P I L O T T R A I N I N G G U I D E
AUTOMATIC FLIGHT CONTROL SYSTEM
2-34
For Training Purposes Only
Sept 04
Altitude Hold (ALT) Mode
ALT mode is used to maintain a barometric altitude reference.
ALT mode is activated automatically following preselect altitude capture (ASEL), or
can be activated manually via the altitude switch (ALT) on the guidance panel to
maintain a pressure altitude at time of selection.
If the ALT mode is selected when the airplane is in a climb or descent, FGC will
generate pitch commands to zero the vertical speed and capture the selected altitude.
The pilot may select another altitude reference without canceling ALT mode by
depressing the TCS button, and maneuvering the airplane to a new altitude.
The ALT mode will use a baro-corrected altitude and respond to baro knob changes to
airplane pitch angle up to ± 20° limit.
ALT mode is annunciated in the vertical capture field on the PFD. ALT will flash for 5
seconds, when active.
Vertical Navigation (VNAV) Modes
VNAV mode contains 4 vertical submodes that can be flown using speed and altitude
targets, that are programmed in the active flight plan of the FMS.
A double C-chord (aural) is activated for VNAV vertical track alerts.
VNAV mode is activated by selecting VNAV on the guidance panel. The vertical
mode active at the time shall remain engaged.
FMS submode selections when in VNAV mode are as follows:
•
VFLC - Operates identical to FLC mode, except that the target airspeed and
altitude from the FMS are used for climb or descent. If VALT or VPTH is engaged
and FLC is selected on the guidance panel, VFLC will become active
•
VPTH - Used to fly a fixed flightpath angle to a vertical waypoint during descent.
VPTH will engage whenever FMS initiates a path descent which may occur while
in VFLC or VALT modes. LNAV must be the lateral navigation mode for VPTH to
capture
A VNAV target altitude bug will appear on the altitude tape of selected PFD
104
00
9500
9500
10500
00
Selected
Altitude Bug
VNAV
Target Altitude
Altitude
Trend Vector
VNAV Target
Altitude Bug
GX_02_037
2992
IN
9500
Vertical Speed
Target Readout
VS 1000
100
00
80
20