General Procedure for GPS Non-Precision Approaches

T-6A INSTRUMENT NAVIGATION

CHAPTER EIGHT

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.

WARNINGS

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

holding pattern.

GLOBAL POSITIONING SYSTEM

8-9