Ryanair Boeing 737-800, Rome, 10 November 2008
The report on an unusual attempted go-around following a severe birdstrike on short final approach to Rome Ciampino 10 years ago has finally been published by Italian investigator ANSV. On 10 November 2008, a Ryanair Boeing 737-800 flew through a dense flock of starlings just 300m (984ft) before the threshold of runway 15 while descending through a height of 140ft. The ANSV says go-around thrust was selected, but then the crew retracted the flaps to their 10° setting, rather than the 15° required for a go-around. The aircraft suffered about 90 bird impacts, resulting in a loss of power in both engines just 100m from the runway threshold. The 737 briefly climbed from 112ft to 173ft but failed to maintain the climb and it began to descend. There was a stick-shaker warning at 21ft, and the aircraft struck the ground in a stalled condition. The flaps were still retracting and had reached 12.1° at the time of impact, which registered 2.66g. The aircraft came to a halt 50m from the far end of the runway having sustained serious damage to its left-hand main landing-gear, aft fuselage and left engine from contact with the runway. The investigator comments that since the multiple birdstrike was likely to have caused damage, the decision to go around was questionable, but understandable given the surprise factor. The inquiry believes the startle effect explains the retraction of the flaps to 10° despite the existence of a detent in the 15° position intended to reduce the risk of flap retraction beyond the go-around setting. The ANSV notes that Boeing has since added recommended birdstrike techniques to the 737 crew training manual, and that Ryanair has adopted specific training for birdstrikes during take-off and landing.
TAP Air Portugal Airbus A340-300, Rio de Janeiro, 8 December 2011
After seven years, Brazilian investigator CENIPA has finally disclosed that a taxi route error caused an Airbus A340-300 (CS-TOD) to overrun the runway on take-off from Rio de Janeiro, resulting in a collision with approach lights and navigation aids before climbing away and flying safely to its destination at Lisbon. The crew of the TAP Air Portugal aircraft, bound for Lisbon, had been instructed to taxi for runway 10, which had already been effectively shortened by construction works that rendered the first 1,270m unavailable. Take-off calculations showed that the remaining 2,730m was sufficient for a reduced-thrust “flex” take-off, from the displaced threshold, at a temperature of 34°C (93°F). To reach the displaced threshold the aircraft needed to taxi to the AA intersection. But the crew inadvertently taxied to the BB intersection, which lay some 600m further down the runway – leaving just 2,095m for the take-off run. Airbus analysis showed that this distance was insufficient for the A340 to become airborne, even if it had used maximum take-off thrust. The inquiry highlights the layout of the taxiway system which, it believes, contributed to the blunder. While visibility was good, the departure occurred at 22:37, some 2h after sunset. The A340 overran the runway, leaving tyre marks for 200m beyond, and striking approach lights, as well as the localiser antenna 360m from the runway end. “The pilots did not realise they had crossed the runway boundaries, because of the aircraft’s nose-up attitude,” it adds. Neither could see the lights at the end of the runway. None of the 255 passengers and 11 crew was injured, although the aircraft sustained minor damage, and approach lighting parts were found in its landing-gear after arrival.
Malaysia Airlines MH370, 8 March 2014
Malaysian authorities have published what may well be the final report on the loss of Malaysia Airlines flight MH370. It proposes that the aircraft was probably deliberately manoeuvred off its planned course to its final oceanic resting place. The 777-200ER (9M-MRO) has not been found and, considering that its believed location is on the seabed somewhere in the southern Indian Ocean, it may never be. For lack of specific evidence, the finger of blame has not been pointed at any particular individual in the crew. Meanwhile, although the evidence for deliberate direction of the aircraft is circumstantial, there is a considerable quantity of it, starting with the aircraft’s silent turn-back at an airspace boundary, a point at which surveillance continuity is naturally broken. This coincided with the abrupt loss of five systems specifically for communicating location, without any indication of a technical fault. Studies of the intriguing subsequent flightpath have been unable to attribute the track to system anomalies. Indicators in the mystery include the disturbingly precise course from the turn-back point to Penang (the captain’s birthplace), then the careful avoidance of Indonesian airspace before heading for oceanic oblivion. Finally, there was the discovery, on the captain’s home simulator, of plotted waypoints charting a similar course. That verdict, however, is only likely to be validated if the aircraft’s wreckage is ever discovered, but all searches have been called off and will not be re-instated, unless completely new evidence is uncovered.
