What happened here?

[Adam24]

Hello everyone
Yesterday I was taking some photos of planes passing over, and in one of them something wierd happened. Can you explain me whats this phenomenom? This is an Air China Boeing 777-300. All other planes didnt had any contrails, so this is even more wierd...

[JSkorna]

This one did have a contrail.

[Adam24]

Thats clearly not a typical contrail. Normal contrails come from the engines, and they look differently. And you can see iridescence on them, what you wont see normally.

[JSkorna]

It's from the sunlight lighting things up. The angle of the sun and plane were just right.

[mrzippy]

Hey Adam24,

Some planes don't always have a smoke contrail coming from the engines. Some are condensation contrails. Here's a great link explaining the phenomenon. http://contrailscience.com/why-do-so...t-others-dont/

Good thing it didn't drop any BLUE ICE!

[Adam24]

But the shape of the contrail looks different. Compare it to this one: http://www.flickr.com/photos/pointnshoot/6304605405/
Something is not okay, right? In that photo, the contrail clearly comes from the engines. Here we see something different.

[garryrussell]

That's not unusual given the right conditions

It's a full condensation trail and as Jim says the light is hitting it just right

Sometime the altitude band where trails form can be narrow or low meaning only an occasional aircraft will trail.

On occasions a single small trail can be seen off the tailcone.

This sort of trail is moisture being squeezed out of the air by vortices rather than the normal heat effect and is more like the wingtip and flap edge streamers seen on landing rather than the usual engine trail.

[mrzippy]

I agree! like this shot.


Attachment 130117

[Adam24]

Thankyou everyone, especially MrZippy. Your photo looks very similar to mine! Now I know why that happened. Still, that contrail looks so mistycal... Thanks!

[propjob]

If the air temperature at that altitude is close to its dew point temperature, the pressure reduction over the top of the wing can lower the temperature enough to reach the dew point, and condensation occurs along most of the wing.

Art

P.S. The contrails forming behind the engines in the flickr photo are caused by the moisture added from the combustion process saturating the air behind the engine. Water vapor is produced when a hydrocarbon, like jet fuel, is burned.