ILS GLIDESLOPE FAILURE
Loss of ILS glideslope signal is indicted by the appearance of the GS flags on the HSI and ADI and the
loss of glideslope indications on these instruments. With this failure, you have the choice of downgrading
your approach to a localizer only, discontinuing the approach, or flying another type of approach (TACAN,
VOR, PAR, or ASR) depending on the situation and availability of approaches. Remember that if you
downgrade to a localizer only, you will have to adjust your approach minimums.
VOR/ILS receiver failure - See NATOPS, Chapter 21
Figure 49 shows the location of the GS flag on the HSI. A similar flag is located on the ADI.
ILS LOCALIZER FAILURE - See NATOPS, Chapter 21
Figure 50 shows the location of the NAV flag on the HSI and LOC flag on ADI. Remember, a LOC flag on
the ADI serves the same function in the event of a localizer failure.
ILS MARKER BEACON FAILURE
If you lose ILS marker beacon indications, you may still be able to complete your approach, if you can use
TACAN/DME, radar, or TACAN crossing radials to determine marker beacon positions. Remember that
you may have to adjust your approach minimums when you lose marker beacon indications.
FLIGHT WITH PARTIAL PANEL
See Basic Instrument Maneuvers section of this FTI for further information.