 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] SMS: B27693      ]
 ]N. R. TACKLIND      ]    BFS PROGRAM NOTE         ] DR:  106265      ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE: 5/11/92    ]
 ] (562) 922-3526     ]      RELEASE NOTE ( )       ] REV A 4/15/97    ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI-26 & SUBS                  ]  CREW (X)  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]           MAJOR SOFTWARE AREA:            ] OPS MODES AFFECTED:     ]
 ]BSL( ) BSS( ) GNC(X) SEQ( ) SM/SP( ) IPL( )]       1                 ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: FCS                                              ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: MG038105 / 3.2.4.3                             ]
 ]_____________________________________________________________________]
 ] TITLE: ATTITUDE ERRORS AT ROLL TO HEADS UP                          ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ] DURING THE ROLL TO HEADS UP MANEUVER IN MM103, BFS IN LISTEN MODE,  ]
 ] LARGE ATTITUDE ERRORS MAY BE SEEN ON THE BFS XXXXXX TRAJ 2 DISPLAY, ]
 ] AS WELL AS THE DOWNLIST.  THESE ATTITUDE ERRORS MAY OCCUR WHENEVER  ]
 ] A ROLL TO HEADS UP MANEUVER IS COMMANDED.  FOR OI-20 THROUGH OI-25, ]
 ] ONLY TAL MODE IS AFFECTED.  FOR OI-26 AND SUBS, THE AFFECTED MODES  ]
 ] ARE NOMINAL SECOND STAGE, ATO AND TAL.  AN AOA IS NOT DECLARED      ]
 ] UNTIL MM104, AFTER ANY ROLL TO HEADS UP MANEUVER IS COMPLETED       ]
 ] DURING MM103.                                                       ]
 ] THESE LARGE ATTITUDE ERRORS OCCUR AS A RESULT OF THE SUBTLE         ]
 ] SKEW IN PASS AND BFS CALCULATED VEHICLE ATTITUDE. IN THE EVENT THAT ]
 ] THIS SKEW CAUSES PASS AND BFS CALCULATED ATTITUDE TO RESIDE ON      ]
 ] OPPOSITE EDGES OF 180 DEGREE MARK AT THE TIME THE ROLL TO HEADS     ]
 ] UP IS REQUESTED, PASS AND BFS WILL DETERMINE ROLL DIRECTIONS        ]
 ] WHICH ARE OPPOSITE.                                                 ]
 ] VEHICLE PERFORMANCE, PRE OR POST BFS ENGAGE, IS NOT AFFECTED.       ]
 ] ON ENGAGEMENT OR COMPLETION OF THE MANEUVER, THE ATTITUDE ERRORS    ]
 ] DISPLAYED AND DOWNLISTED, CONVERGE.                                 ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ]                                                                     ]
 ] NONE REQUIRED. ON ENGAGEMENT OR ON COMPLETION OF THE MANEUVER,      ]
 ] BFS WILL CORRECTLY DISPLAY AND DOWNLIST THE APPROPRIATE ATTITUDE    ]
 ] ERRORS.                                                             ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]BNA: <S> D. CORBIN        DATE 04/22/97]                             ]
 ]     -------------------      ---------]                             ]
 ]ASD:   ERIC C. BINGHAM    DATE 05/20/97]                             ]
 ]     -------------------      ---------] MELVIN R. ROTHER   06/06/97 ]
 ]PF MGR:JOHN W. CRAFT.,JR. DATE 06/04/97]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_____________________________________________________________________]
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