 +_____________________________________________________________________
 ] AUTHOR:            ]     RECONFIGURATION         ] DR:              ]
 ] K. A. KOBLER       ]       PROGRAM NOTE          ]     101784       ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:            ]
 ] DP2/483-4391       ]      RELEASE NOTE( )        ]      05/02/90    ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI8D/35RC1,35FL1,38RC1,38FL1, ]  CREW (X)  GROUND (X)  DUMP ONLY ( )]
 ]      40RC1,40FL1,41RC1,41FL1, ]                                     ]
 ]      37RC1                    ]                                     ]
 ] OI8F/42RC1,39RC1              ]                                     ]
 ]_______________________________]_____________________________________]
 ] MAJOR SOFTWARE AREA:    PASS(X) BFS( )] OPS MODES AFFECTED:         ]
 ] SSME**( ) DEU**( ) T&G( ) DFL/FPL**( )] S2, S4                      ]
 ] TFL**( ) TCS**( ) I-LOAD( ) LEVEL C(X)]                             ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: DISP                                             ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: SYSTEMS MANAGEMENT, SM SYS SUMM 1 (S5.2.2)     ]
 ]_____________________________________________________________________]
 ] TITLE:  MISLEADING DISPLAY OUTPUTS FOR V92R4935C                    ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:  ON SPEC 78, THE CRT FIELD FOR EQ DP/DT                ]
 ] (MSID V92R4935C) IS DEFINED AS A +/- .XXX.  THE SOFTWARE CAN        ]
 ] COMPUTE A VALUE GREATER THAN +/- .999.  WHEN THIS HAPPENS, THE CRT  ]
 ] WILL TRUNCATE THE DATA TO FIT THE CRT FIELD (EX. WHEN THE EQ DP/DT  ]
 ] IS +1.500, THE CRT WILL DISPLAY +.500).  FOR POSITIVE VALUES OF     ]
 ] DP/DT, WITH BOTH O2 AND N2 LEAKING INTO THE CABIN (WORST CASE       ]
 ] REQUIRES A MIN OF 4 FAILURES), THE EXPECTED DP/DT WOULD NOT EXCEED  ]
 ] +0.45 PSI/MIN; THEREFORE A VALUE HIGHER THAN +0.999 PSI/MIN IS      ]
 ] EXPECTED ONLY WHEN THERE IS A CABIN PRESSURE TRANSDUCER FAILURE.    ]
 ] FOR NEGATIVE VALUES OF DP/DT, THERE IS CLASS 3 FDA SET AT -0.12     ]
 ] PSI/MIN, THEREFORE, VALUES THAT WOULD TRUNCATE WOULD ALSO HAVE      ]
 ] AN FDA ALARM.  THE NOMINAL PERFORMANCE WILL NOT CAUSE THE DP/DT     ]
 ] TO EXCEED -.999 PSI/MIN.  HOWEVER, IF A CABIN LEAK CAUSED           ]
 ] A DP/DT GREATER THAN -.999 PSI/MIN, THERE ARE AT LEAST 5 OTHER      ]
 ] PARAMETERS ON THE SAME CRT THAT COULD BE INDICATIVE OF A CABIN LEAK.]
 ] THESE FIVE MEASUREMENTS ARE: CABIN PRESSURE, DECREASING; PRIMARY H/W]
 ] DP/DT, DECREASING; PPO2, DECREASING; FAN DELTA P, DECREASING AND    ]
 ] O2 AND N2 FLOW, INCREASING.  THEREFORE, EQUIVALENT DP/DT IS NOT A   ]
 ] SINGLE POINT INDICATION FOR CABIN LEAKS OF THIS SIZE, AND THE       ]
 ] INDICATED DISCREPANCY WITH THIS COMPUTATION IS ACCEPTABLE.          ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ]                                                                     ]
 ] CREW SHOULD BE MADE AWARE OF THE STATEMENTS ABOVE.                  ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]RSOC:   SILVIA WERRE      DATE 05/08/90]                             ]
 ]     -------------------      ---------]                             ]
 ]MOD:  GEORGE BULL         DATE 05/08/90]                             ]
 ]    --------------------      ---------]DARRELL E. STAMPER   05/09/90]
 ]SW MGR:CHARLES L. STOUGH  DATE 05/08/90]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
 @

