Tech Log The very best in practical technical discussion on the web

AF447

Old 15th Jun 2009, 17:36
  #1601 (permalink)  
 
Join Date: Jun 2009
Location: British Isles
Age: 72
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
AF447

Re-comment by Dave Gittens:
MY personal opinion (which I detect is shared by many here) is that I have never known an aeroplane break up and then carry on for '50 or so' miles. Space Shuttle - yes. A330 I do not believe it is remotely possible.

There could be a couple of reasons for this:
1 - if the a/c broke up in the air with one part in a violent CB updraught and the other perhaps in downdraught, or falling into a different updraught, significant separation could easily occur.
2 - perhaps more likely - debris 'floating' at different depths could be sepatared by currents in the area e.g. the 'surface currents' are only a few hundred metres deep but move several miles per day relative to deeper water.
Triskel is offline  
Old 15th Jun 2009, 17:42
  #1602 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes on 0 Posts
Chaps and chappesses - to avoid further confusion/embarrassment/laughing at xxx/distraction from the thread, can we all refer to them FROM NOW as Prandtl tubes please? 1732 is a better date too. Don't forget good old Henry Darcy as well. Now, where were we...........?

EDIT: Thank you Triskel...........
BOAC is offline  
Old 15th Jun 2009, 17:44
  #1603 (permalink)  
 
Join Date: Apr 2008
Location: merseyside
Posts: 81
Likes: 0
Received 0 Likes on 0 Posts
yahoo news - new photos of wreckage

on yahoo news .
search for air france photos .

a few new pics of wreckage from different angles .
you guys may be interested in them .

particurly images 10 & 11 .

They show A technician of the French Bureau of Investigation, B.E.A, taking pictures of debris belonging to crashed Air France flight AF447. from the quayside .

sorry could not get them to load up .
dicksorchard is offline  
Old 15th Jun 2009, 17:46
  #1604 (permalink)  
 
Join Date: Jun 2009
Location: I am where I am and that's all where I am.
Posts: 660
Likes: 0
Received 0 Likes on 0 Posts
onetrack

Not testing for extended UV performance is a critical failure on the part of AirBus. Of course, requiring that the composites always remain well covered with UV opaque paint should solve that problem.
JD-EE is offline  
Old 15th Jun 2009, 17:52
  #1605 (permalink)  
 
Join Date: Jun 2009
Location: ATL
Age: 67
Posts: 131
Likes: 0
Received 0 Likes on 0 Posts
Can't help it, but whenever the subject of computerised flying controls comes up it puts me in mind of a programmer who has never learned to ride a bike trying to program one that would work automatically.

One can imagine the programmer saying to his cyclist adviser, "About turns, I'm not clear about them yet. If someone wants to turn, do they turn the handlebars first, or lean over first........?"

Flying has always been a mixture of art and science. Ever since 1903......
The programmer doesn't decide how the program works. Programmers write software defined by the engineers/pilots and communicated in the form of a Software Specification. Each element of the software is tested to verify compliance with the specification.
ClippedCub is offline  
Old 15th Jun 2009, 18:00
  #1606 (permalink)  
 
Join Date: Jun 2009
Location: ATL
Age: 67
Posts: 131
Likes: 0
Received 0 Likes on 0 Posts
I have never known an aeroplane break up and then carry on for '50 or so' miles.
It doesn't. The 50 miles of debris can be explained by trajectory analysis if it broke up in flight.

http://www.asc.gov.tw/author_files/Ballistic.pdf
ClippedCub is offline  
Old 15th Jun 2009, 18:28
  #1607 (permalink)  
 
Join Date: Mar 2002
Location: Surrey, UK
Posts: 897
Received 10 Likes on 6 Posts
A300/330/340

We've had a LOT of people basically assuming that the A300 and A330 are identical, cos they're French like and they've got a computer thingy. We've also had two detailed reports of similar events with an A330 (Air Caraibes and Air France).

