Eugenio Lo Cicero

SIMBRIEF AND PMDG RESERV FUEL %

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Hello everyone

i have a question about the flight planning made by simbrief and the part about the reserve fuel on the pmdg ngx,below is an example of my last flight

 PLANNED FUEL
---------------------------------
FUEL ARPT FUEL TIME
---------------------------------
TRIP MXP 5922 0102
CONT 15 MIN 1412 0015
ALTN FRA 5349 0103
FINRES 2220 0030
---------------------------------
MINIMUM T/OFF FUEL 14903 0251
---------------------------------
EXTRA 0 0000
---------------------------------
T/OFF FUEL 14903 0251
TAXI FCO 500 0020
---------------------------------
BLOCK FUEL FCO 15403
PIC EXTRA .....
TOTAL FUEL .....
REASON FOR PIC EXTRA ............
------------------------------------

now if I'm not mistaken the part about the fuel reserve is "finres" I wondered how I can determine this value in percentage to be included then in the programming in the FMC on the ngx at voice res fuel % ?

another little question about ngx fuel sistem in general: in this case on board in total I had 15403 lb of fuel, inserting this data in the appropriate section on the fmc I have to divide the value in the 3 tanks two wings and the central or I leave it as default by the FMC or only divided into two wings with empty central tank and the related fuel pump off

thanks for the support

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Best way to load fuel is to enter the total and let PMDG fill the individual tanks.  Same goes for ZFW.  On the same subject, the center never gets fuel unless the wings are full (simplified, you might have less than 1000 lb in center tank left over from last flight.. different subject).

Enter the RSV value on the PERF page that you want to enter.  This is not a magic number, the only thing it serves to do is trigger a fuel advisory message when the fuel on board drops below this  value.  I look at having enough for alternate as the absolute minimum but you might want to add all the allowances to see if your trip burn is close to prediction.... you decide.

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Ciao Eugenio,

just for curiosity..

if you was planning a Rome(Fiumicino) FCO-MXP (Malpensa) flight (i,.e. NEMBO T313 ELB M729 IDONA, by memory) why you should choose Frankfurt (FRA) and 5950 kg of reserve fuel as alternate? That is a nonsense (you left the alternate choice as "automatic") but the best choices as Malpensa alternate (if weather is forecasted not to bad) are Bergamo-Orio (LIME) es. 1100 kg of reserve fuel or Turin (LIMF) es 1300 kg reserve fuel. Anyway for flying from LIRF (FCO) to LIMC (MXP) you should need no more than 5500kg of fuel (i.e. 200 taxi, 2500 trip , and 2800 reserves (alternate + final reserve i.e. 30 min holding))

Ciao, a presto

Andrea Buono - I - Como

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3 hours ago, downscc said:

Best way to load fuel is to enter the total and let PMDG fill the individual tanks.  Same goes for ZFW.  On the same subject, the center never gets fuel unless the wings are full (simplified, you might have less than 1000 lb in center tank left over from last flight.. different subject).

Enter the RSV value on the PERF page that you want to enter.  This is not a magic number, the only thing it serves to do is trigger a fuel advisory message when the fuel on board drops below this  value.  I look at having enough for alternate as the absolute minimum but you might want to add all the allowances to see if your trip burn is close to prediction.... you decide.

Thanks for your explanation all clear now 

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2 hours ago, Andrea1 said:

Ciao Eugenio,

just for curiosity..

if you was planning a Rome(Fiumicino) FCO-MXP (Malpensa) flight (i,.e. NEMBO T313 ELB M729 IDONA, by memory) why you should choose Frankfurt (FRA) and 5950 kg of reserve fuel as alternate? That is a nonsense (you left the alternate choice as "automatic") but the best choices as Malpensa alternate (if weather is forecasted not to bad) are Bergamo-Orio (LIME) es. 1100 kg of reserve fuel or Turin (LIMF) es 1300 kg reserve fuel. Anyway for flying from LIRF (FCO) to LIMC (MXP) you should need no more than 5500kg of fuel (i.e. 200 taxi, 2500 trip , and 2800 reserves (alternate + final reserve i.e. 30 min holding))

Ciao, a presto

Andrea Buono - I - Como

ciao Andrea

ti rispondo in italiano 😄 sinceramente non ci avevo fatto caso ma di solito lascio tutto su auto sulle impostazioni di simbrief me lo da come areoporto auto di alternativa se provo a ricambiare con "auto" mi da un fatal error, ci darò piu spesso un occhio allora grazie ancora 

for all users: 

