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Taxiway Collisions

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Category: Ground Operations Ground Operations
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Description

An airport is a complex interface between the air and the ground environments, where access must be controlled and separation between aircraft or between aircraft and vehicular traffic must be maintained and optimised. While most occurrences on airport aprons and taxiways do not have consequences in terms of loss of life, they are often associated with aircraft damage, delays to passengers and avoidable financial costs.

This article examines collisions and near collisions whilst aircraft are on the airport manoeuvring areas inclusive of taxiways and ramp areas. The article On-Gate Collisions provides insight into aircraft collisions occurring whilst on, entering or leaving an assigned gate.

Occurrences

As previously stated, to ensure efficient and safe airport ground operations, separation between aircraft or between aircraft and vehicular traffic must be maintained and optimised. On occasion however, minimum separation, particularly aircraft/vehicle separation is compromised. Whilst all of these events do not result in collision with an aircraft, the majority of taxiway occurrences involve vehicle operators deviating from a surface movement controller clearance. These "failure to comply" occurrences most usually involve vehicles:

  • using an incorrect taxiway
  • failing to stop at a taxiway holding point
  • failing to stay on the surface movement control radio frequency or ground frequency as appropriate
  • failing to obtain a clearance before entering an area subject to control.

In all cases, these actions have the potential to put the vehicle in conflict with an aircraft which, in turn, could:

  • lead to collision
  • require aggressive braking by the aircraft which could result in personnel injuries. Cabin crew are especially vulnerable as they might be moving within the cabin preforming pre-departure or post-landing duties


Most of the remaining occurrences are related to one of the following:

  • reduced aircraft clearance with ground equipment or obstacles. Reduced clearance accidents or incidents can occur in various ways. These include:
    • inappropriate use of a restricted taxiway - some taxiways are restricted by wingspan. Use by a larger aircraft could compromise obstacle clearance
    • manoeuvring around an aircraft partially blocking a taxiway (as might be the case if the aircraft was approaching, but not yet at the stop point of, a gate). If misjudged, this could result in a wingtip striking the tail of the stopped aircraft or it could compromise clearance between obstacles or other aircraft and the wingtip opposite the stopped aircraft
  • aircraft-aircraft collisions or near collisions - collisions can result from:
    • failure to follow taxiway centreline guidance
    • failure to stop prior to a stop bar
    • taxiing at speeds unsuited to the conditions or level of congestion
    • taxiway deviation whilst trying to manoeuvre to "squeeze" past another aircraft
  • jet blast -inappropriate thrust settings or following too closely can result in aircraft damage due to jet blast. Jet blast can also cause unsecured equipment such as ULDs to move and strike other aircraft, equipment or personnel

Prevention

Accidents and Incidents

The following accidents and incidents describe collision or near collision between two aircraft, an aircraft and a vehicle or an aircraft and a stationary object.

