Austro Control developing innovative approach procedures The new localiser performance with vertical guidance (LPV) approach procedures offer an economical alternative to ILS systems. LPV can be used on larger airfields as well as at airports.
The new LPV approach procedures are built on satellite-based augmentation systems (SBASs) that supplement existing satellite navigation systems such as GPS, and GNSS in general. Europe’s SBAS system, the European Geostationary Navigation Overlay Service (EGNOS), increases the positional accuracy of GPS in the region from 10-20 metres to 1-3 metres, thus making a considerable contribution to increased safety. In future, it will be possible to implement approach procedures similar to ILS systems without the need for any ground-based infrastructure. These LPV procedures will significantly improve safety levels at airports and airfields not equipped with ILS, and in general aviation.
LPV procedures are divided into three categories:
- LPV (localiser performance with vertical guidance): approach procedures based on SBAS technology with a decision height down to 250 feet.
- LPV 200: this is the latest version of LPV, with a published decision altitude of down to 200 feet i.e. equivalent to an ILS Category I landing, but without the need for ground-based infrastructure.
- LP (localiser performance without vertical guidance) is useful where the topography and difficult terrain surrounding an airport make vertical guidance unusable, e.g. Innsbruck.
The IMPROWE project (implementing RNP APCH operations with EGNOS) initiated by Austro Control in collaboration with the German Aerospace Center and LPS, the Slovak air traffic management organisation, will focus on the implementation of SBAS-supported approach procedures. For Austro Control, this EU-supported project entails the design and implementation of four LPV/LP procedures in Austria: two LPVs for Vienna Airport (RWY 16/34), one LP for Innsbruck and a further LPV200 procedure for Vienna. At present, the airports in Linz and Graz have corresponding SBAS/LPV approach procedures installed. Implementation should be completed by the end of 2016 or early in 2017.
As a supplement to existing ILS procedures, LP/LPV procedures introduce a cost-effective alternative that is not intended to displace ILS landings but rather to provide an attractive approach alternative with height information, particularly for general aviation. Austro Control has been a European pioneer in developing these procedures.
The IMPROWE project now offers the opportunity to design Category I approaches for airports or airfields with the appropriate ILS infrastructure but without ground-based ILS stations. The use of this new procedure, particularly in general aviation, is made possible in large part by the increased use of modern avionics systems. While SBAS equipment is rarely used by commercial airlines, it is likely to spread quickly in general aviation. Existing equipment such as the Garmin 430W is already LPV-compatible, so as far as the aircraft are concerned such approaches are already possible.
Under EASA regulations, an IFR runway with an appropriate approach and runway lighting system is still required for LPV approaches, but especially for smaller airfields, creating an IFR-compliant system is a considerable expense; the UK is leading an initiative to have the new procedures approved for use even where there is no IFR runway. The thinking is that this would in all events result in higher levels of safety than the existing published procedures.
