At Ryanair we now store extra fuel in the baggage compartment !! We put the baggage on a special roof rack but it does make things more trickyfor the dispatchers.

After a bit more research... The auto-shut-off feature has been used since May 2004

It makes more sense that way. An automatic feature saves time , therefore money , to pilots. A warning helps in case a fault is detected but what if a pump sensor fails ? I mean the sensor who has to pass the information to the cockpit if the pump sensor fails. Thx

With the main tank fuel pump No. 1 FWD Switch ON, the center tank fuelscavenge jet pump operates automatically to transfer any remaining center tankfuel to main tank No. 1. Fuel transfer begins when main tank No. 1 quantity isabout one-half. Once the fuel scavenge process begins, it continues for theremainder of the flight.

Well I could give you a question. Is the scavenge pump attached to the No. 1 FW pump switch, and then is is a seperate pump or is it some sort of extra line of the No. 1 FWD pump? E. g. if you turn the No. 1 FWD off after scavenge process has started, would it stop again?

I vaguelly recall the 767 having a metal pump or one of its components in the tank. With the remaining fuel gases being ignited by a spark in an explosion. All pilots had to leave a certain percentage of fuel in the tank until they were changed over. The newer models I believe were built a different way. I may not be on the mark but fairly close to it. Its scary really some of the designed safety features that get missed, with many similarities between different aircraft models and ranges.

Well I could give you a question. Is the scavenge pump attached to the No. 1 FW pump switch, and then is is a seperate pump or is it some sort of extra line of the No. 1 FWD pump? E. g. if you turn the No. 1 FWD off after scavenge process has started, would it stop again?

Ill have to look at the fcom again, but I think i remember seeing a separate pump in the fuel system schematic.Or it could be driven by the main pump by perhaps a solenoid/drive mechanism. Not quite sure. However once the fwd no.1 pump is switched on and the fuel level indicator indicates 50% fuel remaining in the main no 1 tank(left handside wing looking down on the plane), the scavenge pump will engage, sending remaining fuel to the number 1 tank. Now because the pump automatically comes on once the 50% fuel mark is reached in the no 1 main tank, the scavenge pump must be connected somehow via the fuel measurement system. So in essence, its not directly connected at all to the fwd no1 pump switch, however, without the fwd no 1 pump not working, it wont come on. The fwd no1 pump switch must send power to a relay contact and the fuel measurement system must energize the windings in the relay to close the relay contacts, sending power to the scavenge pump. (Reminds me of my auto electrical days!) LOL thats probably no where near it. WIll look it up and see how far off I am! Edit: There is also mention of a venturo pump which is also the scavenge pump so not sure. Ill have to do some swotting.

theres a thread on airliners.net about this very thing. I cant link to it, but google 737 ng scavenge pump. I think its number one.

Ah right, it turnes out that:The scavenge "pump" indeed relies on venturi, which means it won't "operate" when the No. 1 FWD pump is not running, because, well, there ain't no venturi then. Flow rate around 100-200 kg/hr so you can estimate how long it would approximately take to empty the center.

Ah right, it turnes out that:The scavenge "pump" indeed relies on venturi, which means it won't "operate" when the No. 1 FWD pump is not running, because, well, there ain't no venturi then. Flow rate around 100-200 kg/hr so you can estimate how long it would approximately take to empty the center.

Did you get that information from the link? I cant seem to find anything on what type of fuel pumps are used or how much they pump per hour in the FCOM. Is that found in maintenance manuals?I also read that the fuel only flows through the scavenge pump when the scavenge pump transfer valve opens, which opens when the no 1 tank reaches half empty. ???

I also read that the fuel only flows through the scavenge pump when the scavenge pump transfer valve opens, which opens when the no 1 tank reaches half empty. ???

Yes, as the pump doesn't really do anything without the main pump operating, it's only "on-off" switch is that SOV.

http://www.b737.org.uk/fuel.htm#Centre_Fuel_Tank_Inertinghttp://www.b737.org.uk/images/schemefuel.gif might be of interest. Then entertain yourself:http://www.b737.org.uk/quiz_fuel.htm

http://www.b737.org....l_Tank_Inertinghttp://www.b737.org..../schemefuel.gif might be of interest. Then entertain yourself:http://www.b737.org.uk/quiz_fuel.htm

I see you were a RC beta team member.....any chance to have a RC 5 ? thx BTW I need a pill to deal with such stuff......they are anyway very interesting indeed.