What happened
On the night of September 10, 2006, a high volume of traffic at Brussels National Airport led to a ground collision between two Boeing aircraft. The first aircraft, a Singapore Airlines Cargo Boeing 747-412 (registration 9V-S0F), was taxiing toward its takeoff position. Simultaneously, a Royal Air Maroc Boeing 737-5B6 (registration CN-RMV) was queued at the intersection of taxiways Outer 7 and Inner 6/E6, waiting for departure from runway 25R.
Due to a prior emergency involving another aircraft, runway 25R had been blocked for several hours, resulting in a backlog of departing flights. As the 9V-SFO was cleared to cross the intersection and follow a preceding DC-10, its left wing tip struck the right horizontal stabilizer of the CN-RMV. The impact was not felt by the crew of the 9V-SFO, but the CN-RMV crew immediately noticed the collision and alerted Air Traffic Control. There were no injuries to the passengers or crew involved.
The investigation
Investigators from the AAIU(Be) examined flight recorders from both aircraft, ground radar data, and tower communications. The investigation focused on the visibility conditions at the intersection, the instructions provided by Ground Control, and the physical dimensions of the aircraft involved. The inquiry also reviewed the movement of several other aircraft in the vicinity, including a DC-10 that had passed through the intersection just prior to the collision.
Findings
Several contributing factors led to the collision:
- The 9V-SFO was cleared to cross the intersection with instructions only to follow the preceding DC-10; the controller did not specifically mention the presence of the CN-RMV to the 9V-SFO crew.
- The position of the CN-RMV on the taxiway was constrained by preceding traffic, leaving it in a location that was not compatible with the wingspan of the B747-400.
- Nighttime visibility from the flight deck was restricted, making it difficult for the 9V-SFO crew to monitor the position of their wing tips.
- The Ground Controller's attention was divided due to unusually high traffic volume and multiple simultaneous aircraft movements across the airport.
- The physical layout of the intersection and the lack of direct camera coverage made it difficult for the tower to evaluate the potential conflict between the two aircraft.
Safety action
Following the investigation, recommendations were made to BCAA/Belgocontrol to:
- Review ground markings and lighting at the Outer 7/Inner 6 intersection to improve visibility.
- Amend taxiing procedures at intersections to ensure that aircraft exiting the area are positioned compatibly with crossing traffic.
- Enhance Air Traffic Controller training regarding the significant wingspan differences between aircraft types.
- Review holding limits for aircraft on taxiway B1 based on aircraft dimensions.