On Thursday 29 March 2018, at around 19.56 hours, an incident occurred in the airspace of Amsterdam Airport Schiphol. A Boeing 737-700, which was engaged in a go-around on Runway 18C, experienced an undesirable loss of separation from another aircraft, a Boeing 737-800, which had just started its takeoff procedure from runway 24. Because the two runways converge, the aircraft found themselves on a course which was set to intersect.
Procedure for reduced separation
Shortly before landing on runway 18C, the crew of the Boeing 737-700 reported their intention to perform a go-around. At that time, the runway controller had already issued clearance to the Boeing 737-800 to start its takeoff procedure from runway 24. The runway controller wanted to instruct this aircraft to abort its takeoff, but because the wrong flight number was used in the instruction to abort the takeoff, the crew did not respond to the instruction and the aircraft took off. The runway controller recognized the potential conflict and issued instructions to both the Boeing 737-700 and the Boeing 737-800 to perform divergent turns in order to establish a greater separation between the two aircraft. The crews of both aircraft immediately complied with these instructions, also because they had themselves recognized the potentially hazardous situation.
The procedure for reduced separation has not been explicitly approved by the Human Environment and Transport Inspectorate (ILT). The procedure was already present in the former manual of LVNL at the time when the manual was converted into the current Operations Manual. This Operations Manual in its entirety was approved by the ILT, such that the above procedure was implicitly permitted. The ILT was however unable to trace back the actual way in which the former manual was converted into the Operations Manual. The procedure for reduced separation was not considered during subsequent amendments to the Operations Manual, which were approved by the ILT.
This occurrence is also the subject of a joint investigation by the parties involved, in the framework of the joint sector Integral Safety Management System (ISMS). The investigation and report have been concluded. All that remains is the decision-making on the measures to be taken.
Removal of the procedure from the Operations Manual
The procedure ‘Reduced separation during the use of dependent takeoff and landing runways’ of Air Traffic Control the Netherlands is used to increase the air traffic capacity of Schiphol. However, the use of dependent runways can create an undesirable and potentially dangerous situation under certain circumstances. Such incidents have occurred before. The Dutch Safety Board therefore issues the following recommendation:
To Air Traffic Control the Netherlands
1. Remove the procedure “Reduced separation between takeoff and landing traffic” from the Operations Manual and adhere to the standard procedure for using dependent runways.
Review of procedures in the Operations Manual
Because this procedure was established in the past, the Human Environment and Transport Inspectorate did not have to give permission for this procedure. It is not clear whether all procedures in the Operations Manual regarding dependent runway use, are compliant. The Dutch Safety Board therefore issues the following recommendation:
To the Minister of Infrastructure and Water Management
2. Have Air Traffic Control the Netherlands’ procedures regarding the use of dependent runways assessed against current legislation and regulations.
Afwijkende procedures op Schiphol zorgen voor ongewenste risico’s