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B737, Amsterdam Netherlands, 2003

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Summary
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.
Event Details
When December 2003
Actual or Potential
Event Type
Ground Operations, Human Factors
Day/Night Night
Flight Conditions On Ground - Normal Visibility
Flight Details
Aircraft BOEING 737-700
Operator EasyJet
Domicile United Kingdom
Type of Flight Public Transport (Passenger)
Origin Amsterdam Airport Schiphol
Intended Destination London Gatwick Airport
Take off Commenced No
Flight Airborne No
Flight Completed No
Flight Phase Taxi
TXI
Location - Airport
Airport Amsterdam Airport Schiphol
HF
Tag(s) Ineffective Monitoring
GND
Tag(s) Taxiway collision,
Aircraft / Object or Structure conflict,
Surface Friction,
Accepted ATC clearance not followed
Outcome
Damage or injury Yes
Aircraft damage Major
Non-aircraft damage Yes
Injuries Few occupants
Causal Factor Group(s)
Group(s) Aircraft Operation,
Air Traffic Management,
Airport Operation
Safety Recommendation(s)
Group(s) Aircraft Operation,
Air Traffic Management,
Airport Management
Investigation Type
Type Independent

Description

On 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.

EHAM GND B737
EHAM GND Diagram

Investigation

The Accident was investigated by the Dutch Safety Board. It was established that having noted from the Automatic Terminal Information Service (ATIS) the presence of ‘slippery spots’ on the taxiway system the aircraft commander, who had noted an instruction from ATC to taxi via taxiway ‘V’ to Runway 36L, decided not to taxi via this taxiway, but via the parallel taxiway ‘VS’. He reported taking this decision because, among other things, the aircraft would then need to make fewer sharp turns. He observed that during earlier flights which he had made to Amsterdam, he had noted that he had always been able to choose between these two taxiways. The fact that taxiway ‘VS’ was at that time untreated, then led directly to the taxiway excursion and collision.

A comprehensive review of the response of the Airport Authority to the known airside slipperiness by the Investigation, including the communicating of relevant information to ATC came to the conclusion that it had been inadequate. The investigation found that surface friction measurement and surface treatment against slipperiness airside were largely focused on Runways, a situation which it was considered also applied at other Dutch airports. The Investigation noted that both National and International regulations and procedures on the measurement of braking action / friction and the prevention of slipperiness on runways, taxiways and aprons “are virtually non-existent.”

A particular concern of the Investigation in this respect was that the collision created a fire risk which might have needed a rapid response from the Airport RFFS who were delayed by the slippery surfaces around the airport even though they arrived at the accident aircraft within the maximum allowed three minutes.

It was noted by the Investigation that at the place where the accident occurred ATC are required to give a positive instruction to aircraft crews in respect of taxiway use and although this was done just prior to the accident, it was common practice at this location for ATC to leave the choice of taxi route up to flight crew. It was also noted that although ATC had not been informed of specific slippery areas, they knew from their own observation that it was very slippery there and in consequence issued a specific taxi instruction to the accident aircraft, they did not explain their reason for doing so. The absence of a taxiway guidance system, which meant that all taxi routes were similarly illuminated, was also noted.

In respect of the Aircraft Operator, it was noted that the flight crew did not communicate with one another about the decision to take a different taxi route to the one that had been instructed. It was also considered that the division of tasks and the communication between the two members of the crew was not optimal and not in accordance with the Crew Resource Management concept. More generally, it was considered clear that the Easyjet Quality System and Safety Management System had failed to recognise the risk of an accident such as the one which occurred.

The Conclusions of the Investigation, taken as published from the official report, were as follows:

“The fact that the flight crew did not follow up the instructions from air traffic control and decided to follow another taxiway route led to the pilot flying not being able to keep the aircraft under control, due to the slipperiness on that other route. The decision to take another route can be explained, among others, by the common, though incorrect, practice to let flight crews choose which taxiway they use in connection with the illumination of the taxiway lighting of both parallel taxiways and the lighting of the aprons. The crew had not been informed and could not be aware of the nature and degree of slipperiness on the scene. The Dutch Safety Board does hold the view that Air Traffic Control the Netherlands must point out to its air traffic controllers that they should comply with existing procedures.

The information of the ATIS was not correct, both in terms of phraseology and in terms of the actual situation. Moreover, it took too long before this not entirely correct information became available to flight crews.

The accident with Easyjet shows that the (management) system regarding the entire chain of realisation of information reporting at the Schiphol airport up to and including the actions stemming from said reporting creates risks of human failure.

Given the recommendations made in the past, the Dutch Safety Board deems that the parties responsible for the entire chain of information reporting to airmen at Schiphol could have done more towards taking their (joint) responsibility regarding the decrease of risks in the information reporting up to and including the subsequent actions as regards fighting slipperiness at the airport. Therefore, the Dutch Safety Board holds the view that there is a structural safety shortage.

The Easyjet flight crewmembers did not consult with one another on the fact that another taxiway route had been chosen than the one instructed by air traffic control. It also appears from other events that the crew paid insufficient attention to all aspects of the work during this part of the flight. The assignment of tasks and the communication between the two flight crewmembers was not optimal and not compliant with the crew resource management concept.

Finally, it appeared there were flaws in parts of the manual of Amsterdam Airport Schiphol. The 'snow and iciness control measures'-regulation was not subject to a risk assessment and to monitoring of safety objectives. The manner in which the friction was measured on taxiways and aprons turned out to be mentioned in a very concise fashion. This also appeared to be the case at the other airports in the Netherlands.”

The Final Report of the Investigation was published on 23 March 2006 and may be seen in full at SKYbrary bookshelf: Investigation 2003133 - Loss of steering on a slippery runway

Five Safety Recommendations were made as a result of the Investigation and are reproduced below as published in the Final Report:

  1. All parties at Amsterdam Airport Schiphol, who are responsible for the system of provision of information to airmen, should give a more adequate substance to their (joint) responsibility as regards diminishing the risks involved in the reporting of information. In this respect, the use of the non-ICAO term 'slippery spots' needs to be assessed.
  2. It is recommended to Amsterdam Airport Schiphol to assess the functioning of the business manual and the underlying regulations, such as the “snow and iciness control measures 2003-2004” and remedies the flaws therein.
  3. It is recommended to Air Traffic Control the Netherlands to give more adequate substance to the task of air traffic controllers in special circumstances, such as in the event of slipperiness.
  4. It is recommended to Easyjet to include the flaws pertaining to the crew resource management in its training courses and to take appropriate action to prevent this in future.
  5. It is recommended to the Minister of Transport, Public Works and Water Management to encourage further rules to be set, both at national and international level, as regards the operational state of taxiways and aprons at airports.

Further Reading