"Leaking" B-737

[Göran]

These two shots were taken early this summer at Arlanda (ESSA) at runway 2. They are not the of greatest quality and excitment I admit, but since I know there are some members here at BM who are involved in the aviation industry one way or the other, "you" might offer an explanation to what that leak from the port wing was? I never whitnessed it before or after for that matter. If there was an "unplanned" leakage, some sort of warning must have sounded in the cockpit no? Anyway the leak continued during the climb out and me and my photo buddies are still puzzled over this. Thanks in advance.

[eng]

The "leak" looks to me like fuel vapour being drawn out of the wing NACA vent on the lower surface, this is probably due to the aircraft wing tanks having been fuelled to max capacity and a small amount of fuel overfilling into the vent/surge tank on the left wing. The surge tank is there to allow for fuel expansion and movement during operation. Quite often, more so on large longhaul aircraft, if the high level automatic fuel cut-off system doesn't work during refuelling there can be spillage of fuel from these vents. The vent scoop itself is there to allow air to be "scooped" into the tank to effectively pressurise the fuel tanks during flight and to relieve pressure as fuel is added during ground refuelling.

Check out these pic's below - the vent and exactly what you've seen!

http://www.b737.org.uk/fuel_tank_vent.htm

Rgds,

Eng

PS - Lovely pics!!

[Göran]

Thanks for the informative answer Eng

[eng]

No worries! Glad I could help.

Eng