AIRPLANE
OPERATIONS
MANUAL
NAVIGATION AND
COMMUNICATION
MARCH 30, 2001
2-18-30
Page
23
Code
01
– For DG: - amber when the same AHRS is supplying both
sides.
- white when both AHRS are supplying on-side.
− When both AHRS are supplying on-side, annunciation is
removed.
− If a heading source becomes invalid the heading source
annunciation will refer to the invalid heading source, HDG1 or
HDG2, as applicable.
5 - HEADING COMPARISON MONITOR DISPLAY
− Color: Amber.
− Label: HDG
− Activated when a difference of 6 degrees between both PFDs is
detected and airplane roll is less than 6 degrees.
− For airplane rolls greater than 6 degrees, annunciation will be
displayed if the difference between both PFDs is greater than
12 degrees.
− The HDG threshold will be restored to 6 degrees if airplane roll
is less than 5 degrees for 90 seconds. Otherwise, a 12 degrees
HDG threshold will be maintained.
6 - HEADING FAILURE DISPLAY
− Digital heading bug symbol is removed and a red HDG FAIL
annunciation is displayed on the PFD and MFD compass cards.
− The bearing pointers, map display, To/From, selected heading
bug, drift angle, selected course/track and course deviation
displays will be removed.
− Heading source annunciation will be HDG 1 or HDG 2.
− Heading select and course select/desired track digital display
will be replaced by amber dashes.
NOTE: In case of heading splits, check if there sources for magnetic
interference near the airplane. If this is cause for the problem,
the heading split should disappear during the taxi.
7 - COURSE DEVIATION FAILURE
− Pointer is removed.
− Red X displayed over the scale.
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