
Abnormal Procedures
5-19
GLIDE SLOPE INVALID
Failure Indication:
If the DFC-PFD system recognizes that the VHF vertical nav
signal (glide slope) from the GPS Nav-Com is invalid, a yellow
“
GS INVALID
” message is displayed on the PFD. In addition, the
Vertical Deviation Indicator (VDI) along the right edge of the ADI
will be Red-
X’d.
Functionality Lost:
The ability to track a VHF vertical course (Glide Slope) from the
selected GPS Nav-Com navigator has been lost.
Recommended Pilot Action:
Consider switching the navigator that is driving the PFD VDI and
autopilot.
If unable to select a usable alternative navigation source, take the
proper action when the glide slope signal has been lost. If on a
published ILS approach, transition to non-precision approach
procedures and minimums or go missed approach.
Change 3