rudderrudderrat

Hi BOAC,
Very true. But throw in the lowest circadian body clock time & no natural horizon. The simultaneous loss of 3 air speeds, and an apparent Altimeter drop of 400ft (due loss of Mach correction). Now which instrument is still telling the truth?

Lyman

From 2:10:08 until impact the a/c was in AL2b. (BEA)
...perhaps sooner, but it was annunciated at :08. And even then, crew did not know which AL....

AL2b latches when none of three ADRs is available.
.....which was immediate, and the reason the THS stopped moving

At no time was a/s available to the crew, from 2:10:08 on.... By definition.
...There was no way for them to get whether subsequent speeds were valid. It took the DFDR to explain it, after they were dead.

Whether or not the a/s was demonstrably "accurate" at any time, the pilots could not have known, by definition.

The THS is inhibited when 3ADRs are unavailable, by design...
.....after it started up again, was the LAW changed? The Protections? The DFDR showed it hadn't. Again, after they were dead.

Yet the THS was moving prior to STALL... Whether the crew knew it was moving or not, they had no reason to want to stop it.

By definition, the a/c was demonstrably in the incorrect flight control LAW when the THS was moving... If it moves, Alpha prot must be available, according to Flight Law. So why stop it? Protection applies.

I was taught never to maneuver with trim, trim is trim, not a flight control....

As the aircraft was dissipating energy rapidly, the THS was not trimming, it was flying the aircraft...Once STALLED, the airstream never allowed valid speeds?

So if the ADRs are never available, the crew have no airspeed, ever, by definition. It is unlikely this was trained, 330 pilots here were unfamiliar with 2b.

At times in the critical path, airspeed was "valid" (BEA).
......excellent, how was the crew to know?

NO, it was not valid, not in any useful way. "vitesse feu".

next, Flight Directors....

The FDs were not turned off, nor was A/P, shouldn't this be part of automatic disconnect, along with Thrust? If leaving them active prevents autoflight, how does leaving them on, help recovery? Especilly when they return intermittently, to resume random modes?

CONF iture

I’m operating the A-330 … but I’m not airfrance.
That’s the Airbus responsibility and duty to publish such stuff.
An OEB has a DIRECT entry in our QRH.
What is an info OSV in the middle of the box letter of an AF pilot …

HazelNuts39

Well, if the info OSV was still in their letter box, and they never got the QRH out, ...

gums

Gotta admit it, but Lyman has a point:

As many of we human factor folks and at least one experienced FBW pilot from over 30 years ago ( yep, 30+ steenkeeng years), there is no substitute for a clear, straightforward reversion sequence for the flight control system and same for the displays that the "monitors" seem to use all the time nowadays.

So I give Airbus a "D minus" in that regard. Training and attention to the previous airspeed problems is a whole other topic, and seemed to be ignored by the company/ Air France. I cannot forgive them.

bubbers44

I agree with what you are saying gums.

If the PF had done his part with the UAS immediate actions he would have verified AT off AP off and FD off, pitch 5 degrees and climb power. They didn't do that so crashed.

Not everything was AB's fault and training inadequacy's, a great deal was due to pilots not doing their job after thousands of hours experience.

Lyman

There was no UAS SOP, none. Every incident was a fresh abnormal, subject to the unquantifiable readiness of the AF crews to instantly interpret what was happening, and deal with no airspeeds, until the Controls Law changed, which it never did.

Straightforward does not mean simplistic, and STALL training should never have become an issue. STALL TRAINING? At the flight levels?

you have got to be kidding.

It was not UAS at the time, it did not have the familiarity it attained on this epic website.

ALTERNATE did not appear until the fourth screen, and the descriptions given here by professionals are not necessarilt the waynit was. Everything in the reort is an interpretation, subject to after the fact pause, and weighing this against that, including politics, and personalities.

The Pilots are quite naturally at the center, and it is exquisitely frustrating to see the slow and measured sculpture of a new urban myth.

NO ONE knows what the screens showed, and that is why the regulators now require CVVR format in future.

If there were usable honest cues on the panel, do you think they would have said nothing about the Attitude until GPWS?

These crew had a dozen seconds or so to get it right, up to the point the cueing got unsussable, imo.....

NeoFit

bubbers44 wrote:
IF... !

