 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] J. ZOPHY           ]    PASS PROGRAM NOTE        ]      55307       ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE: SEPT. 1987 ]
 ] IBM/282-8409       ]      RELEASE NOTE( )        ] REV A: 09/27/90  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI20 AND SUBS                 ]  CREW (X)  GROUND ( )  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW ( )  GNC (X)  VU ( )  SM/PL ( )] G2                              ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: FCS, IMU                                         ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: 4.35                                           ]
 ]_____________________________________________________________________]
 ] TITLE:  IMU DATA LOSS DURING MM 202 PREBURN MANEUVER                ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:  IF IMU DATA IS LOST FOR AT LEAST 960 MSEC DURING A    ]
 ] MM202 PREBURN MANEUVER, THE DAP WILL DOWNMODE TO MANUAL FREE DRIFT  ]
 ] MODE (ROTATIONAL PULSE SUBMODE IN ALL AXES).                        ]
 ] THIS DOWNMODE NORMALLY TERMINATES THE MANEUVER. HOWEVER, IF THE DAP ]
 ] WAS NOT IN THE AUTO MODE AT ANY TIME BETWEEN THE START OF THE       ]
 ] MANEUVER AND THE TIME THE IMU DATA WAS LOST, AND,                   ]
 ] A. THE IMU DATA IS RESTORED WHILE IN MM 202, THE MANEUVER WILL      ]
 ]    RE-ACTIVATE IMMEDIATELY (NOTE: THE DAP WILL REMAIN IN THE MANUAL ]
 ]    FREE DRIFT MODE). SEQUENTIAL TRANSITIONS TO MM 201 AND BACK TO   ]
 ]    MM 202 IN BETWEEN THE LOSS AND RESTORATION OF IMU DATA WILL NOT  ]
 ]    AFFECT THIS SITUATION.                                           ]
 ] B. THE IMU DATA IS RESTORED WHILE IN MM 201, THE MANEUVER WILL      ]
 ]    RE-ACTIVATE IMMEDIATELY UPON RE-ENTRY INTO MM 202, UNLESS AN OPS ]
 ]    TRANSITION OUT OF OPS 2 IS EXECUTED BEFORE RETURNING TO MM 202.  ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ] A. IF THE IMU DATA IS RESTORED WHILE IN MM 202, AND,                ]
 ]  1. IT IS DESIRED TO TERMINATE THE MANEUVER, EXECUTE A MODE         ]
 ]     TRANSITION TO MM 201, OR CYCLE THE DAP MODE TO AUTO, THEN ANY   ]
 ]     MANUAL MODE (INRTL, LVLH OR FREE DRIFT), THEN BACK TO AUTO.     ]
 ]  2. IT IS DESIRED TO CONTINUE THE MANEUVER, EITHER:                 ]
 ]   A. USE THE RHC TO MANUALLY MANEUVER THE VEHICLE (IN ANY DESIRED   ]
 ]      ROTATIONAL SUBMODE) ACCORDING TO THE ADI, OR                   ]
 ]   B. SELECT THE AUTO MODE.                                          ]
 ] B. IF THE DATA IS RESTORED WHILE IN MM 201, EITHER                  ]
 ]  1. EXECUTE AN OPS TRANSITION PRIOR TO THE NEXT ENTRY INTO MM202, OR]
 ]  2. MODE THE DAP TO THE AUTO MODE PRIOR TO THE NEXT TRANSITION INTO ]
 ]     MM202. THEN, ONCE IN MM202, CYCLE THE DAP TO ANY MANUAL MODE    ]
 ]     (INRTL, LVLH, OR FREE DRIFT), THEN BACK TO AUTO MODE.           ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]IBM: PATTI A. THORNTON    DATE 10/09/90]                             ]
 ]    --------------------      ---------]                             ]
 ]FDSD:   SAM ANKNEY        DATE 10/10/90]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 10/31/90 ]
 ]PF MGR:  K. L. LINDSAY    DATE 10/30/90]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
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