I think it's fair to say my focus on control surfaces might be annoying. If so, I simply find BEA's explanation wanting. I would like nothing more than to simply say, that's it!

The colored surfaces in red of the missing controls say quite a bit. It is possible of course that the airliner just sat in, with the VS equilaterally driving vertically down into the tail's support structure, then being spit out, with only a leading edge squash left instead of shrapnel, (spoiler). Then too, takata points to a lack of hydraulics problems on the ECAM. As the linked essay states, the comparable "peace" of a deep stall, potentially cueless, (compared to buffet and airstream noise of other ua's) might have been the last attempt to establish controlled flight. Controls that require airflow parallel to their surface are useless in vertical mush. Especially when trying to move a stubborn 150 tons

I have some folks working on animations of possible paths 447 took downward.
I'll look at them and decide if they are appropriate.

bear

Sensor_Validation:

Here's a graphic overlay of the latest BEA Search Area Update, 17 May, 2010, centered on the Last Known Position. As you can see, no part of the central 20nm diameter area has been searched. Some search traverses were made northward and eastward about 12 miles out from the LKP. The blue area directly north of the LKP is very deep.

The bodies seemed to drift in a cluster along a course setting due northward from this central area (see post 1120).

No reason to believe the aircraft didn't end up southward of the LKP, either. Once the upset developed, heading became irrelevant.

http://i958.photobucket.com/albums/a...earchZones.jpg

GB

Agreed. So unless there was sufficient forward motion through the air, the V/S would have no stabilizing effect, and neither would +/- 4° of rudder. Likewise HN39's comment regarding a yaw to starboard and the right wing dipping slightly because of the V/S moving to port would have caused a small roll effect, also comes unstuck.

The scenario of a high vertical acceleration with a small nose up pitch and wings nearly level, equates more to a slowly rotating flat spin where all the control surfaces had no affect because of the lost lift and the vortex created. The fact that the BEA reported that damage to the hull was symmetrical leads me to believe that the aircraft's heading nearly matched the real direction of "flight" [travel] at the point of impact.

HN39;
Your description of the forces involved on the V/S at the point of impact is appreciated. They have of course exceeded the magical "36 g"!

mm43

I wonder if Dr. Ballard will be called in, if anyone can find something on the bottom, he's the man for the job. With Titanic, Bismark, Yorktown and several others, I'm sure he would do well. I hope that it will be found

jsfboat
I wonder if Dr. Ballard will be called in, if anyone can find something on the bottom, he's the man for the job. With Titanic, Bismark, Yorktown and several others, I'm sure he would do well. I hope that it will be found

I think this gentleman was the one who found the location of the HMAS Sydney off Western Australia.


Mike

The FAB screen shot shown in post #1127 shows the early search was a grid search along the route from the LKP to TASIL and it commenced 10NM before the LKP and included 10NM each side of projected track to about 42NM from LKP. A more intensive search was done from LKP to TASIL at about 3NM each side of track. The finding of some unidentified debris to the SE of the LKP disrupted any further searching in what we now believe was the area of real interest.

mm43

A simple SLF asks
 

Has anybody thought about the main body of the aircraft not sinking to the bottom of the ocean?

Some composite boats reach a depth in the water where the hull is just the same density as the water and stop there,and just float with the tide,or so I have been told.???:confused::confused:

crippen
 

The mainly composite part broke off, floated, and was fished out.

The rest of the structure is metallic. It's not airtight, so it will sink.

Where? Where? Where?
 

Hello GreatBear,
In fact, this is the first place the BEA searched with its best assets (USN's dedicated TPLs = pinger locators) when the recorder's balises where still working.
You should remember that the search operation is in phase 3 and that the previous two phases were detailed in BEA 2nd report, annexe 2, p. 77-86.

In short: they defined the most probable crash zone called "Alpha zone" starting about 10 nm South of last know positition and extending to 10 nm South of Tasil. This is the black box pictured in the map below:
http://takata1940.free.fr/search1.jpg
Each grid box is 10 x 10 nm.
When pingers stopped to work, they assessed the above "quality" map to continue into phase 2 where other means were deployed by oceanic survey vessel Pourquoi pas? consisting of deep sonar robots (i.e. J-K-L-M 24 previously skipped boxes were searched this way). The goal was to systematically finish the Alpha zone and eventually also the 40 nm radius defined circle centered at LKP.

As you can see it now, phase 3 is completing the previous work using better reverse drift models newly developped, but they were also scanning already searched boxes having low quality scores (mostly from Emeraude's assigned zone).

