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.