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  AUTHOR:                                          DR:              
  PAUL TICE              PASS PROGRAM NOTE               108680     
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  ORG/PHONE:          OPS NOTE (X)  USER NOTE ( )  DATE:  02/17/94  
  LSIS/282-7297            RELEASE NOTE( )         REV A: 03/28/94  
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  OI/FLIGHT EFFECTIVITY:          USER AFFECTED:                     
  OI-21 AND SUBS                  CREW (X)  GROUND (X)  DUMP ONLY ( )
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         MAJOR SOFTWARE AREA:        OPS MODES AFFECTED:             
 SSW (X)  GNC (X)  VU ( )  SM/PL (X) G1, G2, G3, S2, S4              
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  SOFTWARE SUB-AREA: TRANSITIONS                                      
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  PRINCIPAL FUNCTIONS: SACH, SDEU, SULK, OPSC                         
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  TITLE:                                                              
  ITEM ENTRIES MAY BE LOST OR MISEXECUTED NEAR MAJOR MODE TRANSITIONS 
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  DESCRIPTION:                                                        
                                                                      
  ITEM ENTRIES PROCESSED DURING THE CLEANUP AND INITIALIZATION OF     
  A MAJOR MODE TRANSITION AND INTENDED FOR THE CURRENT/OLD MAJOR      
  MODE MAY RESULT IN THE ITEM ENTRIES BEING IGNORED OR ACCEPTED BY    
  THE NEW MAJOR MODE.  THIS APPLIES TO MANUAL AND AUTOMATIC MAJOR     
  MODE TRANSITIONS, AND APPLIES TO BOTH ITEMS ENTERED FROM A KEYBOARD 
  OR UPLINKED VIA DEU EQUIVALENT.  THE WINDOW OF EXPOSURE DURING A    
  MAJOR MODE TRANSITION WHERE THIS PROBLEM CAN OCCUR IS VERY SMALL    
  (MILLISECONDS).                                                     
                                                                      
  IT HAS BEEN DETERMINED THAT THE GNC202-201 AND GNC303-304 MANUAL    
  MAJOR MODE TRANSITIONS HAVE SCENARIOS RESULTING IN UNPREDICTABLE    
  CODE EXECUTION.  IT HAS ALSO BEEN DETERMINED THAT THE FOLLOWING     
  MAJOR MODE TRANSITIONS HAVE SCENARIOS RESULTING IN IGNORED OR       
  MISEXECUTED ITEM ENTRIES: SM201-202, SM202-201, SM401-402,          
  SM402-401, GNC103-104, GNC201-202, GNC202-201 AND GNC303-304.       
                                                                      
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 USER RESPONSE:                                                       
                                                                      
  COMPLETE ALL ITEM ENTRIES OR UPLINKS AT LEAST 10 SECONDS PRIOR TO   
  ANY MAJOR MODE TRANSITION OR ALLOW A MAJOR MODE TRANSITION TO       
  COMPLETE BEFORE KEYING OR UPLINKING ITEM ENTRIES.                   
                                                                      
                                                                      
                                                                      
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 CONCURRENCE:                           APPROVAL:                    
 LSIS:   JEAN L. ZOPHY     DATE 05/03/94                             
      -------------------      ---------                             
 FDSD:   W. R. PRUETT      DATE 05/04/94                             
      -------------------      --------- DARRELL E. STAMPER 05/06/94 
 PF MGR: ERIC C. BINGHAM   DATE 05/04/94------------------- -------- 
        -----------------      --------- CHAIRMAN, SASCB      DATE   
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