With the implementation of a new procedure, Air Traffic Control the Netherlands (LVNL) can achieve safe take-off and landing of more aircraft per hour during reduced or low visibility conditions at Schiphol airport. In such situations, the new procedure uses local visibility conditions to differentiate between capacity on runway 36L (Polderbaan) on the west side of Schiphol and the other runways at Schiphol Centre.
By doing so, LVNL boosts capacity by 20 to 35% during foggy conditions. For airlines and passengers, it means fewer delays on foggy days. On average, this situation occurs about 10 times a year. The new procedure makes it possible to add five more arrivals and, depending on the runway combination, between three and seven extra departures per hour. In this situation, it results in a significant reduction in airline schedule disruptions.
'When there is fog or low-hanging cloud cover at Schiphol, air traffic controllers have to increase the distance between aircraft, which reduces flight handling capacity. This new procedure leads to fewer delays and flight cancellations when it is foggy at Schiphol,' says José Daenen, LVNL director of operations. 'This is an improvement for airlines and for passengers who can be severely impacted if flights are unable to depart or arrive on time due to the weather.'
Until now, the location with the lowest visibility conditions had been used to determine flight handling capacity for the entire airport. The Polderbaan runway regularly has lower visibility than Schiphol Centre, due to its lower elevation and the fact that the runway is surrounded by meadows and fields and situated several kilometres from Schiphol Centre. Now that differentiated visibility readings can be used for the Polderbaan runway and the other runways, the airport’s overall flight handling capacity improves during reduced visibility. Safe air traffic control will obviously continue, as well as the practice of using noise preferential runways for take-off and landing wherever possible.
This new procedure was designed in consultation with our partners, including Schiphol Airport, ground handling agents and the Human Environment and Transport Inspectorate (ILT). After receiving ILT approval, LVNL updated the rules and regulations in the manuals and trained the air traffic controllers accordingly. LVNL is now prepared for operational launch of the new procedure as soon as the weather conditions require it.
When visibility is less than 1,500 metres and the cloud ceiling is lower than 300 feet, the air traffic controllers and pilots are no longer able to make accurate visual observations of flight movements on and around the airport grounds. At that point, Low Visibility Procedures (LVP) take effect. In recent years at Schiphol, LVNL has encountered low visibility on about 30 to 40 days a year. On about 10 of these low visibility days, Schiphol Centre had a different runway visual range than runway 36L (Polderbaan). When Low Visibility Procedures take effect, various safety precautions are implemented, such as increasing the distance between aircraft and adding extra security on the departure and landing runways by placing stop bar lights on the runway entrances and exits. There are four LVP categories, designated phases A through D, with phase D representing the worst visibility conditions.
LVNL experts about the new procedure