offset by the requested altitude by more than 10 feet, VNAV performance will
suffer.
If altitude hold is offset by more than 10 feet, simply leave the autopilot in ALT
HOLD for 5-10 minutes in smooth air. During that time, the autopilot will
automatically remove the erroneous altitude offset. Once the offset is resolved, the
autopilot will be able to track VNAV guidance ideally.
Selecting VNAV always causes ALT HOLD to engage, with the VNAV mode armed. Only when the
glideslope/ or VNAV Indicator next to the HSI can be captured – as the GS/VNAV indicator
comes alive – will the Autopilot sequence to VNAV mode.
The altitude that is held prior to VNAV must be below the glideslope/VNAV profile. In other
words, when VNAV is armed, the glideslope indicator should be above its centered position. If
you descend through a vertical course from above with VNAV mode armed, the autopilot will
ignore the vertical need and simple fly through the course with no intercept.
When the autopilot mode sequences, the autopilot annunciation in the top bar will blink for 10
seconds.
Flight Director
The flight director is a visual indication on the PFD that shows what the aircraft should do in
order to satisfy the targets of the currently active autopilot modes. A flight director allows the
autopilot to provide guidance while you is still allowed to provide direct control of the aircraft.
There are two types of flight director symbologies available in the Expert autopilot control
scheme: a single cue or inverted-V; or a dual cue or cross bars.
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