Air France 447: The ‘Coffin Corner’ and a ‘Mesoscale’ Maw

http://trueslant.com/milesobrien/2009/06/08/the-coffin-corner-and-a-mesoscale-maw/

by old-gregg • 17 years ago

71 53 17 years ago

TrevorJ• 17 years ago

A very insightful examination. A lot of things I didn't know.

anigbrowl3• 17 years ago

True. Too bad about the tabloid-style typography and literary style, which does serve a purpose of highlighting the takeaways but also gives it an air of sensationalism.

dschobel• 17 years ago

I agree, but he's pretty glib about it all (quoting star-trek? really?). Strikes me as a pretty odd tone to take.

shizcakes• 17 years ago

Insightful but it seems that there's a lot of speculation about this. Theres an article from timesonline that tied some pieces together and answered some questions for me (like: "How do they know this much detail of the flight without the black box?" A: ACARS).

I hope this is helpful to someone else: http://www.timesonline.co.uk/tol/news/world/us_and_americas/...

samlittlewood• 17 years ago

Thanks. I assume that the forum mentioned in the article is http://www.pprune.org.

The current thread about this accident is http://www.pprune.org/rumours-news/376433-af447.html

Apart from the current tragedy, it's a great window into another professional sphere.

mhb• 17 years ago

Q: ACARS? A: automatic communications and reporting system

telma• 17 years ago

The weather was never considered "horrible" and still isn't. [edit:] At least 12 planes took the same route that night without any incident.

http://ibnlive.in.com/news/12-planes-shared-sky-with-af-447-...

joshwa• 17 years ago

From the very last paragraph of the same article (which originates from CNN, incidentally):

> Although none of the other flights are known to have reported weather problems en route, aviation experts said weather can change suddenly and vary over short distances, so one plane might experience conditions far worse than another.

run4yourlives• 17 years ago

Reports seem to indicate that they almost made it through the stormcell.

Very unfortunate. Whatever it was probably happened extremely fast. Perhaps a (ridiculously unlikely) wing snapped off? Or they stalled and spinned violently?

stcredzero4• 17 years ago

Boeing tests its wings to breaking by bending them behind the back of the plane until they are pointed up at ridiculous angles. The kind of force that would break the wings of a modern jetliner would also break the necks of a large number of the passengers.

http://www.youtube.com/watch?v=pe9PVaFGl3o

EDIT: I stand corrected. As pointed out below, that huge deflection doesn't represent neck-breaking forces. But imagining the force of an updraft that can accelerate an airliner upwards at 2G's -- that's still a heck of a lot of power.

DocSavage• 17 years ago

Cool video. I wonder how much of an engineering/structural difference there is between the heavier 777 and the Airbus A330-200 that crashed.

davepage• 17 years ago

Not at all. The A340 limit load factor is something like +2.5 / -1.0g. This is not a condition injurious to seated passengers. It is unrestrained passengers who are injured in turbulence -- but that is due to the passenger/cabin collision, not the initial acceleration. The wings in the video flex a long way under these relatively light load factors because the wings are designed to be only a little bit stronger than they need to be.

Aerobatic airplanes and pilots routinely experience transients to +/-6g with no ill effects.

TweedHeads3• 17 years ago

I will always say it was a bomb, and the more they try to make it look like it wasn't, the more I believe they are just trying to hide it from the public not to scare them to fly like in 2001.

It was a bomb.

TweedHeads3• 17 years ago

For a hundred years we've been flying planes thru storms, lightnings, adverse conditions of every kind, so fuck the coffin corner.

The pilot and copilots had thousands of flight hours under their belt.

Not a single mayday call.

nopassrecover• 17 years ago

Radio communication fail? Weird electrical/magnetic phenomena? Meteor? These are just some of the more plausible ideas than "covert terrorism".

hunterjrj• 17 years ago

Why has no one stepped forward to take credit for downing the plane with a bomb? Isn't that the MO for terrorist organizations?

Accidents happen, unfortunately. Sometimes planes crash. Our technology isn't perfect, and all we can hope for now are useful lessons to be learned from the crash itself.

TweedHeads3• 17 years ago

If I was a terrorist org, I wouldn't take credit. The new modus operandi is stealth mode, the days of TV shows about terror are over.

Terror to create havoc on the world economy and air traveling will be the first hit.

Expect more "accidents" in the future.

david927• 17 years ago

Both pilots of an Air Comet flight from Lima, Peru, to Lisbon, Portugal, sent a written report on the bright flash they said they saw to Air France, Airbus and the Spanish civil aviation authority, the airline told CNN.

"Suddenly, we saw in the distance a strong and intense flash of white light, which followed a descending and vertical trajectory and which broke up in six seconds," the captain wrote.

http://edition.cnn.com/2009/WORLD/americas/06/04/plane.crash

I think you were voted down unfairly. We don't know what happened, but whatever it was, it was instantaneous and caused a bright flash.

biohacker424• 17 years ago

So while you are napping, eating or watching a movie on that flight to LAX, you should know the plane you are flying is cruising along at the ratty edge of its capabilities. Why? Money. The higher an airliner flies, the better gas mileage it gets.

