On 8 November 2014, two aircraft breached the airborne separation minima during their approaches to Amsterdam Schiphol Airport (SPL). LVNL has reported this incident to the Dutch Safety Board and is conducting its own investigation.
Loss of separation
The horizontal or vertical distance between aircraft in flight is referred to as their “separation”. Separation minima have been established to maintain air traffic safety, whilst at the same time making optimum use of airspace. Air traffic control is responsible for maintaining these minimum distances between aircraft in its control zone. When two aircraft come closer to one another than the minima allow, the situation is known as a “loss of separation”.
The criteria for separation minima have been designed in such a way that they allow enough time to correct the situation before it presents a serious danger. An air traffic controller faced with a loss of separation must undertake a number of steps in a very short time.
- Detect the loss of separation;
- Identify an effective solution;
- Communicate that solution to the pilot(s) concerned, in the form of instructions regarding their altitude, bearing and speed;
- Ensure that the pilot(s) follow these instructions in order that safe separation is restored as quickly as possible.
LVNL’s primary safety task is to maintain the separation of aircraft from one another, and also from vehicles and other obstacles when on the ground. Air traffic controllers internally report any incidents falling within our area of responsibility, with the aim of learning lessons from them and so reducing the chance that similar occurrences will take place again in the future. All reported incidents are investigated by LVNL, as part of our ongoing commitment to improving safety.
On Saturday 8 November 2014, at approximately 08.00 CET – the start of the morning landing peak – a loss of separation occurred at Amsterdam Airport Schiphol. The situation arose because an Embraer 145 (E145) aircraft approaching from the south failed to make the final turn on its approach to Runway 27 immediately when instructed to do so by air traffic control. Another aircraft, a Boeing 777-200 (B772), was approaching the same runway from the east. The E145’s delay in turning, combined with a strong southerly wind, caused a loss of separation. At their closest, the two aircraft were 1.8 nautical miles (horizontal) and 4000 feet (vertical) apart. LVNL has reported this incident to the Dutch Safety Board and is conducting its own investigation.
Summary of investigation results
In the morning of Saturday, November 8 th 2014, two aircraft came closer than the separation minimum during their approach to Amsterdam Airport Schiphol. An Embraer 145 approached Schiphol from the west to land on runway 27. At the same time a Boeing 777-200 approached Schiphol from the east to land on the same runway. The E145 was given course instructions from Air Traffic Control (ATC) for a left turn and was cleared to begin a final approach to runway 27. ATC did not immediately receive a response from the crew of the E145. After repeating these instructions to the crew of the E145, ATC received an acknowledgement of the instructions by the pilot. Some more time passed before the E145 executed this left turn. As a result, the horizontal separation between the E145 and B772 was reduced to 1,8 NM and the vertical distance to 400ft. The actual separation distance was thus 60% of the prescribed separation distance. The crew of the B772 had the E145 in sight. Both aircraft continued their flights uneventfully and landed safely.
Classification: serious incident
Current rules and guidelines provide air traffic controllers sufficient opportunities to achieve and maintain the required separation as well as options to recover any separation loss. In this occurrence, the applied vertical distance between two aircraft, combined with the delay in the execution of heading instructions, turned out to be insufficient and a separation loss resulted. Air traffic control restored the separation distance to the required minimum.
Infographic loss of separation November 8th 2014