T-6A INSTRUMENT NAVIGATION
4. The aircraft must be heading towards the FAF and the FAF or co-located IAF/FAF must be
the active waypoint.
If any of the these conditions are not met and conditions do not change prior to the FAF, the GPS
will not transition to approach active and a missed approach must be performed. Do not delay
the switch from OBS to LEG mode. A late switch could inhibit the approach active mode or
compress the scale factor change on the CDI/RMI. An abrupt scale factor change could be
mistaken for actual deviations on final causing the pilot to make unnecessary corrections. Once
in the approach active mode, the CDI scale will change to + 0.3 NM. If the GPS APR switch is
pressed when the GPS is in approach active mode, the GPS will deselect approach active and
return the system to approach arm mode and CDI scale to + 1 NM. Once past the FAF, it is not
possible to return to the approach active mode without conducting a missed approach and flying
back to the FAF.
1. In no case will aircrew fly the final approach segment using
manual waypoint sequencing.
2. Use of the KLN 900 may cause excessive "Heads-down"
time. Aircrews must continue to maintain a vigilant "See and
Avoid" doctrine while conducting GPS approaches in VMC.
If the receiver does not sequence into the approach mode or a RAIM failure/status annunciation
occurs prior to the Final Approach Waypoint (FAWP), the aircrew should not descend to MDA,
but should proceed to the MAWP via the FAWP, perform a missed approach, and contact ATC
as soon as practical. If the RAIM flag/status annunciation appears after the FAWP, the missed
approach should be executed immediately by climbing to the FAF altitude and flying along the
FAC to the MAWP and conduct the published missed approach procedure. Turns should not
begin prior to the MAWP.
Once an approach has been added to the active flight plan, a new entry is placed following the
MAP. The new line entry reads "NO WPT SEQ" and stands for no waypoint sequencing.
Because many missed approach procedures require certain specific actions to be completed prior
to proceeding to the missed approach holding point, the GPS will not automatically sequence
past the MAP. To call up the missed approach procedure, press the "Direct To" button once past
the MAP. The first waypoint in the missed approach procedure will be the active waypoint. To
confirm the missed approach procedure waypoint, press ENT. Always refer to the approach
plate when conducting the missed approach and comply with the charted missed approach
procedures. Missed approach routings in which the first track is via a course rather than direct to
the next waypoint require additional action by the pilot to set the course. Being familiar with all
of the inputs required is especially critical during this phase of flight. The OBS mode is usually
needed at some point during a missed approach and is always required to fly the missed approach
GLOBAL POSITIONING SYSTEM