But we do know, with more than 36 UAS events, that it seems difficult to recognize such an event (Thread 7 #1321) :
It seems to me that we must go to "Machine-Man Interface" Thread, rather than "HF" Thr.



Lyman
But we have some idea:

- PF Erroneous airspeed display between 02:10:07 and 02:11:37 (Final, page 93), PNF between 02:10:07 and 02:10:37

- Fantastic FD pitch orders till 02:11:40 AND stall warrning since 02:10:51 (Final, p 96)

- FD1 + FD2 mostly not available between 02:10:08 and 02:10:47,
and disapeared again at 02:11:40 (IR 3 CVR transcript and Final report)
We know(?) that PF was following FD and pulling up (Final, p 96).
But why NU SS inputs after 02:11:40 ?

- CAS/ISIS CAS out of duty (NCD) beginning 02:12:14 (and computerized again btw 02:13:00 and 02:13:24 (IR 3 CVR transcript),

- Invalid AOA beginning at 02:11:40.

And plenty of "may be", "perhaps" in Final report.

Lyman

Hi NeoFit, nice to see you.

Take a closer look at your excellent review of DFDR determined data. Those data cannot be assumed to have been displayed!

Especially not AoA....

Let me introduce something from what is on another thread. Having to do with displays, let's look at what the pilots were experiencing in the cockpit on the way down. The PITCH was consistently around 16 degrees, the a/c was falling at about 1g, and the airstream is assumed to have been LOUD.

Cover the panel with a tarp, and put hoods on the pilots. No cues, save kinesthetic. The pilot, standing, is on his feet on a 1g floor at an angle of 16 degrees, quite uphill. The pilots, both seated, sense the angle of the a/c in their back and buttocks, also 16 degrees uphill. This continues for two minutes.

And none of these experienced airmen are aware of the deck angle? Of course they knew their Pitch was unacceptably high. No Comment, at all? They ignored it?

To believe the BEA report is to believe in the Mad Hatter, and Rumplestiltzkin

And they had VSI to corroborate their kinesthetics! And Instruments! But, dumbfounded, they descended to their death, unaware of their condition?

nonsense.

NeoFit

Hello

Regrettably!

CONF iture

The proposed OEB here is not to be visited when things happen - Too late for that - It is to be known - It is to be prepared.
On the 4 red OEB I have in my QRH right now, 2 are of that type.

30 known events of UAS in cruise prior AF447 - I feel cheated Airbus kept me in the dark.
Today the average pilot I am is certainly more prepared, not because Airbus informed me, but because AF447 happened ... What a shame !

Clandestino

Impossible. Somatogravic illusion means longitudinal acceleration or decelaration gets interpreted as pitch-up or pitch-down. AF447 was flying steadily when CM2 pulled first time and subsequent deceleration was not very quick anyway, mushing around 0.05 and peaking at 0.1G prior to stall (annex3, page 6)

By the time the aeroplane stalled, each and every instrument in the cockpit was telling the truth.

While the UAS was going on, there was no indication any inertial reference was not available or any display unit failed, so with three attitude displays agreeing, it wasn't supposed to be difficult to fly the attitude.

They knew it was inaccurate. They said it so and then it is not overly difficult to deduce if your speed indication as dropped below minimum needed for sustained flight and you are still flying pretty normally, then the indication must be false.

Fact that in every manual, I've used, from C-150 to A320, trim is listed under flight controls. There are proper ways to use it, blanket "don't use it to manouever" just isn't one. It might be applicable for turning the Cessna 172, though.

70 kt indicated (appx 118 true) over a minute.

As commanded by the pilot. Per design. Certified. Proven.

True, but reversion sequence on FBW Airbi is totally straightforward. No matter what law you are in, as long as you have flight controls continuity and are within envelope's lift limit, behaviour of the aeroplane is strictly conventional, nose & wings follow the stick displacement. Now there's another clue you have stalled; if you can't rise the nose with nose-up input or full stick in roll can't help you pick up the wing. Sadly, crew missed even that.

Based on PPRuNe hearsay.

Report explicitly says otherwise.

AF crews did experience UAS before AF447. Their control laws did degrade to alternate. They survived. What's your point, again?

Who cares! As long as proper control of the aeroplane is not achieved, no ECAM actions are to be done! If crew just did nothing aeroplane would have continued to fly of its own accord, it would not have not gone anywhere near the parameters that would trigger the normal law protections. Unfortunately, picture is messed up in the English version but French report, page 96 refers.

