What is that liquid which oozes from the wings of the passenger aircraft while landing?

Question

I'm not talking abt fuel dump. Is it hydraulic oil? if yes why does it leak?

Thanks for your answers but i'm sure it is not condensation & nor I,m talking about droplets. I,ve noticed this in many jets from both inside the cabin & also from the ground. It is fair bit of liquid, which appears to be bleeding from a hole or a nozzle when the flaps are extended

Answer 1

If it was one plane it might have been a leak, hydraulic fluid or fuel but it's not normal and if you see it often, I highly doubt it's a leak.

It could be deicing fluid. It collects in the flap mechanisms and canoes. The canoes have drain holes in them but it all doesn't drain when the flaps are up. Sometimes the flaps have to be cycled a few times to get it out of all the nooks and crannies. I've seen leaks like you described when the plane gets to the gate, even when the plane wasn't deiced at the departing airport. This type of deicing fluid is very similar to antifreeze you use in your car. So when it leaks, it looks very different from water and more similar to fuel or hydraulic fluid. It even has the sweet taste to it.

Answer 2

Hydraulic fluid has a very distinctive red color, and if it were leaking enough to be running off the wings, there would be a major problem with the aircraft.

I'll agree with the other answers about condensation of moisture from the air onto the cold surfaces of the wing fuel tanks, but this time of year, what you're seeing could also be a bit of deicer fluid that was trapped inside the wing when the aircraft was deiced before takeoff. Lowering the flaps will change the angles of some of the spaces where fluids can accumulate, and allow them to drain.

Answer 3

As one stated it is condensation. In the air, the airflow is directed around the flap hinges which accumulates more of the condensation which acts like a wick and the wick effect makes it more heavily concentrated . When on the ground ,gravity takes effect and the wings are angled so the water flow runs in toward the aircraft and aft toward the back of the aircraft. If it was a hydraulic leak you would see maintenance out there looking at the aircraft cause the pilot would notice the loss of fluid in flight and i guarantee he wouldn`t fly the aircraft until it was fixed.

Answer 4

If it's at the wing tips, it's moisture from the airflow...as the pressure changes at the wingtips during the landing approach, during certain atmospheric conditions of temperature and/or humidity, there will be produced this almost "smoky" trail from the tips of the wings If you are talking about the upper surface of the wing, that is also condensation and the moisture,being sweptback over the wing by the airflow, appears to be "oozing" from the seams. Remember that there is cold-soaked (from high altitude) fuel inside the wings and as the aircraft descends into warmer air there will be condensation on the surface of the wing.

Answer 5

It is simply the condensation from the fuel tanks which are in the wing.

While flying at altitude the temp at 30,000 feet may be 30F below zero. The metal skin is cooled to near this temp and the wings are giant fuel tanks.

As the aircraft reaches the ground the very cold metal remains colder than the surface air and the humidity in the air chills on the cool skin causing water droplets to form.

Answer 6

I've never seen it on a commercial aircraft but some Hawkers have a "weeping" wing. They have tiny holes in the leading edge of the wing and they pump TKS fluid out to prevent ice from building up. This would coat the wing and then ooze over the top and down the back. What type of an aircraft were you on?

Answer 7

Nothing "oozes" at 140 knots. It's condensation moisture and de-icing fluid. Not as much as it appears to you, and nothing to worry about.

Answer 8

It's not supposed to leak oil. There could be a malfunction.

Answer 9

You think it could be ice melting off?

Answer 10

It's condensation, or you are about to crash...