But the A340 is meant to need minimal conversion from the A330. And, well, designed 20 years later than the A300. Have there been any comparable events with the A340?
steamchicken is offline  
Old 15th Jun 2009, 18:58
  #1608 (permalink)  
 
Join Date: Sep 2008
Location: MI
Posts: 570
Likes: 0
Received 0 Likes on 0 Posts
NotPilotAtALL -
Sure they played their part ... [referring to the remark I made about computers possibly playing a part in this accident]
They just performed nicely the job for what they are designed.
When the job required (or informations given) go over their design or limits .. (due to fail safe limitations coded) they go out the game and give hand to the pilot(s)
You'll have to refer to the post that contained the info I was writing about. And if your Screen Name reflects your connection to aviation, I suggest you let those associated with the flight deck decide.
DC-ATE is offline  
Old 15th Jun 2009, 18:58
  #1609 (permalink)  
 
Join Date: Jun 2009
Location: Italy
Age: 50
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
???

I have a question:
It has been stated that the aircraft was facing rough weather (a strong turbulence).
But... how comes the belts of the crew seats were not fastened?? Do we know anything about the passengers: i.e. if the belts on the seats they found were fastened, if the bodies showed ligature marks due to the belts...
If the belts were not fastened the turbulence would not be a key factor anymore
wizele is offline  
Old 15th Jun 2009, 19:00
  #1610 (permalink)  
 
Join Date: Feb 2008
Location: Subterranea
Age: 70
Posts: 187
Likes: 0
Received 0 Likes on 0 Posts
Airbus Systems have all been well tested with multiple redundancies built in. Something else happened that made both automatic and manual control impossible.

Much speculation concerns the ACARS messages - but if there was a catastrophic failure some of the more informative fault reports may not have gotten through to the COM link or they may have been queued for transmission but never made it. We shouldn't assume that the faults transmitted were the principal faults that occurred. For instance if another unreported fault disrupted power to the pitot heating, then the latter problem would be a symptom and not a cause.
Could solar weather conditions have been a contibuting factor, possibly triggering single event efects (SEE) and/or a solar proton event (SPE)?
Source:

SolarSoft Latest Events

There was an increase in X-ray activity from the Sun (ref. GEOS 10 in upper graph), starting late May 31st which continued through June 1st and in the same time frame the coronal hole graph show a pronounced dip at the approximate time the aircraft went missing (Kyoto Det/PFSS in lower graph). The accident site is also slightly north of the South Atlantic Anomaly, an area of radiation in the form of trapped protons where the lower Van Allen belt reaches down into the atmosphere. The X-rays preceded a solar flare which occurred approx. 12 hrs after the aircraft went missing.
Green-dot is offline  
Old 15th Jun 2009, 19:02
  #1611 (permalink)  
I don't own this space under my name. I should have leased it while I still could
 
Join Date: Dec 2002
Location: Lincolnshire
Age: 80
Posts: 16,777
Received 5 Likes on 5 Posts
Originally Posted by wizele
I have a question:
It has been stated that the aircraft was facing rough weather (a strong turbulence).
But... how comes the belts of the crew seats were not fastened?? Do we know anything about the passengers: i.e. if the belts on the seats they found were fastened, if the bodies showed ligature marks due to the belts...
If the belts were not fastened the turbulence would not be a key factor anymore
I presume you mean the cabin crew. I suggest you read the thread as there are many possibilites.

As for the passengers, short answer is No. Nothing, as far as has been posted here, has commented on the passenger seat belts.
Pontius Navigator is offline  
Old 15th Jun 2009, 19:04
  #1612 (permalink)  
 
Join Date: Jun 2009
Location: Brazil
Age: 75
Posts: 35
Likes: 0
Received 0 Likes on 0 Posts
4 fractures

.............But... how comes the belts of the crew seats were not fastened?? Do we know anything about the passengers: i.e. if the belts on the seats they found were fastened, if the bodies showed ligature marks due to the belts...
If the belts were not fastened the turbulence would not be a key factor anymore
We do not know if the crew seat belts were fastened.. I presume you are referring to the photos of the 2 jump seats.. These are seats only used occasionally by cabin crew...
The fact that most of the bodies found so far have the " 4 fractures" ( legs and arms broken), suggests they had their belts fastened, and this at the time of relatively a horizontal impact with the sea,,
Gringobr is offline  
Old 15th Jun 2009, 19:51
  #1613 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 76
Posts: 2,483
Received 0 Likes on 0 Posts
RWA, DC-ATE;
Once again, a non-flying, non-experienced, non-trained, non-pilot offers an "IT" opinion on something he knows nothing about and says so, and you think the remark is "brilliant", a "truly great comment...", or "very well put..." ? Why?

