AF447 wreckage found

[Man Flex]

PPRuNe should really be renamed "Arm Chair and Flight SIM Wanna Be Airline Pilots" because the vast majority of the so called "experts" on these forums are exactly that and not current professional airline pilots.

Studi,

The aeroplane reverts to Alternate Law whenever a "dual" failure is detected. The failure of the A/P, A/THR and reversion to Alternate 2 Law all occurred simultaneously.

Ironically perhaps but the aeroplane reverts back to being a Cessna 150 whenever the failures are such that the automation feels that it can no longer cope. I say Ironically because it is on these rare occassions when the protections are probably most needed.

In this case the autopilot had at least two or more unreliable airspeed indications and it would be unsafe for the autopilot to continue to fly the aeroplane when it is being fed unreliable information. The protections are also abandoned because they too rely on this information. What's the difference then between the autopilot flying and the pilot flying when both will receive the same limited, reduced and unreliable information? Because the pilot is human and hopefully has the ability to recognise and reason out the solution based on the evidence available. First and foremost he must take control and fly the aeroplane.

If you bother to read the other interim reports produced by the BEA then you will know that the very many previous occurrences of this issue have resulted in the same symptoms and an almost immediate stall warning occurring. Partly due to the abrupt change in measurements (pressure) and also due to the turbulence that was encountered.

The margins that an airliner flies within at 35000' are pretty small and a pitch attitude of 10 degrees nose up would never be seen in normal everyday operations at this altitude.

[sekant]

"NOD's reference to Air China upset(and others) is not so open-minded and unbiased if hes attempting to use it to compare the two designs.The Air China upset was a clear case of pilot error.The culprit was the pilot.We dont know yet to what extent(if any) system design played a part in 447.The jury is out.The BEA is that jury and it will be interesting to see if they can remain totally impartial and unbiased.I doubt it but lets wait and see. "

So, let me guess. If the BEA faults the plane, you will judge that it remained impartial. But if it faults the pilot, it is clearly because it is biaised.

I mean it is so transparent from your posts that you are the biaised party that is starting from a preconceived position. In other words, if Boeing crash, always a pilot error. If airbus, the suggestion of pilot error should be discounted. If BEA goes into another direction it is because it is biaised to protect French interests. For its part, US authorities are always totally unbiaised and never whithewash Boeing (here, allow to laugh for a good five minutes.).

[sd666]

Quit the Airbus bashing, puhlease.

OK. So this thread again degenerates into Airbus bashing. No surprise there then.

Let's just step back a minute and consider the frequent calls to ditch all that fancy automation and put full authority back into the hands of a human pilot.

Consider what the objective of the Airbus laws are - from first principals.

They allow a pilot to control the aircraft with maximum performance when the muck hits the fan. Prevent a stall, keep the aircraft flying, even on the brink of maximum AoA. Prevent overloading the airframe. Prevent overspeed. If you are faced with looming CFIT, pull back, all the way, and the Airbus will deliver maximum performance to avoid it.

Case in point: The Hudson river incident. The media loves a hero pilot, but by rights they should have been equally applauding a bunch of anonymous engineers in France. Because they are just as responsible for delivering a 100% survivable ditching as the men in the cockpit. The reason everyone walked (floated?) away from that incident was because of excellent CRM, a very good call by Sully (He activated the APU which kept the aircraft in Normal Law) and Airbus' Alpha protections.

So what's the downside? We'll I'm not a pilot - I'm an experienced Control Engineer - servo systems, process control, you name it - the kind of safety critical systems you find in an Airbus are found everywhere from a Nuclear power station to your Toyota Prius. If you ever crash you car into a power pole and bring down the high voltage lines, there's a good chance that my own software kept you from being fried. Even electric wheelchairs can kill you - should one suddenly propel you off the curb and into traffic. For fun I work out Laplace Transforms.

The problem with all safety critical systems is that you want them to fail-safe. And, when you consider protections and they priorities, you need to start off with a bit of FMECA analysis. The trouble is that some systems cannot fail-safe - you have to compromise by "failing-as-safe-as-you-can"

Another case in point, related to a relatively simple system I developed: You're a skydiver. Your reserve canopy has a microcontroller AAD (Automatic Activation Device). It has one simple objective. If you are going to hit the ground, and haven't deployed your main canopy, or for some other reason, it has not deployed correctly - the AAD will deploy the reserve canopy for you. But while you're freefalling, the AAD self-tests and detects a fault. So what should it do while you fall at 120mph directly toward the ground? What's the *safest* thing for it to do? I'll leave it open for you. But it's not as simple as you think.

Back to Airbus. The downside of an automatic protection system is that it adds a layer of complexity to debug if it fails. Though Airbus' fallbacks are well designed - this is going to mean you have a tougher task to manage when there is a fault. This means Airbus Pilots have to be smart.

