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Difference between revisions of "Taxiway Collisions"

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|control_caption  = About SKYbrary
 
|control_caption  = About SKYbrary
 
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==Description==
 
==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.
 
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.
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==Prevention==
 
==Prevention==
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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:
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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:
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**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 ground controller is responsible for the safe and efficient movement of aircraft and vehicle traffic on the taxiways and aprons. They should:
 +
**provide the appropriate clearance for the requested action
 +
**ensure that the clearance readback is accurate
 +
**to the extent possible, monitor the movement visually, via transponder or by use of [[Multilateration|multilateration equipment]] to ensure clearance compliance
 +
*Pilots - In general, pilots are responsible for the ground movement of an aircraft from the runway to the gate and from the gate to the runway although they may also reposition aircraft from one point on the airfield to another. In all cases they should:
 +
**request, readback and comply with an appropriate clearance
 +
**maintain situational awareness
 +
**taxi at a speed appropriate to the conditions and traffic situation
 +
**maintain the centre of the taxi lane
 +
**be vigilant for taxi lane compromise by another aircraft, vehicle or object
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**not assume that vehicles will yield right-of-way
  
 
==Accidents and Incidents==
 
==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.
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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===
 
===Aircraft/Aircraft Conflict===
 
{{#ask: [[GND::Aircraft / Aircraft conflict]]
 
{{#ask: [[GND::Aircraft / Aircraft conflict]]
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*[http://www.skybrary.aero/bookshelf/books/3524.pdf ACRP Report 148: LED Airfield Lighting System Operation and Maintenance], J. Burns et al., Transportation Research Board (U.S.), 2015
 
*[http://www.skybrary.aero/bookshelf/books/3524.pdf ACRP Report 148: LED Airfield Lighting System Operation and Maintenance], J. Burns et al., Transportation Research Board (U.S.), 2015
  
[[Category:Ground Operations   [[Category:Operational Issues
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[[Category:Ground Operations]]

Latest revision as of 10:02, 28 June 2018

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

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 ground controller is responsible for the safe and efficient movement of aircraft and vehicle traffic on the taxiways and aprons. They should:
    • provide the appropriate clearance for the requested action
    • ensure that the clearance readback is accurate
    • to the extent possible, monitor the movement visually, via transponder or by use of multilateration equipment to ensure clearance compliance
  • Pilots - In general, pilots are responsible for the ground movement of an aircraft from the runway to the gate and from the gate to the runway although they may also reposition aircraft from one point on the airfield to another. In all cases they should:
    • request, readback and comply with an appropriate clearance
    • maintain situational awareness
    • taxi at a speed appropriate to the conditions and traffic situation
    • maintain the centre of the taxi lane
    • be vigilant for taxi lane compromise by another aircraft, vehicle or object
    • not assume that vehicles will yield right-of-way