Taking into account the very high probability that TPLs would have picked any signal from the recorders along the flight path to TASIL (where the relief is much more gentle), it is very probable that AF447's wreck is not located into this zone... or, if it is really there, that both pingers were destroyed during the crash.

You are right considering two big 'IF'.
- If upset did take place at 0210... [nothing is telling us it did].
- If end of flight was ~0215... [there is still very good chances it was not].
About the time it could take for AF447 to go down, something as fast as 1 minute and half is possible from cruise level. Then if ~0215 was the end of flight, an upset could have occured as late as ~0214, making quite some distance between 0210 (LKP) and crash site.

Consequently, the next major step into this investigation would have to be the localization of the wreckage which, by itself, will reveal a lot more about this upset/crash sequence. Last declarations (yesterday) are telling us hoppefully that the search will not stop here and big efforts will continue until they find it.

S~
Olivier

Boeing Aeromagazine on Upsets
 

In his post #1358 sensor validation offers a link to an article by "Dark Matter". While that article is mainly the usual mix of truths, half truths, and misconceptions, it contains a link to an interesting article in the Boeing Aeromagazine on Upsets, that I would like to recommend to many readers of this thread:

Boeing Upset article

HN39

HN39

Very interesting.

Well, I´m new here, so forgive me if this was already asked by someone, but what are the prerequisites to becoming an airline pilot and, specially, to piloting large aircraft like an A-330 or a 7x7?

The article you linked to stress the need of pilots to be familiar with the laws of physics. It seems to me that this would constrain the pool of would be pilots to engineers, physicists and mathematicians. Maybe some economists also. :)

What is the usual extraction of the pilot workforce in the airlines?

ps: I´m a brazilian that for profissional reasons fly over the south atlantic quite often, including in the ill-fated AF447. I have read this thread from the beggining, and also the old one. I´m an engineer, but have no training in the aeronautics industry, and must confess that I´m learning a lot from the very competent commentators here.

Is this where ignorance is bliss ?
Have a look at this site, for instance Smartcockpit flight ops docs

or check John Tullamarine's sticky thread " Useful websites and document references" in TECH LOG.
some knowledge in these two places.

and , of course, your hunch is wrong.

Regards

Bearfoil
Bearfoil,
If I may ask : What is your profession / personal connection to this accident ?

Are you a lawyer or journalist or something completely different that you have people working on this?

Hello Centrosphere,
It is not the same depending on countries. Concerning France, the main courses are ENAC (École Nationale de l'Aviation Civile, in Toulouse, one of the French prestigious "grandes écoles") and, for older generations also l'École de l'Air (Armée de l'Air). Both course are following a very serious scientific baccalaureat plus preparation and will provide a diploma at least equivalent to an engineer.
See ENAC page here: ENAC - Ecole - Accueil
S~
Olivier

Lemurian;

Thank you for your useful and very welcome link to the Smartcockpit site. I wasn't aware of it and certainly still have to learn a lot about sources of information freely available on the web. On second thoughts, I have removed the remark from my post.

Regards,
HN39

certification
 

The second BEA interim report into AF447, (p62-67), identified 32 other incidents caused by or related to freezing of pitots on A330-A340 and also stated that the test/certification regime (JAR25) for those pitots was for a maximum altitude of 30,000ft.
Why is it that one of the most heavily regulated industries in the world allows almost all of its commercial operations to be conducted using a critical speed sensing technology that is neither tested nor certified for critical icing factors at the very altitude that almost all of their commercial flights are conducted.
Maybe they should limit all flights to within the certified envelope (30,000ft) and wait for the business out-cry to put funds into solving the problem.

Where?
 

Takata,

Aaaaah yes, there are so many Unknowns! So many IFs. So many Possibilities. So many Questions.

My bad, not to clarify "BEA have not searched there yet" by adding "with side-scanning sonar." Appendix 2 of the 2nd Report includes a graphic ("Lanes defined in the search zone") and states "The SAR was operated on line 24, squares J,K, L and M." That's eight to ten nautical miles southwest of the Last Known Position, so it seems that IFREMER’s Towed Acoustic Sonar (TAS), with its 1 pixel for 25 cm resolution, only explored a tiny corner of the area within a 10nm radius of the LKP during Phase 2.

It's unfortunate that the very best assets (including a nuclear submarine) and TPL technology could not locate the pingers during Phase 1 in the Alpha Zone or elsewhere before their predicted battery life expired. As you say, if the wreckage is really in a tight circle near the LKP, both pingers could have been destroyed during the crash. Recommendations are already in place for lowered beacon frequencies, and pinger specs and CDR methodologies are undergoing a broad re-evaluation by the industry.

