AeroGav

Tsunami about to smash an airport... what would you do?

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Here's a fun little topic for discussion - and we all love a good disaster movie.

You're at an airport,  queuing up on the jet bridge to board your plane,  when word reaches of an incoming Tsunami.   The airport's built on low lying or reclaimed land and is right in the firing line.    You've got a couple minutes at most, and everyone is freaking out.

Should you look for a sturdy part of the building,  maybe tie yourself to a roof pillar? 

Or do you rush to board the airplane, strap yourself in,  and put on (but not inflate) the life jacket ?   It's very unlikely to take off, the crew won't have time to start the engines and taxy to the runway - they might even scarper themselves.       But,  which is more likely to survive the wave ?

The building or the airplane?  Obviously the building is much more substantial.     But it's anchored to the ground, which is probably not going to help it maintain integrity.   It's made of concrete, not aluminum.   It is probably engineered to a higher safety factor than the airplane,  and weight is less critical, though it still has to support its own weight, which is an issue on very tall structures.   The building is only designed for 1g , but storm/earthquake scenarios were probably considered.   On the other hand,  the airplane is stressed for 2.5G,   and 10G loads in crash landing scenarios (the floor needs to remain intact, among other things, even if the plane itself will break up and likely rupture fuel tanks),    They also have to survive ditching,  and have buoyancy, at least for a while ? 

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In a building, of course.
I saw those planes. Flimsy things.

P.S.
If I'm at the airport next to my place and there is a tsunami, that would mean the tsunami has overflown several mountain ridges (after probably having crossed Mediterranean) and still stays a half-kilometer high, so no difference what to choose.

Edited by kerbiloid

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Assume you're at the Osaka Airport, which was flooded by a typhoon recently.

 

Personally, I'd make tracks for any service access to the roof of the building... and steer well clear of the main terminals, as they almost always have massive windows. Failing that, I'd run for outside, so I could at least have some chance of choosing where I wind up, rather than being at the mercy of water and architecture.

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While both water and air are fluids, water is significantly denser.  Even if the aircraft is facing the tsunami, fast moving water could easily exceed the dynamic pressure the aircraft is designed for. Best bet is getting away from windows and off the ground floor.

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If there are GA aircraft, I'd try to make it to one of these. The door and master can usually be forced even if you don't have the key, at least on older models, and unlike jets, a prop will start on demand, and I can be wheels off in minutes. I have enough experience with both trikes and tail-draggers to know that I can take off on whatever's available, and I'd have better than even odds of walking away from the landing, even if I have to land in the field on an unfamiliar aircraft.

Of course, a lot of larger airports, even if they have some GA aircraft, would have them quite far from passenger terminals. So there's a pretty big question on that option even being available. Outside of that, idea of getting a raft from one of the regional jets, which have them stored separately, rather than build into the doors, is tempting. But odds of holding onto a raft seem low. You're more likely to be trampled by panicked crowd when people fight over it. Vest does you little good, as if you stay in the water, hypothermia's the thing that will get you. Vests are only good if there will be enough rafts to pick up people shortly after, and odds of that are low.

So you want to be high and far from crowds. Roof of the terminal seems like the place to be, and probably try to find access point from outside, since everybody's going to be filling up stairs, etc. Getting into the jet and hoping it survives the surge, giving you opportunity to get into a life raft afterwards, feels like the last resort. I'd rather take my chances with the terminal building.

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I've seen videos of tsunamis, When it reaches land, it turns from a wave of water into a wave of debris. Cars, trees, furniture, pieces of buildings. No flimsy raft or vest will keep you alive in such grinder. I'd go for highest possible roof of a sturdiest building in sight immediately.

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The water is not likely to reach you as a shock wave, but more as a rising tide that doesn't stop rising for a while. I'd try to walk calmly for the highest available floor of the building, and from then maybe onto the roof, depending on how bad things get. Airport buildings tend to be quite a bit taller than most tsunami surges.