But given the huge safety benefits of their automated protections, the answer is not to remove them - the answer is to improve their robustness, refine their fallback modes and ensure that failure conditions are adequately trained and simulated.

To round off in line with my argument about protections and in a roundabout way come back on topic: I don't understand why Air France didn't purchase BUSS (Back Up Speed Scale) - designed specifically for loss of speed data incidents.

[Man Flex]

I don't understand why Air France didn't purchase BUSS (Back Up Speed Scale) - designed specifically for loss of speed data incidents.

Because it wasn't developed until after this accident.

[jcjeant]

Hi,

Because it wasn't developed until after this accident.

Ohhh .. this is completely wrong statement.
Why do you post such disinformation ? ignorance I hope ....
Was already available during the 90

[Man Flex]

Was never a mod on the airbus until recently.

[bearfoil]

For this aircraft, both BUSS and steam AHI were available. Air France did not select either. This was established in the original thread, as I recall.

[KBPsen]

Originally Posted by jcjeant

Why do you post such disinformation ? ignorance I hope ....

You should acquaint yourself with the difference between disinformation and misinformation.

BUSS have certain limitations that makes it questionable whether it adds anything safety wise.

[jcjeant]

Hi,

Google Vertaling

This press article from l'Express had not yet triggered any official reactions or any reactions in the other medias.
It is to notice that the author of this article is Christophe Barbier
This journalist is well know journalist and chief editor and he is exposed everydays ...
I would be astonished if what he write is false.

[Lonewolf_50]

jc, that article doesn't do much to unlock the mystery of why, all it does is report that a finger has been pointed.

Not a very productive link.

[Rananim]

So, let me guess. If the BEA faults the plane, you will judge that it remained impartial. But if it faults the pilot, it is clearly because it is biaised.

It is my strong suspicion(based on what we know) that a good air accident authority would fault both plane and pilot in this case.It is also my strong suspicion that only fault will be found with the pilots.They can quite legitimately use the old excuse "the pilot did not know/understand the aircraft".

Sekant,
Im never politcial when it comes to flying believe me.Frankly,I dont care where the plane's built.I write from one perspective only;that of a pilot.Did this aircraft through its design confuse/obstruct the pilot in any way,shape or form?

[Lonewolf_50]

Rananim:

It is my strong suspicion(based on what we know) that a good air accident authority would fault both plane and pilot in this case.

It is also my strong suspicion that only fault will be found with the pilots. They can quite legitimately use the old excuse "the pilot did not know/understand the aircraft".

In that last sentence lies a large body of investigation that either will or won't get answered: why?

You are I am sure aware of the following, but FWIW as this forum has lots of non pilot readers ...

A good accident authority ought to uncover systemic factors (training, culture, SOP, scheduling, maintenance, equipment, etcetera), and other contributing factors that help align the holes leading to the human factors you point to. Man-machine interface ain't out of the woods yet ...

The subtlety of some of those factors is lost on the public. In the rush to get to court and settle via money, when "blame fixing" trumps pursuit of detailed causes and remedies for accidents, the public noise may drown out the voices speaking of "problem(s) -> solutions(s)" ... with the risk that the right ears won't hear and decide upon which to implement.

If the root causes are not both identified and addressed, something like this will happen again. A question we learned to ask when I contributed to mishap investigations:
were they set up to fail?
If so, how?

[jcjeant]

Hi,

As far we can see that accidents are not all treated the same way or with the same rigor ...
We have very recently the Falcon 7X after a malfunction (do not know why) is immediately banned from flying before any investigation start
Note that this incident did not cause any casualties
On the other hand we have AF447 ... which has claimed many victims.
After initial analysis of black boxes .. BEA announces that do not know what happened and the investigation continues ...
So long as the BEA does not know (and it is not even able to show that the plane is not faulty by design or management system) that aircraft presents a potential risk that must be assessed
Why grounded the Falcons .. and why let fly the A330
Both aircraft are not recently commissioned .. and both had so far proven reliability.
I see nothing about from EASA
Where is the logic?

[Jig Peter]

@ Lonewolf

I'd be very surprised indeed if the BEA's final report doesn't cover all the points you mention, as would the authorities in your country. It's a major, and respected, authority, fully conscious of its responsibilities (and incidental pressures that might be brought to bear).

PS @ jcjeant: Couild be, in the Falcon case, that a "whoopsie" came to light in the "first look" that people "in the loop" always make, without necessarily waiting for an official investigation to start. In my military flying days, I remember one or two cases where safety of crews demanded urgent and immediate action - not saying that this was the case with the Falcon, of course - I just wouldn't know.

[Lonewolf_50]

Jig Peter, I'd be surprised (and disappointed) as well if it turns out that way when the final report is released.

What is worrisome from the outside, (which is as true of mishaps in our country as anywhere, see the wake stirred up by Colgon Air accident) is my last concern: which cause factors will be actioned, and which paid lip service? (Ref: Sully's testimony in Congress ...)

