Patrick Roddie claims this is an air traffic controller telling a pilot "It looks like there's a chemtrail off your left wing".
At about 1 minute.
At about 1 minute.
a similar trail sometimes can be seen after takeoff in summer:
It is fuel from the overflow valve, when the tank is full and the fuel heats up and expands. The overflow valve is by Boeing in the front of the wing.
Interesting, but is that what your photo is showing? The trail seems to be coming from the body, not the wing. Shouldn't it look like this:
The vents (NACA ducts), located near each wing tip, provide a small positive head of pressure on the fuel in all three tanks. This prevents a vacuum forming as fuel is used, assists the fuel pumps and reduces evaporation. NB if you overfill the fuel tanks, then this is where the ensuing fuel spillage will come from!
And notice these are all from the left wing.
Published on Mar 16, 2016
Thank you all for watching this video. Taken in the morning of June 27th last summer this Thomson Airways Boeing 737-800 appears to be leaking fuel from the outer left wing during its takeoff run, rotation and climb from Manchester Airport. It is possibly fuel coming from the overflow valve.
As the sun was beginning to appear over the horizon and the air was getting warmer the fuel in the likely full fuel tank would begin to expand which might be the reason for the leakage.
We can't say for sure whether this is a fuel leak or not, but internet sources suggest that this is a fuel leak. Otherwise, it would be a very odd vortex.
This one could be mistaken for a contrail:A Boeing 727- 2S2F(RE) operated by T2 Aviation Oil Response takes off with fuel leaking from the pilot side wing, from Gander International Airport ( CYQX ) for Keflavik International Airport ( BIKF ).
The problem was simply due to warm temperatures and the fuel release valve opening up releasing some fuel, the pilot was told of the situation and continued on to its destination.
So do you think a controller familiar with the chemtrail theory saw a fuel leak, knew it wasn't anything to worry about, and decided to have a little fun with it? It seems a bit strange that they didn't follow up to mention the fuel, though. And they later change their mind to say "contrail".