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Guest skyhog

Fuel Question

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Hi,I have tried using fuel from the center tank and it sets off the master caution light for fuel. Also I'm confused about the forwardand aft tanks. Which is the center tank (fuselage) and which isthe wing tanks? I use the top 2 switches on the overhead panel andyou can see the fuel from the center gauge being used but it setsoff the master caution light. Explanation or help will be welcomed.Great Planes PMDG.Ron Off

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I have noticed the same thing. If you have the 2 pump switches for the center tank on, it runs the center out first and then the warning light comes on. I just switch the center off at that point and it draws from the wing tanks. I am just guessing that is the right way to go about it, but I was wondering how the system is actually supposed to be managed in a Real 737.

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This is exactly how the real one works. The center tank is always used first. The warning light comes on because when the tank is low or empty you will need to turn off the tank pumps on the overhead. Best Wishes,[h4]Randy J. Smith[/h4][h3]P M D G's 747-400[/h3][h4]coming to a runway near you[/h4][/font color]Caution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

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Bob,Yes, that's exactly how it is upposed to work. The master caution will extinguish once you switch of the pumps for the center tanks after running them dry.Boeing recommends that at least 1,000 lb of fuel are in the center tanks if the wing tanks are full. So many arlines specify in their operating procedures that the center pumps are switched off once center fuel level goes down to 1,000 lb. This is also refllected in Ross Carlson's fuel planner, which always places 1,000 lb in the center tank, even if the center tank is not used for the planned flight (center tanks is usually not used if the wing tanks are less than 100% full at departure). In this case you would just leave the center pumps off. Or for the short version: The center tanks is always filled last and used first, down to 1,000lb,Best RegardsMax (Bern, LSZB)http://www.hifisim.com/images/as2004betateam.jpg http://www.precisionmanuals.com/images/forum/800driver.jpg>I have noticed the same thing. If you have the 2 pump>switches for the center tank on, it runs the center out first>and then the warning light comes on. I just switch the center>off at that point and it draws from the wing tanks. I am just>guessing that is the right way to go about it, but I was>wondering how the system is actually supposed to be managed in>a Real 737. >>

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Mr. Bill Bulfer (FMC USER's GUIDE) suggest to use the fix page to place a distance circle on the MAP when you estimate the center tanks to be about 2500-1500 LBS so you do not forget.Best Wishes,[h4]Randy J. Smith[/h4][h3]P M D G's 747-400[/h3][h4]coming to a runway near you[/h4][/font color]Caution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

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I have a similar problem with forgetting to turn it off :) I also have the same problem with starting the ET timer on take off. Always a bummer that.

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>Bob,>>Yes, that's exactly how it is upposed to work. The master>caution will extinguish once you switch of the pumps for the>center tanks after running them dry.>>Boeing recommends that at least 1,000 lb of fuel are in the>center tanks if the wing tanks are full. So many arlines>specify in their operating procedures that the center pumps>are switched off once center fuel level goes down to 1,000 lb.>>>This is also refllected in Ross Carlson's fuel planner, which>always places 1,000 lb in the center tank, even if the center>tank is not used for the planned flight (center tanks is>usually not used if the wing tanks are less than 100% full at>departure). In this case you would just leave the center pumps>off.> >Or for the short version: The center tanks is always filled>last and used first, down to 1,000lb,>>Best Regards>Max (Bern, LSZB)>http://www.hifisim.com/images/as2004betateam.jpg>http://www.precisionmanuals.com/images/forum/800driver.jpg>>>>I have noticed the same thing. If you have the 2 pump>>switches for the center tank on, it runs the center out>first>>and then the warning light comes on. I just switch the>center>>off at that point and it draws from the wing tanks. I am>just>>guessing that is the right way to go about it, but I was>>wondering how the system is actually supposed to be managed>in>>a Real 737. >>>>>What is the logic that is used to rule that the wing tanks should be filled first. Why not fill and use the center tank first??

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The wings "carry" the fuel in them, if you put it in the center tank the load increases on the wing roots and airframe.

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>The wings "carry" the fuel in them, if you put it in the>center tank the load increases on the wing roots and>airframe.Thanks, I would have never figured that one out.

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That is what I suspected. The master caution fuel light is just a reminder then? Next question. Are there 2 tanks in each wing, Fwd andAft? and are the lights on the overhead panel for the center tanksupposed to come on at any time? using or not using fuel?

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Skyhog,As far as I am aware, there are only 3 tanks in the 737. 2 winds and a centre. The jumbo has about 8! The reason you see AFT and FWD pumps for each tank is because the tanks have a pump at each end. (As is my understanding)The lights on the overhead only come on if you have fuel pumps on with no fuel in the tank! ie the pumps are pumping nothing. Im sure someone will correct me soon Ross

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For max,Max: where can I find the Fluel Planner you mentioned (Ross Carlson)?ThanksBPilot

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"The reason you see AFT and FWD pumps for each tank is because the tanks have a pump at each end. (As is my understanding)"Sort of correct, Ross. On a 737NG, the wing pumps are at the front and back of the wing (just outside the tank). However, Boeing usually name their pumps according to where in the tank the fuel is being sucked up by the pump. The pump may be at the back of the wing tank, but it may may suck fuel from a point in the tank well forward of the pump. In some cases, a "Fwd Boost Pump" may be further aft than the "Aft Boost Pump"! (Some 747-400 pumps are like this).Hope this makes sense.Cheers.Ian R>

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Not that I'm Max..The Fuel Planner can be found under the Downloads tab on the main PMDG website. It is in the Miscellaneous Files section and is called 737 Fuel Planner Utility (3rd Party).Hope you find it OK.James

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