Notification
On Monday 25 July 2016 a sport aircraft entered Amsterdam Airport Schiphol airspace without permission. It flew in the vicinity of a flight controlled by air traffic control, approaching Schiphol for landing. The two aircraft came closer to each other than is allowed by the separation minima. LVNL is investigating the occurrence and has reported the occurrence to the Dutch Safety Board.
What is an airspace infringement?
Internationally, an airspace infringement is defined as: “A flight into notified airspace without previously requesting and obtaining approval from the controlling authority of that airspace in accordance with international and national regulations.”
Occurrence investigation
LVNL’s primary safety task is to maintain the separation of aircraft in the air, and between vehicles and other obstacles when on the ground. Air traffic controllers internally report any safety related occurrence, with the objective to learn lessons from those occurrences, thereby reducing the chance that similar occurrences will take place again in the future. All reported occurrences are investigated by LVNL, as part of LVNL’s ongoing commitment to improve safety.
Description of the situation and results of the investigation
An aircraft type Airbus A319 is approaching the Polderbaan runway from the south for landing and receives instructions from the approach controller at Amsterdam Airport Schiphol. At the same time, an aircraft type Sukhoi SU-26 is heading southward at low altitude along the North Sea coastline between Bergen aan Zee and Castricum. The airplane has radio contact with the Amsterdam Flight Information Centre and is flying below the airspace monitored by Schiphol Approach.
The approach controller instructs the Airbus flying on a northern heading west of the coastline to descend to an altitude of 2,000 feet – approximately 600 metres. The Sukhoi is flying in the opposite direction along the coastline at an altitude of 500 feet – approximately 150 metres – on a southward course.
Near Castricum, the Sukhoi unexpectedly climbs to an altitude of some 1,700 feet – approximately 500 metres – which takes it within the control area of Approach Control without clearance. The approach controller immediately informs the Airbus of the Sukhoi’s proximity. The pilot of the Airbus indicates that they are flying through clouds and consequently do not have a visual on the Sukhoi. The Airbus flight crew do not report having received a TCAS alert.
The flight information centre immediately instructs the Sukhoi to descend to an altitude below the airspace controlled by Approach Control. The Sukhoi’s pilot complies with this instruction without delay and descends to an altitude below the Approach Control’s control area.
Both flights continue their flight without incident.
Minimum separation
The smallest distance between the two aircraft occurs while the Airbus is proceeding on its northward course in the direction of the Sukhoi: 0.3 nautical mile - approximately 600 metres - horizontally and 250 feet - approximately 100 metres - vertically.
Aircraft – in many cases recreational – travelling below the airspace controlled by Schiphol Approach are allowed to fly at an altitude of no more than 1,500 feet - approximately 450 metres. This air traffic is not allowed to enter the area controlled by Schiphol Approach. In turn, Schiphol Approach makes sure that air traffic under his or her control does not descend below a minimum altitude of 2,000 feet – approximately 600 metres. This ensures that there is always a minimum vertical buffer of 500 feet – approximately 150 metres – between aircraft approaching Amsterdam Airport Schiphol and recreational air traffic.
Conclusion
The incident was a consequence of the Sukhoi entering the airspace controlled by Schiphol Approach without first gaining clearance to do so. Corrective instructions were issued immediately after the deviation in the Sukhoi’s altitude was detected, after which both aircraft could continue their flight without incident.