On Friday 27 July, a runway incursion occurred on the 'Zwanenburgbaan' – runway 18C – at Amsterdam Airport Schiphol. An aircraft at the start of the runway was given take-off clearance, while at the same time, another aircraft had been given clearance to enter the same runway at an intersection further along.
The take-off of the first aircraft was aborted and the second aircraft stopped in the intersection. LVNL reported this incident to the Dutch Safety Board and the incident will also be investigated by the parties involved. This investigation will be conducted as part of the recently established Joint Sector Integrated Safety Management System.
An Embraer 190 (E190) type aircraft and a Boeing 737-800 (B738) type aircraft both took off from runway 18C (Zwanenburgbaan). The Embraer was lined up at the start of the take-off runway. The tower controller gave the Boeing permission to move onto the take-off runway from an intersection, one ‘entry point’ farther down the runway. The air traffic controller then cleared the Embraer for take-off. The cockpit crew in the Embraer and in the Boeing saw each other’s aircraft. As a result, the cockpit crew of the Embraer saw that the Boeing did not stop at the intersection, but continued moving towards the runway. This was the reason why the crew of the Embraer waited to take off; they wanted to be sure that the Boeing would come to a halt. From the beginning of the take-off runway, it was not possible to see exactly where the Boeing stopped. The Boeing ultimately stopped on the entry lane, without blocking the take-off runway, but was already with the 90-meter protected area of the take-off runway. The Embraer started its take-off run. Shortly after the Embraer started its take-off run, the Runway Incursion Alerting System Schiphol (RIASS) sounded an alert. The RIASS goes off when a runway incursion occurs. The air traffic controller heard the announcement ‘Runway Incursion 18C’ in the tower and saw flashing circles around the relevant aircraft on the ground radar. After the RIASS alert, the air traffic controller terminated the Embraer’s take-off run and instructed the Boeing to wait at the intersection. After cancellation of the take-off, the Embraer left runway 18C.
Results of the investigation
This occurrence was investigated by Air Traffic Control the Netherlands (LVNL) in conjunction with the airlines involved and Schiphol Airport based on the newly established ‘Joint Sector Integral Safety Management System (ISMS)’.
Runway 18C (Zwanenburgbaan) is usually used as a landing runway in a southbound direction. The investigation into this runway incursion revealed that the use of this runway as a take-off runway in a southbound direction played a role. The take-off runways that are customarily used, and that air traffic controllers frequently work on from Tower Center, are runway 24/06 (Kaagbaan), runway 18L/36R (Aalsmeerbaan) and runway 27 (Buitenveldertbaan). In the former situation at the air traffic control tower, where the air traffic controllers were in fixed positions, the main difference between these frequently used take-off runways and runway 18C (Zwanenburgbaan) as a take-off runway was the lines of sight. The numbering at the entry and exit points (intersections) is also different on runway 18C (Zwanenburgbaan) as a take-off runway; the numbers are in reverse order, because this runway is usually used as a landing runway.
In the context of the investigation, a Human Factor analysis was performed, which also looked at which factors played a role for the air traffic controller during the occurrence. This revealed that there was a mismatch between the actual situation around the take-off runway (‘external’) and the mental picture that the air traffic controller had of the situation (‘internal’). That is why the Boeing was cleared to move onto the runway before the Embraer had taken off.
The potential conflict was identified and prevented because both crews of the involved aircraft saw before the Embraer took off that the take-off could lead to a conflict. The Boeing stopped moving and the Embraer deliberately waited to see what was happening. Then the RIASS alert occurred, and the air traffic controller instructed the Embraer to cancel its take-off because the Boeing was in the runway’s protected area. There was no collision hazard during the take-off run, because the Boeing was standing still on the entry lane.
Follow-up action based on this investigation
Lines of sight from the air traffic control tower
The renovations of the air traffic control tower will be completed at the end of July 2019. A raised platform has been added in the middle of the tower, providing good lines of sight from the tower to runway 18C (Zwanenburgbaan). In combination with the introduction of Electronic Flight Strips at the end of April 2019, the work positions can be used much more flexibly, significantly improving the view of the runway and the connecting intersections. These measures represent a safety improvement for taking off from runway 18C (Zwanenburgbaan).
An analysis was performed to determine whether it would be possible to improve the timely release of RIASS warnings involving conflicts with departing air traffic. The results of this analysis will be considered further within the ISMS.
Intersections along runway 18C (Zwanenburgbaan)
The Runway Safety Team Schiphol is reviewing whether there are ways to reduce the impact of the current intersection numbering on runway 18C (Zwanenburgbaan).
Classification: major occurrence