As libertarian I prefer an airline which will charge me premium for flying more expensive but safer routes.

However, as a realist I realize that the barrier to entry for airlines is very high and competition is sub-optimal.

So I'd settle for a government mandate of how high commercial airlines can fly.

frisco• 17 years ago

That's a bit of a jump. How'd you go from "As a libertarian..." to "So I'd settle for a government mandate" in 3 lines?

staunch• 17 years ago

He's that smart.

Retric• 17 years ago

However, as a realist...

I would assume HN would favor people who looked beyond knee jerk responces. Just because you like to use the free market when it's possible does not mean you need to apply it in all cases.

biohacker424• 17 years ago

Well simple.

I really do want the market to work, but I know in reality it very often does not work at all. Most often with big industries where the startup costs are high.

Do you prefer to continue to fly in a needle's eye rather then have the government step in?

Ideally at least one airline would offer the safer option as a way to gain customers, but what if no one does?

Is your libertarianism that pure? If so, that's admirable, I guess my ideals are just not quite as strong.

JimmyL2• 17 years ago

>> As libertarian I prefer an airline which will charge me premium for flying more expensive but safer routes.

How would you even know? Saying "I'd pay more for a safer routing" is rather reminiscent of Steve Yegge's Shit's Easy Syndrome - you say you want a safer routing, but what does that mean?

You'd pay an extra ten percent on your ticket to fly ten percent lower? What about other factors - would you demand more reinforcements on the wings of the planes you fly on? How about longer flight times due to having to stop for fuel? What about how this would impact global route scheduling?

I could keep going with that, but the bottom line is that you don't understand what makes a plane safe. I don't understand what makes a plane safe. Few people - unless they're Airbus or Boeing design engineers - on this site know what makes a plane safer, and how much that would cost.

Airlines have a huge interest in making their flights safe - think off all the shitty PR that Air France (one of the world's most respected airlines) and Airbus (one of two real manufacturers of jumbo jets) are getting, and how much it will directly and indirectly cost them. The last people died on an American airline was in February. Before that, it was in August 2006. The last time an American jumbo jet crashed and killed people was in 2001. Flying is an incredibly safe way to get from point A to point B - but like everything, there are some times when nature throws us a curveball, and we get hit by it.

>> So I'd settle for a government mandate of how high commercial airlines can fly.

I wouldn't trust Congress to determine how high an airline can fly. If I want to know how high an Airbus can safely fly, I'd ask Airbus - they know the planes better than anyone, and have a huge vested in interest in keeping them safe.

lutorm4• 17 years ago

Flying lower = flying slower. You can already do that, just pick a plane that flies lower, like a commuter jet...

But in general, when flying it's safer to be higher and faster. By far the most dangerous thing you might encounter when flying is the ground...

biohacker424• 17 years ago

you don't understand what makes a plane safe

Agreed. Now if the captain Sully (the guy who landed in the Hudson) says flying out of the coffin corer is safer would you believe him?

Airlines have a huge interest in making their flights safe

Yes, they also have a huge interest in being profitable, they are trying to optimize both.

There's nothing wrong with that, but as a consumer I'd like a bit more choice.

But as other in this thread have pointed out the particular nature of the airline business makes it impossible for that kind of market differentiation to happen. That's known as a market failure.

Hence my desire for a government mandate.

Alternatively, do you think we need any of the current government regulations on airlines?

anamax• 17 years ago

> However, as a realist I realize that the barrier to entry for airlines is very high and competition is sub-optimal.

Is the barrier actually high? (I see new airlines every so often.)

What are the actual barriers? If they're govt, why isn't reducing the barriers the right response?

> So I'd settle for a government mandate of how high commercial airlines can fly.

And govt would get it right because that's what they do.

Didn't we just have a nice discussion of regulatory capture? (My favorite comment was by someone who thought that regulatory capture was the act of promotiing govt power grabs.)

dpifke2• 17 years ago

Is the barrier actually high?

Besides the obvious cost of acquiring multi-million dollar jetliners (which, if bought new, typically have to be ordered 5-10 years in advance of delivery) and signing leases for gate space and hiring ground crew at airports and so on?

You also need FAA and TSA approved operations plans, adding for instance the cost of screening all your employees and equipping your planes with things like black boxes and weather radar.

Then you end up like Virgin America, who can't fly to Chicago because the incumbent carriers there claim there are no available gates at O'Hare (despite the number of flights in and out of the airport being down like 10-20% from previous peak).

Doesn't seem that high to me...

tomiles4• 17 years ago

Why when internet is becoming available in planes is something as simple and and essential as updated weather reports not possible during a flight?

Why are these practices seemingly stuck in a stone age of paper weather reports, printed before the flight leaves, that could have been outdated even before the planes takes off.

