Smoke from engine? [No, it is Water vapour]

[miniyazz]

Flying on QF36 today (SIN-MEL) and coming in to land noticed what appeared to be smoke coming over the wing around where the near port side engine would be located: 2019-11-15 06.01.23.jpg

It came and went seemingly related to the amount of thrust being applied, at least based on my subjective assessment.

Thoughts?

 

[tgh]

I believe that it is water vapour , probably caused by differential air pressures.
Repost on the " Ask the pilot" thread if you don't get a definitive answer here

 

[miniyazz]

It was noticeable for at least a few minutes towards the end of the flight, and only from that one point on the wing that I could see. Just more information - not sure how it relates the the possibility of water vapour.

Thanks

 

[mannej]

This is the thread you need to ask the question in as suggested above - Ask the pilot

 

[woodborer]

I've seen that or something similar quite a few times. As far as I know it's water vapour (or a contrail)

 

[eric2011]

"These are a by-product of the lift forces which hold aircraft up in the sky. Lift comes about because the air pressure is low above the wing, and a drop in air pressure (and temperature) tends to cause invisible water vapour (gas) to condense into the visible water droplets (liquid) we see as what you described as smoke"

Moisture will condense around other spots too, such as the flap fairings and engine attachment pylons. You’ll witness what appears to be a stream of white smoke pouring from the top of an engine during takeoff and landing. This is water vapor caused by invisible currents around the pylon. Other times the area just above the surface of the wing will suddenly flash into a white puff of localized cloud. Again, this is condensation brought on by the right combo of moisture, temperature and pressure

 

[DC3]

I see water vapour.

Edit: No need for a new thread. See post # 4

 

[miniyazz]

Thank you for the detailed explanation, eric2011!

Quite cool to watch, reminiscent of aerodynamics testing on e.g. cars. Apart from the imminent death and destruction, of course

 

[Happy Trails]

Worn piston rings?

 

[eric2011]

Worn piston rings?

Check for oil in the radiator

 

[jb747]

Wingtip vortices - Wikipedia

en.wikipedia.org

They occur at many points. Not just wing tips, but they are the strongest. Over engines, or any break in the leading edge, gives a good start point.

 

[AviatorInsight]

Not limited to over the wings either. As an engine spools up for take off and if there’s plenty of humidity, as the air is being drawn in you may see what appears to be a little cyclone extending from the bottom of the nacelle to the ground.
There may also be a white cloud that forms inside the nacelle as well as the pressure drops.