View Full Version : Calling 737 Chaps - Whats this bit do ?

Squealing Pig
16th Feb 2002, 04:27
Sorting out old photos I came across this one, it was taken some 7 years ago on final to Dublin.. .Observe very carefully at this picture, I may be asking questions


The pic shows a B737-200 wing with either approach or land flap set with vapour coming from the end of the flap, water vapour! nothing unusual in this. or so I thought but look carefully there appears to be a pipe at the end of the flap that looks to be venting the vapour.


As I am pretty certain that the 737 has no fuel dumping system and I really don't think you would be dumping fuel on final anyway. I began to wonder what it was, Is it part of the aircraft that does something else and just looks like is venting or is it some thing on the ground that just happened to be in the right place on the photo.

Any 737 guys out there care to comment ????

Sorry chaps but its been bugging me for days

Red 69
16th Feb 2002, 05:06
That 'pipe' is something on the ground which just looks like it is attached to the wing by the position in which it was taken. There is no pipe in that position on the 737. Looking closely at your picture it seems to be reflections of sunlight from a building. The vapour which is present is caused by differential pressures brought about by the flaps. Hope this clears up your query! (Ex 737 driver)!

16th Feb 2002, 08:17
Bit hard to tell what the photo contains .. however the flaps leave a fairly strong trailing vortex and in conditions of moderate to high humidity the core will be seen due to condensation.

A characteristic of any vortex is a significant radial pressure gradient. The pressure reduction is associated with an adiabatic temperature drop .. the RH increases and at dew point you have a visible record of the vortex core in the condensate.

This is probably what you were seeing, I suspect ?

[ 23 February 2002: Message edited by: john_tullamarine ]</p>

16th Feb 2002, 08:31
Send the photo to the "Chemtrail" guys, they would love it!

16th Feb 2002, 13:00
Definately no pipe fitted on the wing-it is definately a building on the ground and if your eyes are really good you can see a guy on the roof of the building installing a TV aerial ???

Golden Rivet
16th Feb 2002, 16:13
have to agree - think your seeing things.

Maybe Elvis is on the other wing ?

Squealing Pig
18th Feb 2002, 19:54
Thanks, the more I look at it the more plainly obvious to me now that its a building.

Golden Rivet, Elvis was sat next to me so could not on be the other wing (now I am seeing things <img src="tongue.gif" border="0"> )

Might send it to chemtrails - wind em up and watch em dance :)

23rd Feb 2002, 10:35
Yeh John T is 100% correct. You see it a lot in conditions of high humidity. The 747-classic was the best at this during TO or ldg with high wing loadings. Youd swear blind there was fuel p!ssin out off the tops of the wings!