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

  • A321 / B734, Barcelona Spain, 2015 (On 25 November 2015, an Airbus A321 taxiing for departure at Barcelona was cleared across an active runway in front of an approaching Boeing 737 with landing clearance on the same runway by a Ground Controller unaware that the runway was active. On reaching the lit stop bar protecting the runway, the crew queried their clearance and were told to hold position. Noting that the event had occurred at the time of a routine twice-daily runway configuration change and two previous very similar events in 2012 and 2014, further safety recommendations on risk management of runway configuration change were made.)
  • B763 / A320, Delhi India, 2017 (On 8 August 2017, a Boeing 767-300 departing Delhi was pushed back into a stationary and out of service Airbus A320 on the adjacent gate rendering both aircraft unfit for flight. The Investigation found that the A320 had been instructed to park on a stand that was supposed to be blocked, a procedural requirement if the adjacent stand is to be used by a wide body aircraft and although this error had been detected by the stand allocation system, the alert was not noticed, in part due to inappropriate configuration. It was also found that the pushback was commenced without wing walkers.)
  • B738 / B738, Dublin Ireland, 2014 (On 7 October 2014, a locally-based Boeing 737-800 taxiing for departure from runway 34 at Dublin as cleared in normal night visibility collided with another 737-800 stationary in a queue awaiting departure from runway 28. Whilst accepting that pilots have sole responsible for collision avoidance, the Investigation found that relevant restrictions on taxi clearances were being routinely ignored by ATC. It also noted that visual judgement of wingtip clearance beyond 10 metres was problematic and that a subsequent very similar event at Dublin involving two 737-800s of the same Operator was the subject of a separate investigation.)
  • DH8D / B737, Winnipeg Canada, 2014 (On 4 August 2014, the crew of a DHC8-400 departing Winnipeg continued beyond the holding point to which they had been cleared to taxi as a B737 was about to land. ATC observed the daylight incursion visually and instructed the approaching aircraft to go around as the DHC8 stopped within the runway protected area but clear of the actual runway. The Investigation found that the surface marking of the holding point which had been crossed was "significantly degraded" and noted the daily airport inspections had failed to identify this.)
  • 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.)
  • 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/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.)
  • DH8C / P180, Ottawa ON Canada, 2013 (On 1 December 2013, a small aircraft taxing for departure at night was cleared to cross an active runway and did so as a DHC8 was taking off from the same runway. Separation was significant and there was no actual risk of collision. The Investigation found that the GND controller had issued clearance to the taxiing aircraft when he had responsibility for its whole taxi route but had neither updated the aircraft status system nor directly advised of the taxiing aircraft when passing responsibility for part of its cleared route to the TWR controller who therefore remained unaware of it.)

Aircraft/Vehicle Conflict

  • 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.)
  • 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 / 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.)
  • 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.)
  • Vehicle / B752, Dublin Ireland, 2009 (On 29 May 2009, a Boeing 757-200 being operated by UK Airline Thomson Airways on a passenger charter flight from Sharm-el-Sheikh, Egypt to Dublin and having just landed on runway 10 at destination at night in poor visibility overtook a small ride-on grass mower moving along the right hand side of the runway in approximate line with the aircraft’s right hand wing tip. The driver of the mower was unaware of the arriving aircraft until he heard it on the runway behind him. Prior to the landing, ATC had been informed that all grass-cutting equipment previously working on and around the runway had cleared it.)
  • 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.)
  • 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.)

Aircraft/Object Conflict

  • B737, Amsterdam Netherlands, 2003 (n 22 December 2003, a Boeing 737-700 being operated by UK Operator Easyjet on a scheduled passenger flight from Amsterdam to London Gatwick was taxiing for departure at night in normal visibility and took a different route to that instructed by ATC. The alternative route was, unknown to the flight crew, covered with ice and as a consequence, an attempt to maintain directional control during a turn was unsuccessful and the aircraft left wing collided with a lamp-post. The collision seriously damaged the aircraft and the lamp post. One passenger sustained slight injuries because of the impact. The diagram below taken from the official investigation report shows the area where the collision occurred.)
  • 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.)
  • 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”.)
  • 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)
  • A321, Daegu South Korea, 2006 (On 21 February 2006, an Airbus A321-200 being operated by China Eastern on a scheduled passenger flight from Daegu to Shanghai Pudong failed to follow the marked taxiway centreline when taxiing for departure in normal daylight visibility and a wing tip impacted an adjacent building causing minor damage to both building and aircraft. None of the 166 occupants were injured.)
  • 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.)
  • 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.)
  • B738, Djalaluddin Indonesia, 2013 (On 6 August 2013, a Boeing 737-800 encountered cows ahead on the runway after landing normally in daylight following an uneventful approach and was unable to avoid colliding with them at high speed and as a result departed the runway to the left. Parts of the airport perimeter fencing were found to have been either missing or inadequately maintained for a significant period prior to the accident despite the existence of an airport bird and animal hazard management plan. Corrective action was taken following the accident.)

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