TM 1-1520-238-10 4-14 Change 4 The missile system prompts presented to the CPG are shown in either the sight status or weapons status section of the high action display. Autonomous designation mis- sile launch prompts are shown in the weapons status sec- tion: remote designation missile launch prompts are shown in the sight status section. Autonomous designa- tion is defined as when the missile code of the priority channel and the code of the LRF/D are the same and the selected sight is TADS plus the laser power is turned on. Remote designation is defined as when the missile code of the priority channel and the code of the LRF/D are not the same. Time of flight is displayed for all missile launches and re- flects the time of flight for the missile closest to the target. Temperature compensation is incorporated when calcu- lating missile time of flight / . Ripple fire engage- ments have individual time of flight counters displayed, one for the autonomous missile, and one for the remotely designated missile, regardless of the order of their launch. With –45 software the pilot cannot launch missiles for au- tonomous designation; consequently only one set of prompts is displayed in the weapons status section of the high action display . Time of flight is displayed to the pilot for any missile that he has launched. With –49 soft- ware the pilot can conduct autonomous launches. Pilot prompts and TOF displays remain the same as described above. Steering commands for the missile constraints box will be driven by the TADS LOS during LOAL DIR. The missile constraint steering box will be driven by the NAV LOS regardless of autonomous or remote moding during LOAL HI and LOAL LO launches / . The sight status section will reflect the codes of the upper and lower channels, UP=ALO=B; the code of the priority channel will flash. Authorized engagement ranges for the Hellfire System are from 500 meters to 8000 meters. 4.11 FIRE CONTROL COMPUTER (FCC). The FCC is the primary bus controller. The FCC controls all data transmissions on the multiplex bus during normal operations. The FCC processes and computes data for all fire control capabilities on board the helicopter (fig 4-8). The FCC continuously executes internal built-in-tests and in the event of a failure signals the BBC to assume control of the bus. The FCC, BBC and FAB MRTUs are turned on with the switch labeled FCC/MUX ON (fig 4-14). Flight crew personnel shall ensure that this switch is in the ON position at all times, except for when applying power to the aircraft systems when the aircraft has been heat soaked in direct sunlight for more than 1 hour and the ambient tem- perature exceeds 100 degrees Fahrenheit. With these conditions present, the FCC/MUX switch shall be placed in the OFF position for at least two minutes after power has been applied with the FAB fans running in the STBY position to remove the superheated air from within the crit- ical LRUs. Otherwise the switch is ON during any ground or flight operations. The FCC receives 115 vac power from the No. 1 essential bus and 28 vdc power from the No. 3 essential dc bus and is protected by the FCC AC and FCC DC circuit breakers located on the CPG circuit breaker panel. To determine the FCC software code, place the DEK to SP1 and enter C. The software code is dis- played to the right of the dash. To determine the FCC software code, press the CDU PGM FAB. The software version is displayed on line 6 of the CDU display. 4.12 BACKUP BUS CONTROLLER (BBC). The BBC is part of the CPG MRTU (fig 4-8). The BBC monitors the primary bus controller for faults during nor- mal operations. The BBC automatically assumes control of the multiplex bus when it senses a failure of the FCC. The CPG can manually select the BBC as the primary bus controller by placing the MUX switch on the CPG FIRE CONTROL panel (fig 4-14) to the SEC position. When the BBC is the primary bus controller several fire control op- erational capabilities are not available. They are: Gun and Rocket ballistic solutions; Fault Detection/Location Sys- tem; and Waypoint/Targeting. All other fire control capabil- ities are available and function identically as under FCC bus control. The BBC receives 28 vdc power from the No. 3 Essential DC bus and is protected by the MUX/CPG cir- cuit breaker located on the CPG circuit breaker panel. The status of the BBC is continuously monitored by FD/LS; the on command test (test 08-MUX) will fault isolate to the LRU. 4.13 MULTIPLEX BUS SUBSYSTEM (MUX). The MUX (fig 4-8) consists of remote terminal (RT) units and a redundant data bus. The RTs are used to interface the various subsystems on board the helicopter. Three helicopter subsystems, the digital automatic stabilization equipment (DASE), the remote Hellfire electronics (RHE) unit, and the symbol generator also function as RTs. The RHE provides multiplex bus interface for the missile sys- tem electronics. The DASE provides multiplex bus inter- face for itself, ADSS, transmission and APU FD/LS, BUCS LVDTs, and the heading attitude reference system. The symbol generator receives only data from the bus to use in generation