Fuel leak? AA738 (Photos attached)

[[email protected]]

I took these photos some months ago, and when I saw them on my computer I noticed some kind of "trail" coming out of the right wing.

It doesn't seems to be a vortex, because it coming from the bottom of the wing.

Does someone know what this is? Fuel leak?

Regards,
Daniel

[JordanD]

It could be a small amount of fuel coming out of the fuel vent, meaning that it's supposed to happen, but I really know nothing about fuel vents on airliners. I know in a 172 fuel with sometimes drip out of the vent while it's taxiing, and taking off I suppose (I never looked at that during takeoff). When it happens on the 172 it's normal thought, but like I said, not too sure about on a 738.

[Sam at MAN]

On that last photo looks asif it is coming from the wing, so i guess its fuel

[JordanD]

On that last photo looks asif it is coming from the wing, so i guess its fuel

Vortices come from the wing too.

[G-DALE]

Definitely looks as though it's fuel. I believe this mainly happens on very hot/humid days. Basically the fuel expands due to the heat and then ventulates out of the wing. Here's another couple of occassions where this has occurred -

[photoid=305179]
[photoid=5844266]

Hope that helps,

Dale

P.S I'll stick this one in The Briefing Room, as it's probably more appropriate in there.

[[email protected]]

I wasn't aware that airliners had some sort of relief valves, besides the ones used for fuel dumping.

The photo was taken at 4:38pm, the sun was coming down at that time, so it wasn’t very hot, maybe the humidity was high at that time or the fuel tanks were full. This aircraft was heading to KMIA from MROC (SJO).

Thanks for the replies so far.

[screaming_emu]

I wasn't aware that airliners had some sort of relief valves, besides the ones used for fuel dumping.

yup, all aircraft need fuel vents to allow air to fill the fuel tanks when the fuel is drawn out. If they dont, a vacuum would be formed and they would no longer be able to get any more fuel. Its also there for when the fuel expands due to changing temperatures to allow it to leak out, instead of making the pressure inside the fuel tank get too high.

[ExpressJet145]

I'll chirp in since I used to be a fueler . That is in fact the #2 Main Tank fuel Vent. The wind going over it creates a suction, and/or the overfill tank is draining some. Nothing major.

[screaming_emu]

I'll chirp in since I used to be a fueler . That is in fact the #2 Main Tank fuel Vent. The wind going over it creates a suction, and/or the overfill tank is draining some. Nothing major.

I've actually had fuel come out of my fuel vent in flight. Was getting bounced around pretty hard in a Cirrus SR-20 and every once and a while we'd see some fuel come out below the trailing edge.

[[email protected]]

I'll chirp in since I used to be a fueler . That is in fact the #2 Main Tank fuel Vent. The wind going over it creates a suction, and/or the overfill tank is draining some. Nothing major.

This is very interesting, as screaming_emu I have seen fuel coming out of the vents of smaller aircrafts such as PA-28s and C177s.

How many fuel vents does a 737 has and where are they located?

[ExpressJet145]

This is very interesting, as screaming_emu I have seen fuel coming out of the vents of smaller aircrafts such as PA-28s and C177s.

How many fuel vents does a 737 has and where are they located?

On the 737s, there is one fuel vent for each tank, located near the wing tips on each wing (like in the pic). As far as the center fuel tank, Im really not sure to be honest with you. I dont think the center tank vents through the wings, it has its own vent, but Im not sure where it is. With MD80s you cant fill the wing tanks to max capacity of 9300lbs until the center tank is properly loaded accordingly to the fuel load. Hope this helps!

[AJ]

From the 737 notes at http://www.smartcockpit.com/

4. FUEL VENT SYSTEM
¡ The purpose of the fuel vent system is to prevent damage to the wings due to excessive buildup
positive or negative pressure inside the fuel tanks and to provide ram air pressure within the
The tanks are vented into surge tanks which vent through a single opening at each wing tip.

[Admin Airbus]

thats a slipstream i think

is that not a slipstream. if the pressure on the plane below the wing is higher than the upper part of the wing then the slip stream comes from the bottom... I THINK ONLY

[JJR]

I'll chirp in since I used to be a fueler . That is in fact the #2 Main Tank fuel Vent. The wind going over it creates a suction, and/or the overfill tank is draining some. Nothing major.

Probably nothing to do with trying to squeeze in that last 15 gallons when it VTO's @ 8.5 on a wicked hot day?????? Maybe he forgot to let go of the button.....

[Foxtrot]

Re:

Wow, interesting info. I never knew either that airplanes have fuel tank vents, but it makes sense now that I know. This also explains what I saw from an AI 742 back in '91. Right after takeoff, I saw a small stream of white coming out of the wing, from underneath it, between the engines (I was right behind the trailing edge). I was a little alarmed at first, but after a while it stopped and we continued w/o any problems. You may say it was vapour streaming from the flaps or flap guide, but this was the only white stuff streaming back and there was nothing else streaming from the wing. Also, it was continously streaming, not like vapour which is random in behaviour.