Eurocontrol, the European Space Agency and the European Commission have been testing helicopter approaches using the European Geostationary Navigation Overlay System. The agencies recently completed a series of EGNOS trials in Lausanne, Switzerland, where the system was used to guide a Eurocopter EC155 helicopter as it approached and landed at an helicopter emergency medical services landing pad.
The trial approaches were designed by Swiss air navigation services provider, Skyguide for 6° and 9° approach angles. According to ESA, which is jointly developing EGNOS with the European Commission and Eurocontrol, "initial feedback from the test pilots indicates that, despite of the steepness of the approaches - the standard approach angle is 3°- the approaches were easy to fly due to the three-dimensional guidance provided by EGNOS. Vertical guidance for the pilot provides a major advantage EGNOS offers over standard GPS."
The increased approach angles also reduce noise nuisance on the ground as the helicopter can remain at high altitude until it is closer to its destination before starting its final descent. In addition, a steeper descent angle reduces the noise generated by the rotor blades as the helicopter approaches the ground.
These recent trials were carried out as part of an EC Sixth Framework Programme project called "GNSS introduction in the aviation sector" (Giant). Its objective is to support the introduction of EGNOS and finally the use of Europe's own GNSS constellation, Galileo in aviation operations. EGNOS/Giant trials for fixed-wing aircraft were held late last year in Valencia, Spain and additional trials are scheduled this year at European airports and an oil rig in the North Sea.
Source: Flight International
