his leg outside the airplane and fallen. This is consistent with statement of the second technician. The accident occurred during the maintenance technician’s 6th hour of his shift, which had started at 07:00 and ended at 15:00. It was his fourth task since commencing his shift. In the time period when the accident took place, the workload was usually high [he said]. He was in a hurry, since he had to do maintenance on other airplanes, and this was a routine visual inspection, so he did not consider calling for a platform. As a safety measure to avoid a repeat occurrence, however, he would recommend the use of a platform any time a door is open. The CIAIAC also comment that: …the safety strap, as it does not prevent falls, cannot replace a work platform installed outside the door as a safety barrier. Further Safety Resources Airbus have published an article on preventing falls from height. On the door strap they say: It should only be used for a limited time pending the closure of the door. A safety strap does not prevent from a fall. The Cabin Crew Operating Manual (CCOM), states that whenever a cabin door is open with no stairs or no gateway in position, the safety strap should be installed and the door should not be left unattended. When a door remains open and unattended for a long period of time, Airbus recommends the installation of a safety barrier in absence of stairs or gateway. This same recommendation is made in IATA’s Airport...
read moreUsage Related Ex-Military Helicopter Accident
Usage Related Ex-Military Helicopter Accident (UH-1H, N175SF) On 5 October 2016 Tamarack Helicopters (Bell) UH-1H N175SF, operated on a Part 137 agricultural aerial application flight by Farm AG Enterprises under a restricted certificate of airworthiness, rolled over during a forced landing near Gila Bend, Arizona, after the 90° tail gearbox (TGB) separated. The pilot, the sole person, onboard sustained minor injuries. The US National Transportation Safety Board (NTSB) say in their safety investigation report that: The pilot reported that he had just completed a series of passes over a cotton field, and was maneuvering the helicopter for a return to the fuel truck. The helicopter was moving at about 20 knots and climbing, when after reaching about 100 ft above ground level he heard a loud bang. The helicopter then began to spin to the right, and would not respond to foot pedal inputs, so he lowered the collective and initiated an autorotation. The helicopter was still spinning as it descended, and as it approached the ground the skids made contact with cotton bushes, and the helicopter rolled onto its left side. The tail rotor assembly and TGB was found 30ft from the wreckage. The input quill and sleeve assembly remained attached to the vertical fin. Safety Investigation The TGB was installed about 300 flying hours earlier on 19 August 2014. A representative from Tamarack Helicopters stated that the 90° gearbox is typically removed and overhauled after 1,200 flight hours, or if grey material indicative of fretting is observed at any of the gearbox mating surfaces. In this case: Examination revealed that the six studs which attached the gearbox case to the input quill sleeve assembly on the fin had fractured at the gearbox housing joint line. The threaded portion of the fractured studs remained within the gearbox case. All six stud fracture surfaces displayed topographies and arrest lines indicating bending fatigue cracking. In each case, the fatigue initiated in the thread root radii on the same side of each stud relative and perpendicular to the center of the bolt hole radius. The fatigue cracks propagated diametrically across each stud terminating in small overstress regions, with a small area of secondary reversed bending fatigue cracking at the opposite side of each stud. Magnified examinations of the corresponding stud sections from the vertical fin revealed fracture areas with fatigue cracks that had initiated at either the first, second or third full thread from the grip portion of the stud. The thread roots were smooth and typical of rolled thread roots, and yellow paste material consistent with zinc chromate paste was present in all thread roots. The fatigue cracks penetrated between 89% and 98% of each stud cross section. They then failed in overload. Fatigue is typically the result of insufficient preload in the fastener often due to insufficient torque during installation or by the loss of preload after installation. Fretting wear on the studs and in the holes indicated that there were small amounts of relative movement between these components and thereby also indicated insufficient preload. However, the interface between the input quill housing and the vertical fin showed no significant fretting or wear. The locations of the main fatigue origins in the studs and the fretting location between the studs and fin holes were both consistent with normal torsional loads in the tail rotor drive system. The studs exhibited a large percentage of...
read moreTwin Otter Nose Wheel Steering Misused in Runway Excursion
Twin Otter Nose Wheel Steering Misused in Runway Excursion On 23 April 2018, Daily Air‘s flight DA7012, a Viking DHC-6-400 Twin Otter, B-55573, departed Qimei Airport for Kaohsiung International Airport. According to the Taiwan Aviation Safety Council (ASC) safety investigation report (only available in full in Chinese) the aircraft landed at Kaohsiung: …in a right crosswind. After touchdown, the pilot flying (PF) attempted to correct the lateral deviation but misused the nose wheel steering lever which caused the aircraft veered-off the runway from its left hand side with a 35 degrees drift angle. The aircraft turned 180 degrees left and stopped on the grass area. The aircraft commander was PF. ASC Safety Analysis The ASC made 10 findings related to risk, 8 of which are reproduced below in full: At the time of the occurrence, the DHC-6-400 level D flight simulator was not yet available in the aviation industry. The Daily Air could only carry out pilot training and check in a real aircraft. However, it is not only impossible to simulate various scenarios and weather conditions in a real aircraft, but also contained higher risks, thus restricted the effectiveness of pilot training and check. Daily Air did not specify standard call-outs in relevant manuals for pilot monitoring (PM) to remind lateral deviation during landing roll. Thus the flight crew acted on their own style and it weakened the effectiveness and accuracy of the communication. Daily Air did not specify the timing or speed limit in relevant manuals for the use of “nose wheel steering”. It may result in divergence of views and actions toward this issue and adverse effect on standardization in the DHC-6-400 fleet. Daily Air did not have a clear policy regarding the usage of asymmetric thrust to assist directional control during landing roll. There were divergences in opinions between management, instructor pilots, check airmen and flight crew in the DHC-6-400 fleet. The captain of this occurrence had already carried out all flying tasks, including take-off and landing operations manually for 8 legs, and his flight duty period had exceeded 10 hours. The captain’s decayed physical and mental conditions due to his accumulated workload could weaken his alertness and ability to perform tasks safely. Although flight crew schedules of Daily Air was in compliance with the CAA regulations, a bio-mathematical model analysis of pilot fatigue showed that the eastern Taiwan routes with 12 legs a day may exist a high risk of fatigue, the Taiwan eastern routes with 10 legs a day may exist a moderate-to-high risk of fatigue; the western Taiwan routes with 8 legs a day may exist a moderate risk of fatigue. Shortage of pilots in Daily Air DHC-6-400 fleet has existed at least for a year before the occurrence happened, especially in the case of a shortage of captains, which may result in high risk of fatigue on the pilot flight schedule. The cockpit of DHC-6-400 aircraft owned by Daily Air was not equipped with effective air-conditioning, which may result in unpleasant mental situation or fatigue of flight crew members due to potentially heat stress environment. There were also two rather vague findings on the airline’s “internal evaluation program” (IEP). One that the IEP was spread across the Safety Management Manual and the other that flight crew recurrent checks were included in the IEP. While both might be symptoms of weaknesses in...
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