Maybe this accident will speed up a much needed needed technological update in this aspect of air-travel. We should stop wasting dollars on security theater measures and invest it in real safety measures that can save lives.

JimmyL2• 17 years ago

They get weather updates en-route sent to them by their home airline (via the radio system) - not to mention that jets of that size carry along with them a better weather radar system than most local news channels have.

tomiles4• 17 years ago

I'm talking about satellite imagery like it is shown in the article, which is the only kind that would provide reliable and usable info for storm evasion. You need a view from above to see a storm size and not just a surface look at it from the sides (with a radar). Weather radar only provides limited information, like the article says.

"interpreting its display is a bit of a black art." - "It is akin to a blind man with a cane;" - "For instance, the radar mostly detects rain and hail – and if that first layer of storm cells was particularly heavy, it might have acted like a curtain – hiding the reinforcements from radar beams."

You can't know what's inside a walled garden or know how big it is just by looking at one side of the outside walls, you need something that allows a top view.

grandalf• 17 years ago

The article suggests that a stall is a horrible outcome.

Old style biplanes used to do "stall landings" all the time. If you know the characteristics of the wing, then a stall can be anticipated and is not necessarily cause for alarm.

How is it that the autopilot system (or other systems on the plane) would not be programmed to handle a stall gracefully?

In a stall the wing loses lift, but as the plane falls the air thickens and the angle of attack decreases and the wing ought to regain lift sufficient for the pilot to be able to control the plane.

I'm not suggesting that handling a huge jet in a stall would be easy, but I would guess that knowing how to do it is part of the requirements for flying one.

lutorm4• 17 years ago

This was my question too. But I think stalls in large airliners are a very different thing than in GA aircraft. I'm pretty sure full stalls are still part of the test regimen, but I don't think normal pilots ever do a full stall. It may also be other factors playing in at high altitude, and of course in severe turbulence a recovery might be even more difficult.

marvin• 17 years ago

Glider pilot here. I have decent knowledge of aerodynamics, but have never studied large jets in detail. This is my personal theory - essentially what lies behind the words of a few articles I have read over the last few days, but the authors haven't been able to formulate it clearly.

Assuming that the autopilot and fly-by-wire systems were somehow compromized, a full stall in the "Coffin Corner" (Q-corner) would be a very, very serious condition. A stall causes the nose to drop and speed to accumulate. Since the difference between the stalling speed and the never-exceed speed is so small at the altitude in question, this accumulation of speed could easily cause the plane to exceed its critical Mach number, causing supersonic shockwaves around certain parts of the airfoil. In planes not designed for supersonic flight, these shockwaves will eventually cripple the effect of the control surfaces. If the plane is in a nose-down position when it looses effect on its elevator rudder, the plane will overspeed and eventually suffer structural failure (essentially meaning the loss of some critical part) due to flutter (resonance in parts of the airframe) or aerodynamic stresses.

A stall during normal flight conditions doesn't have to be a serious problem, but these weren't normal flight conditions. And the information that we have suggests that certain Airbus models have had problems with their pitot (speed measurement) systems in icing conditions, leading to erroneous speed readouts. The fly-by-wire system, which prevents the pilot from flying the aircraft into stall or overspeed, cannot function correctly without a correct speed measurement. And as I have detailed, a proper stall might be enough to doom the airplane.

DanielBMarkham• 17 years ago

Miles is a pilot and aviation enthusiast, and I've admired his work in the past.

I hope this bit of writing is more public-serving than self-serving. After all, we still know very, very little about what happened, aside from the data transmissions. Even speculating on structural disintegration is problematic because the obvious next question was: why wasn't the plane configured for heavy turbulence?

So you're left with this article that goes over some cool new facts (for those of you outside the aviation community) but really doesn't shed much light on the incident at all. It's not a news piece, it's not an opinion piece. It's kind of a science piece hanging off a news story -- one that puts the author in the role of expert without facts and one in which hundreds of people get killed.

Not my cup of tea.

noonespecial• 17 years ago

I know its all very serious and its sad commentary on the mental baggage I now carry from watching too much TV when I was 15, but I couldn't help but do a double take when a guy named "Miles O'Brien", quoted Scottie describing engines.

chipmunkninja• 17 years ago

While there is a lot of good information in this article, the tone is a bit too tabloid-sensationalist for my tastes.

"So while you are napping, eating or watching a movie on that flight to LAX, you should know the plane you are flying is cruising along at the ratty edge of its capabilities. Why? Money. The higher an airliner flies, the better gas mileage it gets."

Boo those big corporations for trying to pick optimal flight paths, save customers flight time, or otherwise make a buck (and who cares about all the environmentalists breathing down their necks about burning so much kerosene). How DARE they? Think of the children!!

The one thing common after all these crashes is the amount of looney speculation that goes on right after, and then we magically forget about it. Does anybody even remember the British Airways 777 from Beijing that landed short at Heathrow a couple of years back? The reason: entirely mundane - faulty fuel pump.

Air France 447: The ‘Coffin Corner’ and a ‘Mesoscale’ Maw

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