 +_____________________________________________________________________
  AUTHOR:                                          DR:              
  HIRAM THOMPSON         PASS PROGRAM NOTE                101072    
 ____________________                             __________________
  ORG/PHONE:          OPS NOTE (X)  USER NOTE ( )  DATE:  06/21/88  
  SSOAS/282-7225           RELEASE NOTE( )         REV A: 07/11/96  
 ___________________________________________________________________
  OI/FLIGHT EFFECTIVITY:          USER AFFECTED:                     
   OI-25 AND SUBS                CREW (X)  GROUND ( )  DUMP ONLY ( ) 
 ____________________________________________________________________
         MAJOR SOFTWARE AREA:        OPS MODES AFFECTED:             
 SSW (X)  GNC (X)  VU ( )  SM/PL ( ) G1, G3, G6                      
 _____________________________________________________________________
  SOFTWARE SUB-AREA: TRANSITIONS                                      
 _____________________________________________________________________
  PRINCIPAL FUNCTIONS: N/A                                            
 _____________________________________________________________________
  TITLE: NO PROTECTION AGAINST INADVERTENT MAJOR MODE TRANSITIONS     
 _____________________________________________________________________
  DESCRIPTION:                                                        
                                                                      
   SOME LEGAL, MANUAL MAJOR MODE TRANSITIONS ARE INAPPROPRIATE UNTIL  
  CERTAIN CONDITIONS ARE MET.  NO SOFTWARE PROTECTION EXISTS TO PRE-  
  VENT THESE TRANSITIONS IF THE CONDITIONS ARE NOT MET, AND IN MANY   
  CASES THE TRANSITION IS NOT REVERSIBLE.                             
                                                                      
   A SUBSET OF THIS ISSUE CONCERNS A MANUAL TRANSITION WHICH          
  MAY BE PROCESSED AT THE SAME TIME AS AN AUTOMATIC TRANSITION.  THIS 
  WILL MANIFEST ITSELF IN TWO POSSIBLE SCENARIOS:                     
    1) AN ILLEGAL REQUEST TO A MM THAT IS 2 MODES PAST THE CURRENT MM 
         FOR EXAMPLE, AN INADVERTENT MANUAL MM 601 TO MM 603          
         TRANSITION MAY BE ACCEPTED IF AN AUTOMATIC MM 601 TO MM 602  
         TRANSITION IS PROCESSED AT THE SAME TIME.  SYSTEM SOFTWARE   
         WOULD SEE AND HONOR REQUESTS FOR TRANSITIONS TO MM 602       
         FOLLOWED BY MM 603.  APPLICATION SOFTWARE, HOWEVER, WOULD    
         NEVER SEE THE TRANSITION TO MM 602 AND A GREAT DEAL OF       
         FUNCTION ACTIVATION/DEACTIVATION AND INITIALIZATION WILL     
         NOT TAKE PLACE.  A NON-FUNCTIONAL HYBRID OF MM 601 AND MM    
         603 SOFTWARE WILL RESULT.  SIMILAR CONDITIONS CAN RESULT     
         FROM OTHER COMBINATIONS OF TRANSITIONS.                      
                                                                      
                - CONTINUED ON SUPPLEMENT PAGE -                      
                                                                      
 _____________________________________________________________________
 USER RESPONSE:                                                       
                                                                      
  EXERCISE CAUTION WHEN PERFORMING MANUAL MAJOR MODE TRANSITIONS      
  AROUND THE TIMEFRAME OF AN AUTOMATIC MM TRANSITION.                 
 _____________________________________________________________________
 CONCURRENCE:                           APPROVAL:                    
 SSOAS:  HUGH D. STOVALL   DATE 07/18/96                             
     --------------------      ---------                             
 ASD:   ERIC C. BINGHAM    DATE 07/18/96                             
     --------------------      --------- DARRELL E. STAMPER 07/25/96 
 PF MGR: KAYLENE F. KINDT  DATE 07/18/96------------------- -------- 
        -----------------      --------- CHAIRMAN, SASCB      DATE   
 ____________________________________________________________________
 @


 +_____________________________________________________________________
                                                                      
                        SUPPLEMENTAL SHEET                            
                                                                      
 _____________________________________________________________________
  AUTHOR:                                          DR:              
  HIRAM THOMPSON         PASS PROGRAM NOTE                101072    
 ____________________                             __________________
  ORG/PHONE:          OPS NOTE (X)  USER NOTE ( )  DATE:  06/21/88  
  SSOAS/282-7225           RELEASE NOTE( )         REV A: 07/11/96  
 ___________________________________________________________________
  TITLE:                                                              
         NO PROTECTION AGAINST INADVERTENT MAJOR MODE TRANSITIONS     
                                                                      
 _____________________________________________________________________
  DESCRIPTION:                                                        
                                                                      
    2) A VALID REQUEST TO THE NEXT MM                                 
         FOR EXAMPLE, IT IS POSSIBLE FOR A MANUAL MM 103 TO MM 104    
         REQUEST TO OCCUR AND BE ACCEPTED AT THE SAME TIME AS AN      
         AUTOMATIC MM 103 TO MM 104.  SYSTEM SOFTWARE WILL HONOR THE  
         VALID MANUAL TRANSITION AND NOTIFY APPLICATIONS.  HOWEVER,   
         APPLICATIONS IS ALREADY MODING TO MM 104 FROM THE AUTOMATIC  
         REQUEST.  THE END RESULT IS THAT APPLICATIONS WILL BE IN MM  
         105 DUE TO THE MANUAL AND THE AUTOMATIC MM OCCURRING         
         SIMULTANEOUSLY.                                              
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
 _____________________________________________________________________
 USER RESPONSE:                                                       
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
 _____________________________________________________________________
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