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Difference between revisions of "Taxiway Collisions"

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==Prevention==
 
==Prevention==
 
Most taxiway accidents and incidents are preventable. This prevention is dependant upon appropriate training and testing, compliance with clearances, published procedures and right-of-way rules, maintaining situational awareness and adapting speed of movement to suit the weather and surface conditions. Some specific accident prevention strategies are as follows:  
 
Most taxiway accidents and incidents are preventable. This prevention is dependant upon appropriate training and testing, compliance with clearances, published procedures and right-of-way rules, maintaining situational awareness and adapting speed of movement to suit the weather and surface conditions. Some specific accident prevention strategies are as follows:  
*Vehicle operators - It is imperative that vehicle operators be properly trained, tested and authorised for ramp and taxiway operations. Infractions should be investigated and additional training provided where appropriate. Multiple infractions should be considered grounds for suspension of airside driving privileges. Operators should:
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*Vehicle operators - It is imperative that vehicle operators be properly trained, tested and authorised for ramp and taxiway operations. Driving infractions should be investigated and additional training provided where appropriate. Multiple infractions should be considered grounds for suspension of airside driving privileges. Operators should:
 
**ensure daily inspection for their vehicle is complete and that beacon/hazard lights are operating when the vehicle is airside
 
**ensure daily inspection for their vehicle is complete and that beacon/hazard lights are operating when the vehicle is airside
 
**maintain situational awareness
 
**maintain situational awareness
**operate their vehicle safely and in accordance with airport rules
+
**operate their vehicle safely and in accordance with all company and airport rules
 
**obey all "rules of the road" inclusive of speed limits, stop signs and right-of-way guidance
 
**obey all "rules of the road" inclusive of speed limits, stop signs and right-of-way guidance
 
**yield to aircraft at all times
 
**yield to aircraft at all times
**obtain and read back any ground movement controller clearance prior to entering an area where clearance is required
+
**obtain and read back any ground movement controller clearance prior to entering an area where clearance is required. If clearance is not understood, ASK!
*Tow crews -
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*Tug operators - Tug operators have the additional responsibility of moving aircraft on and off gates as well as positioning aircraft from one location on the airfield to another. In addition to the aforementioned items for vehicle operators, the tug operator must:
*Controllers -
+
**know the size of the aircraft in tow inclusive of the wingspan
 +
**be conversant with the normal taxi routes from one airfield location to another
 +
**understand the stopping distances required for a tug with an aircraft in tow
 +
**comply with all clearances, especially runway crossing clearances
 +
**use wing and tail walkers when manoeuvring in congested areas
 +
*Controllers - The controller is responsible for
 
*Pilots -
 
*Pilots -
  

Revision as of 23:40, 30 May 2018

Article Information
Category: Ground Operations Ground Operations
Content source: SKYbrary About SKYbrary
Content control: SKYbrary About SKYbrary
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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 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:

  • aircraft-aircraft collisions or near collisions - collisions can result from:
    • failure to follow taxiway centreline guidance
    • failure to stop prior to a stopbar
    • taxiing at speeds unsuited to the conditions or level of congestion
    • taxiway deviation whilst trying to manoeuvre to "squeeze" past another aircraft. 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) can lead to collision. 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
    • taxiway configuration - converging taxiways can potentially lead to reduced or compromised clearance, especially where they cross
  • 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
    • failure to follow taxi lane guidance - deviation from the lane guidance whilst manoeuvring in proximity to light stands, gates or stationary equipment can result in collision
  • 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 Unit Load Devices (ULD) to move and strike other aircraft, equipment or personnel

Prevention

Most taxiway accidents and incidents are preventable. This prevention is dependant upon appropriate training and testing, compliance with clearances, published procedures and right-of-way rules, maintaining situational awareness and adapting speed of movement to suit the weather and surface conditions. Some specific accident prevention strategies are as follows:

