Garmin GNS 430 Pilot's Manual And Reference page 202

SECTION 12 – FAULT DETECTION
AND EXCLUSION
12.2 PRE-DEPARTURE VERIFICATION OF
FDE
Since FDE is based upon the exclusion of 'bad' satellites,
it is necessary to ensure there will be an adequate number
of satellites in the GPS constellation that are still able to
provide a navigation solution. An FDE prediction must be
performed prior to departure for a flight involving:
• Oceanic/Remote operation where GPS is to be the
sole source of navigation per FAA Notice 8110.60
• U.S. Area Navigation (RNAV) routes, Standard
Instrument Departures (SIDs), or Standard
Terminal Arrival Routes (STARs) if a NOTAM
indicates a GPS satellite (or satellites) is scheduled
to be out-of-service, per FAA AC 90-100 'U.S.
Terminal and En Route Area Navigation (RNAV)
Operations'
12-2
Prior to departure, the operator must use the FDE
Prediction Program supplied with the 400 Series Trainer
Software (Figure 12-2) to demonstrate that there are no
outages in the capability to navigate on the specified
route of flight (the FDE Prediction Program determines
whether the GPS constellation is robust enough to provide
a navigation solution for the specified route of flight). The
trainer software and the document '400/500 Series FDE
Prediction Instructions' (190-00643-00) are available on
Garmin' s web site for free download (www.garmin.com).
Figure 12-2 Garmin 400 Series Trainer Software
GNS 430 Pilot's Guide and Reference