Have you ever wondered about the AFM limitation (01-03-10: Types of Airplane Operations Permitted) that says in several places: GNSS FDE availability must be verified prior to flight? In previous airplanes we assumed this meant the RAIM check but our AFM doesn’t put it that way. RAIM (Receiver autonomous integrity monitoring) simply assesses the integrity of global positioning system (GPS) signals in a GPS receiver system and we do have ways of checking that from our cockpit avionics. FDE (Fault Detection and Exclusion) goes one step further and lets us know which satellites to exclude from consideration. The regulations require FDE for oceanic and other operations. Our FMS doesn’t do this automatically and our AFM says that “GNSS FDE availability must be verified prior to flight.” How do we do that? I asked and was told that is up to us and our service provider. My service provider is ARINC Direct and our defaults did not include FDE. One phone call later and it does. (See screen grab.) The pull-down menu did not include an FDE option until we asked for it. If you solve this riddle with another service provider, please let me know how you did that and I will pass that along. See AC 20-138D for more about RAIM versus FDE.
Once this is done, you should get a reassuring note about FDE at the end of your flight plan:
Gulfstream GVII-G500 Airplane Flight Manual, Revision 4, August 29, 2019
Gulfstream GVII-G500 Production Aircraft Systems, Revision 3, July 15, 2019
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