|CAP2191: Clued Up Update: GPS Approaches|
From June 25 2021 the UK no longer has an agreement to use the European Galileo European Geostationary Navigation Overlay Service (EGNOS), which was used to provide better lateral and vertical position accuracy to allow LPV approaches to be made to lower minima. The full update can be found here.
Properly equipped aircraft can use ‘GPS procedures’ for an approach to suitably equipped runways with minima similar to a Category 1 Instrument Landing System (ILS).In practice that means aircraft using approved onboard equipment, rather than ground-based navigation aids such as an ILS, can descend to 200ft on the approach before deciding whether to continue to land or go-around. Without it the Minimum Descent Height tends to be 400ft or higher.
Without the use of the European ‘augmentation system’, and in close co-ordination with the affected aerodromes, NOTAMs are being issued to notify pilots that LPV lines of minima on the RNP IAPs are not available for use from the 25 June 2021 until further notice.
As a result, pilots will need to make use of the other elements of the RNP instrument approaches, LNAV and LNAV/VNAV(BaroVNAV) or alternative instrument approach procedures where available, and plan flights taking account of the loss of LPV operating minima at affected airfields.
Crown Dependency aerodromes such as Jersey, Guernsey and Alderney have separate arrangements for access to EGNOS and will retain their LPV procedures after June 25.
There are two EGNOS Ranging and Integrity Monitoring Stations (RIMS) in the UK and they will continue to operate; it’s also expected that the signal-in-space will remain unchanged after 25 June 2021. So, provided that the received signal is still indicating adequate integrity, pilots won’t be required to de-select the EGNOS signal from their GPS and the service can still be used in other flight phases.