 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] L. HOLLAND         ]    PASS PROGRAM NOTE        ]    45703         ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE: SEPT. 1987 ]
 ] IBM/282-7305       ]      RELEASE NOTE( )        ] REV B: 01/30/91  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] REL 19 AND SUBS               ]  CREW (X)  GROUND ( )  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW ( )  GNC (X)  VU ( )  SM/PL ( )] G6, G3                          ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: NAV, RM, SPEC, ENTRY                             ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: 4.77                                           ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ] TACAN DILEMMA INDICATION                                            ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ] SCENARIO:                                                           ]
 ]  MAJOR MODE IS 304, 305, 602 OR 603.  THE USE OF TACAN DATA HAS     ]
 ]  BEEN ENABLED VIA HORIZ SIT DISPLAY (SPEC 50, ITEM 19).  ONE TACAN  ]
 ]  IS LATER LOST DUE TO POWER FAILURE OR COMMFAULT.  THEN ONE OF THE  ]
 ]  REMAINING TACANS EXPERIENCES A TRANSIENT ERROR IN THE BEARING DATA ]
 ]  FOR LESS THAN NINETEEN SECONDS (A DILEMMA WILL SUBSEQUENTLY BE     ]
 ]  DECLARED).  MORE THAN NINETEEN SECONDS AFTER THE TACAN TRANSIENT   ]
 ]  ERROR FIRST APPEARS, EITHER THE CONE OF CONFUSION IS ENTERED, OR   ]
 ]  BOTH REMAINING TACANS FAIL AT EXACTLY THE SAME TIME DUE TO POWER   ]
 ]  FAILURE OR COMMFAULT.  PRIOR TO MLS DATA ACQUISITION, EITHER THE   ]
 ]  CONE OF CONFUSION IS EXITED OR THE SAME TWO TACANS WHICH HAD A     ]
 ]  DILEMMA AND WERE THEN FAILED SIMULTANEOUSLY, AGAIN BECOME AVAIL-   ]
 ]  ABLE AT EXACTLY THE SAME TIME.                                     ]
 ] RESULT:                                                             ]
 ]  THE DILEMMA BETWEEN THE REMAINING TWO TACANS' BEARING DATA REMAINS,]
 ]  AS INDICATED BY A '?' IN THE STATUS FIELD OF THE BEARING DATA ON   ]
 ]  HORIZ SIT DISPLAY.  THERE IS ALSO DATA IN THE RESIDUAL AND RATIO   ]
 ]  FIELDS FOR THE TACAN BEARING ON THE HORIZ SIT DISPLAY; THIS        ]
 ]  INDICATES THAT NAVIGATION IS PROCESSING THE BEARING DATA FROM THE  ]
 ]  TWO TACANS.                                                        ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ]                                                                     ]
 ] ON SPEC 50, DESELECT AND THEN RESELECT ONE OF THE TWO AFFECTED      ]
 ] TACANS TO CLEAR THE DILEMMA.                                        ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]IBM:J.ZOPHY FOR P.THORNTONDATE 02/26/91]                             ]
 ]    --------------------      ---------]                             ]
 ]FDSD:   W. R. PRUETT      DATE 02/26/91]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 02/27/91 ]
 ]PF MGR:  M. N. MONTEZ     DATE 02/27/91]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
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