View Full Version : 747 Stab Tank

28th Nov 2006, 22:42
What is the point of the stab tank on the 747. Apparently it is emptied first so it's not for C of G control. Is bi directional fuel control possible. Is the C of G on a 747 fore or aft normaly? Could the stab tank be just another place to stuff fuel?
So many questions, so little time.......

28th Nov 2006, 23:04
The point is carriage of an extra 10 tonnes of fuel - the pumps are commanded on with an eicas message when the centre tank reaches 36,500 kgs. Bi -directional flow not possible. Extra fuel wherever you 'stuff it' is extra range! Good luck with the interview!!

Cornish Jack
29th Nov 2006, 11:31
In this area, failure of the Stab tank pumps used to put you neatly between a rock and a hard place!!:eek: Boeing subsequently produced much less restrictive main tank quantities for the follow-up drill but it is still an interesting management problem.
It has happened, by the way, (Birdseed out of HK, for one) and it would be illuminating to read the incident report.

3rd Dec 2006, 12:47
If the Stab tank on the 74 is not for aft C.G. does it gain aft C.G. due to a large sweep in the wings?
And if so how is the fuel burned to maintain the best C.G.?

3rd Dec 2006, 12:50
.... and i found my answer on another thread.
So no worries:O