Desertia states right at the start of the post:
As nothing more than a curious member of the SLF, I've obviously not posted my groundless theories on what could have happened, preferring to read the myriad of alternatives offered on here, and keeping an open mind given that it's obvious that there is still insufficient evidence to identify the cause of this crash.

But one thing I would like to say, having been in the IT field in a variety of positions over the years, is that you cannot underestimate the risk of human error, or at least limitations in putting together the millions of line of code required to automate something as complex as flight.
I have flown 18,000+hrs since 1967 and have flown as captain and as an A320 instructor, 319s, 320s, 330s and 340s since 1992, (I'm now retired) and even with that background I do not consider myself beyond learning, (fearing to go where angels tread), am not an IT or structural engineer, but I know a thing or two about flight safety work and about the Airbus (and other types, B767, B727, L1011, DC8, DC9). There are many people here with similar and greater qualiications who, because they are experts, know what they dont' know and are prepared to ask questions instead of making sweeping, grandiose pronouncements on "Airbus dangers", "fly-by-wire" or comparing the Airbus with the difficulties of designing "computerized bikes". There is simply no comparison with the metaphor in this last.

Gentlemen, no one at Airbus is underestimating the risk of human error, nor are they at Boeing. The record of millions of takeoffs, landings and hours flown by both manufacturer's transports without fatal accident proves this to be true. To support statements that claim otherwise is to offer thoughts in basic ignorance of the aircraft involved.

There is no "smoking gun" latent in these designs which good training and experience cannot address. Neither the B777 nor the 340 designs have such faults; nor are they invincible when circumstances overwhelm the man-machine interface.

Neither one of you fly the Airbus or even know the first thing about its systems or how it's built yet you're willing to condemn the airplane based on the flimsiest notions of someone who isn't even in aviation.

This is not how flight safety or investigative work is done, and if I may make the observation yet again, THAT is the problem with this thread, while the contributions of those who are the experts and who do the work go ignored, unrecognized or unread.

Specifically - RWA, you recommended the CSM (Christian Science Monitor) article as something to read to understand this accident. Frankly, it is composed of the same imaginative analysis and reporting that exists here and in any other media; it's noise and it's print filling the vacuum. For example, the article states that, "the cabin had lost pressure and was climbing at a rate of 1800fpm".

Except perhaps from the thousands of non-expert, non-pilot, non-engineer, non-maintenance comments, where did they get that from? Where does anyone get this information from? Even if it's "18,000fpm"...where does that come from? There are other problems with this article as many know.

I have the ACARS messages just like the rest of the world now does and I have access to an AMM. Interpreting the thin, tiny bit of information available through the ACARS messages is not a straightforward exercise in reading the AMM. From the start of the last thread and this one, I and many experts have advocated reserved and cautious approach when interpreting these messages. For many reasons, this list could be, (and almost certainly is, given the intent and design of the ACARS-CMS-FIDS systems and the SITA protocols handling the messages) much larger but we do not have that information.

Here is an example of just a few of the ATA messages that can be generated by the BITE system just within the CPC, (Cabin Pressure Controller). This is by no means a complete ATA fault diagnosis list for the cabin pressue controller. As far as I know, there is not ATA code for "cabin depressurization, Cabin Rate of Climb = nnnnn feet-per-minute":





Here are examples of ATA fault/failure codes for pitot-static probes/sensors. The same issues obtain - the list is by no means complete.

Meaningful interpretations of ATA codes are not straightforward even if the correct documentation, tools and resident expertise are all available. This will not be a straightforward process for the BEA, for Airbus or for AF. It is folly to endeavour to think or do otherwise. Regarding the pitot "faults/failures", notice that the 3 sensors have the same six-digit ATA code. Someone here wisely observed that "underneath" this bread-and-butter ACARS message dump is very likely a highly-detailed message. We do not know if that message was transmitted or received or available.




The way to find things out here in this example is to answer the question, Which is the right ATA code?, and Where is the evidence that tells us we are right?

There is no ATA code for "pitot icing". The theory is the result of hind-sight bias and not the result of any knowledge or evidence. There is only the cryptic ATA message indicating that the receiving computers, (ADIRS, TCAS, CPC, DMUs) were not receiving data that was within specified parameters and therefore caused a BITE and a latched fault/failure message. Nobody anywhere, knows why, yet.