 

Hi Andrea

I answer you in Italian 😄 honestly I had not noticed but usually I leave everything on the auto on the symbrief settings me as a auto alternative if I try to reciprocate with "auto" gives me a fatal error, I will give more often an eye so thanks again

Edited by Eugenio Lo Cicero

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17 hours ago, Andrea1 said:

if you was planning a Rome(Fiumicino) FCO-MXP (Malpensa) flight (i,.e. NEMBO T313 ELB M729 IDONA, by memory) why you should choose Frankfurt (FRA) and 5950 kg of reserve fuel as alternate? 

I think the weakest part of Simbrief is the alternate selection. After you enter origin and destination it auto fills the alternate. I assume that’s where FRA came from. Sometimes the alternate offered makes sense. Frequently it doesn’t, as in this case. Best to check it for reasonableness. You can of course enter your own choice and Simbrief will use that for planning. 

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4 hours ago, kevinh said:

I think the weakest part of Simbrief is the alternate selection. After you enter origin and destination it auto fills the alternate. I assume that’s where FRA came from. Sometimes the alternate offered makes sense. Frequently it doesn’t, as in this case. Best to check it for reasonableness. You can of course enter your own choice and Simbrief will use that for planning. 

Thanks i will do like this 

 

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Hi Kevin.

yes, you're right, alternate has to be inseted manually. Another weak point of simbrief is sometimes, it is unable to keep account of fuel burned during sid ans star, so i.e. you have to add 400-500 kg of  reserve fuel to the worked out block fuel amount to get a realistic value.

On the other end its point of strenght is that it can workout a very realistic flightplan format according with different airlines print-out scheme. When I passed a my simbrief flightplan to a friend of mine who was a (now former) Captain for the bigger European airline employing the B737-800, he asked me if I had an ID and password to enter in their company LIDO-based flightplan database system...

Best Regards

Andrea Buono

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On 1/22/2019 at 11:19 PM, Andrea1 said:

Hi Kevin.

yes, you're right, alternate has to be inseted manually. Another weak point of simbrief is sometimes, it is unable to keep account of fuel burned during sid ans star, so i.e. you have to add 400-500 kg of  reserve fuel to the worked out block fuel amount to get a realistic value.

On the other end its point of strenght is that it can workout a very realistic flightplan format according with different airlines print-out scheme. When I passed a my simbrief flightplan to a friend of mine who was a (now former) Captain for the bigger European airline employing the B737-800, he asked me if I had an ID and password to enter in their company LIDO-based flightplan database system...

Best Regards

Andrea Buono

for this last night when atc say to me to take a determinate sid for the take off the  FMC say to me "using reserve fuel" so i just put more and now i know that problem i will try to use another program for the fuel by the way "fuel planner" suggest to me the same quantity of simbrief

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To be honest, the Simbrief fuel planning is as accurate as you are likely to get provided you are using real-world weather (i.e. the same weather as when you calculated he . If you put the SID or STAR in the route it will include it; if you really want to force it to, say, plan you at the SID level all the way to the end of the SID you could enter that in to the FP as well and it should respect the constraint but I can't say I've ever felt the need.

If you are ending up consistently very short of fuel you may wish to increase the fuel bias factor; the aircraft profiles are based on real world performance models but obviously there is variation in the FS world in terms of the accuracy of fuel burn modelling/engine type etc (I don't own the NGX but I know the old 744, of similar vintage, was about 8-9% too thirsty whereas the latest version of the 744 is pretty well spot on; I think in more recent models PMDG may have overcome some of the limitations associated with the MSFS atmosphere and quirks in relation to fuel burn).

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Also, there is a great section in the tutorial that deals with fuel planning - and a way to calculate the necessary reserves by incorporating info gathered from the FMC. 

Interestingly, when following the tutorial's fuel planning method the values I get are always lower then the SimBrief suggestion. I still go through the exercise of fuel planning but pretty much always round up the value calculated by SimBrief. The reserves though I always calculate through the FMC.

I haven't looked into it too much, but the fuel that I should have as predicted by the FMC is always higher then it is when I actually arrive. I've never had to divert, but I would think I wouldn't have enough to do two go-arounds and a 30 minute hold and still make it to the alternate if the actual fuel value on the first approach is so much lower then what the FMC predicted it should be when calculating in the pre-flight. 

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