Posts by user "Shaggy Sheep Driver" [Posts: 67 Total up-votes: 0 Page: 4 of 4]¶

Casper, I'm not aware of any fuel tank protection by either BA or AF prior to the accident.

Overweight & aft GC was due too much fuel as well as captain authorising baggage to be loaded (in the rear baggage cabin) when the aeroplane was already about 5 tons overweight.

Something else germane to the accident was that the fuel tanks were overfilled leaving no airspace to absorb any shock waves on the basis this extra fuel would be burned off during taxi, but the change of runway (to a downwind one) meant a much shorter taxy so it wasn't burned off and the FE didn't ask for a delay while it got burned off. They just 'went'.

Worse - realising they had a rearward CG, fuel was being transferred from tank 11 (in the tail) to the wing tanks DURING THE TAKE OFF ROLL. an absolute no-no in Conc ops. The idea being as fuel was burned off from the wing tanks and replaced by fuel from tank 11, the CG would move foreward.

The result was the wing tanks were always overfull even though they were supplying fuel to the engines, so when one tank was hit by a big piece of tyre the shock waves travelled up through the fuel, bounced off the top surface of the tank, having found no gap of compressible air to absorb the overpressure, and travelled back down and burst the tank floor from inside.

Extra taxi fuel I should think, which should be burned off before take off (it wasn't on the accident aircraft because of the change to a nearer runway).

So Hutch is wrong when he says in the interview that tank 5 was being continuously topped up from tank 11 as fuel was burned off during the T/O? I've had a quick look at a simplified fuel system diagram and while it shows no direct transfer route from tank 11 to tank 5, would there be an indirect one via the forward trim tanks?

And as the extra baggage was in the rear hold, and Tank 11 was full, that would explain the rearward CG and the desire of the crew to get fuel out of tank 11 ASAP and into the wings, Did it all go to tanks 1 to 4 via the forward trim tanks, with none going to tank 5 ( the 'accident' tank)?

Because the forward trim tanks were already full so not an option to put it there, unless there is a route from there to tank 5, in which case it might be being transferred to the trim tanks from tank 11, and on to tank 5? The only place to put fuel (if all tanks are brimmed) is into a tank(s) which are being emptied by feeding the engines. If there is no route from the forward trim tanks to tank 5, then perhaps in normal ops tank 5 would be topping up the feeder tanks as the engines drain them, but topping up the feeders from tank 11 meant tank 5 remained full?

The objective is to get it out of tank 11 ASAP to try to get the CG further forward.

Hutch says they should be 'off' for T/O roll, but on this occasion, to shift CG forward, they were 'on'.

CliveL

From this video. Have you not seen it? Ignore the garish sensational 'cover'. John is a highly experienced BA Concorde captain.

OAC was the first off the Filton line, and therefore the heaviest (they learned to add lightness as production progressed!). That would have had an effect on range and possibly CG for that aeroplane. It also had a wing repair (following an engine fire I believe) which added even more weight.