OTOH, constantly reproducing the old one about the-guy-whose-name-I-forgot being serious when mentioned that concierges can fly an Airbus is not even funny anymore.

Display units integrity is monitored for the benefit DFDR. Guess what fault was recorded. Yup, none. Anyway, roll disturbance was quickly stopped by CM2, proving he was looking at the functioning attitude display. Also there were references to altimeters recorded on CVR.

They said something about the altitude well before GPWS.

This crew would be far better off with going-into-fear-induced-stupor option than with what they did. Tragic part is that CM2 believed he was saving himself and everyone else on board with his actions, while they were what killed them.

Well, IAS shows 274 kts one moment and 52 kt next. What could it be? Hitting the anti-gravity field, therefore remaining airborne at speed well below Vs1g?

There were crews that didn't recognize UAS. They did nothing. So survived.

It was not. Are DFDR traces really so difficult to read?

Believing kinesthetic cues is certain to get one killed when flying in IMC. Proven again and again.

Weirder things can happen when one is scared mindless.

Would you be so kind to provide us with plausible alternative?

NeoFit

Lyman, I am so sorry, but I don’t agree with your #590 add-on.

I wonder if we have read the same other thread!
I need to read it again because I had understood all the opposite of what you wrote.
.

Pitch is not relevant
Liners Pilots are not flying with their pants since a long time, and furthermore, they have order to distrust their sensations (which are often erroneous). The internal ears (semi-circular canals) are not precision gyroscopes.
Watch instruments!

The fall of about 1g
does not seem to me an appropriate remark, because we are only perceiving the speed variations, thus only accelerations change ( positive or negative). 1 g is the earth acceleration, nothing abnormal !!
That to say, when speed is constant, you can’t feel it, flying at FL350 with G/S 550 kt or stalling with V/S 160 kt.

the airstream is assumed to have been LOUD
Yes, of course: “j’ai l’impression” … “crazy speed”


As you wrote previously: “NO ONE knows what the screens showed ...”

Lyman

Clandestino:

"By the time the aeroplane stalled, each and every instrument in the cockpit was telling the truth."

Possibly, maybe probably. And the crew were to know this exactly....HOW?

Oh, that's right, the large green bulb, center panel:

"We're valid now, trust me!!"

as if.......


Clandestino:
Quote:
Originally Posted by Lyman
"If there were usable honest cues on the panel, do you think they would have said nothing about the Attitude until GPWS?"

You say:
"They said something about the altitude well before GPWS."

I referenced Attitude, something they never mentioned, and I find that bizarre.



NeoFit:

Quote: Quoting Me....
… what the pilots were experiencing in the cockpit on the way down.
The PITCH was consistently around 16 degrees,
the a/c was falling at about 1g,
and the airstream is assumed to have been LOUD."


After "stabilised" in final descent. Yet they do not reference attitude (NU), only altitude. This to me means they actually did, and the CVR is not released with this data. I simply cannot fathom no mention of PITCH, they have no AoA, and PITCH is all they have to start with, in any recovery. Altitude is fascinating, and informative, but a SYMPTOM, not the CAUSE. How can they have been silent, hint, they were not.....



Clandestino, HERE:

Quote:
Originally Posted by Lyman
NO ONE knows what the screens showed.....

YOU SAY:
Display units integrity is monitored for the benefit DFDR. Guess what fault was recorded. Yup, none. Anyway, roll disturbance was quickly stopped by CM2, proving he was looking at the functioning attitude display. Also there were references to altimeters recorded on CVR.

I am not talking FAULT, you misunderstand. And what the instruments display is decidedly NOT recorded. Only that they are functioning...... That is obvious, NO?

jcjeant

I disagree ...
Bonin and his co-pilot are telling (to Dubois) that they don't understand what happen and they don't control the plane anymore .. and be sure ...they know what it means !
I don't think someone think he is saving everyone with such arguments !
Actually they hope that Dubois will save everyone (Robert call him frantically) .....

Clandestino

My bad, I misread.

Oh yes, they referenced attitude, just not explicitly pitch. CM1 mentions "Horizon" at 2:12:25 and both CM1 and Captain urge CM1 to "get the wings level" from 2:12:54. First GPWS alert is recorded at 2:14:16.

