Copyright D.P. Browne 2011
Mode Reversion
Climb
Change of FCU Selected Altitude
Vertical Mode engaged |
FCU Altitude change |
Vertical mode changes to : |
CLB OP CLB EXP CLB |
Below aircraft Altitude |
V/S initialized to current V/S |
DES OP DES EXP DES |
Above aircraft Altitude | |
ALT * |
Any change |
Loss of NAV Mode
Vertical Mode engaged |
Event |
Result |
CLB |
Loss of NAV mode For any reason |
OP CLB engages |
DES |
V/S engages initialized to current V/S |
Speed protection F/D only
Vertical Mode engaged |
FCU Altitude change |
Vertical mode changes to : |
CLB OP CLB EXP CLB |
Below aircraft Altitude |
V/S initialized to current V/S |
DES OP DES EXP DES |
Above aircraft Altitude | |
ALT * |
Any change |
Speed protection in V/S FPA mode
The V/S or FPA guidance has priority over the aircraft’s speed control. If too much V/S or FPA is targeted, then the Auto thrust may not have sufficient authority to control the aircraft’s speed.
Only when the aircraft’s speed reaches the upper or lower limits, does the V/S or FPA target automatically change to maintain that limit. When this happens the FMA V/S or FPA annunciation is boxed and the target value pulses. An Aural triple click is initiated if the A/P is engaged.
Refer to V/S Speed Protection for more detail.