A320 CRZ FL ABOVE MAX FL fms message....

[Nick 1]

Does anyone know more about this ?
In cruise ex. FL340 FMS start with this message "FMS 1/FMS 2 SPD TGT DIFF"
with flight plan stored or manully loaded , no difference.
After a period of time "CRZ FL ABOVE MAX FL"
FMS reverts from Max Rec Alt es.365 to Fl325 .
Varius test fron Aid Data Computer or Probes report no item.
Thank you.

[LOFT]

"Fms1/2 spd tgt diff"
This particular case is mentioned in the new fcoms in flight crew bulletins

It happens when changing the Crz FL using the altitude knob.

The new fcu altitude is sent by the master fmgc to the slave, therefore the predictions are not computed at the same time on both fmgc's, a speed difference may occur during a very short period, triggering the message.

Solution: diregard the message.

[capt. solipsist]

try applying the supplementary procedure for FMGS ERRONEOUS PREDICTIONS

[Eric Janson]

Just over-write the cost index on the climb/cruise page.

[capt. solipsist]

Correct, that is one of the techniques (although note that in descent or approach, a CI change does not restart a computation). Another is do a Copy Active, then activate Secondary. Yet another is do a DIR TO to the "TO" Waypoint.

[FlexibleResponse]

"CRZ FL ABOVE MAX FL"

This message is generated by one of or both of the following:

1. Pilot inserted or FM calculated Temperature at the CRZ FL is too high; or
2. FM calculated AUW at the point in the flight plan when climb to new FL, is too high.

Normally to fix, enter the correct forecast or reported temperature at the planned CRZ FL.