rudderrudderrat

@ Clandestino,

Post #477
"From the CVR report:
02.06.54 the crew say "Minus forty-two we won’t use the anti ice that’s a plus."

There are very few TAT recordings reported.
However, please see the report published in July11, page 86.
Time 0hr.09min FL. 349.92 Static temperature (°C) -43.5
Time 2hr.10 FL 350.44 SAT -38.8"
@ 02.06.54 the crew observe the SAT as -42°C
@ 02.10.00 (Interim report July11 page 86) SAT -38.8
By my maths, I make that 3 minutes and 6 seconds,
How do you make it two hours?

Edit.
The aircraft had 45° angle of attack.
Even if the nose was lowered by 25° I still make that 20° angle of attack.
Do you still think that that "aerodynamics were not enough to keep AF447 stalled"?

slats11

Thanks for these times Rudder. So using these data points, TAT was increasing at the rate of 1 degree per minute. Similar to the rate of increase with routine descent. You would expect the climate control to cope with this without the cockpit becoming uncomfortably warm.

So why did PF note at 2.08.47 that "You can feel already that it’s a lot hotter"

And why did PNF agree at 2.09.20 that "It’s amazing how hot it is all of a sudden"

It certainly doesn't sound normal or routine.

In fact, the increased temp is pretty much the last thing that PF and PNF ever agreed on.

mm43

I agree with you on their comments, but when viewing the FDR printout it is difficult to detect the change as the graphics have insufficient resolution. One possibility is not so much the temperature, but a sharp rise in the relative humidity which would have created the same feeling.

philip2412

captain.
Ithink that pnf was hesitating to take over brcause he was not assigned pilot flying.and it feels like there had been personal issues that bonin was pf.Maybe we should no more about the personality of the captain.pnf had quite a lot experience,so why was he so eager that the captain comes back,instead of taking command and doing the right thing.

AlphaZuluRomeo

Hi gums,

Would you be so kind as to elaborate on the bolded sentences? Source and so on?

Why do I ask? Two things:
- AFAIK, stick free the aircraft holds its path, not "1 g". It may be that the path gives 1g (often it is!) but the law is "g demand" (i.e. stick not free) not "g holding".
- I was unable to find any credible document indicating that the stick free longitudinal behavior is different in Alternate law versus Normal law.

Thanks in advance


Hi rudderrudderrat,
The aerodynamics alone: you don't know. What you may notice is that the THS & elevators, commanding nose up, might have slightly influenced clean aerodynamics at that point.
What you don't know is what AoA will have been reached with thrust idle + stick full nose down and maintained there as long as needed (meaning eventually the elevators and THS would have winded down).
It can't be proven until test flights take place, and we all know there won't be such tests and why. OTOH, all indications so far show the nose would have gone down, down down, and the AoA would have followed.
Therefore I too do think that aerodynamics were not enough to keep AF447 stalled, and that this PoV ('locked in stall') is irrelevant. And it also may be used to used to divert attention BTW (this is not for you, rudderrudderrat, I'm thinking about organisations that have an agenda, out there).

Cheers.

HazelNuts39

I wonder whether the heat exchangers in the air conditioning packs could be obstructed by ice particles.

HazelNuts39

FCOM 1.27.30 Reconfiguration control laws: As I read this, alternate law pitch control is not identical to normal law.

Lyman

EMIT:

"What she said is duly noted in the CVR transcription
(at times as noted by previous posters)

allo?

oui

allo?

Then no word, but a sound similar to one putting the phone back in the cradle

(word or group of words with no relevance to the conduct of the flight)?

Then no words but a sound similar to the ending of the cabin interphone communication

Needless to say that the pilots were to busy to pick up the phone."


If the pilots did not pick up their phone, how did she end up on the Cockpit voice recorder?

woodja51

"All the rest is academic , a bunch of folks died due to failure to fly the aircraft " that appears to be the case. However, failure to fly the a/c is a huge topic. Can you include some other evidence?

woodja51

Lots of talk about lots of stuff... Facts:

Unreliable airspeed , if aircraft flight Jeopardised , ap at fd off. No more no less

Then

Stall recovery( if you put it there)...


Lower attitude

End of event.

Simple , problem solved no crash no dead people.

All the rest is academic , a bunch of folks died due to failure to fly the aircraft

And transit a temporary anomaly.

I sympathise with the loss of life , but the race to the bottom in flight training must be to blame at the core of this and is due to airline, manufacturers race to the lowest flight training cost base possible to meet min regs only.