The timing of events with clues only in the ACARS messages is very tricky. My thinking is that for the 02:14:26 cabin vertical speed message to be sent, it had to be triggered by a rapid descent at least a minute or two PRIOR to its transmission. As the BBC experiment showed, a fall of 19,000 feet in 50 seconds might be a worst-case possibility. So the actual falling event must have begun well before that last message was timestamped and sent. In any case, it would seem that loss of control (the upset) occurred closer to 02:10, well before the cabin vertical speed message was sent. The idea of straight-and-level cruise flight much beyond AP Disconnect at 02:10:10 is difficult for me, but I am continually trying to simplify a very complicated event.

Aaaaaah, the unknowns.

Without doubt, the BEA search effort has gathered the best minds and resources to recover the hull and black boxes. It's simply one of the most difficult researches so far undertaken in this 21st Century.

Thank you for your considered feedback.

GB

The French are already familiar with Dr. Ballard, and Paul-Henri Nargeolet has an opinion:

http://www.titanicfiles.org/Essays_e...%20Ballard.pdf

yes, where!?
 

GreatBear,

Good point! my opinion too as one really need to keep open the right possibilities and discarding the wrongs only very very carrefully without being subject to tunnel vision.

There is still a good hope that the Navy picked the right signal. As a former member of this institution, I'm very confident about it, even if MOD's communication nearly ruined its credibility against BEA (to be verified) opinion of "no aircraft South of LKP".
This cabin vertical speed message is still under high scrutinity. It will be very difficult to fully understand it without knowing precisely what was the exact configuration of the aircraft when it was triggered, but also, because it was the last one of the sequence while few more ACARS could have told a lot more about it. We can't know for sure that the flight ended strait after or a while after.
In fact, it left only three choices open: a) crash in the following seconds or b) ACARS failure; c) EMER-ELEC config.

This advisory can be triggered both in PRESS auto or manual mode (crew action). If PRESS manual mode (for whatever reason) was selected when the valve was open, cabin vertical speed could climb quite fast. All we know is that during 5 seconds (at least), the cabin moved (up or down) by 150 ft (at least). If PRESS was in auto mode and no ADR was valid, it is also possible, beside other faults, that the security will work as to keep the DeltaP (internal/external) constant based on other data (then move at the same rate at the aircraft from whatever altitude). AIRBUS FLIGHT SAFETY DEPARTMENT communicated about it that its meaning was not obvious:
But, as it was the last ACARS sent, and like EMER-ELEC could have followed it - without being transmitted due to ACARS shut down - a wider range of possibilities could even occur (i.e. was it the consequence of engine roll back on PRESS/VENT systems before flameout?, etc.).

The BBC show was overall good (I feared worse) but there was still some fair amount of drama over reality; The third pilot would not have been PF if the commandant was resting (which is still unproved but quite possible). More annoying was the fact that they used an A320 simulator showing wrong settings (mach 0.76 in place of min. 0.80) and did not follow the real SOP -quite conveniently- for addressing their "non-moving throttles have been forgotten" theory (not adjusted to right settings), then the aircraft was stalled in heavy turbulences.

But as ATHR was ON, then kicked OFF with AP, it would also trigger a warning every 5 seconds until throttles would be adjusted into the right settings manually. Consequently, it would be pretty hard to forget about thrust and let the airspeed drop down to any dangerous level without noticing it. If turbulences were already an issue, ATHR would be OFF and the correct parameters of pitch and thrust already set before this pitot issue... In short, this is unlikely enough to produce an upset at this stage unless unknown issues or maybe, the appearance of all factors at exactly the same time (freezing, multiples faults, and unexpected heavy turbulences).

Concerning the stall demo, it is hard to tell as important details about the military simulator settings are left vague but it might be possible to go down in about 90 s without breaking appart the airframe. In this case horizontal distance covered would be quite limited and aircraft terminal attitude unlikely level.

S~
Olivier

I am not sure whether any references have previously been made to the Swissair Flight 111 MD-11 crash of 2 September 1998. I would have thought a lot of knowledge was gained in underwater search and recovery operations and techniques from this accident. It took TSB of Canada four years and cost CAD 57 million (approx USD 38million ) to get the answers. The aircraft had crashed closer inshore and the debris lay relatively in much shallower waters.
In the case of AF447 the cost to date is EUR 9 million and the depth and extent of the search area is considerably larger. Should the FDRs and the CVR be eventualy recovered it is not an absolute certainty that the answers will be provided. Should the wreckage be found what would be the challanges and difficulties in recovering it from the great depths of the ocean. What may the final cost amount to.

How much should be spent on accident investigation for the sole benefit of flight safety. Surely in these days of global economic austerity there must be a limit.