On Sunday 1 May 2016 an aircraft entered Maastricht Aachen Airport airspace without permission and without radio contact with air traffic control. This aircraft flew in the vicinity of another flight controlled by air traffic control. A loss of separation occurred during this occurrence.
LVNL has reported this occurrence to the Dutch Safety Board and is conducting its own investigation.
An Airbus 320 is instructed for the approach of runway 03. A Cessna 152 enters the Maastricht Aachen Airport airspace without the mandatory permission of air traffic control and flies in the vicinity of the Airbus. The minimum distance between both aircraft is 1 nautical mile (more than 1.8 kilometres) horizontally and 400 feet (122 meter) vertically. In this situation the separation should be either 1000 feet vertically or 5 nautical mile horizontally.
At the moment the Cessna enters the Maastricht airspace in a south-easterly direction the loss of separation occurs. At that time the Airbus is flying in a north-westerly direction. The Cessna is not controlled by air traffic control.
As soon as air traffic control finds out that the Cessna is entering Maastricht airspace, the controller informs the Airbus crew about this other traffic. Shortly after giving this informatioen, the Airbus is instructed to climb, to enlarge the distance between the two aircraft.
The Airbus landed safely, the Cessna continued its flight.
Results of the investigation
An Airbus receives heading instructions for interception of an IFR approach of Runway 03. After the Airbus has initiated a north-western course at an altitude of 1,800 feet – approximately 550 metres – a Cessna enters the local ATC area, flying in the opposite direction. It is the Cessna pilot’s intention to follow a route between the respective airspaces of Liege and Maastricht; however, the pilot has made a navigational error. This means the Cessna’s flight path is further to the north than intended.
It is not unusual for aircraft to change their heading to the south-east shortly before the edge of the controlled airspace, so that they can circumvent the local ATC area. However, contrary to expectations, the Cessna enters the Maastricht airspace, resulting in a loss of minimum separation between the Cessna and the Airbus.
The air traffic controller notifies the Airbus of the Cessna’s proximity, after which the Airbus flight crew indicate that they do not yet have a visual on the Cessna. There is no contact with the Cessna. The air traffic controller issues a climb instruction to the Airbus in order to create sufficient separation. The smallest distance between the two aircraft is 1 nautical mile – over 1.8 kilometres – horizontally and 400 feet – approximately 122 metres – vertically. As soon as both aircraft have passed one another, the air traffic controller instructs the Airbus to adopt a north-eastern heading that will allow it to track and turn onto an IFR approach of Runway 03. The air traffic controller informs the Airbus that the Cessna has passed and instructs the Airbus to descend to 1,800 feet and commence its approach. The Airbus subsequently approaches and lands on the runway without incident.
The incident is the result of a navigational error on the part of the Cessna that caused the Cessna to enter Maastricht airspace without ATC clearance. Due to its geographic situation, the available aviation space around Maastricht Aachen Airport is smaller than usual. As a consequence, the airspace violation immediately resulted in a separation conflict between aircraft involved.
This situation was immediately recognised by air traffic control, after which additional separation was achieved by issuing a climb instruction to the Airbus flight crew.
Follow-up in response to the investigation findings
The safety investigation shows that due to the relative proximity of the edges of the available aviation space, the air traffic controller has limited time to take action. It is presently being studied whether the situation for the approach of Runway 03 can be improved in some way.