It will only get worse with MPL.....but that is the future.

philip2412

There`s one fact in this whole scenario,which is for me the most unbelievable part in the crew-captain relation.
we have 2 pilots in todays standard with a lot of experience(doing away for a moment the AF defiences in training we all konw about) flying ong haul for years no city hoppers.they were clueless,desperate,no solutions to solve their problems ,both (?) eagerly awaiting the captains return for relief.
And when that moment arrived the cpt back n cp they both are not able to give a professional briefing,the last opportunity maybe to save their lifes.What di they expect from him ? guessing ?
Can somebody pls explain that ? This can`t be explained by their mental state only.

Lyman

I honestly think the actual cause for this accident is at hand. This thread has been three years analyzing incomplete and possibly inaccurate, if not fraudulent data. Stand by.

"There`s one fact in this whole scenario,which is for me the most unbelievable part in the crew-captain relation.
we have 2 pilots in todays standard with a lot of experience(doing away for a moment the AF defiences in training we all konw about) flying ong haul for years no city hoppers.they were clueless,desperate,no solutions to solve their problems ,both (?) eagerly awaiting the captains return for relief.
And when that moment arrived the cpt back n cp they both are not able to give a professional briefing,the last opportunity maybe to save their lifes.What di they expect from him ? guessing ?
Can somebody pls explain that ? This can`t be explained by their mental state only."

More than one fact. For three years this crew has been allowed to seem consummately incompetent, crazy, or impaired. Would it take much to upset the apple cart? Remains to be seen.

thermalsniffer

Philip2141

This has always bothered me. When the CVR first came out, some were quick to support PNF as having some concept of the situation but limited by authority and what PF was actually doing.

BUT

PNF is desperate to get the Capt. back to the flight deck and when the Capt. gets there all he offers is:

"What’s happening? I don’t know I don’t know what’s happening"

and

"We lost all control of the aeroplane we don’t understand anything we’ve tried everything"

IMHO, he was not calling the Capt. back due to command issues, which I believe was suggested earlier--he had no idea what was going on?

Also, what had they tried?

Switch to ATT?

RetiredF4

Well, i´m not sure what you both are getting there, therefore i try to summarize the issue about stability in my own understanding (feel free to correct).

The airframe itself is, no, must be natural positive stable, otherwise it would not be flyable in direct law.

In Nz-Law, which applies in all Laws except Direct Law Ground Law and Flare Law (did i forget one?) the flight control system creates an artificial neutral stability by use of elevators and THS trim, leading to a stable flightpath without SS input. Not the SS drives the elevators, but the flight control system using present flightpath and the demanded change from that flightpath.

Protections are there to keep this flight path stable airframe within the flight envelope, in simple terms to deviate from this ordered stable flightpath when set parameters are exceeded. There are other tasks to be fullfilled by those protections as well, but not of relevance what i try to get at.

When those protections are degraded or lost, we still have an airframe with artificial neutral stability, as the flightcontrol system still works along the demands of Nz Law, but the protections to keep the aircraft within the flight envelope are gone and have to be replaced by the skill of the crew.

In the case discussed here once on the way up to the apogee the Flight Control System was trying to maintain the flightpath with elevator deflection and THS trim blind to the fact (protections lost) that it would run out of airspeed in doing so, will finally stall, as it did. The crew, who should have compensated for those lost protections was most probably unaware of that fact too, otherwise they wouldn´t have continued to apply NU SS. This NU SS had not much influence after the stall happened, as the flight control system was beyond it´s capability to maintain the flightpath (descending already instead of continueing on the ordered climbing trajectory). The SS movement between NU and Level had no effect and showed no reaction to the aircrew, thus it might have contributed to the confusion.
Neutral SS wouldn´t have cured the problem, only ND SS would have changed the trajectory.

What BEA was getting at with the cited paragraph few posts before is imho, to show the reason for this behaviour without getting too much into details.

@ gums my friend in arms, if i remeber correct the F16 airframe was naturally unstable and a diferent beast. Your comment to blend the Nz-Law with the present (and available) AOA value for a backup in ALT laws with normal protections lost seems a reasonable consideration.

HazelNuts39

2:10:53,5 A first cabin crew or flight rest facility call (high-low chime) was heard
2:10:55 A noise on track 1 of the CVR, which may be the impact of the microphone striking a panel
2:10:55,9 Track 1: allo?
2:10:59,4 oui
2:11:02,3 allo?
2:11:08,3 noise of someone trying to park cabin interphone handset
2:11:09,8 - 2:11:27 Five call signals to the crew rest facility

AlphaZuluRomeo

Hi HazelNuts39

Thanks, I maybe should have precised that I've read that too ; "limited pitch rate feedback and gains" apply to a manoeuver, i.e. when the crew commands something via the stick.
My question was about the stick free longitudinal behavior. It remains unanswered.

jcjeant

Maybe it's because AF culture .......