  • Vehicle operators - It is imperative that vehicle operators be properly trained, tested and authorised for ramp and taxiway operations. Driving infractions should be investigated and additional training provided where appropriate. Multiple infractions should be considered grounds for suspension of airside driving privileges. Operators should:
    • ensure daily inspection for their vehicle is complete and that beacon/hazard lights are operating when the vehicle is airside
    • maintain situational awareness
    • operate their vehicle safely and in accordance with all company and airport rules
    • obey all "rules of the road" inclusive of speed limits, stop signs and right-of-way guidance
    • yield to aircraft at all times
    • obtain and read back any ground movement controller clearance prior to entering an area where clearance is required. If clearance is not understood, ASK!
  • Tug operators - Tug operators have the additional responsibility of moving aircraft on and off gates as well as positioning aircraft from one location on the airfield to another. In addition to the aforementioned items for vehicle operators, the tug operator must:
    • know the size of the aircraft in tow inclusive of the wingspan
    • be conversant with the normal taxi routes from one airfield location to another
    • understand the stopping distances required for a tug with an aircraft in tow
    • comply with all clearances, especially runway crossing clearances
    • use wing and tail walkers when manoeuvring in congested areas
  • Controllers - The controller is responsible for
  • Pilots -

Accidents and Incidents

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

Aircraft/Aircraft Conflict

  • 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.)
  • 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.)
  • A343 / B752, London Heathrow UK, 1995 (On 23 November 1995, in normal daylight visibility, an Airbus A340-300 being operated by Gulf Air on a scheduled international passenger flight from London Heathrow taxied past a Boeing 757-200 being operated by British Airways on a scheduled domestic passenger flight and also departing from London Heathrow which had stopped on a diverging taxiway within the departure holding area for Runway 27R such that the wing tip of the Airbus impacted the tail fin of other aircraft. Two of the 378 occupants of the two aircraft suffered minor injuries and both aircraft were damaged. Passengers were deplaned uneventfully from both aircraft.)
  • B733 / DH8D, Fort McMurray Canada, 2014 (On 4 August 2014, a Boeing 737-300 making a day visual approach at Fort McMurray after receiving an ILS/DME clearance lined up on a recently-constructed parallel taxiway and its crew were only alerted to their error shortly before touchdown by the crew of a DHC8-400 which was taxiing along the same taxiway in the opposite direction. This resulted in a go around being commenced from 46 feet agl. The Investigation noted that both pilots had been looking out during the final stages of the approach and had ignored important SOPs including that for a mandatory go around from an unstable approach.)
  • B752 / CRJ7, San Francisco CA USA, 2008 (On 13 January 2008, a Boeing 757-200 and a Bombardier CL-600 received pushback clearance from two adjacent terminal gates within 41 seconds. The ground controller believed there was room for both aircraft to pushback. During the procedure both aircraft were damaged as their tails collided. The pushback procedure of the Boeing was performed without wing-walkers or tail-walkers.)
  • 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.)
  • A332/A345, Khartoum Sudan, 2010 (On 30 September 2010, an A330-200 was about to take off from Khartoum at night in accordance with its clearance when signalling from a hand-held flashlight and a radio call from another aircraft led to this not taking place. The other (on-stand) aircraft crew had found that they had been hit by the A330 as it had taxied past en route to the runway. The Investigation found that although there was local awareness that taxiway use and the provision of surface markings at Khartoum did not ensure safe clearance between aircraft, this was not being communicated by NOTAM or ATIS.)
  • DC91 / B722, Detroit MI USA, 1990 (On 3 December 1990 a Douglas DC9-10 flight crew taxiing for departure at Detroit in thick fog got lost and ended up stopped to one side of an active runway where, shortly after reporting their position, their aircraft was hit by a departing Boeing 727-200 and destroyed by the impact and subsequent fire. The Investigation concluded that the DC9 crew had failed to communicate positional uncertainty quickly enough but that their difficulties had been compounded by deficiencies in both the standard of air traffic service and airport surface markings, signage and lighting undetected by safety regulator oversight.)

