Air France 447 - On topic only!

[Myndee]

BEA Press Conference:

http://www.bloomberg.com/news/2011-05-12/air-france-crashed-plane-s-black-boxes-probably-intact-investigator-says.html

- investigators are fairly confident the data will be intact
- they will start working on the black boxes today
- it will take several hours just to open them
- investigators are still contemplating retrieval of bodies, sensitive to the wishes of some families, but only if DNA makes identification possible
- hoping to release final report in early 2012

I am still hoping they release transcripts before then.

[Fear_of_Flying]

First volunteer to match qualifications with the guy? How did the person who "noticed" his massage therapist qualification ONLY manage to notice that? But I think the above might possibly explain why Scientific American would feel safe in publishing what he said.
Granted, a totally detailed discussion of every point would run to many more pages.

News articles are now calling the remains of victims "mummified". I'm wondering what sense they are that. But they did get some bodies back, still strapped to seats. Wonder if anyone will get to do an autopsy before burial. Surely there is vital information in those remains. Maybe the non-French won't be subject to French jurisdiction.

No comment on your first point, other than I'm glad someone else sees the irony.

As to the mummified condition of the bodies, I've read that it's quite horrific. Some recovery workers have asked to be removed from the assignment, as the remains have been compared to wax museum figures, frozen in their moment of death. RIP.

[Fear_of_Flying]

CNN said all of that along with the stupid belly flopping comment? JEEZ!

I actually find "belly flop" to be an apt metaphor, particularly for a casual follower of the story.

[Myndee]

No comment on your first point, other than I'm glad someone else sees the irony.

As to the mummified condition of the bodies, I've read that it's quite horrific. Some recovery workers have asked to be removed from the assignment, as the remains have been compared to wax museum figures, frozen in their moment of death. RIP.

Ugh. How awful.

[Joe H]

I actually find "belly flop" to be an apt metaphor, particularly for a casual follower of the story.

I would also agree, and have said as much in the past, I still think the aircraft impacted in a nose high, relatively slow forward speed attitude, tail first, then that caused the main fusilage to impact in a fairly flat 'belly flop' , WHOLE tail (rear) area from behind main structural wing area, breaks away, along with forward area - forward from main wing area, the main heavy items, wing area, centre fusilage etc has greatest weight and momentum. All areas then tumble and disintegrate at a rate determinied by there mass an integrity. Note practically all images of debris field first released are from the main central box structure of wing unit and fusilage in this area.

The bodies 'thing', well, it is as some have said, it is the wishes of SOME of the family, so we are not in a position to disagree with that, we might not agree with how they think, but at least they (the french) are respecting the wishes of some, after the attempts, maybe the families decide not to want this, but at least they tried to comply.

Many think hitting water is a fairly soft landing, like falling into an airbag, it isnt, it is like hitting concrete !. (depending on vertical and forward speed!)

Hopefully we should have some 'snippets' of the cvr and fdr within a few days or a week.... the all the speculation can start again ..

[Myndee]

Yes, I know the motion would be akin to a belly flop, but it wasn't really anything like a belly flop. When I hear that term, I think of my sons jumping into the pool. I know that I am nit-picking, but this wasn't a Sully-esque water landing whose images people have gotten used to (without understanding that the occurence was basically rarer than rare.) As we know, this was a horrific, devestating crash. I guess what I am saying is that I wish that a different term was used because it seems disrespectul in a way.

As for the remains of the victims, I think that honoring the wishes of the family in accordance to what the victim may have wanted, or in accordance to their religious customs, should be taken into account whenever possible. However, this seems like it would be more distressing rather than helpful. Seeing as the remains will not stay solid during the ascent, what special equipment can be taken that far down to properly contain the remains as they change? It's just really not possible. I think it would be far more respectful to the deceased to leave them where they lay. After all, this is not an area that is easily accessable, and I imagine that nature will take its course even at those depths and the body will return to dust as it would if it were buried. That said, I do understand that some people possibly have a hard time accepting the death of a loved one and not having a body to bury makes it difficult for them to get the closure they need in their grief process. Any way you look at it...it's just a sad state of affairs.

Obviously the best we can hope for is that these lives were not lost in vain and that a definitive cause is found and steps are taken to prevent it from happening again.

[Evan]

Obviously what? What scenario described by who? What this guy wrote could be perfectly understood also as they holding altitude despite the speed, something that would eventually lead to a stall.

You are right that he doesn't mention a change in pitch before (leading to) the stall. But you fail to note that he doesn't mention change of altitude either. Are you choosing those parts that support your POV and discarding those that doesn't. There was a name for that behaviour...

The scenario as described in the Scientific American article...

Here's what he wrote:

If the lift produced by the flow of air over the wings becomes less than the weight of the aircraft, you are no longer flying, but falling in a "stall". The minimum safe operating velocity (Vmin) for an aircraft is set enough above the stall speed so that normal fluctuations in wind and aircraft altitude won’t cause an airplane to stall.

You and I both know this statement is incorrect. He never mentioned anything about pilots holding altitude with pitch as a factor. It is very important to note that there is no mention of pitch input, because in speculating what might have gone wrong with AF447, you have to distinguish between pilot action and pilot inaction. If these pilots had their heads together they would not have added pitch anywhere near stall AoA and therefore the entire issue of "coffin corner" (the subject of the article) is overblown, as insufficient airspeed alone would not result in stall and loss of flight control, but only result in an initially controlled descent (barring any extreme wind-shear, which isn't mentioned here either).

