Copyright D.P. Browne 2011

 

 

 

 

Home.Cockpit.Aircraft Systems.Worked Example.Program Controls.Before Flight.

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.