Fuel leak? AA738 (Photos attached)

[meneses24]

I got a simmilar picture one of this days

[photoid=5873774]

[RingwaySam]

I saw a 747-300 with fuel coming out a few months ago. The airport had to shift the mess which was on the runway. They carried on there journey though.

[B7772ADL]

Here's another couple of occassions where this has occurred -

[photoid=305179]

I remember that one very well....the chief fire officer wasn't a happy chappy at all that Snowbird was venting fuel all over the place. The aircraft elected to continue on it's journey and safely got away, if a little alarming to see.

[m.swofford]

Fuel Venting

Airliners generally have one fuel vent near the outboard end of each wing. Passenger 747-400s also have a 22,000 lb fuel tank in the horizontal stabilizer and its vent is located on the outboard starboard horizontal stabilizer. The fuel vent system is usually connected to a surge tank nearby which takes up excess fuel due to expansion and returns the fuel to the associated tank as the fuel drops due to consumption.

On rotation or shortly after takeoff as in the case of these photos, some fuel still in the surge tank is being vented throught the fuel vent. These vents are on the bottom of the wind and use a NACA duct that is usually pressure neutral, neither pressurizing or suctioning fuel from the surge tank and their shape avoids contamination and blockage from ice or rain.

Vapor trails also seen during takeoff and especially landing usually form in high humidity conditions in vorticies from the outboard trailing edge flaps and not the wing tips. The low pressure in the center of these cause water vapor to temporarily form droplets due to the drop in temperature and pressure.

Continuous vapor trails normally only form in very cold or humid conditions during high angle of attack flight such as fighter maneuvres or during takeoff and landing. Continous fuel vapor trails would be evidence of fuel leakage and cause for concern. But it would be difficult or impossible to tell the difference from the ground.

Older jet, turbine and reciprocating engines vent oil and unburnt fuel as a dense smoke trail from the engine itself.

[fabster4444]

Related!

http://aviacioncr.net/foto.php?id=47459

f.

[brianw999]

I recall an occasion when the passengers on a Phuket Airlines 747 flatly refused to all ow a takeoff when fuel was seen pouring from a wing vent.

...with that airlines track record on maintenance before they went bust it's probably the best decision those passengers ever made in their life.