OK465;
QRH, Ch.5, "Flight Control Architecture".



http://www.smugmug.com/photos/i-Qjmb...QjmbNFp-X2.jpg

I'm not so sure. There are other explanations, chief among which is the known tendency for pilots to pull back when startled by a warning (including a stall warning) - this was written up in the BEA report on the Orly A300 incident.

Added to this, both F/Os are on the CVR shortly before the start of the accident sequence discussing the fact that they're about as high as they can safely go for the conditions - as such, it's fairly unlikely that the PF would have consciously been pulling up - my personal opinon for all it's worth is that it was an unintentional control input initiated by the startle factor. If the PF believed that the protections would allow them to pitch up and climb safely then the whole conversation about altitude was moot.

The big red X on the speed tape and the disappearance of the Vx indicators should have been a significant clue, no?

I was under the impression that troubleshooting via ECAM was intended for when the aircraft is stable rather than during an attempt to regain control. It's also possible that IAS DISAGREE/ADR FAULT was bumped off the ECAM when the ADR DISAGREE appeared, as OK465 attests to.

The ACARS timings are very vague - the final report contains more accurate timings which I'd imagine came from the DFDR.

Beg your pardon, but that could be a relatively good description of the airliner/transport pilot job, when comparing it to the fighter pilot job...:E

Now... hat, coat... ;)

Not necessarily - remember that even the most competent and experienced pilots have made grave mistakes while under duress.

Because it's one of the most difficult situations to reliably work out - as has been stated previously. The fact that the CVR transcript has the PNF reporting no speeds at 02:10:15, despite the NAV ADR DISAGREE message not appearing until past 02:12 implies that at least half the crew on the flight deck were well aware what the problem was. This flatly contradicts any assertion that the systems were not providing the relevant information to the crew.

How many times can one person say "The turbulence was not sufficient to cause AP disconnect" before you believe them?

The conversation about the altitude does not prevent the pilot think he can easily take more altitude .. if it has the protections active ..
If a problem occur (too much altitude) .. protections will act
Why not try ...
Those 4 minutes (yes .. they were startled for 4 minutes ..a long time for experienced pilots .. no ? ) were just ...the game " trying anything and we will see " ...
They just not try one thing ... push .. push forward the stick ....
Again .. the "surprise" effect ... ?

Q. Would it be possible to program a F/CTL IR DISAGREE which should activate DIR LAW and possibly still retain all flight control surfaces ... ?

Then why say that they shouldn't go any higher prior to the problem if he believes the protections will keep them out of trouble?

The zoom climb followed by an ever increasing descent should have been a clue that the protections weren't helping them - at no point until it is too late is the loss of altitude remarked on by the PF. If he was expecting protection, then why did he not remark on the altitude and why did he not remark on the Stall Warning (which should never sound when protections are active)?

It would be unfair to speculate as far as I'm concerned. We do have at least three previous incidents (Stony Creek 727, West Caribbean MD-80 and Birgenair 757) where a stall at altitude led to the pilot in command pulling back all the way to the ground - none of those aircraft had protections.

Is it again something of your own making ?

No - The disappearance of some characteristic speeds is NOT a positive signal of UAS.

No - First a IAS DISAGREE ECAM MSG does not exist and second such message or its equivalence would have been part of the FDR if it had appeared even momentarily.
Also, it is not what OK465 was attesting.

Forget about the ACARS timings then ...

Absolutely not conclusive.

This flatly contradicts nothing.

Actually it came from Hunter58 earlier in the thread:

It doesn't necessarily need to be UAS specifically in order to stabilise the aircraft and then try to troubleshoot.

OK - "IAS DISCREPANCY" then - talk about nitpicking! And has it occurred to you that it may well have been on the DFDR but was not considered relevant given that the PNF reported speeds being unavailable already?

The PNF's reference to losing the speeds is at approx. 02:10:15.

I'm not sure - the DFDR indicates that ground speed was available (and slowing) during that period - approx 02:10:27 (and airspeed returned at approx. 02:10:33). Perhaps he was referring to that?

I just don't see how an argument that the crew were unaware of an air data/speed problem until the ECAM displayed NAV ADR DISAGREE at 02:12:44 can stand up in the face of a clear reference to speed being unavailable at 02:10:15.

Fundamentally I have no problem with a hypothesis whereby there was a technical issue that misled the crew - however if you want that hypothesis taken seriously then you must work forward from the evidence at hand to support your hypothesis. Throwing mud in the form of unsupported assertions because you've already decided that the aircraft and its design must be at fault is unlikely to convince anyone other than those who already share your views.

