freightmover
30th Jul 2009, 05:30
If flight crew have to reset FCMC on cruise. The procedure requires GW CG and GW to be re-entered in to FUEL PRED page.
GW I can figure out.. but where do u get a reliable figure for GW CG to enter
Iceman49
30th Jul 2009, 13:21
Think I used the trim wheel.
bobrun
31st Jul 2009, 05:00
The trim wheel scale is only valid for take-off.
As you change airspeed, altitude, flap settings, etc inflight the trim wheel has to be moved even though the CG is constant. So once inflight, it has no meaning.
I would start with the loadsheet ZFW CG, and use a trim sheet to correct for the fuel distribution. Don't know any other way, but maybe some have other thoughts.
Bruce Waddington
31st Jul 2009, 07:24
Hi,
From the AOM
"FCMC 1+2 ............................................................ .........RESET
– WEIGHT/CG.......................................................... INITIALIZE
In flight, after a dual FCMC reset, the weight (GW) and CG displayed on the FUEL PRED page are those computed by the FE. However, the GW computed by the FE may be less accurate, therefore :
– If the FCMC reset is successful, the FCMC 1+2 FAULT ECAM caution will be replaced by the NO WEIGHT/CG DATA ECAM caution. Refer to this caution for the GW and CG re-initialization
procedure.
– If the FCMC reset is not successful, determine the Fuel on Board (FOB) from the engine start fuel quantity minus the Fuel Used quantity indication."
and then
"This caution is triggered at engine start, if no WEIGHT/CG has been entered by the crew, or following a successful reset of both FCMCs. In flight, after a dual FCMC reset, the weight and CG displayed on the FUEL PRED page are those computed by the FE. However, the FE based GW may be less accurate. Therefore, if time permits, the GW should be computed by using the loadsheet ZFW and the ECAM FOB, and re-entered on the MCDU FUEL PRED page.
– WEIGHT/CG.......................................................... ..... INITIALIZE"
So, use the FUEL PRED page CG and add the zero fuel weight to the fuel on board to determine an accurate aircraft weight.
best regards,
Bruce Waddington