WFDE PREDICTION PROgRAM INSTRuCTIONS
1
OVERVIEW
The following sections provide an overview of the WFDE Prediction Program and guidelines for when it should
be used. Section 1.2 provides a comprehensive set of guidelines for when a WFDE prediction is required that is
applicable to any installation of a Garmin WAAS enabled unit. Section 1.3 provides specific guidance for GTN
6XX/7XX installations.
1.1
FAulT DETECTION AND ExCluSION (FDE)
The GARMIN G1000 with GIA 63W, the GNS480/CNX80, and the GNS 400W/500W series products incorporate Fault
Detection and Exclusion (FDE) features, satisfying the requirements of TSO-C145a/C146a and "GPS Oceanic/Remote
Navigation" per FAA AC 20-138A Appendix 1. The GTN 6XX/7XX series products incorporate Fault Detection and Exclusion
(FDE) features, satisfying the requirements of TSO-C146c and "GPS Oceanic/Remote Navigation" per FAA AC 20-138A
Appendix 1. For the purposes of this document, WAAS FDE Prediction, FDE Prediction, and WFDE Prediction may be used
interchangeably.
FDE consists of two distinct parts: fault detection and fault exclusion. Fault detection (RAIM) detects the presence of an
unacceptably large pseudorange error (and presumably, position error) for a given mode of flight or a satellite failure which
can affect navigation. Fault detection is synonymous with RAIM (Receiver Autonomous Integrity Monitoring). Upon the
detection of a fault, fault exclusion follows and excludes the source of the unacceptably large pseudorange error, thereby
allowing navigation to return to normal performance without an interruption in service. FDE functionality is provided for
oceanic, en route, terminal, and non-precision approach phases of flight. The FDE functionality adheres to the missed alert
probability, false alert probability, and failed exclusion probability specified by TSO-C145a/C146a and TSO-C145c/C146c.
The WFDE Prediction Program is used to predict the availability of RAIM/FDE for a specified flight plan. This program
allows the pilot to specify the planned departure date/time, route type, ground speed, ground speed variation, and maximum
allowable outage. When provided through NOTAM or other sources, GPS satellites with known failures can be excluded
through the program's setup function.
NOTE: WAAS is one of several systems generically known as SBAS (Satellite Based Augmentation System). Garmin
WAAS certified products are designed to work with any TSO-C145a/C146a or TSO-C145c/C146c compliant SBAS
system.
The WFDE Prediction Program is designed for use with TSO-C145a/C146a and TSO-C145c/C146c approved WAAS-
(Wide Area Augmentation System) certified Garmin products. These products include:
• GPS 400W, GNC 420W, GNC 420AW, GNS 430W, GNS 430AW
• GPS 500W, GPS 500W TAWS, GNS 530W, GNS 530W TAWS, GNS 530AW, GNS 530AW TAWS
• GNS 480, CNX80
• G1000 with GIA 63W
• GTN 625, GTN 635, GTN 650, GTN 725, and GTN 750
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190-00643-01_0E.indd 2
GARMIN WAAS FDE PREDICTION PROGRAM INSTRUCTIONS
190-00643-01 Rev. E
2/28/2011 1:24:33 PM
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