XL Airways Airbus A330-200, over the Mediterranean, 26 December 2014
French air accident investigator BEA has described a series of failures that degraded flight control and autonomous navigation systems on an XL Airways Airbus A330-200 (F-GRSQ) in the cruise over the Mediterranean four years ago. BEA says the aircraft ultimately lost all three inertial reference systems (IRS) and suffered a degradation of its autonomous navigation capabilities, as well as a reversion to direct flight-control law. The aircraft had departed Reunion for Marseille, with one of its three IRS demonstrating a significant drift (IRS2). Although the associated air data inertial reference unit (ADIRU) was supposed to have been replaced two days earlier, an identification mix-up meant the wrong unit was swapped. BEA did not have cockpit voice-recorder (CVR) data and it says crew testimonies differ, but proposes a probable sequence of events. About 5h into the flight, IRS3 switched from “navigation” to “attitude” mode – probably through crew action, says the inquiry. The flight-guidance computer rejected IRS3 and used the information derived from the other two systems, IRS1 and the drifting IRS2. This change was only noticed by the relief first officer after he took over some 2h 30min later. The crew attempted to align IRS3. BEA says, however, that the discrepancy between IRS1 and the drifting IRS2 prompted a disengagement of the autopilot, autothrust and flight directors, and the disappearance of position and flightplan information on the navigation displays. While the crew was able to retrieve position and flightplan data by activating a navigation back-up mode, position information on the captain’s side was lost. BEA believes that, as the crew sought to restore the captain’s data, they triggered an in-flight alignment of the three IRS, which resulted in a transition of the A330 to direct flight-control law. No technical fault could be found to explain the triple simultaneous alignment. Primary flight display information disappeared and the crew had to resort to standby electromechanical instruments and manual flight for the rest of the journey. As the aircraft approached Greek airspace, the crew declared an emergency, opted for a diversion to Athens, and the aircraft was vectored to runway 03R, where it landed without further incident. BEA says the loss of positional data was a “major concern”, but that use of a newer flight management system (FMS) standard would have prevented it.
Air France Boeing 777F, Paris Charles de Gaulle, 22 May 2015
An Air France Boeing 777F (F-GUOC) was saved from damage by the operation of its tailstrike protection system during take-off from Paris Charles de Gaulle’s runway 26R in May 2015, according to BEA. The agency reports that the cause was entry of an incorrect take-off weight by the crew during performance calculations. Take-off speeds and power settings for the aircraft’s flight to Mexico City had been calculated using a weight of 243t, rather than the actual figure of 343. This major error meant the calculated rotation speed of 152kt (282km/h) with flap position 5 was well below the required 175kt and flap 15. The crew were alerted by the tail-strike warning to apply full power, which they did some 8s after the protection system engaged, having limited the maximum rotation to 9° nose up. BEA says the 777F passed the opposite-direction threshold at a height of 172ft. There was no stall alarm and the stick-shaker did not activate. While the CVR transcript was unavailable to the inquiry, the investigators state that the crew discussed returning to the airport but ultimately decided to proceed with the flight. Apparently, the computed configuration of the aircraft surprised one of the supernumerary pilots on the flightdeck, but he had failed to voice his doubts.
