Clandestino

Almost every crew nowadays is fed 8000ft air. That most flights end uneventfully and large majority of emergencies are dealt with properly completely rebukes your theory but thanks for the entertainment.

Nice argumentation there. Not.

How about impartial?

Who cares who you are! Amateurs or non-aerospace professionals did contribute significantly to discussions here.

However, this is plainly false.

Inertial data. Per design. Write to EASA if you want to have it changed.

Need to fly pitch and power and disregard the host of false alarms, perchance? How complicated is that?

Here: G-THOF serious incident at Bournemouth. A lot of force, thou sayst? No force could lower the nose and the crew didn't remember to use the manual trim.

The way many a PPRuNer glosses over the fact we need to have very powerful THS in modern turbofan transports and that when mistrimmed they can be lethal on any aeroplane, not just on Bus, would have me worried about the knowledge level in today's cockpits if it weren't for the red warning at the bottom of this page.
It was. Conclusion was it behaved as expected and no recommendations to change it were made. Something wrong with it?

...until you zoom through your initial altitude and then bust it by 2500 ft with rate reaching 7000 fpm? Wouldn't you agree that we may call such a feat "overreaction"?

They had no clue what to do.

At it's best, AF447 was measly 72.1° short of vertical, which is quite a bit of stretch to call "not far short of". Aeroplane never stalls in properly executed hammerhead and is only briefly stalled at very low speed during during tall slide, thence no buffet. Thank you for putting forward this entertaining and quite false theory.

TTex600

Something just isn't clicking here Clandestino. I'm well aware of the need for a powerful THS, as I suspect most every other pilot is also aware and that is PRECISELY the reason I find it disturbing that the Airbus THS operates without pilot awareness so much of the time. As this trim discussion continues, I find myself questioning the system more and more.

The PF took the controls and announced such. That was correct. The PM announced the state of protections. That was correct. Yet you state that they had no clue.

If "they had no clue" is the cause, why haven't we seen a program immediately placed in our training to ensure that we all have a clue?

flyingsaucer

Hello,

I am reading the CVR from AF 447 and I wanted to know if anyone knew what the two letters P L meant when the Captain says "t'es P L toi" at 1h56 into the flight.

Thanks

jcjeant

You can download the english version of CVR transcript here:
http://www.bea.aero/docspa/2009/f-cp...nexe.01.en.pdf
Hope it's help !
Note:
Asking if he have the right license for make the job of PF (pilot flying) when the captain is not in the cockpit

CONF iture

I think I can see now where we don't seem to understand each other :
No autotrim means no alternate law no more Nz demand.
Direct, just direct law, where 20% displacement of the sidestick will produce 6 deg up of elevators.

bubbers44

No pilot I know couldn't have flown this aircraft or any aircrat by just using pitch and power. How about using what it had when the auto systems cut out. Why do we hire these pilots with minimum time that can't do simple tasks without autopilot? This is the future unfortunately.

CONF iture

The Perpignan report told us that the A320 THS has an electric pitch-up stop at 11 deg for a maximum THS deflection is 13.5 deg nose up.
For the A330, according to A33Zab, there is no such electric limitation.
After re-reading his post, I can see he had already produced a possible reason for which the THS did not reach the max deflection.

But once again, it was the BEA job to develop that stuff ...

jcjeant

If I understand A33Zab post (read between the lines ... ) maybe he think at the law (another!) "Unusual attitudes" who inhibit the autotrim system
Nevertheless .. nowhere in the FDR extracts of the BEA is show a trace of this law been triggered ......
I can be wrong ...

HazelNuts39

I don't disagree with that. But you miss the point, or you are evading the issue, so we still don't seem to understand each other. Maybe we should leave it at that.

EDIT:: One last try: If the system had been such that in Alt2B from the onset of stall warning the THS setting had been limited between setting at stall warning onset and 2° nose down (i.e. no further uptrim would be applied), but otherwise as is, i.e. Nz law without high-AoA protections, then the elevator trace on FDR would have been as shown by the purple line on the graph up to the point where the elevator reaches 30° at 02:11:41 (101 seconds after 2h10). Up to that point the airplane's trajectory and the stickforce felt by the PF would have been identical to those in the accident.

