• Vertical Track Flag: Notes:
  • The amber VTK flag shows when the vertical deviation data from the Flight Management Computer (FMC) invalid. Only the vertical deviation scale is blanked in this condition.
    
    
  • The VTK flag will show when the Nav Data Display (ND) is selected to the MAP or PLAN mode.
    
  
  
  VTK flag Possible Causes:

  Before replacing any component perform BITE if available. Perform a FMCS bite through the MCDU.

  
  

  1.Flight Management Computer (FMC)

  
  

  2.Toggling the FMC selector to BOTH on 1 then BOTH on 2, back to NORMAL
  
  VTK Flag:

  

  
  

  

  
  Circuit Breakers:

  FMCS CMPTR #1: P18-2 = E8 & A6.

  FMCS CMPTR #2: P6-1 = D16.

  FMCS MCDU-1: P18-2 = A7.

  FMCS MCDU-2: P6-1 = D15.

  
  
  Applicable deferrals MEL 34-36 Flight Management Computer System

  MEL 34-36 MCDU/CDU

  MEL 34-36 FMC Alert Lights

  MEL 34-36 Navigation Database
  

Training Only