747 fuel from wing tip

[matblack]

At manchester today I noticed a lot of what looked like fuel pouring from the wing tip of a European 747 during the takeoff roll. Is this normal? I've never seen it before.

[gas path]

Certainly not normal, but a couple of reasons.....
Full wing tanks fuel many have expanded due to the heat and filled the vent surge tank at the wingtip (11 gallons capacity!). This would then vent overboard.
A broken vent valve in one of the tanks which would allow fuel into the vent line and thus into the (vent surge) tank.
Only problem with this is someone has got to get into the tanks to fix it, and locate the broken bits.