I suppose the plane could be a viable alternative too, of course. Tsunamis tend to involve a lot of debris flow, but that assumes there's debris around to be picked up. An airport on reclaimed land next to the sea would be a vast expanse of absolutely nothing, maybe a few signs and the odd towing truck, but not enough to form a sea of scrap massive enough to threaten the integrity of a passenger aircraft. Even bushes and small trees are cut down to keep birds away, and there wouldn't be boats docked in the water next to the airport either. The tsunami flowing into an airport would be relatively clear of debris, simply by virtue of there not being a lot of debris around. Then again, the aircraft might be dragged back to the sea when the tsunami recedes, so it's not a place to stay for long either.

Edited by Codraroll
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47 minutes ago, wizzlebippi said:

While both water and air are fluids, water is significantly denser.  Even if the aircraft is facing the tsunami, fast moving water could easily exceed the dynamic pressure the aircraft is designed for. Best bet is getting away from windows and off the ground floor.

When you look at the "Miracle on the Hudson" ditching though,  it hit the water at over 130 mph and remained intact, remained afloat for a number of hours and never fully sank.     Obviously that was a frontal impact, which the airplane is designed for - but you don't imagine the terminal building would survive being dropped into the Hudson at 130mph terribly well.    

Now, If I was the captain of on airplane at this doomed airport,  rather than attempt a rushed takeoff, and crash because you forgot to deploy flaps in the rush,  or collide with another airplane that's also desperately trying to get airborne like the Tenerife air disaster,  I'd probably just try to orient the plane on the ground so its parked with its nose pointing in the direction of the incoming wave,  and tell the passengers to "Brace, Brace, Brace".

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6 minutes ago, AeroGav said:

Obviously that was a frontal impact, which the airplane is designed for

Sorry, but it was as gentle as possible a touch down on calm water without obstacles. A wave, a boat in the way would have changed everything. People reported later the sensation of a hard landing and a gradual deceleration. I am sure the ntsb report has all the details.

As for the escape: I'd make for the roof. If i can't survive there ...

Edited by Green Baron

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Plane will stay stable. Maybe. Until it gets hit by a sideways current or a bigger piece of debris. Then you will be stuck in a rolling aluminium barrel, battered constantly from the sides, losing pieces of wings and the hull along the way. No thanks - i will stay on the roof.

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1 minute ago, Green Baron said:

Sorry, but it was as gentle as possible a touch down on calm water without obstacles. A wave, a boat in the way would have changed everything. People reported later the sensation of a hard landing and a gradual deceleration. I am sure the ntsb report has all the details.

I did read the report - it wasn't that gentle from what i recall, the rate of descent was quite high because the high angle of attack prevention software started soft limiting just as Sullenberg was about to flare for touchdown.   

I take the point that the concrete building is a better place to be if it takes a hit from a fishing trawler picked up by the storm,  but if it goes up against an irresistable force, something where its mass advantage doesn't count, such as a wall of water,  the plane might be better.

I've  pretty well read when it comes to air accident reports.   There was one in the US,  where a plane on a taxiway was hit by an aircraft that was landing.  The aircraft were going in opposite directions and only their wings made contact.     Whilst the fuselage was intact,  it got whipped around sideways very violently and a lot of the pax broke their necks (lap belt restraint system isn't as good as what we have in cars for that).   This either killed them outright or resulted in them not being able to escape the fire afterward.    I guess that's the risk of being in the plane and it gets broadsided by the wave - breaking your neck then drowning when it sinks .  If the wave's that fast and strong though, the building's toast as well.

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3 hours ago, AeroGav said:

Here's a fun little topic for discussion - and we all love a good disaster movie.

You're at an airport,  queuing up on the jet bridge to board your plane,  when word reaches of an incoming Tsunami.   The airport's built on low lying or reclaimed land and is right in the firing line.    You've got a couple minutes at most, and everyone is freaking out.