EgyptAir Airbus A320, over the Mediterranean, 19 May 2016
BEA, which has been aiding the Egyptian probe into the fatal loss of an EgyptAir Airbus A320 (SU-GCC) two years ago, has voiced strong criticism of the inquiry process. The inquiry was turned over to judicial authorities at the end of 2016, and since then, the technical investigators have been denied access to data and evidence. The A320, operating a service from Paris to Cairo on 19 May 2016, departed its cruise altitude of 37,000ft and came down in the Mediterranean Sea. Early evidence from debris, the CVR and avionics systems suggest the “most likely” theory that a rapidly developing avionics bay fire led to the accident. But seven months into the probe the Egyptian investigators declared they had discovered traces of explosives on human remains. This led the inquiry to pursue the theory that sabotage brought down the aircraft, and jurisdiction was transferred entirely to the Egyptian criminal and legal authorities. BEA comments: “[Our] proposals concerning further work on the debris and recorded data were not, as far as BEA knows, followed up.” The French investigator has pressed for the safety investigation to be continued, but when it met the Egyptian attorney general earlier this year, the Egyptians remained inflexible. BEA says Egyptian investigators have not published a final report that would have allowed the BEA to lay down its “differences of opinion”, as permitted by air accident investigation protocol. Should Egyptian investigators opt to restart the safety probe, BEA says it will be “ready to continue collaborating”. It is not the first time foreign accident investigators have clashed with Egyptian authorities over the causes of high-profile air accidents over Egypt, or involving Egyptian aircraft. One of them involved a Flash Airlines Boeing 737-300 fatal crash at Sharm el-Sheikh in January 2004. The US National Transportation Safety Board and BEA both stressed that evidence pointed to spatial disorientation in the crew, but the Egyptian authorities insisted the causes were technical. NTSB investigators also disputed the Egyptian claim that technical failures brought down an EgyptAir Boeing 767-300ER off the US east coast in October 1999, when the NTSB says evidence pointed to deliberate actions by the aircraft’s first officer.
ASL Airlines Boeing 737-400F, Milan Bergamo, 5 August 2016
Pilots of an ASL Airlines Boeing 737-400 freighter (HA-FAX) failed to realise how much runway had passed beneath the aircraft before making a late touchdown, which resulted in a high-speed overrun at Milan Bergamo. The crew had been conducting a night instrument landing system (ILS) approach to runway 28 in poor weather. While the pilots had briefed for an auto-land, the Italian investigation authority ANSV reports that they disengaged the autopilot and landed manually. Some 9nm (17km) from the runway, the captain decided that, owing to the presence of storms in the missed approach path, a go-around would be unwise. The first officer had logged just 86h on 737s, and told the inquiry that, while he was tempted to question this decision, he felt he did not have the experience to evaluate the situation, but admitted that a go-around call “could have been a good idea”, because the rain was intense and only the runway edge lights were visible. Both pilots’ attention was focused on acquiring external visual references and they “did not realise” the aircraft had overflown the wet runway at 20-30ft for 18s at high speed, travelling some two-thirds of its length. After touchdown, the jet overshot the runway end by 520m, suffering extensive damage as it crossed roads and struck obstacles before coming to rest. The inquiry says the crew did not monitor flight parameters adequately during the last stages of flight and failed to disengage the autothrottle before landing, although the captain had one hand on the thrust levers. The inquiry says that he did not recall that moving them would not disconnect the autothrottle. Flight data recorder (FDR) readings showed that the engine thrust reduced as the autothrottle transitioned to “retard” mode, as designed, at a height of 27ft, but engine thrust subsequently showed variations, increasing to as much as 97% N1, which the inquiry states were “presumably due to action by the crew”. This resulted in an increase in the landing speed, and the prolonged float of the aircraft, before it touched down at 159kt. The investigator says fatigue, while not perceived by the crew, could have degraded the pilots’ decision-making processes. Both evacuated the aircraft but had suffered injuries during the accident and were hospitalised.
