ChrisPerkins
Topic Author
Posts: 12
Joined: Wed May 17, 2006 7:57 pm

Contrail-like Vapor Trail From Fuselage

Sun Mar 06, 2011 9:31 am

Hi Everyone,

Flying 2'000ft below an Airbus A330 (FL390) on the same routing I noticed a contrail-like vapor trail forming behind the fuselage. It was only very faint, so not visible from the earth's surface, and it only formed for a few seconds, then vanished, only to reappear roughly a minute later or so.

The reason for this mini fuselage-trail remains unclear to me, yet I have 2 theories:

1) Water released from the fuselage. The origin of the water? Don't think that water drained through galley sink would form a visible trail. So maybe condensation water from the Air Conditioning unit? But why would it only appear on intervalls and not constantly? And it would probably not be that much water released either...

2) Air relesased from fuselage. Maybe also through A/C unit - warm (cabin temperature) air would be humid and at high pressure compared to outside air, so would rapidly expand and maybe form fuselage-trail. Altough, as far as I am aware, this release of air happens constantly so no explanation for the intervall phenomenon.

Didn't mean to mislead you with my theories - maybe the reason is something else?
...who has the correct answer?

Thanks for your comments!
Best regards,
Chris
 
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cotparampguy
Posts: 157
Joined: Sat Jul 12, 2008 2:56 am

RE: Contrail-like Vapor Trail From Fuselage

Sun Mar 06, 2011 10:49 am

I believe what you saw was water coming out of the drain mast. There are pictures on the internet (even on here) of that happening. You'd be surprised how much water they dump out of there.
 
ChrisPerkins
Topic Author
Posts: 12
Joined: Wed May 17, 2006 7:57 pm

RE: Contrail-like Vapor Trail From Fuselage

Sun Mar 06, 2011 4:31 pm

So where does that water come from?
 
tdscanuck
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Joined: Wed Jan 11, 2006 7:25 am

RE: Contrail-like Vapor Trail From Fuselage

Sun Mar 06, 2011 6:38 pm

Quoting ChrisPerkins (Thread starter):
1) Water released from the fuselage. The origin of the water? Don't think that water drained through galley sink would form a visible trail.

I second cotparampguy that it's probably drain mast water...that's intermittent and would appear to come off the back of the fuselage (the drain mast only goes about a foot away from the fuselage).

Quoting ChrisPerkins (Reply 2):
So where does that water come from?

Sinks...galley & lav. Some types also have bilge drain valves, but I'm not sure how that's implemented on the A330.

Tom.
 
Gatorman96
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RE: Contrail-like Vapor Trail From Fuselage

Mon Mar 07, 2011 8:53 pm

 
Fly2HMO
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RE: Contrail-like Vapor Trail From Fuselage

Mon Mar 07, 2011 9:49 pm

I hear that when you see a brown streak behind the galley drain masts on the fuselage it's mainly due to coffee being dumped and sticking to the fuselage.

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