Posts by user "Mechta" [Posts: 7 Total up-votes: 5 Pages: 1]

There are numerous pictures ot the outside of B787 centre tanks on the net. Does anyone one have any internal pictures, showing the tank floor and fuel pump pick ups?
We know the engines lost power in the initial climb, shortly after rotation. If there was water sitting between the tank lower skin stringers, the rotation would have been the point that the water could tumble over the stringers that were previously preventing its movement. accumulate at the back of the tank and enter both pumps more or less simultaneously.

For background, I worked at Smiths Industries wet fuel testing the B777 gauging system on ground rigs, and at Airbus building and testing fuel tank inerting rigs. I've seen inside Airbus tanks, but not Boeing.

Aside from separating the two engines' respective sources of fuel, the Airbus approach also ensures that the pilots can't inadvertently select a centre tank for take off that is empty, or near empty, for a short sector.

The centre tank would have been used up first, so the tank would have been down to undrainables plus whatever is left when switched over. A check of the weather at each previous sector's descent would be worthwhile to see how much water, in all its forms, could have been taken in the centre tank vent. The ejector pump should have emulsified this water it it was doing its job properly.

This video of a B787 drain check states it should be done weekly. Of note is that it says if water is detected the scavenge jet nozzles are removed and cleaned.

Which can block with algae. Hence the advised weekly drain check to look for water.

The Centre Wing Tank is as it says the centre of the wing. The top and bottom skins continue the aerofoil section through the fuselage, with the front and rear spars' webs forming the fore and aft ends. The inner surfaces of the top and bottom skins have spanwise 'stringers' (well that's what we called them at Airbus), which are 'I' sections attached to the inside to provide stiffness to the skins. The inner faces of the centre wing tank are the tank. There is no separate fuel bag.
The tank is unpressurised. It is vents to atmosphere throughout the flight. There is a fuel tank inerting system which feeds nitrogen-enriched air into the ullage (air space above the fuel). On the 787 it does this on all tanks. Other airliners only do it on the centre wing tank (and any other fuselage tanks if fitted).
Entry to the tanks once they have had fuel in, generally needs breathing apparatus once it has been in service.

Pictures of the inside of a completed 787 Centre Wing Tank aren't easy to find. This shows either the upper or lower skin with its stringers.

Probably just a transport dolly for moving the tank skin between processes. This looks more like the mould tool in front of the autoclave.