Aircraft/Aircraft Conflict

  • B789 / A388, Singapore, 2017 (On 30 March 2017, a Boeing 787 taxiing for departure at night at Singapore was involved in a minor collision with a stationary Airbus A380 which had just been pushed back from its gate and was also due to depart. The Investigation found that the conflict occurred because of poor GND controlling by a supervised trainee and had occurred because the 787 crew had exercised insufficient prudence when faced with a potential conflict with the A380. Safety Recommendations made were predominantly related to ATC procedures where it was considered that there was room for improvement in risk management.)
  • B744 / B763, Melbourne Australia, 2006 (On 2 February 2006, a Boeing 747-400 was taxiing for a departure at Melbourne Airport. At the same time, a Boeing 767-300 was stationary on taxiway Echo and waiting in line to depart from runway 16. The left wing tip of the Boeing 747 collided with the right horizontal stabiliser of the Boeing 767 as the first aircraft passed behind. Both aircraft were on scheduled passenger services from Melbourne to Sydney. No one was injured during the incident.)
  • MD82 / MD11, Anchorage AK USA, 2002 (On 17 March 2002, at Ted Stevens Anchorage Airport, a McDonnell Douglas MD82 operated by Alaska Airlines, on a night pushback in snow conditions collided with an inbound taxiing McDonnell Douglas MD-11. The MD82 suffered substantial rudder damage although the impacting MD11 winglet was undamaged.)
  • CRJ7 / CRJ2, Charlotte NC USA, 2008 (On 28 June 2008, a Bombardier CRJ 700 operated by PSA Airlines, during daytime pushback collided with a stationary CRJ 200 of the same company at Douglas International Airport Charlotte, North Carolina.)
  • SH33 / MD83, Paris CDG France, 2000 (On the 25th of May, 2000 a UK-operated Shorts SD330 waiting for take-off at Paris CDG in normal visibility at night on a taxiway angled in the take-off direction due to its primary function as an exit for opposite direction landings was given a conditional line up clearance by a controller who had erroneously assumed without checking that it was at the runway threshold. After an aircraft which had just landed had passed, the SD330 began to line up unaware that an MD83 had just been cleared in French to take off from the full length and a collision occurred.)
  • B732, vicinity Washington National DC USA, 1982 (On 13 January 1982, an Air Florida Boeing 737-200 took off in daylight from runway 36 at Washington National in moderate snow but then stalled before hitting a bridge and vehicles and continuing into the river below after just one minute of flight killing most of the occupants and some people on the ground. The accident was attributed entirely to a combination of the actions and inactions of the crew in relation to the prevailing adverse weather conditions and, crucially, to the failure to select engine anti ice on which led to over reading of actual engine thrust.)
  • B738/B763, Barcelona Spain, 2011 (On 14 April 2011, a Ryanair Boeing 737-800 failed to leave sufficient clearance when taxiing behind a stationary Boeing 767-300 at Barcelona and the 737 wingtip was in collision with the horizontal stabiliser of the 767, damaging both. The 767 crew were completely unaware of any impact but the 737 crew realised the ‘close proximity’ but dismissed a cabin crew report that a passenger had observed a collision. Both aircraft completed their intended flights without incident after which the damage was discovered, that to the 767 requiring that the aircraft be repaired before further flight.)
  • B738/A321, Prague Czech Republic, 2010 (On 18 June 2010 a Sun Express Boeing 737-800 taxiing for a full length daylight departure from runway 06 at Prague was in collision with an Airbus 321 which was waiting on a link taxiway leading to an intermediate take off position on the same runway. The aircraft sustained damage to their right winglet and left horizontal stabiliser respectively and both needed subsequent repair before being released to service.)

