Display Selector
IRS Display Unit (ISDU)
HDG/STS –

  • Left window displays present true heading.

  • Right window displays any applicable maintenance
    status codes.

  • During alignment, the right window displays minutes
    remaining until alignment is complete. For alignments
    greater than 15 minutes, the window displays 15 until
    the time remaining reaches 14 minutes. The display
    then counts down in one minute intervals.