EFIS FAN FAIL annunciator light (amber).
Illumination indicates failure of EFIS cooling fan.
placarded AP EFIS 1 (green) and AP EFIS 2 (amber) on
the pilot's side of the instrument panel and AP EFIS 1
(amber) and AP EFIS 2 (green) on the copilot's side
(indicator only), allows selection of information from
EFIS # 1 or EFIS # 2 for controlling the autopilot.
Autopilot/yaw damper annunciator light. A
split annunciator light (green) placarded AP ENG and
YD ENG, illuminates to indicate that the autopilot and/or
yaw damper is engaged.
Rudder boost/autopilot trim annunciator.
The upper half of this split annunciator, placarded
RUDDER BOOST (amber), illuminates to indicate that
the rudder boost has failed. The lower half of the
annunciator, placarded AP TRIM (amber), illuminates to
indicate that the autopilot trim has run longer than 5 to 8
Table 2-8. Mission Control Panel Annunciator Legend
CAUSE FOR ILLUMINATION
Security equipment is holding cipher key when aircraft's wheels are down and
TWTA INTLK DEFEAT toggle switch on mission status panel is set to OFF
A request for VOW communication is being received by mission equipment.
3 f AC OFF
Loss of three-phase AC power from either mission inverter if 3 0 AC CONTROL
BUS CROSS TIE switch is set to OFF. Indicates a loss of three-phase AC
power from both mission inverters if 3 0 AC CONTROL BUS CROSS TIE
switch is set to ON.
Cabin area containing mission equipment is overheating.
No power to mission equipment.
Overtemperature condition inside IDL nose radome.
Left ELINT power supply failure.
SPCL EQPT OVRD
Aircraft's normal +28 VDC source has been overridden to provide remaining
+28 VDC power sources to mission equipment. Enabled when MISSION
CONTROL switch is set to ORIDE position.
Right ELINT power supply failure.
Tail boom antenna is not in proper position as set by ANT ORIDE switch or
landing gear uplock switch.
NO INS UPDATE
No INS update data from either TACAN, data link, or GPS to aircraft's INS
Indicates that WOW OVERRIDE switch is in the ON Position.
LB PS OVERTEMP
Overtemperature condition in low band receiver power supply.
Transmitting elements of ASE are in passive mode.
LB PS FAULT
Failure in low band receiver power supply.
Tail boom antenna is in horizontal stowed position.
Tail boom antenna is in vertical operating position.
IDL nose radome deicer is on. Enabled by RADOME anti-ice switch on
overhead control panel.
MISSION AC ON
Three-phase AC power is being applied to mission inverter #2 AC bus. Enabled
when 3 f AC CONTROL #2 INV switch is in ON position, or when #2 INV switch
is in OFF position and BUS CROSS TIE switch is in ON/AUTO position and #1
INV switch is in ON position.
INS update is received by aircraft's INS equipment from either TACAN, data
link, or GPS.
MISSION DC ON
+28 VDC power is applied to mission equipment. Enabled by MISSION
IDL waveguides are pressurized.
EXT AC PWR ON
AC power source is connected and applied to aircraft.