747SPA330MD11 From Germany, joined Dec 2003, 97 posts, RR: 0 Posted (8 years 4 months 3 weeks 22 hours ago) and read 3728 times:
Last time when I was flying in a B738 we were landing during very heavy rain.
Why airplanes are not in danger of aquaplaning during the take off or landing. The tires have not much profile, the speed is very high. And sometimes the runway is visibly covered with water.
But the contact area of the tires to the runway is very low compared to the weight of the plane. Is this the reason?
Who can give me an answer?
Buckfifty From Canada, joined Oct 2001, 1309 posts, RR: 24 Reply 1, posted (8 years 4 months 3 weeks 21 hours ago) and read 3693 times:
Aquaplaning is an issue. There are regulations in terms of the amount of standing water (or other contaminants) allowed on the runway for the aircraft to take off and land in. In aircraft, this affects the landing more than the departure, as brake application suffers from the effects of aquaplaning. On departure, frictional losses due to deep water, snow, slush etc. can affect takeoff distances and early directional control (pre Vmcg).
Tokolosh From Netherlands, joined Sep 2001, 358 posts, RR: 0 Reply 2, posted (8 years 4 months 3 weeks 20 hours ago) and read 3653 times:
I remember that this was an issue that came up in the accident report of the Qantas Jumbo that overshot the runway at Bangkok. It is a very informative report -- I think you can find it on the aviation safety network site (http://www.aviation-safety.net/database/index.html).
Mr Spaceman From Canada, joined Mar 2001, 2777 posts, RR: 18 Reply 3, posted (8 years 4 months 3 weeks 10 hours ago) and read 3540 times:
Hi guys.
A long time ago I read a very good article about hydroplaning. It explained that sometimes the heat that's created by the sudden tire friction during touchdown can actually turn the water that's between the tires & the runway into steam!!! This layer of steam can become an inch thick, resulting in a complete loss of contact with the runway & thus ZERO braking action or steering.
An airliner can end up floating down a runway on a layer of steam .... perhaps sideways!
So, as mentioned above by Buckfifty, hydroplaning can be very dangerous.
AJ From Australia, joined Nov 1999, 2366 posts, RR: 30 Reply 4, posted (8 years 4 months 3 weeks 9 hours ago) and read 3519 times:
The washup from Bangkok was the danger of aquaplaning and the need to use all available decelleration aids to safely stop on the runway. To quote from the final report "Touchdown occurred about 1,000 m along the runway and the aircraft entered the overrun at 88 kts. Partial dynamic hydroplaning had occurred during the landing roll. This, along with the absence of reverse thrust, reducing the stopping forces available to slow the aircraft."
This can be achieved by:
Firstly a positive touchdown in the correct touchdown zone for the aircraft type;
Secondly deployment without delay of the spoilers to place the aircraft's weight on it's wheels;
Thirdly prompt use of all available reverse thrust, only reduced if directional control becomes an issue as reverse thrust leads to exaggeration of directional change.
Mr Spaceman From Canada, joined Mar 2001, 2777 posts, RR: 18 Reply 6, posted (8 years 4 months 2 weeks 5 days 8 hours ago) and read 3355 times:
Hi guys.
Check out this photo. Imagine seeing something like this at an airport! There's Major hydroplaning potenial here I'd say. But it's just a test being done.
Bio15 From Colombia, joined Mar 2001, 1088 posts, RR: 11 Reply 8, posted (8 years 4 months 2 weeks 5 days 6 hours ago) and read 3330 times:
Hi all, please don't flame me, but what's the definition of aquaplaning? I don't know a term that means the same in spanish. I get the idea of a plane rolling over a damp surface, but does it refer to some sort of flotation over the water?
Slamclick From United States of America, joined Nov 2003, 10039 posts, RR: 75 Reply 9, posted (8 years 4 months 2 weeks 4 days 17 hours ago) and read 3290 times:
Bio15
Yes, it does refer to flotation over that surface. Best example is one that has been referred to above "reverted rubber hydroplaning" Think of it this way:
Runway can be used in two directions, say, landing north or landing south. Gets lots of use in each direction all summer long. Planes land maybe 300 to 400 meters beyond the threshold. They lay down a heavy coat of rubber in the touchdown zone.
Now rain storms set in and they are landing in the other direction. A plane lands long or fast and the runway is wet. If the pilot does not land firmly and splash through the water layer it is even worse. Water does not compress and if it cannot get out of the way, the plane floats along on a layer of it like a water skier. Someone mentioned a layer an inch thick but it does not take more than a couple of millimeters - just enough to keep the rubber off the pavement.
The friction of the tires sliding over the water film quickly raises the temperature above 100C and we have a layer of steam. Now we get down within 500 meters or so from the far end of the runway and this steam cleaner encounters a layer of rubber over the pavement. It scours it off and rolls it into little balls of semi-molten rubber. It is just like what you find just off "the line" in automobile racing. What British journalists call "getting on the marbles." The combination of steam and marbles and you have almost no friction at all. And it persists down to very low forward speeds.
It takes a very long slide for a plane in this situation to run out of energy. Sadly, it usually runs out of runway first. Brakes are almost irrelevant because the tires are not really touching the runway.
To counter this, we hire contractors to clean the rubber coating off runways. We groove runways so the water will run off better. They apply runway coatings that help shed water and add friction. Tire tread design is a compromise and does not seem to help much.
Patrick L
Anti-lock or anti-skid brakes have been around longer than Concorde, though I'd bet that the engineers on that project made some advances for the rest of us. I remember that the XB-70 had a little wheel attached to the main gear that rolled on the surfaces and provided inputs to an exotic anti-skid system. That system apparently had some flaws because there is a lot of film of spectacular brake fires on that plane. In fact it seems like the wheels caught fire almost every time if flew.
Happiness is not seeing another trite Ste. Maarten photo all week long.
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There's Major hydroplaning potenial here I'd say. But it's just a test being done. 
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