Can't input fuel manually in Perf page

[downscc 1,327]

7 hours ago, killairbus said:

I always set my fuel load to 10% via FS Actions, after loading the default cold and dark panel. Then I imputed the value in Init Perf, only to get "Invalid entry." 

-Angelo Busato

Why?  Why set a 10% load if you are going to set a different value on PERF page?  It sounds like you are trying to fill the tanks by entering a value on the PERF page but of course I know that isn't what you expect to happen so none of this makes sense.

Only when I use the Ground Operations feature, and when fueling is occurring while I preflight, will I use the manual fuel and ZFW entries on the PERF page to allow FMC preflight to continue up to a point... and even in this case one cannot complete preflight by setting takeoff because you need the fuel and payload on board to set CG and CG is used to set takeoff page.

Normally I use FS Actions to set the fuel and the payload before I preflight the FMC.  Why not?

[killairbus 3]

12 hours ago, downscc said:

Why?  Why set a 10% load if you are going to set a different value on PERF page?  It sounds like you are trying to fill the tanks by entering a value on the PERF page but of course I know that isn't what you expect to happen so none of this makes sense.

Only when I use the Ground Operations feature, and when fueling is occurring while I preflight, will I use the manual fuel and ZFW entries on the PERF page to allow FMC preflight to continue up to a point... and even in this case one cannot complete preflight by setting takeoff because you need the fuel and payload on board to set CG and CG is used to set takeoff page.

Normally I use FS Actions to set the fuel and the payload before I preflight the FMC.  Why not?

I input fuel values in the Perf page to see how far off the fuel remaining on arrival calculated by the FMC will be when compared to the remaining fuel calculated by sim brief. 

If there's a close enough match with the FMC and simbrief I start fueling her up. 

However, on long haul flights where I frequently load to MTOW I cannot compare the fuel remaining between the FMC and simbrief because the FMC keeps giving me an invalid entry whenever the projected ground weight goes over 391 tons. 

If I run ground ops and fuel her up to the amount calculated by simbrief only for it to be far off, I'll have to offload fuel and I don't like doing that. I want to get it right the first time so that's why I use the init Perf page before fueling. 

I'll load up the route, set STARS and SIDS, account for weather, input ZFW, and manually insert the simbrief fuel amount to see if the FMC will come up with the same remaining fuel amount as simbrief did. If it's wrong I input some more until I get it close, then I fire up ground ops and put in the adjusted fuel amount. 

-Angelo Busato

Edited September 4, 2018 by killairbus

[Qavion2 39]

I don't know how relevant this is, but the (real) 744 Approach Reference page allows a greater gross weight than your total, Angelo.

A few years ago, on real 744s, I recorded the following values:

Standard freighter (CF6) and pax (RR):

154.2 ~ 408.2 Tonnes
Airspeed range:
(Flaps 25) 120kts to 199 kts
(Flaps 30) 115kts to 191 kts

 

747-400ER pax (CF6)

154.2 ~ 435.5 Tonnes
Airspeed range:
(Flaps 25) 120kts to 206 kts
(Flaps 30) 115kts to 197kts

 

 

 

 

[Qavion2 39]

On 9/2/2018 at 5:10 PM, VHOJT said:

It is fairly common knowledge around the web that QF 744s have extra oxygen bottles that allow for depressurised flight at 14,000ft for a considerable number of hours, and even higher for shorter periods. This would help with minimising decompression fuel vs having to go down to the usual 10,000ft for hours.

Cargo fire suppression is another issue on these long haulers. Some of the aircraft's fire bottles give an instant blast, but then other bottles feed a slower supply for a certain amount of time. After this, nothing... If the fire restarts or if you have a fire in another cargo area, you're in trouble.

[VHOJT 177]

12 minutes ago, Qavion2 said:

Cargo fire suppression is another issue on these long haulers. Some of the aircraft's fire bottles give an instant blast, but then other bottles feed a slower supply for a certain amount of time. After this, nothing... If the fire restarts or if you have a fire in another cargo area, you're in trouble.

Yes indeed - I always wonder why it's not more on regulators minds' when EDTO approval etc. happens.