It seems we have to dumb down this discussion down to non-pilot level. By crosscheck. There are three independent pitots, feeding three independent displays, two of which can be switched to fourth source (ADC3). If they agree at the realistic value, and 183kt after one zoom climbs from cruise altitude is realistic, it works. If they don't, check that all three AIs agree and fly any of them. When I trained for PPL, pitch and power circuits were part of PPL syllabus and it was not fifty years ago, it was in 1996.

What overwhelmed the crew of AF447 is very similar to (and IMHO probably the same thing) that which wiped the crews of KAL 8509 and Birgenair 301 out of existence. First time they were faced with a bit more serious anomaly in flight was when they first really realized that the air is a dangerous place to be and they had no clue how to get out of their predicaments. As was predicted long time ago:

Are you accusing BEA of deliberate falsification?

Of course they weren't but CVR mostly recorded the utterances consistent with being confused and clueless.

They are the instruments that work reliably for thousands of hours and all of a sudden they fail simultaneously, at the exact time airspeed goes unreliable, with bizarre fault that doesn't trigger DU monitoring. Yeah, right. For the record: I wasn't the one that first mentioned "Mad Hatter" in this thread.
How come?

Get the French report, go to page 96. If you are struggling with French: blue line is DFDR readout, red line is produced by simulator fed by winds and control inputs from DFDR. Blue and red are match. Magenta is simulator without any input on the stick.

Do you get it?

They are right; they didn't control the aeroplane anymore because CM2 has chased it away out of control and CM1 did not stop him! Both were pretty clueless from the start of the event.

Airborne equivalent of "Help, daddy, help!". It is tragic that when they realized that flying is no children's play they were left with only minutes to live. Not unprecedented, though.

Lyman

Clandestino..

"Oh yes, they referenced attitude, just not explicitly pitch. CM1 mentions "Horizon" at 2:12:25 and both CM1 and Captain urge CM1 to "get the wings level" from 2:12:54. First GPWS alert is recorded at 2:14:16."

Pitch is all they had to refer to, they had no AoA. Of course it was not wack as AoA, but it was well out of cruise values?

And even AoA was not extreme until after the a/c STALLED....

I appreciate your patience, I stopped flying before you started. 1996?

jcjeant

I agree ....
I admire your honesty and do not use convoluted language to say that these two pilots (maybe three pilots) were qualified to fly an Airbus A330 that only when all goes well
The only thing that could invalidate this constatation would know at least one of these pilots had already in the past saved a aircraft in disarray
Unfortunately it seems that the BEA (human factors) have not investigated it .. or find nothing .. or does not echo in the final report
It is the responsibility of training schools .. the regulator and Air France that is committed

rudderrudderrat

The PF on AF447 attempted to recover the Altitude loss of 400 ft (due loss of mach correction), but for some unexplained reason he continued to pull achieving 7,000ft per min RoC. According to the final report http://www.bea.aero/docspa/2009/f-cp...nexe.03.en.pdf the graph of ground speed shows a reduction from about 500 kts to 400 kts in 30 seconds (between times 02:10and 02:10:30). i.e. about 3 kts per second. Apparently you don't believe that rate of deceleration could cause a somatogravic illusion.

Yet from the incident report of Air Transat Airbus A310-308 C-GPAT (to which you posted the link happless crew), says
1.11.4 “At about 1440:44,” (I think they meant 19:40:44)“ at the end of the climb, the perceived attitude reached greater than 30° whereas the actual attitude was about -3°.” (Due to Somatogravic illusion).

The table in Appendix A shows the aircraft speed and time base.The aircraft accelerated from 0 at 19:39:38 to 209 kts by time 19:40:44 (i.e. 66 secs or about 3.1 kts per second) and produced a somatogravic illusion of 30 degs error in perceived pitch.
The fastest acceleration I can see is between times 19:40:44 at 209 kts and 19:41:29 at 345 kts (VMO) i.e. 136 kts in 45 secs again about 3 kts per second.

Please explain why the crew of C-GPATcould have suffered from Somatogravic illusion with an acceleration of 3 kts per second, but according to you, the crew of AF 447 could not have.
Impossible?

roulishollandais

We needed from BEA a total description of the differents laws ; why, how, rejection, etc. We are here trying to guess details to rebuild analogy.

Why could the BEA not provide that analysis ???

The BEA report (s) does not apply on scientific method (thesis), nor on juridic method. The result is that increases the role of the Court(s) in Aviation. Who wants that ?