HazelNuts39

As I understand the C* control law:
C* = q + a*nz, where q = pitch rate, nz = incremental loadfactor, and a determines the 'blend' between nz and q feedback.
For side stick neutral C* = 0, hence q = -a*nz

Lyman

Hi HazelNuts...

From EMIT: "Relevant
What she said is duly noted in the CVR transcription
(at times as noted by previous posters)"

What I said: "How can her voice appear on the CVR?" The "allo,Oui,allo" is from Pilot Bonin....

Lyman

Thermalsniffer...

I do not mistrust PNF comment, and I believe he is correct: they tried everything to regain the flightpath. Their problem started at autoflight disable, and flight control disable. Pitch control was unavailable, navigation had been lost, and other problems emanating from a problem in the cockpit area were cascading. Neither pilot understood the scope and hopelessness of their issues. After Captain re-entered the cockpit, he immediately understood the crew were doing what they could, but him taking the controls would be not advisable, what control they had might well be lost if a transfer to him was accomplished.

PNF was reluctant to take control, that is why there was no permanent change.

There is no chance they didn't have the experience of STALL, and know exactly what was happening...To this extent: They were in trouble, and they had no control over the aircraft...the stick traces were not Bonin's. They belonged to the aircraft. Robert took the stick back as Captain returned, his input had no effect, as Bonin's controls hadn't either...in the climb, Bonin's confusion is not confusion, the a/c is not responding to his inputs.

Shortly after 447 was lost, another a/c, a 340, also lost Pitch control...

slats11

Trying to assess the human factors issues is crucial - not only to build an understanding of what transpired, but also to decrease the risk of a recurrence. Unfortunately this human factors assessment has been made more difficult as we have only been given selected extracts from the CVR. I am sure there are plenty more clues in the bits left out. In addition, we lack the all important quality of the speech - tone, volume, tempo etc

However I do understand and respect the view of BEA that some things do not belong in the public domain. All we can hope is that the human factors people that were involved in the investigation and privy to all the detail learned all there was to be learned.

Why did the Captain take more than a minute to get back to the cockpit? He was a 58 year old male. He had been in the cockpit for 4-5 hours prior to his rest. He would have had a meal and maybe some coffee. Where would he most likely go immediately after leaving the deck and before resting? I would guess that he was in the bathroom?

Despite all the talk here about the kids in the cockpit, both PF and PNF were reasonably experienced. The Captain seemed happy to leave for his rest, despite commenting that it would be turbulent during his rest.
1 h 51 min 58 It’s going to be turbulent when I go for my rest.

There was a very short handover to PNF when he arrived. Less than a minute between his arrival and Captain's departure. Despite ICTZ. Despite turbulence. Despite rising temp and a discussion only 10 minutes earlier about implications on max altitude.

So he seemed pretty confident in the other two pilots. Maybe too confident?

The guys really let Dubois down with their gibberish when he returned. If he was that confident in them and if they were essentially incoherent when he returned, then he may have been immediately overwhelmed by a perception that something very complicated must have taken place. He didn't rush in and take corrective action - because the problem was not clear to him, and no one told him what had happened. So he had to try and make sense of a cacophony of alarms, faulty data, error messages, and bewildered pilots who he believed were competent.

You can't expect someone to explain what they don't understand. But you can expect a concise account of what they did know. Look I not a pilot. But in my line of work (critical care medicine) I frequently get asked for urgent assistance when things go wrong. I don't expect solutions - that's my job. But I do expect to be given some useful information about events before I arrived. I understand this is harder for pilots than doctors - aviation emergencies are relatively rare, pilots may have concerns that their actions were somehow responsible for a problem, and they may even have concerns about their safety. Clear thinking and analytic skills go missing in the setting of unexpected stress and anxiety. But even allowing for all this, these guys appear to have dropped the ball - and possibly lost the final opportunity to recover the situation.

A couple of interesting comments from the Captain in the hour prior to his rest period:
0 h 58 min 07
Captain Try maybe to sleep twenty minutes when he comes back or before if you want
PF Yeah ok that’s kind, for the moment I don’t feel like it but if I do feel like it yeah
Is Dubois really saying he was happy for PF to have a doze while Dubois was having his rest period? Surely I am misunderstanding this.

1 h 27 min 56 How badly we see in this aeroplane with this lighting. It’s not a success
Could he have had trouble seeing the displays when he returned and was sitting behind the 2 pilots?