Air France 447 - On topic only!

[Gabriel]

I can't imagine why, except due to a mistake or reaching some bytes limit, why a thread in the Aviation Safety forum that is discussing a fatal accident of a plane made by one of the big manufactures and flown by one of the big airlines, a thread where discussion is being taken mainly on-topic, with respect, constructivelly, with technically sound discussion, where everybody is learning, and a thread that is BY FAR the most popular ever in terms of post and views, bringing people to this site to participate or just to lurk (and some times to click on the advertisements), would be closed by the moderators.

EDIT: I've just thought I'd add a link to the original thread:

http://forums.jetphotos.net/showthread.php?t=47442

[Deadstick]

It may be because of a perceived challenge to the professionals who we appreciate and need input from.

[Peter Kesternich]

Well - let's assume an innocent reason Maybe after 167 pages in the old thread it was time to start a new one

[AJ]

Originally Posted by Peter Kesternich

Well - let's assume an innocent reason Maybe after 167 pages in the old thread it was time to start a new one

Spot on Peter. No conspiracy, the other one was betting too hard to moderate.

[TUNISAIR745]

Alright people, can someone make for us in this new topic, a brief and constructive summary about what was discussed previously. Thank you.

It was a bit hard for me to read the whole 167 pages from the beggining!!

[EconomyClass]

Yeh, a summary of months of discussion would be very useful to someone new. Actually, I think it could be extremely brief, too, since almost nothing is known for sure.

[Peter Kesternich]

Originally Posted by Deadstick

It may be because of a perceived challenge to the professionals who we appreciate and need input from.

That's nonsense, Deadstick.

[Peter Kesternich]

Would have been better to call this thread "Air France AF447 accident", though

[Deadstick]

Originally Posted by Peter Kesternich

That's nonsense, Deadstick.

OK. Glad to be wrong if that's the case.

[EconomyClass]

A report prepared by a French-led group of international experts concluded that the concept of transmitting data during emergency situations "is becoming more robust and accepted." The study also found it would be cost-effective if only essential data were sent.

http://online.wsj.com/article/SB1000...636704730.html

Anybody remember how balky images were to send? Then software engineers came along with vector graphics in such things as GIF and JPG. Now image files are a tiny fraction of what they were.

I can see how putting techie minds to the task could produce ways that flight data could be sent encoded to vastly reduce the bytes involved. In fact, I'd go so far as to predict that when its wanted badly enough, it will happen. Saying "there's too much" is really like scoffing at sending bitmap image files as if that's the only way you can represent an image digitally.

[EconomyClass]

Don't see a link to this since it came out, so maybe it hasn't been posted. Very interesting article proposing a scenario for the accident. The part that disturbs me is "an unlucky sequence of events". That makes it sound like A330's have depended perhaps to a tiny degree on luck to achieve a remarkable safety record.

http://www.dailymail.co.uk/news/arti...28-people.html

[Highkeas]

Originally Posted by EconomyClass

Don't see a link to this since it came out, so maybe it hasn't been posted. Very interesting article proposing a scenario for the accident. The part that disturbs me is "an unlucky sequence of events". That makes it sound like A330's have depended perhaps to a tiny degree on luck to achieve a remarkable safety record.

http://www.dailymail.co.uk/news/arti...28-people.html

"But now, for the first time, the story behind this devastating air disaster can be told. A BBC2 documentary, Lost: The Mystery Of Flight 447, to be screened tomorrow night, has brought together leading aviation experts to conduct a forensic investigation into the crash."

Did anybody see this documentary?

[Gabriel]

Originally Posted by EconomyClass

Don't see a link to this since it came out, so maybe it hasn't been posted. Very interesting article proposing a scenario for the accident. The part that disturbs me is "an unlucky sequence of events". That makes it sound like A330's have depended perhaps to a tiny degree on luck to achieve a remarkable safety record.

http://www.dailymail.co.uk/news/arti...28-people.html

Well, everything is always subject to random chance to some extent, no matter how well controlled the situation is.

You can be hit my a meteorite any time. The probability of that is extremely low, so it requires just a tiny bit of good luck not to be hit, and a tremendous amount of bad luck to be hit.

Things like that happen in aviation too (and I am not speaking of this specific case). In fact, critical failures with a chance of less than 1 in ten millions are officially accepted to remain, even if you know that weak point.

[Spectator]

Originally Posted by EconomyClass

Don't see a link to this since it came out, so maybe it hasn't been posted. Very interesting article proposing a scenario for the accident. The part that disturbs me is "an unlucky sequence of events". That makes it sound like A330's have depended perhaps to a tiny degree on luck to achieve a remarkable safety record.

http://www.dailymail.co.uk/news/arti...28-people.html

From the article:

In the cockpit, instrumental display screens would have gone blank, and flight-control computers would have died. One by one, the most critical safety features in the cockpit failed.

Does the flight computer just throw it's hands in the air and switch off it's screen when it encounters problems? They make it sound as if the pilots would have been trying to fly absolutely blind. Possibly effectively so, yes, but very nicely dramatised I must say.

[Peter Kesternich]

Originally Posted by Spectator

(...) They make it sound as if the pilots would have been trying to fly absolutely blind. (...)

Well - once again - main stream journalists know nothing about aviation and how it works. Just like the general public, basically.
Of course every aircraft has analogous back-up instruments so that speed, altitude and attitude/bank angle are displayed, even if all electric power is lost.

[Gabriel]

Originally Posted by Peter Kesternich

Well - once again - main stream journalists know nothing about aviation and how it works. Just like the general public, basically.
Of course every aircraft has analogous back-up instruments so that speed, altitude and attitude/bank angle are displayed, even if all electric power is lost.

Not every aircraft. And the A330 is one of those who don't.
The tendency now it to have third PFD that shows speed, altitude, attitude and heading, with it's own and isolated battery as back-up power.

[EconomyClass]

Originally Posted by Spectator

From the article:



Does the flight computer just throw it's hands in the air and switch off it's screen when it encounters problems? They make it sound as if the pilots would have been trying to fly absolutely blind. Possibly effectively so, yes, but very nicely dramatised I must say.

Does a computer have "hands"? My understanding is that failures like pitot tubes and flight management systems sound warning alarms that let pilots know there is a need for immediate action. The danger I've understood is too many things failing in too short a time, with the plane in severe weather systems. What I've read or seen dramatized of past disasters show that mechanical systems can overwhelm human beings. I guess everyone involved in any aspect of aviation at some level realizes that and considers it part of the acceptable risk level.

[SYDCBRWOD]

Originally Posted by Spectator

From the article:



Does the flight computer just throw it's hands in the air and switch off it's screen when it encounters problems?

There's the first incorrect assumption. There are multiple computers, so if one does go offline, the other two can continue with one or more shut down.

[mfeldt]

Originally Posted by EconomyClass

http://online.wsj.com/article/SB1000...636704730.html

Anybody remember how balky images were to send? Then software engineers came along with vector graphics in such things as GIF and JPG. Now image files are a tiny fraction of what they were.

I think there is a dedicated thread on this, but for short:

JPEG is lossy compression, you want to do that to data.
In fact, when transmitting basically a stream of numbers, there is very little you can gain by compressing.

Plus, it's not necessary! If one would simply copy the blackbox data over several - very cheap - memory storage facilities distributed over all the aircraft, at least one of them would certainly get found!

[EconomyClass]

n fact, when transmitting basically a stream of numbers, there is very little you can gain by compressing.

Sorry, but it done all the time. Just go look at the history of data transmission.