|CHAPTER 3. Navigation
The FMS/GPS unitís nonsequencing mode provides an easy way to fly missed approach procedures, such as the one illustrated in Figure 3-56.
The missed approach procedure shown in Figure 3-56 requires you to climb to 1,900 feet, turn right and climb to 6,000 feet, then proceed direct to the SNS VOR.
The FMS/GPS helps you navigate between waypoints, which are geographically fixed locations. But where will the aircraft reach 1,900 feet on the missed approach procedure at Monterey? This depends on what aircraft you are flying and the chosen rate of climb. A single-engine airplane might be four miles away by the time it reaches 1,900 feet. A small jet might reach 1,900 feet by the end of the runway. The problem is that, given the way the FMS/GPS system uses waypoints, there is no one way to represent the climbs and turns required on a missed approach procedure.
To address this issue, all FMS/GPS RNAV units automatically suspend waypoint sequencing when you reach the missed approach point. The unit waits until you acknowledge the passing of the MAP before it continues the sequencing. When the aircraft has gained the published altitudes and complied with the initial MAP procedures, you can safely proceed to the missed approach holding waypoint, being mindful of any altitude requirements. A waypoint for the missed approach holding point is included as part of the missed approach procedure. In the example above, you can make the missed approach holding waypoint the active waypoint, and re-engage the sequencing mode upon reaching 6,000 feet. You now have sequencing mode guidance to the missed approach holding waypoint. The procedure for one FMS/GPS is illustrated in Figure 3-57.
Since the hold at SNS is part of the published missed approach procedure, it can be carried out using the same technique used to perform a holding pattern. Some FMS/GPS units will automatically switch to the nonsequencing mode when you reach the hold fix. Other units may advise you to switch manually to the nonsequencing mode.
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