The FAA is recommending that operators upgrade certain Collins Aerospace GNSS receivers that are not meeting minimum operational performance standards for processing an integrity message from Europe’s satellite-based augmentation system (SBAS), the agency noted in a Special Airworthiness Information Bulletin (SAIB). Currently, the condition does not warrant an airworthiness directive, the FAA said. EASA issued a mandatory directive last year, AD 2025-0088, requiring replacement of affected receivers for aircraft registered in member states.
According to the FAA, the issue stems from a November 2023 ground system update to the European Geostationary Navigation Overlay Service (EGNOS), which exposed noncompliance in affected Collins GPS-4000S, GLU-2100, GLUS-2100, and GLUS-2100A receivers. This noncompliance results in incorrect processing of the Message Type 6 integrity alert, which the FAA said may affect the availability of Localizer Performance with Vertical guidance and other SBAS-based approach types. The issue is most prevalent within EGNOS coverage but may affect other SBAS regions.