Several questions regarding the NAV ADR DISAGREE message have been lingering in my mind. The ACARS message was time-stamped 0212 and it was received by the ground station at 02:12:51. The 3rd interim report lets it appear on the ECAM at 02:12:XX and the final report at 02:12:44. What new information permitted the more precise timing?

What caused the message at this point in time? The Air Caraibes memo states the thresholds for rejection of the first ADR as: Altitude 3000 ft during 1 second, Mach 0.05 / 10 s, CAS 16 kt / 10 s, TAS 16 kt / 10 s, AoA 3.6° / 1 s, total pressure 20 hPa / 10 s, static pressure 5 hPa / 1 s. The thresholds for rejection of the two remaining ADRs are the same except that the time is always 1 second.

Then the ECAM message (final report, page 99):

NAV ADR DISAGREE
- AIR SPD ...... X CHECK
- IF NO SPD DISAGREE
-AOA DISCREPANCY
- IF SPD DISAGREE
-ADR CHECK PROC ... APPLY

Isn't it odd that the system asks the crew to find out what caused the system to generate that message? If there is NO SPD DISAGREE, the crew is to suspect AOA DISCREPANCY?

I know this will go 'against the grain' for all those 'affectionados' of total computer control etc, but if my idea of a spring-loaded boxing glove in the panel is discarded, what is really need is a soft, HAL-like message:

"Dave - I'm sorry - I really don't know what is happening here. Would you mind being a pilot for a short time?"

As long as we have 'pilots' at the controls we will then be ok.

This equation has two data ...
One is a constant
"Dave - I'm sorry" :)
The other is a variable
"As long" :uhoh:
Not so sure that the result will always be good :sad:

Hazelnuts39

The computer is trying to determine if the ADR disagree is induced by NAV (sic) Maneuvering? Eg slip/skid, asymmetric, etc.

Of course Dozy, why not blind fully pushing the idea of the big red X on speed tape or losing the speeds or speeds being unavailable or airspeed returned later ?
Hunter58 must be working for the BEA after all … no need to check.

Do you only make the difference between characteristic speeds and speed tapes ?

Unsupported assertions and mud … look in your own garden Dozy.

Not at all. The ECAM fault messages are contained in the "Navigation" category.

Chapter*10.*Navigation

I've yet to see a single person on this thread who's advocating totally automated aircraft.

@CONF - coming from someone who's still convinced that Asseline's stuff-up was the fault of the aircraft I wouldn't be throwing stones. Hunter states something that contradicts your hypothesis, so you automatically assume he must be part of the conspiracy.

UAS early warning
 

Hi,

Quote:

---

Because it's one of the most difficult situations to reliably work out - as has been stated previously.

---

This is feasible, should be done long time ago and the approach used by Airbus SAS showed in the earlier mentioned paper from the Design group is IMHO an ERROR.

To diagnose UAS just by "System output" is DANGEROUS and a good example of K.I.C.S. (*)

The System provided a lot of information including processed garbage. What you need is just FAST and PRECISE information.

A good man-machine interface could provide to 100% of the crew (including Capt) reliable information.


(*) Keep It Complex Stupid

ACARS
 

From page 98 of the final:

From I#1 also:


Beats me?

It was what could be achieved with the technology of the day,

Where do you see evidence of this? I must confess I can't. The idea that conflicting information was presented to the crew is in complete opposition to the recorded and proven reference to missing speed data by the PNF at 02:10:15.

To be fair I'm not the only one who isn't sold on your magic DSP theory.#

Remember that when the Captain returned, the airspeed was back online, so he was facing a different set of problems than the initial situation confronting the F/Os.

For what it's worth I think that the initial UAS problem was quickly overtaken by the concern over the aircraft attitude caused by the PF's control inputs as far as the PNF and Captain were concerned.

I believe the transmit order from the CMC is prioritized, e.g.
F/CTRL
NAV
MAINTENANCE etc..

The ECAM and ACARS sequencing will both vary accordingly, and in the case of ACARS the shuffling shows up when a lot is going on.

Whether or not the a/c was reporting it, we are only sure of the crew's cognizance at 2:10:16. That is eleven seconds to be in the dark as to what is wrong.

Loss of Autopilot does NOT mean fly "PITCH AND POWER". It means fly...

You continue to studiedly ignore what RR and myself, among others, have pointed out, that the a/c was not clearly indicating that UAS was the problem, and that the computers did not necessarily include the crew from the outset of suspected duff speeds.

The reference is to what the a/c displayed, RESULTS of bad data.

