 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] SMS:  B28625     ]
 ] R. J. CMELAK       ]    BFS PROGRAM NOTE         ] DR:   106216     ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE: 07/02/91   ]
 ] D282/RID  922-5246 ]      RELEASE NOTE ( )       ]                  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ]    OI8C & SUBS                ]  CREW (X)  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]           MAJOR SOFTWARE AREA:            ] OPS MODES AFFECTED:     ]
 ]BSL( ) BSS(X) GNC( ) SEQ( ) SM/SP( ) IPL( )] 0, 1, 3                 ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA:   OPS, TRANSITION                                ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS:  MG038101/ 3.1.10.1, 3.1.10.4, 3.8.2           ]
 ]_____________________________________________________________________]
 ] TITLE:   BFS INADVERTENT PRE-LAUNCH AND DEORBIT MODE TRANSITIONS    ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ] (1) PRE-LIFTOFF, IF BFS IS TRANSITIONED FROM MM 301 TO OPS 000 THEN ]
 ] MM 101, THE MISSION ELAPSED TIME (MET) WILL NOT BE RESET TO THE     ]
 ] PRE-LIFTOFF VALUE OF 160 MILLISECONDS. THE MET WILL ALSO CONTINUE   ]
 ] TO COUNT UP. THIS WILL LEAD TO INCORRECT GUIDANCE AND POSSIBLE      ]
 ] LOSS OF DISPLAY INTERFACE DURING ASCENT.                            ]
 ]                                                                     ]
 ] (2) WHILE IN ORBIT, AN INADVERTENT 101 PRO WILL CAUSE INDETERMINANT ]
 ] RESULTS FOR ENTRY.                                                  ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ]                                                                     ]
 ] (1) IF THE BFS HAS BEEN INADVERTENTLY MODED TO MM 301 PRIOR TO      ]
 ] PERFORMING AN ASCENT TRAJECTORY, AN IPL OF BFS IS REQUIRED PRIOR TO ]
 ] THE OPS 101 PRO FOR COMPLETE RE-INITIALIZATION.                     ]
 ]                                                                     ]
 ] (2) WHILE IN ORBIT, IF AN INADVERTENT OPS 101 PRO IS ENTERED PRIOR  ]
 ] TO A TRANSISTION TO MM 301, AN IPL OF BFS IS REQUIRED.              ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]RI: <S> A. TROY           DATE 07/17/91]                             ]
 ]    --------------------      ---------]                             ]
 ]FDSD: ROBERT N. HINSON    DATE 07/22/91]                             ]
 ]    --------------------      ---------]DARRELL E. STAMPER  07/22/91 ]
 ]PF MGR:DAVID STEPHENSON   DATE 07/22/91]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_____________________________________________________________________]
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