TM 55-1510-220-10 Table 2-8.  Mission Control Panel Annunciator Legend MISSION ANNUNCIATOR NOMENCLATURE COLOR CAUSE FOR ILLUMINATION GROUND CALL Yellow Incoming call detected on mission voice order wire. No. 1 OPR CALL Yellow Operator No. 1 calling on ICS. No. 2 OPR CALL Yellow Operator No. 2 calling on ICS. AIR LINK Yellow Quality of signal on air-to-air is deteriorating. 3  Ø AC OFF Yellow Three phase AC power to INS is off. BATT FEED FAULT Yellow Ground fault detected in battery external power line. FILTER PRESS Yellow The pressure in one of the UHF diplexers is low, and needs to be recharged by maintenance personnel. GROUND LINK Yellow Quality of signal on air/ground/air link is deteriorating. SPCL EQPT OVRD Yellow Mission override switch in override position. NO INS UPDATE Yellow INS is not updating with GPS or TACAN information. MISSION AC ON Green Mission 3Ø  400 Hz AC is on. INS UPDATE Green INS is updating with GPS or TACAN information. MISSION DC ON Green Mission DC is on. EXT AC PWR ON Green External AC power is on. EXT DC PWR ON Green External DC power is on. BT01491 caution annunciator illuminates, the MASTER CAUTION will illuminate,   and   will   stay   illuminated   until   the   MASTER CAUTION annunciator is pressed to reset the circuit.  If a new condition occurs, the light annunciator will be reactivated and the appropriate annunciator panel annunciators will illuminate. b. Clocks.  One manually-wound 8-day clock is mounted in the center of the pilot's control wheel and an electric digital clock is mounted in the center of the copilot's control wheel. c. Copilot's  Clock.    The    copilot's  clock  (fig.  2-18)  is  a five-function,    six    digit,    clock-timer    utilizing    three    button operation.      Each   of   the   five   functions   can   be   selected   for viewing.      This   clock-timer   has   a   liquid   crystal   display   for readability in sunlight and an internal light for night use.  The clock has an internal battery to maintain time when the aircraft power is off. (1) Mode selection.    The  MODE  button  is  pressed to   select   the   desired   operation.      The   mode   annunciator   is displayed  above  the  mode  identifiers.    Pressing  the  MODE button will advance the annunciator to the desired operation. LC - Local Time ZU - Zulu or Greenwich Mean Time TR - Trip or Flight Timer ET - Elapsed Time DC - Downcounter with Alarm (2) Clock timer mode. (a)    Setting  Local  Time.    Press  the  MODE button  to  advance  the  annunciator  to  LC.    To  set  hour,  press RST button once, then press ADV button and hold until correct hour  is  displayed.    To  set  minutes,  press  RST  button  once  so that minutes and seconds are displayed.  (Always set to the next Change 5   2-78A/(2-78B blank)