 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] J. H. CHUAN        ]    PASS PROGRAM NOTE        ]     25108        ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:            ]
 ] VER/282-8937       ]      RELEASE NOTE( )        ] SEPT. 1987       ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] REL 19 AND SUBS               ]  CREW ( )  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW ( )  GNC (X)  VU ( )  SM/PL ( )] G6                              ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: DOWNLIST                                         ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: 4.43                                           ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ] INVALID TACAN CONTROL REGISTER OUTPUT                               ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ] IN OPS 1, PASS CYCLICALLY OUTPUTS THE TACTICAL AIR NAVIGATION       ]
 ] (TACAN) CONTROL REGISTER AND DISCRETE WORD TO TACAN'S EVEN THOUGH   ]
 ] THE SOP DOES NOT RUN (THIS IS NECESSARY TO ACCOMMODATE RETURN-TO-   ]
 ] LAUNCH SITE (RTLS) REQUIREMENTS). SINCE THE SOP DOES NOT RUN, THE   ]
 ] OUTPUT BUFFER SLOTS FOR THE CONTROL REGISTER ARE ZERO. THIS RESULTS ]
 ] IN THE SYNC BIT BEING OFF WHICH, IN GPC MODE, CAUSES THE TACAN      ]
 ] LINE REPLACEABLE UNIT (LRU) TO REJECT THE CONTROL REGISTER. IN      ]
 ] ADDITION, THE DOWNLIST OF "TACAN CONTROL REGISTER" SHOWS THE DATA   ]
 ] IN THE OUTPUT BUFFER (I.E., ALL ZERO'S) WHICH CAUSES THE GROUND     ]
 ] TO HAVE AN ERRONEOUS PICTURE OF THE STATUS OF THE TACAN (IT MAY BE  ]
 ] TRANSMITTING ON CHANNEL 69 WHILE DOWNLIST SAYS IT'S IN RECEIVE      ]
 ] ONLY/CHANNEL 0).                                                    ]
 ]                                                                     ]
 ] FINALLY, WITH THE INVALID CONTROL REGISTER, IT IS INDETERMINATE     ]
 ] WHAT STATE WILL FOLLOW A TACAN POWER CYCLE.                         ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ] A. RECOGNIZE THAT AS LONG AS NO POWER TRANSIENT OCCURS, THE TACAN'S ]
 ]    WILL REMAIN IN THE SAME STATE IN OPS 1 AS THEY WERE IN OPS G9    ]
 ]    WHEN THE TRANSITION WAS STARTED.                                 ]
 ] B. WITH A POWER TRANSIENT, THE TACAN CONTROL SWITCH SHOULD BE       ]
 ]    MOVED TO THE DESIRED STATE (T/R OR R ONLY, ETC.) AND BACK TO     ]
 ]    GPC TO RETAIN THE KNOWN DESIRED STATE.                           ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]IBM: WYATT COOPER         DATE 07/29/88]                             ]
 ]    --------------------      ---------]                             ]
 ]SSD: SAM ANKNEY           DATE 08/02/88]                             ]
 ]    --------------------      ---------]  JACK G BOYKIN     08/17/88 ]
 ]PF MGR: RAY W NUSS        DATE 07/29/88]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
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