On 30 September 2010, an Airbus 330-200 being operated by KLM on a passenger fight from Khartoum to Abu Dhabi UAE taxied for departure along the main taxiway parallel to the runway in normal night ground visibility and when passing behind a parked Airbus A340-500 with passengers on board hit the lower empennage of that aircraft with its left wing tip without awareness of any impact. When the A340 crew reported the impact a few minutes later after detecting an abnormal jolt and losing the APU function and the services it was providing, the A330 had just been given take off clearance and was about to roll. Signalling from a hand held flashlight and the radio call from the A340 resulted in the A330 holding position and shutting down for a tow back to the Terminal. None of the 142 occupants on the A330 or any of those on the A340 were injured.
The Accident was notified to the Sudan DGCA Air Accident Investigation Central Directorate (AAICD) and an Investigation was then carried out by a Board of Investigation formed for the purpose by the Sudan DGCA. Recorded flight data was not available to assist the Investigation.
Damage to the A330 was found to have been limited to the left winglet but damage to the A340 was found to extend to:
- the left hand stabiliser.
- the aft fuselage lower frame.
- the APU inlet splitter.
- the APU fire bottle compartment access door.
- the right hand stabiliser.
It was established that the A330 had carried out pushback from the gate prior to the accident without the presence of any marshaller which was not permitted under airport regulations. It was also found that marked centreline of the taxiway being used by the A330 when it passed behind the parked A340 was not in the centre of the taxiway. The distance from the marked centreline to the taxiway edge nearest the runway was found to be 15.55 metres whereas the distance to the edge nearest the parking stands adjacent to the opposite side was 11.50 metres. The distance between the taxiway centreline and aft edge of the A340 was found to have been 22.25m with the impact position on the A340 a further half metre beyond this. Since the wingspan of the A330 involved was 60.3 metres, it was apparent that the aircraft had been taxiing approximately 5 metres to the right of the marked taxiway centreline indicating that “the pilot has identified the potential hazard of wingtip collision and turned right in an attempt to increase the space between his aircraft and the parked (A340).” It was noted that, in the absence of any stop markings on the stand used, the A340 had been marshalled to a parking position in which the nose of the aircraft was 4.6m from the edge of the adjacent service road. It was also noted that both wingtips of the aircraft extended significantly beyond the marked limits of the stand.
It was observed that both stand and taxiway measurements and the use / non use of surface markings indicated that the applicable provisions contained in ICAO Annex 14 Volume 1 had not been satisfied in respect of safe clearances on either the taxiway or parking stands for the aircraft involved.
However, the Investigation noted that “the parallel taxiway along which the A330 was cleared to taxi was not approved for use by wide bodied aircraft when adjacent parking stands are occupied and in these circumstances, it is necessary for aircraft to enter the runway at an earlier point and backtrack the runway to reach the required take off position. However, it was found that there was a “lack of clear instructions” to this effect and that “although this hazard was known (it was) not being mitigated by Notice To Airmen or Automatic Terminal Information Service (ATIS)”.
Finally, it was established that the TWR ATCO on duty at the time of the accident had transferred from Khartoum ACC to TWR one month previously without receiving any briefing or refresher training.
The Causes of the Accident were determined to have been as follows:
- Insufficient wingtip clearance between (the parallel taxiway) and (the gate on which the A340 was parked).
- The absence of marshallers during (the A330) engines start up and taxi-out.
- Instructions by aerodrome control tower to KLM A330 to taxi via (the full length of the parallel) taxiway A for runway 18.
- Non-standard construction of aircraft stands.
- Non distribution of information regarding liability of wing-tip clearance to all concerned.
- Limited and narrow width of (the apron area on which the A340 was parked)
Eight Safety Recommendations were issued as a result of the Investigation as follows:
- Approved Safety Management System for Khartoum Airport is highly recommended.
- All apron aircraft stands specifications should be according to ICAO requirements taking into consideration the types of aircraft that could use them.
- Special procedures should be published reflecting the non-conformities to ICAO Standards in respect to taxiways and parking restrictions and circularised to all stakeholders.
- Aerodrome tower controllers should have refresher training before exercising their duties whenever they have been working away from that position for a considerable period of time.
- Utilisation of apron 2.
- Review the training of personnel responsible for providing marshalling guidance on the apron, to ensure that pilots are provided with safe and appropriate signals.
- Review the coordination between ATC and apron marshallers, to ensure that clear guidelines and responsibilities are drawn between the two departments, in relation to aircraft operating in the apron.
- Review the apron design at Khartoum Airport, with a view to redesign of stands that are suitable for the safe parking and general handling of widebody aircraft. Such stands will provide adequate clearance from other aircraft so as not to impede the traffic movement.
The UAE GCAA made a detailed submission in response to sight of the initial draft of the Final Report and this and the response to it by the Sudan DGCA AAICD are included as Attachments ‘A’ and ‘B’ to the released version of the Final Report of the Investigation Ref:-CAAIACC/A6-ERE IPH-AODI12.