Last edited by PJ2; 15th Jun 2009 at 20:39.
PJ2 is offline  
Old 15th Jun 2009, 20:02
  #1614 (permalink)  
 
Join Date: Jun 2009
Location: south africa
Age: 56
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
Are any details of autopsies on web?
frontrow is offline  
Old 15th Jun 2009, 20:06
  #1615 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes on 0 Posts
PJ - thank you for the claw back to sanity. Do you have any take on the jungle of confusion over the ISIS?
BOAC is offline  
Old 15th Jun 2009, 20:11
  #1616 (permalink)  
I don't own this space under my name. I should have leased it while I still could
 
Join Date: Dec 2002
Location: Lincolnshire
Age: 80
Posts: 16,777
Received 5 Likes on 5 Posts
Originally Posted by frontrow
Are any details of autopsies on web?
Yes. Read this thread.
Pontius Navigator is offline  
Old 15th Jun 2009, 20:16
  #1617 (permalink)  
 
Join Date: Oct 2007
Location: England
Age: 59
Posts: 516
Likes: 0
Received 0 Likes on 0 Posts
Any similarities with the Lauda air 767 and/or the Birginair 757?

Perhaps the 'weather' is a red herring?

MM
mickyman is offline  
Old 15th Jun 2009, 20:31
  #1618 (permalink)  
 
Join Date: Jun 2009
Location: WA
Age: 50
Posts: 8
Likes: 0
Received 0 Likes on 0 Posts
Informative, PJ2.

The following paper discusses the design of the 320/330/340 fault tolerant computer systems, for anyone interested in learning about the software side.

http://personales.upv.es/juaruiga/te...jos/AIRBUS.PDF
ukwomble is offline  
Old 15th Jun 2009, 20:52
  #1619 (permalink)  
 
Join Date: Dec 2007
Location: Itinerant
Posts: 825
Received 45 Likes on 10 Posts
(Mods: Please bear with me . . .)

If you are reading this and are new to PPRuNe -- welcome! If and when you are tempted to post for the first time:

1 Read the whole thread.
2 If you feel you don't have time for (1) above, click on the "search this thread" function and type in a word related to what you were about to comment on or ask about. Read ALL the resultant posts.
3 If you still have a reason to post, type your post into a word document (rather than directly onto the PPRuNe page).
4. Go make a sandwich.
5. Re-read your post, asking yourself: Does this post advance the thread, contribute something worthwhile to the discussion/debate, or ask a question that HAS NOT ARLEADY BEEN ASKED?
6. If the answer is "yes", click on "Submit Reply"
7. If the answer is "no", enjoy the sandwich whilst you contine reading PPRuNe.

Last edited by grizzled; 15th Jun 2009 at 21:32.
grizzled is offline  
Old 15th Jun 2009, 20:55
  #1620 (permalink)  
 
Join Date: Sep 2008
Location: MI
Posts: 570
Likes: 0
Received 0 Likes on 0 Posts
PJ2 -

Thank you for your comments.

My answer to Desertia concerning his post related to his comments:

....."I remain of the opinion that, irrespective of the causes of this accident, I would still rather an experienced pilot have a piece of wire or hydraulics controlling the various surfaces under unusual conditions than having one or more computers trying to work it out."

and....."Artificial intelligence still does not - and probably will not for decades to come, unless there is a magnificent leap in technology - mirror the ability of the human brain to eschew logic and do what thousands of hours of flying, and experience of abnormal circumstances allow, which is, for want of a better word, THINK."

Neither one of you fly the Airbus or even know the first thing about its systems or how it's built yet you're willing to condemn the airplane based on the flimsiest notions of someone who isn't even in aviation.
Quite true. But, I have read enough from those that HAVE flown these types to know that I'm glad I never had to. It is utterly amazing to read the differences expressed by those that fly these things as to how various systems operate. There are disagreements everywhere. The manuals are simply too full of information that not even a computer scientist could possibly remember/recall in the time of need. Who ever heard of an aircraft having THREE different flight control laws?!

Whatever happend to AF447, apparently happend so fast, the crew had no chance to sort out all the warnings being displayed on their panel. They probably had no chance to simply FLY their aircraft.

Like it or not, his (Desertia) reference to having a "...piece of wire or hydraulics controlling..." says alot, along with those of us, yourself included, who learned how to "fly" airplanes and not manipulate a computer to do it for us.

But, we digress.....
DC-ATE is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.