That worry crosses all borders.

[Jig Peter]

Lonewolf - That's often the case, sadly. Depends, I suppose, on what seemed relevant at the time the report was drafted, though I agree that Colgon (and possibly AF447?) showed up some training (or understanding of training?) "loopholes". We shall see ...

[jcjeant]

Hi,

PS @ jcjeant: Couild be, in the Falcon case, that a "whoopsie" came to light in the "first look" that people "in the loop" always make, without necessarily waiting for an official investigation to start. In my military flying days, I remember one or two cases where safety of crews demanded urgent and immediate action - not saying that this was the case with the Falcon, of course - I just wouldn't know.

It's also a precedent:
The Concorde was forbidden to fly for sometime (after a first accident with casualties) and long before the investigation was finished ....
As I asked before .. where is the logic ?

[simon001]

Straight and Level?

I have been following this thread on and off for a while. I see contributors range from non pilots to pilots with many years in the accident airplane type.

I am a pilot myself, although only SEL, but I did shoot a message to a friend of mine, a pilot for Virgin. He is not familiar with what happened to the pitot(s), what the autopilot commanded or what the pilots did, so no flaming please on his questions because he does not have all the facts that we now know. His question is more on a basic level of the loss of control and whether the pilot may have been able to regain control by 'conventional' techniques. He has 737 experience but no Airbus experience. I guess we are both wondering whether the the answers to his questions have something to do with the interaction between Airbus systems and the pilot.

So, hopefully someone with Airbus experience can respond. Here goes. Thx.

"Is it difficult to disengage the autopilot, disengage the autothrottle, level the wings and nose in an airbus? This technique used for unreliable airspeed indications and turbulent weather penetration. There is an attitude and a power setting for every phase of flight, airspeed and vertical speed being secondary indications in a way. The difficult thing for me to understand is why didn't they just disengage the autopilot as soon as the nose started pitching up? And a jet will descend at a safe speed with the thrust off at 2.5 to 3 degrees nose down. I guess we'll learn all about it in CRM next time."

[flydive1]

As far we can see that accidents are not all treated the same way or with the same rigor ...
We have very recently the Falcon 7X after a malfunction (do not know why) is immediately banned from flying before any investigation start
Note that this incident did not cause any casualties
On the other hand we have AF447 ... which has claimed many victims.
After initial analysis of black boxes .. BEA announces that do not know what happened and the investigation continues ...
So long as the BEA does not know (and it is not even able to show that the plane is not faulty by design or management system) that aircraft presents a potential risk that must be assessed
Why grounded the Falcons .. and why let fly the A330
Both aircraft are not recently commissioned .. and both had so far proven reliability.
I see nothing about from EASA
Where is the logic?

Dassault decided to ground the 7x, they then asked EASA and FAA to issue the AD

[Me Myself]

Good God mate, you are a test to one's patience.
Bear with me :

1/ pitot probes freeze. Speed doesn't make any sense to autopilot, consequently autopilot goes KABOOM !
Aircraft goes into alternate mode. No big deal. Just a few protections lost....like stall. Errrrrr ! Trim is still functionning though. You have basically your normal A300 only with fly by wire, but the logic is the same. Pull makes you climb and push.....well, you guessed.
2/ in any airline, trained pilot keeps pitch and thrust AS THEY WERE ! The damn thing was flying a second ago, why on earth shouldn't it fly a second later, speed or no speed indication !
3/ pilot for reasons the majority doesn't want to picture and will therefore hzve its nose rubbed in, pulls nose up. 7000 ft / min at FL 350 ! Some kind of pull ! 10 deg pitch ! Plane bleeds off all its speed and STALLS. by that time, still functionning trim has done its job.......it's trimed the aircraft since somebody was pulling !
4/ by that time, speed is back and shows an horrific 215 kt.....pilot pulls some more adding full thrust making things a lot worse than they already were.
5/ the rest is a long 3 minutes ending by a just horrifying death for 228 people if anyone cares.
Don't tell me they didn't feel anything ! 40 deg bank angle, 11 000 ft / min, some kind of smooth ride !
6/ according to rumours coming from Airbus, once stalled and the fuselage hiding the stab, it was too late.
I heard of some stunt which would have consisted of shutting the engines down, pitch down, relight......blablabla.
The trick was not to let it stall in the first place.
As to the skipper whose rest timing was well.......who could make a sense of the mess he had to face getting out of the bunk almost in his undies ?
Why isn't the french press full of this article when the rest of the world is ? Cuz the french press is a joke whose mission is to report what they're told to report exept maybe for Christophe Barbier. But then......who told him to leak this ?



Finally, this speed BUSS thing that was already in service in other airlines, like LH, is not reliable or very reliable above 25 000 ft, so says the rumour.