Jet Airways Boeing 777-300ER, London Heathrow, 30 August 2016
Jet Airways has amended its standard operating procedures for take-off following an incident that involving one of its Boeing 777-300ERs (VT-JEK) at London Heathrow airport. The aircraft was taking off for Mumbai at 20:30 UTC, when it crossed the airfield boundary at 13ft above ground level and an adjacent road at 30ft above ground level. There were no reports of injuries among the 15 crew and 231 passengers on board. The UK Air Accidents Investigation Branch (AAIB) classified the case as a serious incident, and delegated the investigation to India’s Air Accident Investigation Bureau. In its final report, the Indian inquiry found that VT-JEK accepted clearance to take off on runway 27L from intersection S4E, rather than from N1, which would have provided the full runway length. But the crew then used performance figures based on the take-off roll beginning at N1, because the captain selected the first of four entry points for runway 27L presented by the On-Board Performance Tool (OPT), which calculates performance based on the roll beginning at N1. The co-pilot had calculated performance correctly for a take-off from S4E, the actual point of entry to the runway. The discrepancy between the two calculations was noticed during the crosscheck of the OPT outputs, but the co-pilot entered the captain’s figures into the control and display unit (CDU). This meant that power was set assuming full runway length when the distance available was 760m less than that. Rotation was initiated with 556m of runway remaining and lift-off occurred with 97m remaining. Jet now requires its crew to call out and resolve discrepancies between the output of the captain’s and co-pilot’s OPTs before entering data into the CDU.
Aerosucre Boeing 727-200F, Puerto Carreno, Colombia, 20 December 2016
Colombian investigators have found that an Aerosucre Boeing 727-200 freighter’s crew miscalculated crucial take-off speeds before the aircraft overran the runway 25 at Puerto Carreno and collided with obstacles before becoming airborne. It attempted to climb away but, having been badly damaged by the impact, lost height and crashed. Just one of the six occupants survived. Investigation authority GRIAA determined that several factors extended the aircraft’s take-off run by 383m, on a runway just over 1,800m in length. The aircraft had a “Quiet Wing” modification which improved take-off performance by increasing flap droop, but the crew were provided with no guidance about its use, and employed a reduced flap setting of 25°. The flap droop would have given a rotation speed of 122kt, but the crew calculated rotation at 127kt, which added 103m to the ground run. The investigators also found that the 727 had taken off in a 4kt tailwind that lengthened the take-off by another 146m. The two previous departures had used the opposite-direction runway 07, but the inquiry found no evidence that the crew had been passed the actual wind velocity by ATC. Finally, GRIAA added that the pilot’s rotation technique – a slow pitch rate of 7° in 7s – meant the aircraft required a further 134m to become airborne. The inquiry had also been unable to find weight and balance details from the flight among the debris, or a copy of this data in the company’s offices. Analytical calculations estimated the take-off weight at 74.2t, just under the maximum permissible figure of 74.7t. But based on the take-off speeds used by the crew, the inquiry believes the weight was around 75.3t – meaning the jet was overweight by 590kg (1,300lb). The report reveals, finally, that the aircraft should not have been operating at Puerto Carreno airport, because it was not approved by the authorities for this aircraft type. But history also shows the authority had accepted 727 flightplans for the airport for seven years before the crash, without taking action.
Jet Airways Boeing 737-800, Goa, 27 December 2016
India’s investigator reports that a Jet Airways Boeing 737-800 crew did not allow the aircraft’s engines to stabilise their thrust after line-up on Goa’s runway 26 before beginning the take-off run, and asymmetric power caused a runway excursion. The aircraft, bound for Mumbai, had backtracked the runway and performed a 180° turn to line up. The accident report says when the crew began to advance the thrust levers as they lined up, the left-hand engine was starting from 40%, and the right-hand one had only reached 28% when the captain commanded full take-off thrust. “As soon as [full thrust was commanded] the aircraft started drifting right and exited the hard surface,” says the inquiry. The crew attempted to brake and use rudder and nose-wheel steering to bring it back on. The jet left the runway and turned in a wide right-hand arc, eventually coming to rest facing the opposite direction some 220m from the edge of the runway. In so doing it collided with a path-indicator lamp as well as a 2.3m pillar, and the aircraft suffered substantial engine, undercarriage and fuselage damage. Sixteen of the 145 occupants suffered minor injuries during the evacuation. The inquiry states that the rejected take-off manoeuvre was conducted “incorrectly”, pointing out that only the right-hand thrust lever was retarded to idle thrust.