Should you look for a sturdy part of the building,  maybe tie yourself to a roof pillar? 

Or do you rush to board the airplane, strap yourself in,  and put on (but not inflate) the life jacket ?   It's very unlikely to take off, the crew won't have time to start the engines and taxy to the runway - they might even scarper themselves.       But,  which is more likely to survive the wave ?

The building or the airplane?  Obviously the building is much more substantial.     But it's anchored to the ground, which is probably not going to help it maintain integrity.   It's made of concrete, not aluminum.   It is probably engineered to a higher safety factor than the airplane,  and weight is less critical, though it still has to support its own weight, which is an issue on very tall structures.   The building is only designed for 1g , but storm/earthquake scenarios were probably considered.   On the other hand,  the airplane is stressed for 2.5G,   and 10G loads in crash landing scenarios (the floor needs to remain intact, among other things, even if the plane itself will break up and likely rupture fuel tanks),    They also have to survive ditching,  and have buoyancy, at least for a while ? 

Airplane seats and belts are designed for 16g crash loads, not 10g. I think 10g may have been the standard back 2-3 decades ago.

https://www.boeing.com/commercial/aeromagazine/articles/2011_q4/2/

Edited by mikegarrison

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4 hours ago, AeroGav said:

You're at an airport,  queuing up on the jet bridge to board your plane,  when word reaches of an incoming Tsunami.   The airport's built on low lying or reclaimed land and is right in the firing line. 

Well, let's just have a look, shall we? There's plenty of footage of the 2011 Tsunami, after all.

I agree with @Scotius that a life vest will be useless. With some luck you may ride it out sitting inside a car; a plane may fare better or maybe not. A proper building seems to be preferable to either, though.

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3 hours ago, Codraroll said:

An airport on reclaimed land next to the sea would be a vast expanse of absolutely nothing, maybe a few signs and the odd towing truck, but not enough to form a sea of scrap massive enough to threaten the integrity of a passenger aircraft. Even bushes and small trees are cut down to keep birds away, and there wouldn't be boats docked in the water next to the airport either. The tsunami flowing into an airport would be relatively clear of debris, simply by virtue of there not being a lot of debris around. Then again, the aircraft might be dragged back to the sea when the tsunami recedes, so it's not a place to stay for long either.

Clearly, you've not paid terribly much attention to the ramp of an active airport. There's hundreds of vehicles and trailers always driving around, moving garbage, fuel, baggage, ground crew, even passengers in some cases. All this becomes debris to some extent, though how much an electric bag tug (which is a fairly dense vehicle, what with the typical 1.5 ton lead-acid battery pack they use) or a push tug (which are usually ballasted to weights of up to 60 tons) would get floated away is questionable. Belt loaders, bag carts, mobile air stairs, cargo loaders and ULD cans, fuel trucks, all that stuff is going to get swept up and slammed into everything downstream.

 

And for those of you thinking that an airliner is tough enough to survive a hit from something like that, forget it. I'll have to take a picture of it next week, but at my school, we have the aft port section of a Boeing 737, from aft pressure bulkhead up to the wing root trailing edge. You get a VERY good idea of just how thin the skins of an airliner are. I could probably dent it by simply hitting it with my hand, and a hammer would simply knock a hole in it. Getting hit by a floating ground support vehicle would tear it open like a soda can. God knows the ramp rats put dents and knock holes in airplanes enough when they're trying not to.

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4 hours ago, AeroGav said:

Should you look for a sturdy part of the building,  maybe tie yourself to a roof pillar? 

You might be drown if the tsunami turns out to be way higher.

4 hours ago, AeroGav said:

Or do you rush to board the airplane, strap yourself in, and put on (but not inflate) the life jacket ?

I don't want to be strapped to a driftwood. (I would happily take as much life jacket as possible, though.)

