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Landing a plane on water.

by Repetit
Tags: landing, plane, water
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Repetit
#1
Sep11-07, 12:34 PM
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Is it possible to land a large plane on the water (in the ocean for example)? Im of course talking planes not meant for landing on the water. I am wondering whether the heavy weight of the water will cause such a fast braking that the plane would crash? Of course you could say that it depends on the angle of incidence, but when the plane gets like 3 or 4 meters below the surface of the water an awfully lot of water has to be moved and the braking will be very fast.

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Danger
#2
Sep11-07, 01:06 PM
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It wouldn't be pretty, but it can be done.
I was never rated for anything like the size that you're talking about, but my instinct would be to flare farther than usual, keep horsing back on the yoke to keep the nose up as long as possible, and add power (if available) toward the same purpose.
More than the nose, I would expect that the really big 'Oh crap' moment would be when the engines dig in.
Cyrus
#3
Sep11-07, 01:43 PM
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The water is full of waves and airplanes that large come in with a high velocity and a lot of inertia. The sudden stopping effect of the water will tear the airplane to pieces. Airplanes are like soda cans. They are not made to crash land into water.

http://video.google.com/videoplay?do...arch&plindex=4

bye bye airplane.

Danger
#4
Sep11-07, 04:31 PM
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Landing a plane on water.

That wasn't a controlled ditch, Cyrus. I'm certainly not faulting the pilot here, because I have no idea of what the circumstances were, but it's obvious that the port wing dug in first. Nothing would survive that situation.
AlephZero
#5
Sep11-07, 04:38 PM
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The OP didn't ask about "crash landing" into water. Ditching into water is a recognized emergency procedure (though most pilots only get to practice in a simulator).

Planes have successfully ditched into the sea, and they float well enough for the passengers to get out. Doing a cross wind landing so you don't hit the waves head on is a good idea.

If there was no chance of a successful ditching into water, there wouldn't be any point in commercial flights over water providing the passengers with emergency lifejackets. A lifejacket isn't going to do much for you if you jump into the sea from 1,000 feet wearing it. If you climb out of the emergency exit onto the wing while the plane is still afloat, that's a different matter.

I know an air freight pilot who admits (off the record!) to accidentally doing a touch-and-go on the North Sea one night. Flying on autopilot, he realised something was not right when there was a bang from underneath the plane. Having maxed the power and started to climb he then noticed the altimeter was only reading a few hundred feet. The rest of the trip was flown without autopilot and without any further excitement. After landing, there were some "interesting" stain marks to be seen on the fuselage, which were probably never officially explained!
Danger
#6
Sep11-07, 04:57 PM
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Quote Quote by AlephZero View Post
After landing, there were some "interesting" stain marks to be seen on the fuselage, which were probably never officially explained!

First, let me compliment him upon a sweet recovery. Secondly... damn, but I wish I had a cockpit voice tape of that situation.
He probably made up new names for 'George' that would blister the ears off of a drill sargeant.

Russ, I'm waiting for you to contribute here. From a lot of the things that you've posted, and your obvious expertise in the subject, I'm under the impression that you were a carrier-based Tomcat pilot. What say you about dropping something like an L1011 in the drink?
Loren Booda
#7
Sep11-07, 07:17 PM
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One thing may be learned from a seaplane, like the Curtis SOC my father flew in WWII. He could take off with the bi-wing at less than 100 mph (propelled by a dynamite charge to get him going - hopefully into the wind - from the USS Minneapolis), and land at even slower speeds.

Reduce the landing speed in half, and forces on a ditching conventional plane are reduced anywhere from 2 to 4 fold!
DaveC426913
#8
Sep11-07, 08:06 PM
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Quote Quote by Danger View Post
What say you about dropping something like an L1011 in the drink?
The ideal would be to get as close to nape of Earth as possible* and stall the thing, right? That would kill all its forward speed and it would drop. Or would it just disintegrate upon hitting?


*that's redundant, isn't it?
Cyrus
#9
Sep11-07, 08:12 PM
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Quote Quote by AlephZero View Post
Planes have successfully ditched into the sea, and they float well enough for the passengers to get out. Doing a cross wind landing so you don't hit the waves head on is a good idea.
I've never heard of an airplane the size of a 747 ditching into the ocean before.


If there was no chance of a successful ditching into water, there wouldn't be any point in commercial flights over water providing the passengers with emergency lifejackets. A lifejacket isn't going to do much for you if you jump into the sea from 1,000 feet wearing it. If you climb out of the emergency exit onto the wing while the plane is still afloat, that's a different matter.
Those life jackets are good if the plane goes off the runway into the water. If that plane is going to crash land into the water, I wouldnt hold my breath. I wouldnt want to land my cessna into the water at 60 KTS, much less a 747.

You can come into the water nice and straight, my gripe is that the moment u touch the water your are along for the ride and have no control anymore. All it takes is one small perturbation from a wave to turn you ever so slightly and your airplane will flip and tear itself appart.
Danger
#10
Sep11-07, 09:43 PM
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Quote Quote by DaveC426913 View Post
The ideal would be to get as close to nape of Earth as possible* and stall the thing, right? That would kill all its forward speed and it would drop.
Well, as I said before, I'm waiting for Russ to weigh in here, or Andre if he's still around. As a non-turbine rated civilian pilot, my inclination would be to dip the tail in as straight an attitude as possible and try to maintain as much airspeed as possible until that tail drag brings it down to a low enough speed that the cowls hitting the drink won't pull enough drag to rip the wings off. I don't know what the structural integrity of something like an Airbus is, but for the sake of the passengers I would sincerely hope that the thing can stop at less than -8 g.
russ_watters
#11
Sep11-07, 10:05 PM
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Quote Quote by Danger View Post
...I'm under the impression that you were a carrier-based Tomcat pilot.
You're not serious, are you? First of all, I'm 31, and the Tomcat was already being phased-out when I was at the Naval Academy. Regardless, I didn't finish there, and never realized my dream of being a navy pilot. The only thing I've ever flown was a glider on an instruction flight (the instructor said I was good, but he may have been kissing my *** - though he didn't take the stick from me until we were over the airstrip and 20 feet off the ground).

Anyway, as cyrus's video showed, a level landing and smooth seas are essential for a successful ditch (or landing on land without gear). I would also think that a plane like a DC-9 would fare better than a plane like a 757 - for a 757, the engines are the first thing to hit the water (in cyrus's video, the engine is what made the plane carthweel, not the wingtip). Otherwise, the wing dihedral (they are angled up) means that it is possible for most commercial planes to hit the water fuselage first (and nose high).

Fundamentally, big seaplanes aren't much different from other big planes - they just have hull-shaped fuselages and high wings so they don't catch a tip.
russ_watters
#12
Sep11-07, 10:16 PM
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Wik's article is pretty good and has some good info on that particular ditching, too (1/3 of the passengers survived and it probably would have gone better had the pilots not been fighting hijackers while ditching the plane!):

http://en.wikipedia.org/wiki/Ditchin...rcial_aircraft
Danger
#13
Sep11-07, 11:09 PM
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Quote Quote by russ_watters View Post
You're not serious, are you? First of all, I'm 31
Yeah, I was serious. Just going by your picture, I figured that you were about my age. ()
No, I knew that you were younger by a bit, but the knowledge that you've demonstrated regarding F-14's is worthy of a reference book. Your political opinions also indicated that you had a military background. I just put 2 and 2 together and got... ?.

edit: Okay, on a Mac, that last question mark was a pi symbol.


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