Airbus FBW - triple clicks
 

Just seeking clarifcation of reasons for the triple click 'alert' to sound. My understanding is that it occurs on a downgrade from say cat 3 to cat 1. Some other text says that it also occurs when a new altitude is selected during ALT* and the ALT knob is not pushed or pulled.

Are these statements correct and are there any other causes?

Thanks in advance

AirbusFan.

You are both correct. The triple clicks or the cricket sounds:-
1) When the aircraft is first powered up & the FMGCs have completed their self tests
2) When there is a downgrade in the approach capability.
:O

Also;

Depending on options and FMGC standard, triple click will sound;

- If "GPS PRIMARY LOST" during approach

- With CLB + NAV modes active, NAV mode is lost or disengaged (OP CLB engages).

rgds/mcdude

The following sequences, or mode reversions, are highlighted by a triple click :

V/S selection in ALT*

SPD selection in SRS

CLB (or EXP CLB) to OP CLB, upon lateral crew action while climbing toward a constraint

ALT* to V/S, upon ALT target change

FD disengagement in OPEN modes

Alerting FMA display when V/S-(FPA) target is not held

CLB to OP CLB reversion, upon profile loss

Automatic FD re-engagement in basic mode

DES to V/S upon flight plan loss, or upon no lateral crew action

FINAL DES to V/S, upon NAV loss

Reversion to V/S when selected ALT crosses the current altitude

Automatic FD re-engagement in basic lateral mode

NAV to HDG, upon NAV loss

(ILS) CAPABILITY DOWNGRADE.

Condition(s) required for CAT3/CAT2 are no longer fulfilled.

GPS PRIMARY LOST




plus a few others I guess !!!!!!!!!!!!

Thanks FlapsOne,

I got the impression it occured during reversions (at least with later software).

AirbusFan