Question. If the a/c had ceased displaying IAS from the outset of suspected bad speeds, would not the pilots have had obvious cue of loss of Airspeed (literally)

Displaying any cue that is known to be false is counter to good design, if said cue can be left out.with impunity.

Why waste precious time in a situation that is easily remedied with Pitch and Power?

The fact that pilot started handling the a/c demonstrates his belief it needed handling, period, speeds or not.

CONFiture, i lived in that particular country for five and a half years, and I am more than happy for every day I left it. However, that will not blend over the fact that once the HALs decide they have insufficient info he shows you what he does not understand anymore.

OTOH, Air France by now managed to be the first to wreck any Airbus since the A320, typically by not following procedures. You seem to be French, you should not be suprisd by such culture...

Oh, any anyone who believes Airbus is French has not lived there.

It also means "don't pull up". The correct response was to observe and then correct as necessary.

Even with RR_NDB's DSP algorithm, it would take time to work it out. Whether the system reported UAS or not is not the issue, the issue is and has always been the tendency to pull up when startled

The PNF had a handle on things at approx 02:10:15 though - as I've said before this flatly contradicts the idea that the aircraft was providing confusing information. I don't believe the PF pulled up because he believed in the protections, nor because he was unaware that UAS was the problem - he did it because he freaked out under pressure.

An instant appraisal cannot be done - even RR_NDB's hypothesis would still take a few seconds in order to work reliably. There's nothing to indicate that the PF's pitch inputs were an attempt to regulate airspeed - except for the response to the PNF's "Watch your speed" comment, which could have been taken from groundspeed. At that point, the PF actually briefly put the nose down, but then pulled it up again within a few seconds.

Detecting UAS is difficult, and the Airbus system is more conservative than most, disconnecting AP at the onset of the potential problem. Compare this to the Birgenair B757 where the autopilot continued to try to fly on the bad data.

In this case, it looks like the startle effect took precedence.

But it doesn't mean his belief was correct. The right thing to do was to monitor the aircraft's attitude and correct *only if* the attitude started to creep towards abnormal.

Exactly...and is that 2:12:44 time for ADR DISAGREE an ACARS downlink time, or an ECAM appearance time?

Under what pressure .. that of the the panic?
Panic because the autopilot disengages at cruising altitude?
If this is the case .. it says a lot about the criteria for selection of pilots and particularly on the selection made by AF
BTW it's not only on Air France !


:ok:

Disagree - even top-drawer pilots mess up when taken out of their comfort zone.

Exactly - and "fly" is what they did not do. The question is why.

If we assume that incompetence (never trained how to fly the plane) and negligence (knew now to but failed to) are out, then something caused PF to seek 10-15 degrees pitch up. Your (and RR and others) premise is that lack of precise indication of UAS from the outset is causative, right ?

So... perhaps you could humour this non-pilot and fill in the blanks, because I still don't understand how you get from:

- A/P has gone off, I have control
- Plane needs handling
- Plane hasn't told my WHY A/P dropped out

to...

- I need to pull up 10 degrees in cruise (even though that would normally be a crazy thing to do)


The only thing I can think of is airspeed indicated erroneously high (very high) - but that didn't happen, it went erroneously low.

So, what was it ? What piece of garbage information presented to the crew could have lead to that response ?

:confused:

Autopilot is now the comfort zone of pilots :confused: ... :uhoh:

infrequentflyer789
How you can assume this is out ? .. on what basis ?
Remember ... Bonin ask (or dunno) what is St Elmo fire ... :E
Even a uneducated poor fisherman know what is St Elmo fire .....

infrequentflyer789

Hello. "And fly is what they did not do..."

The autopilot was actively maneuvering until it quit, at handoff the a/c was rolling 4 degrees per second to the right, the nose was low, and they had exited moderate turbulence in conditions that I submit were more of a challenge than they were acknowledging, at least to each other, if not to themselves. If Bonin had not arrested roll, they would have been banked fourty five degrees when Robert said "So, we've lost the speeds..." eleven seconds later. In the eleven seconds I submit Bonin was unaware of UAS, his Pitch was not "full back" in fact it included several ND excursions.

Much has been made of "Do nothing". Not possible, given the conditions. Once Bonin got responses in Pitch (Was it sluggish? "Beware unusual control responses") he could easily have lost his sense of attitude. He was always the one flying, and his Panel was not recorded. What did he see and what was he using for references for his inputs? I don't know. At one point, PNF "Put him in ATT/HDG."?

Had he been using IAS? For the longest time I have defended this pilot, and I will not stop, though I do have to admit some strange examples of "pilotage" have shown up in other accidents (Colgan) (Schiphol) (Caraibes) and incidents.

