 +_____________________________________________________________________
  AUTHOR:                                         SMS: B20077       
  C. SEBASTIAN           BFS PROGRAM NOTE         DR:  109706       
 ____________________                            ___________________
  ORG/PHONE:          OPS NOTE (X) USER NOTE ( )  DATE:             
  RSS/922-3747             RELEASE NOTE ( )            01/26/98     
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  OI/FLIGHT EFFECTIVITY:          USER AFFECTED:                     
  OI27                            CREW (X)  GROUND (X)  DUMP ONLY ( )
 ____________________________________________________________________
            MAJOR SOFTWARE AREA:             OPS MODES AFFECTED:     
 BSL( ) BSS(X) GNC( ) SEQ( ) SM/SP( ) IPL( )    1, 3, 6              
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  SOFTWARE SUB-AREA: DISP                                             
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  PRINCIPAL FUNCTIONS: PRD MG038101 /  3.5.2.2.4  HSI                 
 _____________________________________________________________________
  TITLE:                                                              
          MEDS HSI COURSE POINTER FLUCTUATES 90 DEG.                  
 _____________________________________________________________________
  DESCRIPTION:                                                        
                                                                      
  THE MEDS HORIZONATAL SITUATION INDICATOR (HSI) SELECTED COURSE      
  POINTER FLUCTUATES +/- 90 DEGREES DURING APPROACH AND LANDING. THIS 
  CAN ALSO HAPPEN ANY OTHER TIME THE ORBITER HAS A SELECTED COURSE    
  THAT IS AT OR NEAR 360 DEGREES.                                     
                                                                      
  THIS FLUCTUATION WILL ONLY HAPPEN ON MEDS AND IT WILL ONLY LAST FOR 
  80 MILLISECONDS.                                                    
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
 _____________________________________________________________________
  USER RESPONSE:                                                      
                                                                      
  DISREGARD THE FLUCTUATION. THE HSI WILL CONTINUE TO DISPLAY CORRECT 
  DATA 80 MILLISECONDS AFTER ANY OF THESE 90 DEGREE FLUCTUATIONS.     
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
 _____________________________________________________________________
 CONCURRENCE:                           APPROVAL:                    
 BNA:<S> D. CORBIN         DATE 02/06/98                             
     --------------------      ---------                             
 ASD:   W. R. PRUETT       DATE 05/06/98                             
     --------------------      --------- DARRELL E. STAMPER 05/07/98 
 PF MGR:<S> DAN WOOD       DATE 05/05/98------------------- -------- 
        -----------------      --------- CHAIRMAN, SASCB      DATE   
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