AFMS N°D01 FOR GARMIN GFC700 AUTOPILOT INSTALLATION AND
RNAV/RNP NAVIGATION ELIGIBILITY
Section 4 – Normal procedures
ADDITIONAL GUIDANCE FOR RNAV GPS
NOTE: The instrument approach procedures associated with RNP APCH are en-
titled RNAV (GNSS) to reflect that GNSS is the primary navigation system. With
the inherent onboard performance monitoring and alerting provided by GNSS, the
navigation specification qualifies as RNP, however these procedures pre-date
PBN, so the chart name has remained as RNAV.
Missed approach procedures
Before commencing an RNAV (GNSS) missed approach, a MAP should be pos-
sible without reference to GPS derived navigation so that, in the event of a loss of
GPS accuracy or loss of integrity during the approach, a safe return to above Min-
imum Sector Altitude can be made.
This may be possible by dead reckoning (DR) navigation but where this is not
possible and the MAP requires reference to terrestrial navigation aids, these must
be available, tuned and correctly identified before passing the IAF and remain
available throughout the approach.
Reasons for a missed approach are many and if GPS information remains availa-
ble for the MAP, the pilot must be able to sequence the system correctly past the
MAP, in order to follow the published MAP correctly.
Pilots should be fully competent in the necessary selection routines required by
their own equipment, in order to transition to the MAP and preserve accurate nav-
igation throughout.
When GPS navigation is NOT available for the MAP, it may be necessary to re-
set the display function of the HSI/CDI to disengage GPS information and regain
VOR/LOC display. Pilots must be fully conversant with navigation display selec-
tions in order safely to follow the MAP.
Abnormal procedures for approaches
As the aircraft approaches the FAF (LNAV Only, without SBAS), the receiver au-
tomatically perform a final RAIM prediction for the approach. The receiver will
not enter the approach mode if this RAIM prediction is negative. In this case, the
approach should be discontinued.
However, this RAIM check assumes availability of the full constellation and will
not take account of scheduled interruptions or failures. This can lead to a success-
ful RAIM prediction at this point when the RAIM function itself is not available.
If RAIM is lost after passing the FAF the equipment should continue to provide
navigation, where possible for five minutes, before giving a RAIM loss indication
and this should be enough to complete the approach.
Should RAIM detect an out of tolerance situation, a warning will be given and a
missed approach should be initiated immediately.
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