Efis/Eicas Reversionary; Du And Sg Failures - General; Du Reversionary Modes - Honeywell SPZ-8000 Maintenance Manual

2. I. EFIS/EICAS Reversionary
Modes
This section goes into detail on the various reversionary
modes available
to the crew in the EFIS and EICAS systems.
(1) Display
System Reversionary Panel
The display system reversionary panel is located in the overhead
between the pilot and copilot. The reversionary panel layout is
shown in Figure 248. The display system reversionary (REV) modes
are divided into display unit (DU) REV modes and symbol generator
(SG) REV modes. These modes are discussed in more detail in the
following paragraphs.
(2) DU and SG Failures - General
(a) DU Failure Mode Indications - The failure mode indication for a
DU failure is a blank display. This may be caused by a cooling
air failure or an internal DU failure. A cooling air failure
gives a clue that the display is going down. When a DU
overheats, the raster (PFD - ADI sky blue, ADI ground brown,
and altitude and speed gray shading/ND - WX returns) is
removed. The next indication is a blank display.
(b) SG/Interface Mode Indications - An SG or interface failure is
indicated by displaying a red "X" over the entire DU display
area as shown in Figure 249.
(3) DU Reversionary Modes
(a) Pilot's DU Reversionary Modes - The pilot's PFD reversion is to
transfer the PFD format onto the NAV display. This is done by
moving the pilot's DU reversionary switch to the PFD XFER
position. The display configuration for this reversionary mode
is shown in Figure 250.
In the event the pilot's ND fails, the reversionary mode is to
turn the DU reversionary switch to the ND OFF position.
(b) Copilot's DU Reversionary Modes - The copi1ot's DU reversionary
modes (Figure 251) are identical to those discussed in the
previous paragraph except the copilot uses the right-most set
of DU REV switches.
22-14-00
Page 298.27
Aug 15/91
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