Without a complete disclosure of the CVR it is impossible to know exactly what happened in the initial 20 seconds, the phase when the die was cast. I think that is deplorable...

My recent post addressed the fact that erroneous Airspeed was displayed. I consider that unfortunate, yet Dozy says it is unavoidable.

If IAS can be lost temporarily without risk, dump it until it can be verified. Given the state of the industry and the apparent lack of readiness to fly manual at altitude, nothing should be left to chance.

It is the ECAM appearance time of NAV ADR DISAGREE, and the ACARS received time was 2:12:51. Allowing 4 secs for the up/downlink, that would give 3 secs processing between CMC and ACARS. The previous message via ACARS was received at 2:12:16, which indicates the ACARS system was probably clear.

Which out of sequence message(s) do you think the report is referring to, if any at all?

Dozy, talkin out your backside again, are ye?
You make an overly broad assertion, which is far more accurately stated as:

Some high performing pilots (call them set A) make errors when taken out of their comfort zone.

Others don't. Why? They adapt to unexpected changes in their environment better than the set A pilots do. Why? No short answer. If you could bottle it, you'd make your fortune many times over.

Have seen this through personal observation over and over again.

Temp Temper Temperament. Better to bottle "cool under Pressure".

It is in the Amygdala.

As usual, when out of argument, you're back to Habsheim with a deformed analysis which is supposed to be mine.
Educate yourself on my view once for all - It's here.

Hunter58, as the instigator of the Big red X over the speed scale early in the sequence at AP disconnect, here and here, would you give a hand to Dozy who put his trust in you to locate such reference in the BEA reports ?

Startled ?
 

I cannot know whether this was the case :
IF PF had seldom ( if ever) manually flown an A330 - except premeditatedly for a very few minutes after T/O and again, just prior to Landing, both of these at low level, it would be natural for him to be startled.
The Drill for UAS (then) empathised Terrain clearance.

On earlier, less sophisticated aircraft, I soon learned to hand fly through Cbs, IFR and at night, before radar was available. St. Elmo's Fire and lightening strikes occurred. And my knees got wet because the windscreen leaked until a blanket was made available ! I logged my first 250 hours of hand flying, sometimes doing a couple of 3 hours sessions in a day, alternating with the Captain. ( My quality did deteriorate - but there were no flight time limitations, then.)

CONFiture

The BEA does not loose a single word on the representation of the speed tapes. If mentiones mesured speeds only, and focuses on the representation of the ECAM messages. There is no reference on whether there was a visual clue of the rejection of data via a cross (as it should be in that case) or not (which could be interpreted as erroneous data).

Obviously this factor was not worth a detailed description, which I believe is not a good call as there would be no discussion about it. However, since the speed values seem to have been rejected, this would have triggered the cross.



I am sure you can clarify this to our satisfaction, or would it trouble your picture of the supposedly corruptive power of a certain aircraft manufacturer too much? However, since you seem to at least have been in France once you should remember that such power would be extremely limited as every little local politician with ambitions would try to grab national attention by disclosing whatever information he has available. There are no secrets in 'La Grande Nation', the are simply too may elements ready to disclose them for their own short term publicitary benefit...

Hunter, I inferred, perhaps incorrectly, that the pilot's remark "we have lost the speeds" was a response to an indication failure of his airspeed indicator, which I presume, also perhaps incorrectly, would be something like an "off flag" or "red X" or other marked change in presentation.

It may have seemed far too obvious a detail for the BEA to dwell on?

If I am off the mark here, please advise.

Maybe time for you and Dozy to pay another visit to the BEA report as there is a paragraph named Analysis of the airspeed displayed on the PFD’s and ISIS.
The SPD flag (There is no such thing as a big red X) which replaces the speed scale, was not displayed before 02:11:40

Personnaly I think Dozy is one of the smart guys in this group. I think he believes as I do that it doesn't matter what aircraft you fly, if the IAS goes away just fly attitude and power. That is what the autopilot was doing until it disconnected so why change anything. I don't care if Airbus says go to climb power and 5 degrees up in their situation, they didn't even do that, they pulled up to over 15 degrees for no reason and the PNF let him. Bad. Do we need the old timers to come back and teach them?

300 hr pilots flying on autopilot for a thousand hours are not real pilots. They cause crashes like this because they can not hand fly and trust automation to bail them out. When automation fails they are lost. AF proves it.

If the autopilot didn't have adequate info to fly the airplane, what makes you think the pilot had any better?

It's easy to second guess from the rocking chair.

I would have second guessed from my MD80, but now I fly an Airbus and there but for the grace of God go I.