On Friday 11 December 2015, an incident took place on the airport premises of Amsterdam Airport Schiphol. Two departing aircraft were given clearance for push-back, but the push-back routes were in conflict.
Push-back involves pushing a plane backwards from the gate. After push-back, the plane can taxi, if it has received permission to do so.
Guiding ground traffic
On the airport premises, Air Traffic Control the Netherlands (LVNL) is responsible for guiding ground traffic. Part of the guidance is delegated to the airport (Apron Control), but only when visibility is good. For the traffic at Schiphol, this means that Air Traffic Control the Netherlands guides the traffic on the airport premises, such as arriving and departing planes that are taxiing to the gate or the runway. When visibility is good, the airport guides vehicles and towing traffic: a combination whereby a vehicle pulls a plane. The driver is then responsible for separation with other planes.
Incident investigation
LVNL’s primary task with regards to safety is to keep planes separate from one another (including planes combined with vehicles on the ground). Traffic control reports and investigates incidents in order to learn from them and to minimise the chance of a similar incident occurring in the future. LVNL is continuously improving safety.
Situation, investigation and follow-up
Late in the morning on Friday 11 December 2015, an incident took place on the southern side of the D-pier, level with the aircraft stands D22, D24 and D26. It happened during the push-back of two planes
At aircraft stand D26, an Embraer 190 plane was ready for departure. The pilot asked for clearance for push-back. The trainee ground controller informed the pilot that push-back was permitted as soon as the plane arriving at D24 (directly adjacent to D26) had been parked. Once this plane was parked, the Embraer commenced push-back. In accordance with standard procedure, the tail of the aircraft was pushed to the south-west, so that it could then taxi eastwards, to the Aalsmeerbaan (18L) via lane A8.
Half a minute later, the pilot of a Boeing 737-800 at aircraft stand D22 (directly adjacent to D24 and two stands to the left of D26) reported to the trainee ground controller that the plane was ready for departure. Initially, the ground controller had the aircraft wait, but one minute later, the ground controller gave permission to start the engines (start-up) and for push-back. In accordance with standard procedure, the tow driver pushed the tail of the aircraft to the south-east, so that the aircraft would then be able to taxi to the Kaagbaan (24) via lane A6.
The routes for the standard push-backs from aircraft stands D22 and D26 are located in the same area on the platform. This means that they cannot take place at the same time, unless the push-back from stand D22 is also performed with the tail of the aircraft heading south west.
Nonetheless, the trainee ground controller granted the Boeing clearance for a standard push-back, and not for an alternative push-back with the tail heading south west. The trainee ground controller’s instructor did not notice this mistake. When the trainee ground controller saw that both planes were being pushed towards each other, he first asked Apron Control of Amsterdam Airport Schiphol whether the Boeing’s push-back was going smoothly. The apron controller replied that they would not have carried out the push-backs this way. Immediately after that, the ground controller asked the Boeing’s crew to stop the push-back. The pilot of the Boeing did not answer.
The tow driver who was pushing the Boeing backwards stopped the push-back just before the so-called ‘push-back limit line’ and had the personnel wait until the Embraer had taxied away prior to starting the engines. The minimum distance between both tails is estimated to have been three to five metres. No damage was caused and both aircraft departed without further incident.
The findings from this investigation have been reported to the trainee and instructor ground controllers for learning purposes.
Classification: serious incident