TM 1-1520-238-10
Change 10
9-21
9.16.5 DELETED.
9.16.6 Symbol Generator Failure.
Failure of the
symbol generator will result in the loss of video to the
VDU and video recorder. Both the PLT and CPG HDUs
will automatically revert to PNVS FLIR-2 (PNVS video
with no symbology). The ORT, HOD or HDD, as se-
lected, will automatically revert to TADS FLIR-2 (TADS
FLIR video). If the CPG VID SEL switch is positioned to
TADS, the LOS reticle and the IAT gates (if operational)
symbology from the TEU will be displayed. If the CPG
VID SEL switch is set to PNVS, these symbols will not
be displayed. The AND display will continue to operate
normally. The pilot may continue flight in a degraded
mode without flight or weapon symbology. The CPG
may continue weapons engagement in a degraded
mode without range information.
9.16.7 TADS Electronic Unit (TEU) Failure.
Com-
plete failure of the TEU will cause the CPG’s displays to
lose imagery and the AND to blank. The pilot may be
limited to 75 degrees in azimuth on the PNVS and the
message PNVS DIRECT will be displayed in the HAD
sight status section.
9.16.8 FLIR Cooler Failure.
Failure of the PNVS or
TADS FLIR cooler normally occurs during FLIR cool-
down prior to flight. However, the cooler may fail in flight.
Cooler failures are indicated by a loss of resolution on
the FLIR. Resolution loss occurs gradually initially, and
becomes more rapid as detector temperatures increase
until resolution is lost completely. In the event of a PNVS
cooler failure, proceed as indicated in PNVS failure
emergency.
9.16.9 FCC Failure.
Failure of the FCC (primary
MUX BUS Controller) will be indicated by illumination of
the MASTER CAUTION and PRI MUX caution segment
lights in the pilot and CPG stations. MUX BUS control
will be automatically assumed by the BBC. In addition to
the degradations listed in Chapter 4, the following ef-
fects will be present: DASE channels may disengage
causing temporary instability; range inputs thru the DEK
range page will be accepted but will have no effect on
ordnance delivery; laser designator codes may not
transfer to BBC registers and boresight correction data
will not be available in the BBC. In the event of a PRI
MUX failure, DASE channels should be re-engaged.
The MUX switch should be placed in SEC. If weapons
system use is necessary, correct laser codes should be
confirmed and outfront boresight alignment should be
checked prior to weapons systems engagements.