Sunwing Airlines Boeing 737-800, Belfast, 21 July 2017
Pilots of a Sunwing Airlines Boeing 737-800 twice entered an incorrect temperature figure during take-off calculations, so it took off from runway 07 at Belfast, Northern Ireland with insufficient thrust and almost overran the runway. A figure of -47°C was erroneously entered as the outside air temperature. Such an abnormally low temperature figure would cause the N1 calculation to be “significantly below” that required for take-off thrust, says the UK AAIB. It points out that -47°C was the outside air temperature for the first waypoint after top-of-climb, recorded on the pilot’s log. Following a delay for a tyre change the crew entered revised figures but made the same entry error as before. As the 737 reached 120-130kt during its take-off run, the crew realised it was “not accelerating normally”, says the inquiry. The take-off run available was 2,654m. No action was taken, either to increase thrust or abort the take-off. Some 900m before the end of the runway the aircraft reached the V1 threshold and rotated shortly afterwards. Once airborne the crew checked the take-off performance figures, finding that the N1 level had been just 81.5%, far below the 92.7% required. Thrust was not increased until the aircraft had reached 800ft, some 2nm after becoming airborne. Investigators state that the 737 escaped damage and continued to its destination. But the inquiry points out that only the absence of obstacles and a “benign” nature of the runway location and surrounding terrain prevented a potentially “catastrophic” accident, should the jet have suffered engine failure.
CityJet Bombardier CRJ900, Turku, 25 October 2017
Investigators report that a CityJet-operated Bombardier CRJ900 landed at Turku, Finland in a 10kt tailwind on a contaminated runway, hydroplaned, and finally spun more than 180° before coming to rest. The crew of the aircraft, conducting a service for SAS, had opted to use runway 26 despite the tailwind, because there was no ILS on the reciprocal. The aircraft was also near its maximum landing weight. The CRJ900 landed at 148kt in the touchdown zone, and the landing was relatively hard at 1.95g. The captain had selected reverse thrust immediately after touchdown but the aircraft’s bounce inhibited this system by taking the weight off the undercarriage and preventing the wheels from spinning, so the engines remained at reverse idle. When the nose-gear made runway contact the captain initiated manual braking, but the aircraft’s wheels were hydroplaning and did not spin up. The wheels locked some 5s after landing and the aircraft skidded for 2,050m, almost the entire length of the landing roll, says the Safety Investigation Authority of Finland. Some 1,200m from touchdown the jet began veering to the right, striking runway edge lights, and almost exiting the runway surface. But it started rotating to the left, still travelling at 42kt while sliding sideways. The aircraft eventually came to rest just 160m from the runway end, having turned through an anti-clockwise arc of 196°. The air temperature was around freezing, with a gusting wind from the southeast, and the runway was covered with more than 10mm of slush. Runway conditions had been assessed 21min before the CRJ900 landed, and an estimate passed to the crew, but heavy snow was falling and the runway conditions were “changing rapidly”, says the inquiry. No new measurements were carried out before the jet landed, and maintenance personnel had decided to clear the runway only once the aircraft arrived and another flight had departed. None of the tyres deflated and the inquiry says this meant the friction between the wheels and the runway was “extremely low” throughout. None of the 92 occupants was ultimately injured, but the report adds: “The occurrence had potential for a serious or major accident.” Investigators point out that the logic of the reverse-thrust system on the CRJ900 is such that, if selected prematurely on landing, it cannot be regained without specific pilot actions. The inquiry has recommended that Bombardier provides information to operators regarding this aspect of the thrust-reverser system.
Source: Flight International