 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] J. ZOPHY           ]    PASS PROGRAM NOTE        ]     14444        ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  AUG. 1987 ]
 ] ENG/282-8409       ]      RELEASE NOTE( )        ] REV C: 02/13/90  ]
 ]____________________]_____________________________]__________________]
 ] 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 ( )] G1, G2, G3                      ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: FCS, OMS                                         ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: 4.64                                           ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ] OMS ENGINE PROBLEMS CAUSED BY GPC OR STRING FAILURES                ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ] IF, DURING THE DE-ORBIT FLIGHT PHASE, GPC-1 OR GPC-4 FAILS AND IS   ]
 ] MODED TO HALT, THEN THE LEFT OR RIGHT OMS ENGINE ACTUATOR ACTIVE    ]
 ] SELECT DISCRETES, RESPECTIVELY, REMAIN IN THE HIGH STATE AT THE     ]
 ] MDM OUTPUT (IF FORWARD MDM'S ARE NOT CYCLED DURING DE-ORBIT).       ]
 ] THIS RESULTS IN BOTH THE ACTIVE AND STANDBY SELECT DISCRETES, FOR   ]
 ] THE SAME OMS ENGINE ACTUATORS, BEING SET IN THE HIGH STATE WHEN     ]
 ] THE SECONDARY ACTUATOR DRIVE CHANNEL IS SELECTED. WITH BOTH         ]
 ] ACTIVE AND STANDBY SELECT DISCRETES SET HIGH, THE ASSOCIATED        ]
 ] ACTUATORS WILL FREEZE IN THE LAST COMMANDED STATE. (A DOWN ARROW    ]
 ] MAY APPEAR ON THE MNVR DISP AT THIS TIME).                          ]
 ]                                                                     ]
 ] NOW, IF THE R-OMS ENGINE SHOULD FAIL (FOLLOWING A GPC-1 FAILURE)    ]
 ] DURING A TWO ENGINE DE-ORBIT BURN, THEN THE L-OMS ENGINE CANNOT     ]
 ] RESPOND TO THE SINGLE ENGINE TRIM COMMAND FROM GUIDANCE. LIKEWISE,  ]
 ] IF THE L-OMS ENGINE SHOULD FAIL (FOLLOWING A GPC-4 FAILURE) DURING  ]
 ] A TWO ENGINE DE-ORBIT BURN, THEN THE R-OMS ENGINE CANNOT RESPOND TO ]
 ] THE SINGLE ENGINE TRIM COMMAND. SEE FIGURE 14444-1 FOR DETAILS ON   ]
 ] GPC CHANNELIZATION AS RELATED TO OMS ACTUATOR CONTROL. THIS RESULTS ]
 ] IN A SINGLE ENGINE BURN WITH A TWO-ENGINE TRIM NECESSITATING RCS    ]
 ] WRAP AROUND TO CONTROL VEHICLE ATTITUDE (SIMULATION STUDIES SHOW    ]
 ] THAT RCS WRAPAROUND ACTIVATED AT TIG + 90 SEC INTO A 2:28 DE-ORBIT  ]
 ] BURN COULD CONSUME 600 LBS. OF AFT RCS PROPELLANT OR APPROXIMATELY  ]
 ] 5 LBS/SEC TOTAL AFT PROPELLANT AVERAGE USAGE RATE).                 ]
 ]                                                                     ]
 ] FURTHERMORE, IF FOR ANY REASON MULTIPLE FC STRINGS ARE LOST DURING  ]
 ] AN OMS BURN, THEN THE OMS ENGINE(S) MAY NOT BE SHUTDOWN             ]
 ] AUTOMATICALLY. THE COMBINATION OF LOST STRINGS THAT WILL RESULT IN  ]
 ] THE ENGINE(S) REMAINING ON ARE: FA1 AND FA2 OR FA3 AND FA4. SEE     ]
 ] FIGURES 14444-2 FOR DETAILS ON GPC CHANNELIZATION.                  ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 @



 +_____________________________________________________________________
 ]                       SUPPLEMENTAL SHEET                            ]
 ]_____________________________________________________________________]
 ] AUTHOR:            ]                             ] DR:              ]
 ] J. ZOPHY           ]    PASS PROGRAM NOTE        ]     14444        ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  AUG. 1987 ]
 ] ENG/282-8409       ]      RELEASE NOTE ( )       ] REV C: 02/13/90  ]
 ]____________________]_____________________________]__________________]
 ] TITLE:                                                              ]
 ]        OMS ENGINE PROBLEMS CAUSED BY GPC OR STRING FAILURES         ]
 ]_____________________________________________________________________]
 ] FIGURE 14444-1:                                                     ]
 ]                        LEFT OMS ENGINE                              ]
