1+_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] C. ELLIOT          ]    PASS PROGRAM NOTE        ]       101362     ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  11/17/87  ]
 ] LSIS/(407) 861-3439]      RELEASE NOTE( )        ] REV B: 01/30/95  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ]   OI-8A/8B, AND SUBS          ]  CREW (X)  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW ( )  GNC (X)  VU ( )  SM/PL ( )] G1                              ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: SEQ                                              ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS:  4.114, 4.181                                  ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ]       MDM FAILURE CAN CAUSE PAD DATA PATH FAIL ABORT OR HOLD        ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]      IF CONSECUTIVE AFT MDM READ ERRORS OCCUR ON THE MDM READ, THE  ]
 ] REDUNDANT SET LAUNCH SEQUENCER WILL REACT AS IF THE ERROR WAS AN    ]
 ] EIU 'PAD DATA PATH FAIL' EVEN THOUGH THE ERRORS OCCUR ON THE MDM    ]
 ] READ.                                                               ]
 ]                                                                     ]
 ]      THIS HAPPENS BECAUSE TEMPORARY COMMFAULTS ARE SET ON ALL THE   ]
 ] ELEMENTS OF A CHAINED READ UNTIL THE PROPER ELEMENT IS BYPASSED.    ]
 ] THE SSME SOP LOOKS FOR ONLY TWO CONSECUTIVE EIU COMMFAULTS (PRE-    ]
 ] VIOUSLY FIVE) TO SET 'PAD DATA PATH FAIL.'  THE RSLS CHECKS ENGINE  ]
 ] DATA FAILURES BEFORE CHECKING FOR MDM FAILURES AND RESPONDS TO THE  ]
 ] EIU COMMFAULTS AS AN EIU PAD DATA PATH FAILURE.                     ]
 ]                                                                     ]
 ]    NOTE THAT THIS IMPLIES THAT A PAD ABORT WILL BE ISSUED ON        ]
 ] HYDRAULIC SYSTEM OR OMS PRESSURE READ ERRORS                        ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ]      BE AWARE THAT IN THE EVENT OF AN MDM FAILURE (MDM'S FA1, FA2,  ]
 ] FA3) AFTER MAIN ENGINE IGNITION, THE MAIN ENGINE SHUTDOWN ORDER     ]
 ] WILL FOLLOW THE ORDER DICTATED BY A CORRESPONDING MAIN ENGINE FAIL- ]
 ] URE.  FOR FA4 FAILURES, ALL SECONDARY EIU CHANNELS WILL SEE         ]
 ] TEMPORARY COMMFAULTS AND SSME 1 WILL BE SHUTDOWN FIRST.  IF THE     ]
 ] MDM FAILURE OCCURS PRIOR TO ENGINE START, A 'PAD DATA PATH FAIL'    ]
 ] LAUNCH HOLD WILL BE ISSUED.                                         ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]LSIS:  JEAN L. ZOPHY      DATE 03/14/95]                             ]
 ]     -------------------      ---------]                             ]
 ]ASD:   ERIC C. BINGHAM    DATE 03/14/95]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 03/22/95 ]
 ]PF MGR:   DON PREVETT     DATE 03/17/95]------------------- -------- ]
 ]        J. P. RUPPERT          03/17/95] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
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