On 9 February, in the approach area of Amsterdam Airport Schiphol, an aircraft approaching the so-called Schiphol Oostbaan - runway 04/22 - and a helicopter came closer to each other than is permitted by the separation minima. LVNL (Air Traffic Control the Netherlands) conducted an investigation into this incident itself and reported it to the Onderzoeksraad voor Veiligheid (Dutch Safety Board).
Description of incident
A helicopter flying above Amsterdam (in the area known as the Amsterdam sector) with permission from air traffic control asked the air traffic control tower for permission to also enter the airspace above the Bijlmer region. The tower controller granted permission to the helicopter.
Business jet approaches runway 04/22
A short time later, approach control reported to the tower controller that a business jet was expected, which was to land on runway 04/22 at Schiphol. This aircraft was going to make what is known as an 'instrument approach'. The pilot contacted the ATC tower and the tower granted landing clearance to the pilot of the business jet.
Helicopter re-enters the Amsterdam sector
At this point, the helicopter had re-entered the Amsterdam sector from the airspace above the Bijlmer. Once the tower controller saw the helicopter on his radar screen, he indicated to be surprised that the helicopter was back in the Amsterdam sector. The tower controller then informed the helicopter pilot that another aircraft (the business jet) was in that area and about to land on runway 04/22. The helicopter pilot replied that there had probably been a misunderstanding.
Informing the business jet
Following the business jet's safe landing, the tower controller told the pilot of the business jet that he had failed to inform the business-jet pilot of the helicopter's presence. When asked, the pilot confirmed that he had not received a TCAS warning.
The fact that the tower controller was unaware he had granted permission to fly in both the Bijlmer and the Amsterdam sectors was caused by a miscommunication. Initially, the helicopter pilot was granted permission to fly above the Amsterdam sector. Later, the helicopter pilot also requested permission to enter the airspace above the Bijlmer, but the tower controller did not hear the word 'also'. For this reason, he was under the impression that he had given the helicopter permission to fly in the airspace above the Bijlmer but had not given permission for the helicopter to fly back into the Amsterdam sector.
The airspace above the Bijlmer is sufficiently far away from the instrument approach to runway 04/22 at Schiphol, and therefore the distance between traffic approaching this runway and traffic flying in the Bijlmer airspace complies with the separation minima.
Helicopter re-enters the Amsterdam sector
At the point that the business jet was approaching Schiphol's runway 04/22, the helicopter had finished flying in the airspace above the Bijlmer and returned to the Amsterdam sector. The helicopter pilot had not been informed about the approaching business jet and had also not heard over the radio that this aircraft had requested landing clearance, as a result of which he was taken by surprise upon seeing the business jet.
The helicopter pilot was able to maneuver out of the way in time by making a right turn. At that point, he was asked by the tower controller why he had re-entered the Amsterdam sector, to which the helicopter pilot responded that he thought he did have permission to use the airspace and a misunderstanding had arisen.
Later, the helicopter pilot stated that he had not received a TCAS warning, which was also the case for the business jet.
Minimum distance between aircraft
The minimum distance between the two aircraft was 0.7 nautical miles (nearly 1.3 kilometers) on the horizontal axis and 300 feet (approx. 100 meters) on the vertical axis.
Follow-up action based on this investigation
To prevent such misunderstandings from occurring in the future, the helicopter operator has since amended the request protocol in such situations. Now, pilots must submit a 'request to operate in both the Amsterdam sector and the Bijlmer area'. In the air traffic control towers, the importance of listening very carefully and ensuring clear communication will be brought to the controllers' attention by means of an article in the Safety Bulletin.
Classification: serious incident