RetiredF4

Might be there does also imply that they might not be there? Wouldn´t it be more usefull to know that they are there or to know that they are absent? Would it be comforting to have an antiskid system built into your car, but not knowing wether it is active or on leave? I can´t see any sense in your position.

Last try, then i give up. What kind of certain protections besides the mentioned load factor limits does it offer you are talking about? Would you please name them and describe them, that i can understand what kind of protections you are talking about? You also can PM me.

korrol

EXENG AF337 had been in the air for over four hours.

The longer the flight at altitudes like 35,000 feet, (at a cabin altitude of 8000 feet) the greater the likelihood that pilots will screw up - see J H Goode (Journal of Safety Research "Are pilots at risk of accidents due to fatigue?" Issue 34: Pages 309–313).
The pilots may feel fine - but they're not. It's not their fault. They haven't got enough oxygen in their bloodstreams. Their problem-solving capacity is degraded. Not a lot, but enough to make a difference in a complicated emergency.

Hunter58

Korrol

Obviously you wrote your post at the incapacitating altitude. AF337???

Lyman

Well, the 337 is a twin. And also has to do with 02.

All things considered, O2 is of course a factor. Pilots get used to it, and it will not likely change. Saying it is no factor is simply simplistic.

CONF iture

You simply cannot obtain a similar trajectory with an identical stickforce with 2 scenarios as different as one with a THS set at 3 deg and another one with a THS moving from 3 to 13 deg.
A simulator experiment would clearly point the difference.

Trimming in a stall is an unknown procedure. It is dangerous stuff.
We need to ask Airbus why they think differently.
As the BEA avoids asking the tough questions, we need to do it.

One Outsider

That is just not correct. At FL350 the cabin altitude would have been around 6500 feet. I note that in the passenger forum you repeated the same incorrect information over and over, despite being corrected by several people who's correct information you chose to ignore. Now you do it here as if repeating it makes it correct.

If the premise your conclusion is based on is wrong, and you know that it is wrong, what does that say about your conclusion or you?

HazelNuts39

What a strange statement!

DozyWannabe

Airbus don't think differently - they simply never countenanced the idea that a pilot would pull into a stall, keep pulling through the stall warning and pull *again* once the stall was established.

Limiting the trim movement under stall conditions would be simplicity itself in terms of implementation - but the secondary implications (of which there are several) need to be thought through.

It's not a "tough question" - not even every contributor on this thread believes it's a *relevant* question.

CONF iture

As I say, at this point if you don't get the difference on a theorical ground, you would certainly get it through the practical experiment - If you ever have the opportunity to put your hands on a simulator, just try it, the word 'strange' won't have the same meaning.

OK465

HN39:

If I may make an input regarding CONF's statement...

The manual (hand flown) stall QTG's for the simulator are specified to be done in Direct Law with a specific stop manual trim speed. As you decelerate below this speed, without benefit of trim, SS movements tend to be exaggerated to some extent in both directions to maintain a stable flightpath, with varying levels of spring force to deal with.

If the entry is done in Alternate Law, as the rate of airspeed decay progressively increases with the drag buildup, the autotrim input essentially outpaces any necessary SS commands and allows a more 'relaxed' SS input, with less awareness of any spring force.

I think this what he is getting at, but I could be wrong, and don't want to speak for him.

(CONF: Thanks for the reference to the A33Zab post)

CONF iture

I need to borrow the formula of HN39 here :
What a strange statement coming from you !
Dozy, you keep coming back on how crews have been pulling back on controls all the way during stalls, but Airbus 'simply never countenanced the idea that a pilot would pull into a stall, keep pulling through the stall warning and pull *again* once the stall was established'.

So you know about it but Airbus don't ... Give them a call.