Hello,

To up my realism in FSX ive turned off unlimited fuel and I want to start properly refuelling my aircrafts,

So I went on a fuel planner on google and it told me my Fuel on board should be 10663 Pounds

So I went into FSX to refuel my 737 however i noticed i have 3 tanks, Left, Centre and Right tanks,

Im just wondering how you work out how you disripute the 10663 Pounds across them 3 tanks,

 

Kindest Regards,

Scott

Hi Scott,

When you're in your Fuel Settings page in FSX, first click on Display Fuel Quantity as Weight, so that your readings will be in pounds.  Keeping in mind the tank limits that are displayed at "Capacity" (i.e. you shouldn't exceed those limits), you can then add the fuel to each of the tanks.  To maintain balance of the aircraft, I would (using your quantity of 10663 pounds), put in the figure 3555 under "Pounds" in each tank (which is 10663 divided by 3).

If you're satisfied that the fuel amount is the correct one for your flight plan, then you may need to add extra fuel for things such as headwinds, go-arounds, taxiing to the runway, etc.  So maybe another 2000 lbs of fuel.

Chris

 

 

If you want to get super-duper-realistic, consider how old the aeroplane you are flying is (i.e. look up the registration of the aeroplane so you can find out when the equivalent real one was built), once you know that, you will know whether it has automatic centre-tank shut off pumps or not. This kind of thing affects the limits on how things are loaded and operated with 737s. Below is most of the stuff you'd need to know for being realistic with a 737, some of which depends on which variant it is...

Any 737 built after mid-2004 has a system whereby the fuel pumps on the centre tank detect low pressure flow (i.e. when the tank is nearing empty) and it shuts the pumps off automatically. This is so that the pumps don't run while on empty, which in high ambient temps can cause them to overheat, if this occurs they could potentially ignite the residual fuel/air vapour in the tanks and cause an explosion (rare, but it has happened a few times).

737 NGs built from early 2006 onwards have a nitrogen generating system on their centre tank, whereby a separator can syphon off nitrogen from oxygen in the air, then vent the oxygen overboard but flood nitrogen into the empty centre tank to reduce the risk of an explosion since there is then no combustible fuel/air mix in the tank. So, if you are flying a 737 NG in your sim, you can cheerfully use the centre tank until it runs dry, if you want to (assuming yours is a model built after March 2006), but if you are running an earlier variant of the 737, then you need to be more careful with the centre tank.

If you are bothered about this sort of level of realism, then the following is most of the rules regarding fuel distribution and control of the pumps etc:

Temperature limitations for fuel on a 737:

Maximum temp: +49°C. Min temp: -43°C or freeze point +3°C

Maximum fuel quantities across all tanks:

1/200: 4300 + 4100 + 4300 = 12,700kg  (2 bag centre bays)

200Adv: 4300 + 5400 + 4300 = 14,000kg  (3 bag centre bays)

200Adv: 4300 + 7000 + 4300 = 15,600kg  (3 bag integral)

Classic: 4600 + 7000 + 4600 = 16,200kg

NG:    3900 + 13000 + 3900 = 20,800kg

MAX: 3,869 + 12,990 + 3,869 = 20,729kg

Maximum allowable lateral fuel imbalance: 

1/200 series 737s: 680kg; All other variants: 453kg. Main tanks to be full if centre contains over 453kg.

When on the ground the centre tank pumps must be not be positioned to ON, unless de-fueling or transferring fuel, if quantity is below 453kgs. Centre tank pumps must be switched OFF when both LP lights illuminate. Centre tank pumps must not be left ON unless personnel are available in the flight deck to monitor LP lights (aka fuel watch). Centre tank pumps should not be allowed to run dry or be left running unsupervised. Crew reset of fuel pump circuit breakers in-flight is prohibited (not that you can do this on most flight sim 737s anyway).

 

Edited August 25, 20214 yr by Chock

3 hours ago, Angels40 said:

Hi Scott,

When you're in your Fuel Settings page in FSX, first click on Display Fuel Quantity as Weight, so that your readings will be in pounds.  Keeping in mind the tank limits that are displayed at "Capacity" (i.e. you shouldn't exceed those limits), you can then add the fuel to each of the tanks.  To maintain balance of the aircraft, I would (using your quantity of 10663 pounds), put in the figure 3555 under "Pounds" in each tank (which is 10663 divided by 3).

If you're satisfied that the fuel amount is the correct one for your flight plan, then you may need to add extra fuel for things such as headwinds, go-arounds, taxiing to the runway, etc.  So maybe another 2000 lbs of fuel.

Chris

 

 

Hello, So basically just devide the number by 3 and put them into each tank

Thank you for the help,

Scott

That's correct, Scott.  Unless, you're flying a non-default aircraft, in which case the extensive details Chock has provided you may be more useful.  I suspect that maybe you're referring to the default B737 where you may not have those options of dealing with specific fuel tank pumps.

As well, when you set up a flight plan (e.g. KLAX to KORD), and when you get into the cockpit & click on the Navigation Log, you'll get all the details of that Plan, including flight distance, duration of flight, fuel required, etc.  Often though, the recommended fuel given doesn't take into account some of those other 'extras' I mentioned earlier that may be required.  You'll need to adjust that figure (maybe increase it by 2000 lbs, test it & adjust as necessary for future flights).  A lot of this is trial error when a more realistic aircraft model & FMC are unavailable.