Aircraft/Vehicle Conflict

  • 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.)
  • 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.)
  • 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.)
  • B738, London Stansted UK, 2008 (On 13 November 2008, a Boeing 737-800 with an unserviceable APU was being operated by Ryanair on a passenger flight at night was in collision with a tug after a cross-bleed engine start procedure was initiated prior to the completion of a complex aircraft pushback in rain. As the power was increased on the No 1 engine in preparation for the No 2 engine start, the resulting increase in thrust was greater than the counter-force provided by the tug and the aircraft started to move forwards. The towbar attachment failed and subsequently the aircraft’s No 1 engine impacted the side of the tug, prior to the aircraft brakes being applied.)
  • Vehicle / E190 / E121, Jersey Channel Islands, 2010 (On 1 June 2010, an Airport RFFS bird scaring vehicle entered the active runway at Jersey in LVP without clearance and remained there for approximately three minutes until ATC became aware. The subsequent Investigation found that the incursion had fortuitously occurred just after an ERJ 190 had landed and had been terminated just as another aircraft had commenced a go around after failure to acquire the prescribed visual reference required to continue to a landing. The context for the failure of the vehicle driver to follow existing procedures was found to be their inadequacy and appropriate changes were implemented.)
  • E190 / Vehicle, Paris CDG France, 2014 (On 19 April 2014, an Embraer 190 collided with the tug which was attempting to begin a pull forward after departure pushback which, exceptionally for the terminal concerned, was prohibited for the gate involved. As a result, severe damage was caused to the lower fuselage. The Investigation found that the relevant instructions were properly documented but ignored when apron services requested a 'push-pull' to minimise departure delay for an adjacent aircraft. Previous similar events had occurred on the same gate and it was suspected that a lack of appreciation of the reasons why the manoeuvre used was prohibited may have been relevant.)
  • B763, Luton UK, 2005 (On 16 February 2005, at Luton Airport, a Boeing B767-300 collided with the tug pulling it forward when the shear pin of the unserviceable tow bar being used to pull the aircraft broke. The aircraft ran onto the tug when the ground crew stopped the tug suddenly. As result of the collision with the tug the aircraft fuselage and landing gear was damaged.)
  • 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.)

Aircraft/Object Conflict

  • B738, Surat India, 2014 (On 6 November 2014, a Boeing 737-800 taking off at night from Surat hit an object as it was approaching 80 knots and the take-off was immediately rejected. On return to the gate substantial damage was found to the left engine and a runway inspection found one dead buffalo and another live one. The runway was reopened after removal of the carcass but the live buffalo was not removed and was seen again by the runway the following day. The Investigation found a history of inadequate perimeter fencing and inadequate runway inspection practices at the airport.)
  • 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.)
  • 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”.)
  • A346, Toulouse France, 2007 (During ground running of engines, the aircraft impacted a concrete wall at a ground speed of 30 kts following unintended movement and the aircraft was wrecked.)
  • 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, London Heathrow UK, 2007 (On 12 February 2007, an Airbus A319-100 being operated by British Airways on a scheduled passenger flight into London Heathrow made unintended contact in normal daylight visibility with the stationary airbridge at the arrival gate. This followed an emergency stop made after seeing hand signals from ground staff whilst following SEGS indications which appeared to suggest that there was a further 5 metres to run to the correct parking position. There was no damage to the aircraft, only minimal damage to the airbridge and there were no injuries to the aircraft occupants or any other person)
  • DH8D, Hubli India, 2015 (On 8 March 2015, directional control of a Bombardier DHC 8-400 which had just completed a normal approach and landing was lost and the aircraft departed the side of the runway following the collapse of both the left main and nose landing gear assemblies. The Investigation found that after being allowed to drift to the side of the runway without corrective action, the previously airworthy aircraft had hit a non-frangible edge light and the left main gear and then the nose landing gear had collapsed with a complete loss of directional control. The aircraft had then exited the side of the runway sustaining further damage.)
  • 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.)

Related Articles

Further Reading

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