EASA SIB 2012-21: WITHDRAWN - Temporary Degradation of EGNOS Performance

What to do

Pilots and operators should review NOTAMs for destination and alternate airports before flight to stay informed about EGNOS performance issues. They must be prepared for possible unavailability of SBAS/GNSS-based vertical navigation during approaches and ensure contingency procedures or alternate approaches are ready. No mandatory compliance deadline is specified, but continuous monitoring and coordination with ANSPs and ESSP are advised.

Summary

EASA Safety Information Bulletin 2012-21 is a notification regarding the temporary degradation of the European Geostationary Navigation Overlay Service (EGNOS) performance in the North and North East of Europe. This affects all aircraft certified for RNAV/GNSS approaches to LPV minima or LNAV/VNAV minima when using SBAS/GNSS altitude guidance. The bulletin informs that while the EGNOS Safety of Life service integrity remains uncompromised, there are periods of degraded performance impacting APV-I and Open Service accuracy, particularly around midnight UTC.

What changed

This bulletin reports a degradation in EGNOS APV-I performance impacting availability and continuity in the specified European regions. It highlights that LPV and SBAS-based LNAV/VNAV approaches may be affected during certain hours, but other GNSS-based operations remain unaffected. The document does not introduce new regulations but provides updated operational information and safety recommendations.

Why it matters

The degradation may cause increased alerts or loss of navigation signals during SBAS-based approaches, potentially leading to loss of vertical navigation functions. Aviation professionals must be aware of these limitations to ensure safe flight operations and maintain compliance with approach procedures. Understanding this situation helps operators and pilots prepare for possible approach interruptions and maintain safety margins.