Your best bet is :

- Be on the tallest, sturdiest building (means roof, if possible)

- Prepare a raft (in case the wave height exceeds the height of the building), possibly tie it to the building (though as it's a disaster see would that help you or kill you, depending on wave height).

Although these are all second option to the primary (go to a higher ground), if a higher ground is absolutely unreachable.

 

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I suspect the terminal building would be safer than a grounded airplane, since, while it's hard to overstate the power of even slowly moving water, tsunamis aren't really waves, just rising water. My understanding is that most structural damage to buildings comes from the earthquake, not the tidal wave. Even if the water should reach the windows of the terminal, most airports have 2 or more interior stories in addition to being built 1 story above the tarmac. 

Maybe an analogous question would be if you would rather be sitting in a tree rooted in the middle of a river, or on a log floating on its surface.

EDIT: The real question though is: will an airplane take off from a treadmill while submerged in a tsunami?

Edited by Mad Rocket Scientist
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It's possible to take two.

Stay in the aircraft, and the tsunami will deliver it to the nearest building.

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Well, that depends on local geography. But a human can not run away from it even if the way is free. They can reach 100s of meters of height in extreme cases (channeling, running up the opposite hill) and enter 10s of kilometers into flat coastal areas or valleys. Or not be noticeable at all :-)

There is a lot of information, including modeling and examples from history or geology if you like it somewhat founded. Youtube has pictures from waves, either breaking into harbour basins or on beaches, water that has broken outside and is rolling onto the shore and into the second row behind it or up through channels from the coast.

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1 hour ago, Cassel said:

How far tsunami can go into land?

It's not how far, it's how high.

On 9/18/2018 at 9:11 PM, Mad Rocket Scientist said:

The real question though is: will an airplane take off from a treadmill while submerged in a tsunami?

You are a real troublemaker, you are.

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22 minutes ago, mikegarrison said:

It's not how far, it's how high.

 

I will ask differently, what is the record for the distance to which the tsunami has reached the land?

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4 minutes ago, Cassel said:

I will ask differently, what is the record for the distance to which the tsunami has reached the land?

What is the world record for how flat your land is?

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21 minutes ago, Cassel said:

I will ask differently, what is the record for the distance to which the tsunami has reached the land? 

I'm not sure if it's a record or not but I do remember watching coverage of the boxing day tsunami (apparently known as a teletsunami) in 2004 that devastated the coastlines of Indonesia, Sri Lanka, India, Thailand and Malaysia with effects as far as Africa.  It prompted the UN to institute a monitoring system for the Indian ocean.

Quote

The maximum runup height of the tsunami was measured at a hill between Lhoknga and Leupung, on the west coast of the northern tip of Sumatra, near Banda Aceh, and reached more than 30 m (100 ft). The tsunami heights in Sumatra: 15–30 m (49–98 ft) on the west coast of Aceh.

Bandah Aceh was the worst city hit:
56DE4991933D69DB85256F86007442A4-unosat_

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56 minutes ago, Cassel said:

I will ask differently, what is the record for the distance to which the tsunami has reached the land?

You mean from its origin to a far coastline over the water ?

The 2004 Indian ocean tsunami @James Kerman mentioned is (to my limited knowledge) one of the best if not the best studied one up to now.

If you are looking for a very bad case: a giant landslide ("flank collapse") sending 100s of km³ from 2000m asl down to the abyss at >4000m depth in one huge submarine "debris flow" would stir up a huge water column. That is about the max earth has in store, because slopes directly near the sea are rarely higher and mostly found on volcanic islands, and sea floor doesn't get much deeper.

There are models for propagation and dispersion of the resulting wave(s) in the open ocean, trying to include the various effects of sea floor, mounts, ridges, reflection of waves, coastline effects, geography, etc. How realistic they are can be debated. Or made into a movie :-)

Edited by Green Baron
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8 minutes ago, Green Baron said:

You mean from its origin to a far coastline over the water ?

 

Coastline over the water.

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