 ]     ACTIVE                                                          ]
 ] SELECT-1  FF1   ___          ______                                 ]
 ] -------------->]   ] GPC 1  ]ACTIVE]                                ]
 ] SELECT-2  FF1  ]AND]------->]CNTRLR]-+                              ]
 ]  ------------->]___] STRNG 1]PITCH/] ]                              ]
 ]                             ]YAW   ]-]-+                            ]
 ]                             ]______] ] ]     _______________        ]
 ]                                      ] +---->]YAW  ]        ]       ]
 ]                                      ]    +->]ACTR ] LEFT   ]       ]
 ]                                      ]    ]  ]-----] OMS    ]       ]
 ]                                      +----]->]PITCH] ENGINE ]       ]
 ]                                         +-]->]ACTR ]        ]       ]
 ]     STANDBY                             ] ]   --------------        ]
 ] SELECT-1  FF2   ___          _______    ] ]                         ]
 ]  ------------->]   ] GPC 2  ]STDBY  ]   ] ]                         ]
 ] SELECT-2  FF2  ]AND]------->]CNTRLR ]---+ ]                         ]
 ]  ------------->]___] STRNG 2]PITCH/ ]     ]                         ]
 ]                             ]YAW    ]-----+                         ]
 ]                             ]_______]                               ]
 ]                                                                     ]
 ]                        RIGHT OMS ENGINE                             ]
 ]     ACTIVE                                                          ]
 ] SELECT-1   FF4  ___          ______                                 ]
 ] -------------->]   ] GPC 4  ]ACTIVE]                                ]
 ] SELECT-2   FF4 ]AND]------->]CNTRLR]-+                              ]
 ]  ------------->]___] STRNG 4]PITCH/] ]                              ]
 ]                             ]YAW   ]-]-+                            ]
 ]                             ]______] ] ]     _______________        ]
 ]                                      ] +---->]YAW  ]        ]       ]
 ]                                      ]    +->]ACTR ] RIGHT  ]       ]
 ]                                      ]    ]  ]-----] OMS    ]       ]
 ]                                      +----]->]PITCH] ENGINE ]       ]
 ]                                         +-]->]ACTR ]        ]       ]
 ]     STANDBY                             ] ]   --------------        ]
 ] SELECT-1   FF3  ___          _______    ] ]                         ]
 ]  ------------->]   ] GPC 3  ]STDBY  ]   ] ]                         ]
 ] SELECT-2   FF3 ]AND]------->]CNTRLR ]---+ ]                         ]
 ]  ------------->]___] STRNG 3]PITCH/ ]     ]                         ]
 ]                             ]YAW    ]-----+                         ]
 ]                             ]_______]                               ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 @



 +_____________________________________________________________________
 ]                       SUPPLEMENTAL SHEET                            ]
 ]_____________________________________________________________________]
 ] AUTHOR:            ]                             ] DR:              ]
 ] J. ZOPHY           ]    PASS PROGRAM NOTE        ]     14444        ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  AUG. 1987 ]
 ] ENG/282-8409       ]      RELEASE NOTE ( )       ] REV C: 02/13/90  ]
 ]____________________]_____________________________]__________________]
 ] TITLE:                                                              ]
 ]        OMS ENGINE PROBLEMS CAUSED BY GPC OR STRING FAILURES         ]
 ]_____________________________________________________________________]
 ] FIGURE 14444-2:                                                     ]
 ]                                                                     ]
