Where in the PMDG manuals do they mention adding alternates into the fmc?

[killairbus 3]

I've never really bothered adding an alternate into the FMC, I always have reserve fuel at 19.5kg as an estimated default value. But now I want to find out a more accurate value by adding an alternate to calculate the fuel I'll need to get there.

Trouble is, I can't seem to find where in the manuals do they talk about adding an alternate airport in the FMC. If someone could give me a page number I'd appreciate it.

Also: What is the MTOW and Max taxi weight for the 400? Is it 394.6 and 395.9kg as stated in the manuals?  

-Angelo

[Captain Kevin 586]

I'm not sure if you can do that, I think you mostly just change the destination via the route page if you actually do need to do it.

[Olympic260 415]

If I remember correctly the 74 FMC does not has the alternate page the 777 has.

You can use RTE2 to set up a route with your alternate as a destination and then activate RTE2.

[killairbus 3]

3 minutes ago, Captain Kevin said:

I'm not sure if you can do that, I think you mostly just change the destination via the route page if you actually do need to do it.

Darn, if that's really the case... have you simulated a Qanats 400 standard KLAX to YSSY? Could you tell me your usual Zero fuel weight and reserve fuel?

-Angelo

[killairbus 3]

2 minutes ago, Olympic260 said:

If I remember correctly the 74 FMC does not has the alternate page the 777 has.

You can use RTE2 to set up a route with your alternate as a destination and then activate RTE2.

Do I put in the route 2 origin as is in route one or or put in route 1's destination as route 2's origin?

 

-Angelo

[Captain Kevin 586]

14 minutes ago, killairbus said:

have you simulated a Qanats 400 standard KLAX to YSSY? Could you tell me your usual Zero fuel weight and reserve fuel?

I have not simulated any Qantas flights or any other flights, as I fly my own airline in the simulator.

[Olympic260 415]

45 minutes ago, killairbus said:

Do I put in the route 2 origin as is in route one or or put in route 1's destination as route 2's origin?

 

-Angelo

Depends on what do you want. If you want to have the final alternate on RTE2 then put as RTE2 origin the arrival of RTE1 and as destination the alternate.

 

If you want to divert while in the air then you can put on RTE2 same origin as RTE1 and the alternate as destination and then just add the new waypoints/route.

 

You can always just copy RTE1 to RTE2 and make any changes on RTE2. As you can see there are multiple ways.

[kevinh 409]

3 hours ago, killairbus said:

Also: What is the MTOW and Max taxi weight for the 400? Is it 394.6 and 395.9kg as stated in the manuals? 

The numbers used in the sim are slightly different to the FCOM. From aircraft.cfg for the -400:

Quote

max_gross_weight      = 877000.0                //
max_gross_weight_1    = 853000.0                // with stab tank not installed
max_takeoff_weight    = 875000.0                // 800, 833, 850, 870, 875 x 10^3 lbs [+2000 for max ramp]
max_takeoff_weight_1  = 850000.0

So 397.8 and 396.9 tonnes for the -400 with stab tank and 386.9 and 385.6 tonnes for the -400 without stab tank. Each model PMDG simulated is slightly different.

The Boeing FMC doesn't use an alternate route to calculate reserves. If it did you wouldn't have to enter a figure, just as with the MD11 (or an Airbus). To work out what your reserve fuel should be you need to use a flight planning tool such as PFPX (payware) or Simbrief (free service). I use Simbrief and that will suggest an alternate airport for your route, or you can choose one of your own. The flight plan it calculates will give you approprate figures for the fuel required to divert to the alternate and for 30 minutes circling there. Add those two figures together to get the reserve fuel you enter in the FMC.

[killairbus 3]

On 10/2/2017 at 9:45 AM, kevinh said:

The numbers used in the sim are slightly different to the FCOM. From aircraft.cfg for the -400:

So 397.8 and 396.9 tonnes for the -400 with stab tank and 386.9 and 385.6 tonnes for the -400 without stab tank. Each model PMDG simulated is slightly different.

The Boeing FMC doesn't use an alternate route to calculate reserves. If it did you wouldn't have to enter a figure, just as with the MD11 (or an Airbus). To work out what your reserve fuel should be you need to use a flight planning tool such as PFPX (payware) or Simbrief (free service). I use Simbrief and that will suggest an alternate airport for your route, or you can choose one of your own. The flight plan it calculates will give you approprate figures for the fuel required to divert to the alternate and for 30 minutes circling there. Add those two figures together to get the reserve fuel you enter in the FMC.

Thank you so much for the mtows and for suggesting simbrief! I wasn't aware there was a free alternative to PFPX. One more question, are the MTOWs the same across all three engine suppliers? 

 

-Thank you

Angelo

[kevinh 409]

10 hours ago, killairbus said:

Thank you so much for the mtows and for suggesting simbrief! I wasn't aware there was a free alternative to PFPX. One more question, are the MTOWs the same across all three engine suppliers? 

 

-Thank you

Angelo

Glad to help. Simbrief is a great planning tool and keeps getting better.

The weights are the same across the engine variants for a given aircraft model (400, 400F, etc).