That is why I am highlighting it. The aspects of stall and 'coffin corner' continue to be incorrectly defined by so-called experts in the media. They are giving the impression to the public that aircraft at normal cruise altitude fly in a tiny band of airspeed, and if they make any error on either side of it, they plane will spontaneously self-destruct. It's just like the scarebus hype. Sensationalism gets you eyeballs these days.

Am I wrong?

[Joe H]

Hi Myndee
A belly flop is a belly flop, a rose by any other name etc, maybe not the best term, but probably apt here. In other words the vertical component probably exceded the forward component.
The foreward toilet area recovered on the surface was 'relatively' intact with a high downward compression force, as was the galley areas and carts recovered. This does not support a HIGH forward speed component.
HOWEVER, the reports tend to indicate the main body hit in a fairly 'flat' dimention. We have a forward toilet area, relatively intact, yet the main heavy area is in pieces, ripped apart... This would support the high downward verical speed with low forward speed, but again, time will tell !!!!

[guamainiac]

Take a look at the Boeing directive regarding .. ice crystal engine events and convective weather.

[Fear_of_Flying]

That is why I am highlighting it. The aspects of stall and 'coffin corner' continue to be incorrectly defined by so-called experts in the media. They are giving the impression to the public that aircraft at normal cruise altitude fly in a tiny band of airspeed, and if they make any error on either side of it, they plane will spontaneously self-destruct. It's just like the scarebus hype. Sensationalism gets you eyeballs these days.

Am I wrong?

I don't consider the article to be media "hype". This is on the Scientific American guest blog, and is simply the author's attempt to explain coffin corner and what significance it may have had on the AF447 accident.

In the second paragraph he states: "The name [coffin corner] does not come from "it's deadly to fly there", but from the shape of a plot of stall velocity versus altitude when the velocity is expressed as Mach number, the speed relative to the speed of sound. The curve then resembles the tapered corner of a coffin as shown at the right." Hardly what I would call sensationalism. Sensationalism is " Study Shows One out of Three Men thinks about Sex every 10 seconds!".

This is mundane article for those who might be interested in learning a bit more about possible causes of AF447. I don't know if he made a factual mistake or not, but even if so, I don't believe it was an intentional distortion of the truth in order to make his article more popular, or an indication that he doesn't know anything about his subject matter.

[MCM]

If these pilots had their heads together they would not have added pitch anywhere near stall AoA

One thing to consider is that in an Airbus aircraft, with the lack of a "feel" sense for where the controls are located, it would be possible to not realise just how much pitch up has been added. In the "heat of the battle", I can see how it would be possible. Remember this crew probably had no idea what was going on, and so it is unlikely they followed the exact steps for an unreliable airspeed indication. So, in absense of that, they would probably be trying to maintain altitude.

as insufficient airspeed alone would not result in stall and loss of flight control, but only result in an initially controlled descent (barring any extreme wind-shear, which isn't mentioned here either)

And what would happen if the temperature suddenly increased by say 20 degrees C as this weather pattern was entered? Would that result in a smooth controlled descent if it wasn't immediately recognised and a descent commenced? If you were suddenly a few thousand feet above your maximum altitude for that weight/temperature combination, and you got some gusts/turbulence increasing your load factor...

[Highkeas]

I am still hoping they release transcripts before then.

The CVR transcripts should be documents fairly soon (but when will they be released to the general public is another question). Of course if the voices are not that clear or there is a lot of background noise it may take longer to make a CVR transcript.

I've seen FDR data being analyzed and that often takes a long time since it needs to be reviewed by different specialists plus sometimes a flight simulator or aircraft is used to replicate the data.

[Evan]

And what would happen if the temperature suddenly increased by say 20 degrees C as this weather pattern was entered? Would that result in a smooth controlled descent if it wasn't immediately recognised and a descent commenced? If you were suddenly a few thousand feet above your maximum altitude for that weight/temperature combination, and you got some gusts/turbulence increasing your load factor...

Yes, I understand the reasons why you would descend, smoothly or abruptly, but why would you stall... ?

The article I'm questioning makes no mention of factors like temperature diversions or wind shear. It simply states, as have many others I have read, that, when flying near coffin corner, you either go to fast and get mach-buffet or you go too slow and stall. In either case, potentially catastrophic consequences.

But I'm having trouble understanding how the slow side of the coffin corner(ish) regime can result in a stall if the pilots know better than to try to hold altitude with significant pitch inputs without having airspeed data or stall warnings to guide them.

[Highkeas]

..................
But I'm having trouble understanding how the slow side of the coffin corner(ish) regime can result in a stall if the pilots know better than to try to hold altitude with significant pitch inputs without having airspeed data or stall warnings to guide them.

I do not know the dynamics of such a stall but it can happen on some aircraft (and perhaps all). I worked on an anti-stall parachute for a biz jet that kept stalling near max altitude if the speed dropped sufficiently. The test pilots always recovered from the stall without resorting to the parachute. On this particular biz jet additional ventral fins were installed to correct the stalling. Of course in this case the test pilots were defining the safe operating envelope.

[guamainiac]

And they were perhaps most importantly aware that something was going to happen.

You didn't do a "blind study" did you?

At night and off guard, unless the color radar was glowing?