I hope I use this forum the right way, as it is my first time!:)Can somebody tell me how to use the fuel from the wing-tanks in the 737NG-700 or 737NG-800I both cases I get a "fuel-low alarm" even with 100% filled wing-tanks; when my central tank is empty.Thanks for any tip to solve my "simple" problem! Charly Everberg

From my understanding when your center tanks are at about 1000lbs of fuel you should turn those pumps off. If you run the center tank dry you will get a FUEL annunciation warning that the center pumps are still on but the tank is dry.When all pumps are on only the center tank is used.

I've heard 500 lbs, but oh well. Open the "Cockpit and Systems Overview" manual and go to Fuel Indicators (page 79). Look at the picture, when you want to switch to wing tanks, switch the 2 switches right below the cross feed switch to off (up).Nick B.Continental Airlines 737NG Pilothttp://www.precisionmanuals.com/images/forum/800driver.jpg--AMD Athlon XP 3200+ @ 2.2 Ghz (Equal to 2.8 ghz)400W Power supply3x 80 mm Case FansSoyo VIA KT600 Dragon PlusnVidia GeForce FX 5200 128 mb2 x 512 PC400100 GB Western DigitalMicrosoft Sidewinder Precision 2

>From my understanding when your center tanks are at about>1000lbs of fuel you should turn those pumps off. If you run>the center tank dry you will get a FUEL annunciation warning>that the center pumps are still on but the tank is dry.>>When all pumps are on only the center tank is used.Thanks a lot! The "problem" is solved! kindest regards

Thank you Nick, it worked as expected.Kindest regardsCharly Everberg

As it was said before, you should use the fuel in the center tank before you ever use the wing tanks. I've also heard 500 lbs is when you shut off the center fuel pumps.:-)

I think it's 500 kgs or 1000 lbs!Cheers,

Sorry gents, but the answer is 1000lbs. Check out http://www.b737.org.uk/faaad.htm which has the FAA AD on it that states the 1000lbs.The relevant quote is: "The center tank fuel pumps must be OFF for takeoff if center tank fuel is less than 5,000 pounds (2,300 kilograms) with the airplane readied for initial taxi.Both center tank fuel pump switches must be selected OFF when center tank fuel quantity reaches approximately 1,000 pounds (500 kilograms) during climb and cruise or 3,000 pounds (1,400 kilograms) during descent and landing. The fuel pumps must be positioned OFF at the first indication of fuel pump low pressure."For those of you too lazy to go to that page :)

That's confusing. If you have less than 5000 lbs in the center before takeoff, you switch it off. So when do you turn it back on?Nick B.Continental Airlines 737NG Pilothttp://www.precisionmanuals.com/images/forum/800driver.jpg--AMD Athlon XP 3200+ @ 2.2 Ghz (Equal to 2.8 ghz)400W Power supply3x 80 mm Case FansSoyo VIA KT600 Dragon PlusnVidia GeForce FX 5200 128 mb2 x 512 PC400100 GB Western DigitalMicrosoft Sidewinder Precision 2

Not to sure if its the same on the B737 but on the B744The centre tank pumps are called{sacvage pumps} these must be turned off at approxx 1400kgs this is when the pumps become exposed and you get the warninig lights{plus a build up of fuel vapour which is what they think caused the TWA crash}.If these pumps are not working you must limit the ZFW wt by 1400 kgsas it has to be unusable fuel.I know its the B744 but i believe it is the same prinsible on the B733 but with different weights.Owen

I would guess you switch them ON after take off i.e during climb. As the quote states they have to be switched OFF only for take off.Cheers,

Hmm, they need to word that better. Made it sound like 3 different thingsNick B.Continental Airlines 737NG Pilothttp://www.precisionmanuals.com/images/forum/800driver.jpg--AMD Athlon XP 3200+ @ 2.2 Ghz (Equal to 2.8 ghz)400W Power supply3x 80 mm Case FansSoyo VIA KT600 Dragon PlusnVidia GeForce FX 5200 128 mb2 x 512 PC400100 GB Western DigitalMicrosoft Sidewinder Precision 2

"Both center tank fuel pump switches must be selected OFF when center tank fuel quantity reaches approximately 1,000 pounds (500 kilograms) during climb and cruise or 3,000 pounds (1,400 kilograms) during descent and landing. The fuel pumps must be positioned OFF at the first indication of fuel pump low pressure.""Don't these two statements contradict each other? Usually pumps will only indicate low pressure if the tanks are empty.Anyway, it doesn't matter if you run the tanks dry in PMDG's 737NG. It has the updated pumps/wiring which doesn't explode. The FAA rule about switching off the pumps at 500kg only applies to aircraft which haven't been modified.I'm sure there was a posting on this not so long ago? (I'm surprised the NG experts haven't adjusted their responses yet). :-)Cheers.Ian.