Aircraft/Vehicle Conflict

  • Vehicle / PA31, Mackay SE Australia, 2008 (On 29 June 2012, a Piper PA31 taking off from runway 05 on a passenger charter flight just missed hitting an inspection vehicle which had entered the take off runway from an intersecting one contrary to ATC clearance. The overflying aircraft was estimated to have cleared the vehicle by approximately 20 feet and the pilot was unaware it had entered the active runway. The driver had been taking a mobile telephone call at the time and attributed the incursion to distraction. The breached clearance had been given and correctly read back approximately two minutes prior to the conflict occurring.)
  • B742, Stockholm Arlanda Sweden, 2007 (On 25 June 2007, a Boeing 747-200F being operated by Cathay Pacific on a scheduled cargo flight from Stockholm to Dubai had completed push back for departure in normal daylight visibility and the parking brakes had been set. The tow vehicle crew had disconnected the tow bar but before they and their vehicle had cleared the vicinity of the aircraft, it began to taxi and collided with the vehicle. The flight crew were unaware of this and continued taxiing for about 150 metres until the flight engineer noticed that the indications from one if the engines were abnormal and the aircraft was taxied back to the gate. The tow vehicle crew and the dispatcher had been able to run clear and were not injured physically injured although all three were identified as suffering minor injury (shock). The aircraft was “substantially damaged” and the tow vehicle was “damaged”.)
  • B737, Gran Canaria Spain, 2016 (On 7 January 2016, a Boeing 737-700 was inadvertently cleared by ATC to take off on a closed runway. The take-off was commenced with a vehicle visible ahead at the runway edge. When ATC realised the situation, a 'stop' instruction was issued and the aircraft did so after travelling approximately 740 metres. Investigation attributed the controller error to "lost situational awareness". It also noted prior pilot and controller awareness that the runway used was closed and that the pilots had, on the basis of the take-off clearance crossed a lit red stop bar to enter the runway without explicit permission.)
  • FA50 / Vehicle, Moscow Vnukovo Russia, 2014 (On 20 October 2014 a Dassault Falcon 50 taking off at night from Moscow Vnukovo collided with a snow plough which had entered the same runway without clearance shortly after rotation. Control was lost and all occupants died when it was destroyed by impact forces and post crash fire. The uninjured snow plough driver was subsequently discovered to be under the influence of alcohol. The Investigation found that the A-SMGCS effective for over a year prior to the collision had not been properly configured nor had controllers been adequately trained on its use, especially its conflict alerting functions.)
  • A320, Dublin Ireland, 2017 (On 27 September 2017, an Airbus A320 being manoeuvred off the departure gate at Dublin by tug was being pulled forward when the tow bar shear pin broke and the tug driver lost control. The tug then collided with the right engine causing significant damage. The tug driver and assisting ground crew were not injured. The Investigation concluded that although the shear pin failure was not attributable to any particular cause, the relative severity of the outcome was probably increased by the wet surface, a forward slope on the ramp and fact that an engine start was in progress.)
  • A320, London Heathrow UK, 2006 (On 26 June 2006, after an uneventful pre-flight pushback of a British Airways Airbus A320-200 at London Heathrow Airport, the aircraft started moving under its own power and, shortly afterwards, collided with the tractor that had just performed the pushback, damaging both the right engine and the tractor.)
  • SB20, Stockholm Arlanda, 2001 (On 18 December 2001, a Saab 2000 being operated by Air Botnia on scheduled passenger flight from Stockholm to Oulu was taxiing out at night in normal visibility in accordance with its ATC clearance when a car appeared from the left on a roadway and drove at speed on a collision course with the aircraft. In order to avoid a collision, the aircraft had to brake sharply and the aircraft commander saw the car pass under the nose of the aircraft and judged the vehicle’s closest distance to the aircraft to be four to five metres. The car did not stop, could not subsequently be identified and no report was made by the driver or other witnesses. The diagram below taken from the official report shows the site of the conflict - the aircraft was emerging from Ramp ‘G’ to turn left on taxiway ‘Z’ and the broken line shows the roadway which is crossed just before the left turn is commenced.)
  • B744, Paris CDG France, 2003 (On 18 January 2003, a Boeing 747-400F being operated by Singapore Airlines Cargo on a scheduled cargo flight from Paris CDG to Dubai taxied for departure in darkness and fog with visibility less than 100 metres in places and the right wing was in collision with a stationary and unoccupied ground de/anti icing vehicle without the awareness of either the flight crew or anybody else at the time. Significant damage occurred to the de icing vehicle and the aircraft was slightly damaged. The vehicle damage was not discovered until almost two hours later and the aircraft involved was not identified until it arrived in Dubai where the damage was observed and the authorities at Paris CDG advised.)

