Honeywell SPZ-8000 Maintenance Manual page 588

The pilot can manually select IAS or
MACH
mode at any time by
pushing the GP-820 IAS/MACH changeover button.
If the FLCH
mode is engaged, selecting
IAS or MACH
mode also causes the
pilot and copilot PFDs speed tapes to change (i.e., MACH
mode
provides a math tape and IAS
mode provides a CAS tape). EFIS
inhibits the Mach tape below 25,000 feet but this will not
prevent the selection of the FLCH MACH
mode
below this altitude
(in this case the FGCwill hold a Mach value but an equivalent
CAS target bug is displayed on the PFD CAS tape).
The FLCH mode will automatically switch from IAS to MACH mode
during a climb when the actual aircraft speed is at or above
the FMS initialized climb Mach (the PFDs will also
automatically switch from a CAS to a MACH tape). Conversely,
the FLCH mode will also automatically switch from MACH to IAS
mode during a descent when the actual aircraft speed is at or
above the FMS initialized descent CAS (the PFDs will also
automatically switch from a MACH to a CAS tape). The pilot can
change this automatic selection at any time by pushing the
GP-820 IAS/MACH button.
At mode engagement, with the speed bug on the PFD synchronized
to existing aircraft speed, the pilot has two options to fly
the mode:
c Retard
the speed bug reference (climb)
. Advance throttle settings (climb)
22-14-00
Page 298.112.1/298.112.2
Apr 15/93
Useor disclosure of information on this page issubject totherestrictions on the title page of this document.