 ]             OMS/GPC CHANNELIZATION FOR OMS CONTROL                  ]
 ]                                                                     ]
 ]  -----                                                              ]
 ] ]     ]                            _____                            ]
 ] ] FA4 ]-------------------------->]     ]                           ]
 ] ]-----]              +----------->] AND ]--+                        ]
 ] ] FA3 ]--------------]----------->]     ]  ]                        ]
 ]  _____               ] +--------->]_____]  ]                        ]
 ]                      ] ]                   ]                        ]
 ]  __________          ] ]                   ]                        ]
 ] ] ENGINE  P]1        ] ]                   ]                        ]
 ] ] VALVE   O]---------]-]-+                 ]    ____                ]
 ] ] OMS     L]2        ] ] ]                 +-->]    ]     OMS       ]
 ] ] SWITCH  E]---------+ ] ]                     ] OR ]---> CONTROL   ]
 ] ]__________]           ] ]                 +-->]____]     VALVE     ]
 ]                        ] ]                 ]                        ]
 ]  _____                 ] ]       _______   ]                        ]
 ] ]     ]                ] +----->]       ]  ]                        ]
 ] ] FA2 ]----------------]------->]  AND  ]--+                        ]
 ] ]-----]                ]   +--->]       ]                           ]
 ] ] FA1 ]----------------]---]--->]_______]                           ]
 ] ]_____]                ]   ]                                        ]
 ]  __________            ]   ]                                        ]
 ] ] ARM/    P]1          ]   ]                                        ]
 ] ] PRESS   O]-----------]---+                                        ]
 ] ] SWITCH  L]2          ]                                            ]
 ] ]         E]-----------+                                            ]
 ] ]__________]                                                        ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 @



 +_____________________________________________________________________
 ]                       SUPPLEMENTAL SHEET                            ]
 ]_____________________________________________________________________]
 ] AUTHOR:            ]                             ] DR:              ]
 ] J. ZOPHY           ]    PASS PROGRAM NOTE        ]     14444        ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  AUG. 1987 ]
 ] ENG/282-8409       ]      RELEASE NOTE ( )       ] REV C: 02/13/90  ]
 ]____________________]_____________________________]__________________]
 ] TITLE:                                                              ]
 ]        OMS ENGINE PROBLEMS CAUSED BY GPC OR STRING FAILURES         ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ]                                                                     ]
 ]  FOLLOWING A GPC-1 OR GPC-4 FAILURE DURING AN OMS BURN, POWER       ]
 ]  CYCLE THE ASSOCIATED FF MDM AND SELECT THE STANDBY (SECONDARY)     ]
 ]  ACTUATOR CONTROL.                                                  ]
 ]                                                                     ]
 ]  IN THE EVENT OF LOSS OF MULTIPLE STRINGS DURING AN OMS BURN, THE   ]
 ]  CREW SHALL ALSO MANUALLY SHUTDOWN THE OMS ENGINES. FURTHERMORE,    ]
 ]  THE POWER TO THE MDM'S ON THESE STRINGS SHALL BE CYCLED BEFORE AN  ]
 ]  IPL IF THE RS HAS BEEN LOST.                                       ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]IBM:  WYATT COOPER        DATE 03/29/90]                             ]
 ]    --------------------      ---------]                             ]
 ]SSD:    SAM ANKNEY        DATE 03/29/90]                             ]
 ]    --------------------      ---------] S. N. HARDEE, JR.  04/03/90 ]
 ]PF MGR:  J. VERNON        DATE 04/03/90]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
 @