Aircraft/Object Conflict

  • B74S, Stockholm Arlanda Sweden, 2006 (On 11 December 2006, a Boeing 747SP being operated by Syrian Air on a scheduled passenger flight from Damascus to Stockholm was arriving on the designated parking gate at destination in normal visibility at night when it collided with the airbridge. None of the 116 occupants of the aircraft suffered any injury but the aircraft was “substantially damaged” and the airbridge was “damaged”.)
  • B773, Lisbon Portugal, 2016 (On 13 January 2016 ice was found on the upper and lower wing surfaces of a Boeing 777-300ER about to depart in the late morning from Lisbon in CAVOK conditions and 10°C. As Lisbon had no de-ice facilities, it was towed to a location where the sun would melt the ice more quickly but during poorly-planned manoeuvring, one of the wingtips was damaged by contact with an obstruction. The Investigation attributed the ice which led to the problematic re-positioning to the operator’s policy of tankering most of the return fuel on the overnight inbound flight where it had become cold-soaked.)
  • A319, Ibiza Spain, 2016 (On 19 June 2016, an Airbus A320 failed to follow the clearly-specified and ground-marked self-positioning exit from a regularly used gate at Ibiza and its right wing tip collided with the airbridge, damaging both it and the aircraft. The Investigation found that the crew had attempted the necessary left turn using the Operator’s ‘One Engine Taxi Departure’ procedure using the left engine but then failed to follow the marked taxi guideline by a significant margin. It was noted that there had been no other such difficulties with the same departure in the previous four years it had been in use.)
  • B744, Johannesburg South Africa, 2013 (On 22 December 2013, a Boeing 747-400 taxiing for departure at Johannesburg at night with an augmented crew failed to follow its correctly-acknowledged taxi clearance and one wing hit a building resulting in substantial damage to both aircraft and building and a significant fuel leak. The aircraft occupants were all uninjured but four people in the building sustained minor injuries. The accident was attributed to crew error both in respect of an inadequate briefing and failure to monitor aircraft position using available charts and visual reference. Some minor contributory factors relating to the provision of airport lighting and signage were noted.)
  • B738, Barcelona Spain, 2015 (On 12 December 2015, whilst a Boeing 737-800 was beginning disembarkation of passengers via an air bridge which had just been attached on arrival at Barcelona, the bridge malfunctioned, raising the aircraft nose gear approximately 2 metres off the ground. The door attached to the bridge then failed and the aircraft dropped abruptly. Prompt cabin crew intervention prevented all but two minor injuries. The Investigation found that the occurrence had been made possible by the failure to recognise new functional risks created by a programme of partial renovation being carried out on the air bridges at the Terminal involved.)
  • AT72, Shannon Ireland, 2014 (On 26 February 2014, an ATR 72-202 which had been substituted for the ATR42 which usually operated a series of night cargo flights was being marshalled out of its parking position with a new flight crew on board when the left wing was in collision with the structure of an adjacent hangar. The Investigation found that the aircraft type had not been changed on the applicable flight plan and ATC were consequently unaware that the aircraft had previously been parked in a position only approved for the use by the usual smaller aircraft type.)
  • B722, Cotonou Benin, 2003 (On 25 December 2003, a Boeing 727-200 being operated by UTA (Guinea) on a scheduled passenger flight from Cotonou to Beirut with a planned stopover at Kufra, Libya, failed to get properly airborne in day VMC from the 2400 metre departure runway and hit a small building 2.45 metres high situated on the extended centreline 118 metres beyond the end of the runway. The right main landing gear broke off and ripped off a part of the trailing edge flaps on the right wing. The airplane then banked slightly to the right and crashed onto the beach where it broke into several pieces and ended up in the sea where the depth of water varied between three and ten metres. Of the estimated 163 occupants, 141 were killed and the remainder seriously injured.)
  • B74S, Stockholm Arlanda Sweden, 1996 (On 14 June 1996, a Boeing 747SP being operated by Air China on a scheduled passenger flight from Beijing to Stockholm was arriving on the designated parking gate at destination in normal daylight visibility when it collided with the airbridge. None of the 130 occupants of the aircraft suffered any injury but the aircraft was “substantially damaged” and the airbridge was “damaged”.)

Related Articles

Further Reading

[[Category:Ground Operations [[Category:Operational Issues