PRIMUS
r
1000 Integrated Avionics System
A28--1146--112--00
8-27
Modes of Operation
VERTICAL SPEED HOLD MODE
The vertical speed (VS) hold mode is used to automatically maintain the
aircraft at a pilot--selected vertical speed reference. To initiate the VS
mode, the pilot can maneuver the aircraft to any climb or descent
attitude, establish the vertical speed reference, and engage the VS
mode. Or, with the autopilot engaged, the reference VS can be changed
by using the SPD knob on the GC. With the VS mode engaged, a new
VS value can be engaged by pushing the TCS button on the control
wheel and maneuvering the aircraft to a new VS reference and
releasing the TCS button.
When the VS mode is engaged, as shown in figure 8--22, the following
occurs:
D
VS is annunciated in green on the PFD
D
The PFD displays the vertical speed target value above the vertical
speed scale in plus or minus feet per minute.
When the VS reference is changed by using the SPD knob on the GC,
the target value changes and the vertical speed reference bug is
repositioned. Actual aircraft VS is displayed on the VS indicator. When
VS is selected, it resets all previously selected vertical modes.
The VS mode is cancelled by any one of the following actions or event:
D
Pushing the VS button on the GC
D
Selecting another vertical mode
D
Selecting go--around
D
Coupling to the cross--side FD
D
If on the active side, selecting SG reversionary selection.
D
Failure of the on--side micro air data computer (MADC).
NOTES:
1. When the VS mode is selected, the vertical speed
reference bug is displayed on the vertical speed display.
2. Aircraft airspeed protection is active in this mode. Refer
to Speed Hold Mode description on the next page.