 +_____________________________________________________________________
 ] AUTHOR:            ]                             ]DR:               ]
 ] R. L. DOBSON       ]    PASS PROGRAM NOTE        ]       106682     ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ]DATE:             ]
 ] LSIS/713-282-7330  ]      RELEASE NOTE( )        ]       09/14/94   ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI-23 AND SUBS                ]  CREW (X)  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW ( )  GNC (X)  VU ( )  SM/PL ( )] G1, G6                          ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: SEQ, MPS, ABORT, ASCENT                          ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: 4.70, 4.165                                    ]
 ]_____________________________________________________________________]
 ] TITLE: INCORRECT LEFT ME HELIUM INTERCONNECT DURING RTLS            ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ] THE MAIN ENGINE HELIUM INTERCONNECT IN/OPEN COMMANDS FOR ENGINE 2   ]
 ] ARE SET ON TO OPEN THE VALVE ON FIRST PASS OF THE MPS DUMP SEQUENCE.]
 ] IN ASCENT THE FIRST PASS IS EXECUTED ANYWHERE FROM 20 TO 21 SECONDS ]
 ] AFTER MECO COMMAND.  IN AN RTLS THE FIRST PASS IS EXECUTED UPON     ]
 ] TRANSITION TO MAJOR MODE 602 WHICH MAY BE AS LITTLE AS 14 SECONDS   ]
 ] AFTER MECO COMMAND.  THE EXACT TIME AT WHICH THE COMMANDS ARE SET IS]
 ] DEPENDENT ON THE PHASING OF THE MPS DUMP SEQUENCE RELATIVE TO MECO  ]
 ] COMMAND.  IN BOTH ASCENT AND RTLS THE HELIUM INTERCONNECT IN/OPEN   ]
 ] COMMANDS FOR ALL THREE ENGINES ARE TERMINATED BY THE SSME OPS       ]
 ] SEQUENCE 20 SECONDS AFTER MECO COMMAND.                             ]
 ]                                                                     ]
 ] WHEN THE MPS DUMP SEQUENCE EXECUTES WITHIN 20 SECONDS OF MECO       ]
 ] COMMAND, THE ENGINE 2 IN/OPEN COMMANDS WILL BE REMOVED BY THE SSME  ]
 ] OPS SEQUENCE IMMEDIATELY AFTER HAVING BEEN SET.  IN ASCENT          ]
 ] THIS MAY HAPPEN FOLLOWING FAST SEP OR WHEN MULTIPLE ENGINE          ]
 ] FAILURES HAVE OCCURRED.  IN AN RTLS IT MAY HAPPEN FOLLOWING A       ]
 ] FAST SEP.  THIS CAUSES THE VALVE TO CLOSE AND PRESENTS AN           ]
 ] UNDESIRABLE SITUATION.  WITH THE VALVE CLOSED, A SUBSEQUENT         ]
 ] FAILURE DOWNSTREAM, SUCH AS A HELIUM REGULATOR VALVE FAILED CLOSED, ]
 ] COULD RESULT IN INSUFFICIENT HELIUM FOR AN AFT COMPARTMENT PURGE    ]
 ] OF HAZARDOUS GASSES LEADING TO A POTENTIALLY DANGEROUS CONDITION.   ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ] RECOVERY MEASURES ARE AVAILABLE TO THE CREW AND INSTRUCTIONS FOR    ]
 ] EXECUTING THEM WILL BE AVAILABLE IN CONSOLE DOCUMENTATION IN MISSION]
 ] CONTROL.  THE INSTRUCTIONS DIRECT THE CREW TO MANUALLY PLACE THE    ]
 ] LEFT HELIUM INTERCONNECT VALVE SWITCH IN THE IN/OPEN POSITION.  THIS]
 ] ACTION BY THE CREW WILL OPEN THE VALVE AND THEREBY MAKE HELIUM      ]
 ] AVAILABLE FOR THE AFT COMPARTMENT PURGE.                            ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]LSIS   JEAN L. ZOPHY      DATE 10/11/94]                             ]
 ]     -------------------      ---------]                             ]
 ]ASD:    W. R. PRUETT      DATE 10/12/94]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 10/13/94 ]
 ]PF MGR:   DON PREVETT     DATE 10/13/94]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
 @
 +_____________________________________________________________________
 ]                                                                     ]
 ]                       SUPPLEMENTAL SHEET                            ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] AUTHOR:            ]                             ] DR:              ]
 ] R. L. DOBSON       ]    PASS PROGRAM NOTE        ]       106682     ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:            ]
 ] LSIS/713-282-7330  ]      RELEASE NOTE ( )       ]       09/14/94   ]
 ]____________________]_____________________________]__________________]
 ] TITLE:                                                              ]
 ]         INCORRECT LEFT ME HELIUM INTERCONNECT DURING RTLS           ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ] FOR ALL CASES INVOLVING A TRANSITION TO OPS 3, INCLUDING TAL        ]
 ] ABORTS, THE ENGINE 2 IN/OPEN COMMANDS WILL BE ISSUED BY THE ENTRY   ]
 ] MPS DUMP SEQUENCE ON FIRST PASS OF THE SEQUENCE FOLLOWING THE       ]
 ] TRANSITION TO MAJOR MODE 303.  THIS WILL CAUSE THE VALVE TO OPEN    ]
 ] REGARDLESS OF THE POSITION CARRIED OVER FROM OPS 1 OR 2.            ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
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 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
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 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 @
