NLR’s Cessna Citation II laboratory aircraft was used to evaluate the approach procedure designed by NLR. This formed part of the EU project ACCEPTA: ACCelerating EGNOS adoPTion in Aviation.
The European Geostationary Navigation Overlay Service (EGNOS) is a European system that enhances the accuracy and reliability of GPS. EGNOS can pinpoint the position of an aircraft within a two-metre margin of accuracy. This is specifically crucial in facilitating vertical guidance based on satellite navigation.
Large airports like Schiphol make use of the Instrument Landing System (ILS) to automatically make landings possible when visibility is extremely poor. The ILS radio navigation system is highly reliable, but also very expensive. At smaller airports such as Eelde, where some runway ends are not supported by an ILS, pilots do not receive automatic support for vertical guidance. Instead, they make use of a table showing the altitude the aircraft should be given the distance to the runway.
At these smaller airports, satellite navigation landings also offer numerous advantages, including greater safety. Should existing ground systems be down or undergoing maintenance, satellite based navigation ensures that landings can be guided vertically. The ILS signal on the ground also needs to be protected from interference caused by aircraft or vehicles. GPS signals are not affected by this, which can help to improve landing capacity.
Satellite navigation also facilitates curved approach landings, making it possible for flight paths to circumvent residential areas and reduce noise nuisance. Additionally, satellite navigation will make landing procedures more efficient, as the airport becomes more accessible because landings are possible even when visibility conditions deteriorate; compared to conventional non-precision approaches using ground beacons. Moreover, no new systems are required at the airport, making it relatively inexpensive.
Eelde Airport was selected to implement the new approach procedure (an airport of national significance) because it accommodates several flight academies and because approaches like this will soon be adopted as the standard. Aspiring pilots will therefore be able to gain experience with such procedures. Donor flights for the hospital in Groningen will also benefit from Eelde airport’s improved accessibility due to this type of approach.
Since November 2014, it has been possible in the Netherlands to carry out an approach using satellite-based vertical guidance. Aircraft that have an operational approval can use the approach procedure as specified in the Aeronautical Information Publication (NL AIP), which pilots and airlines can consult for airport landing maps.
ACCEPTA is partly financed by the European Union (FP7) and largely financed by the Netherlands Ministry of Infrastructure and the Environment (I&M). I&M attaches great importance to implementing approaches using satellite navigation in the absence of ILS, because vertical guidance is prescribed by the International Civil Aviation Organisation (ICAO).