Hi,

Turbine D
Ref
PJ2

Semantics.:= I hadn't referred to the FCOM; just remembered the figure from eons ago.

@Dozy

"Except that Direct Law throws the crew into a situation where the aircraft handles differently in *every axis* compared to what they are used to, which would likely be more risky than the current design."

You are suggesting the crew are better off with a "hybrid" control Law, Direct in Roll, and Load factor in Longitudinal.

That makes no sense, PF handled the Direct axis, but had consummate trouble with his "familiar".

The facts belie your proposal....

@infrequentflyer789

"How are you programming in a 3deg THS limit in your sim when there is not one on the a/c - are you using a THS-failure setup of some sort or are you physically holding the trim wheel to override the autotrim or what?"

The THS did not move for 43 seconds between the two STALL warnings, 1 and 2.
Shouldn't that be programmed into the sim, when replicating the climb?
It stopped at three degrees, then resumed at the top, to smoothly go to MaxNU, where it stayed til impact. This is AUTOTRIM? Ascending, was PF's elevator limited? After the beginning of Autotrim at STALLWARN 2, did he regain elevators fully?

Not post-stall he didn't.

In stall you roll through the rudder pedals.

It may be that in a thread that have become a sorry series of repetitions of misinformation, disinformation, one-upmanship and frankly unhealthy obsessions and agendas, that being accurate and factual is considered as semantics.

Just as a general remark, these threads have run way past they sell by date and there are several posters who would have done themselves a great service had they stopped some time ago.

Post Stall is irrelevant. Stop trying to cape the Bull. Your suggestion of support for the hybrid Control Law does not hold water.

Roll was mastered as Machinbird has eloquently posted. What have you to say re: hibernating Horizontal?

MM43:

Whether you 'hold' the trim wheel or 'fail' the system internally, if you then change airspeed, the ECAM message concerning a THS 'jam' will be displayed when the elevator reaches about half travel and that's the limit to which the FCS will take the elevator.

This gives the pilot both manual nose up and manual nose down elevator authority thru the SS, whereas an elevator at the actual travel limit provides for nose authority in only one direction.

This actually seems intuitive to me. :)

Are we allowed then to call the lack of Autotrim in the climb, "Jammed Stab"?

Lyman:

From 265 to 215, it trimmed.....it doesn't take much, nor a rapid rate.

From 215 on down it takes MORE and rapidly.

You're barking up the wrong tree. :)

What would you have us do? Surf porn?

:ooh:

What part? If you push the sidestick forward the THS will follow - easy peasy.

He said no such thing. He questioned Alt2 because it does not behave as traditional aircraft in that regime (which he's more than welcome to), but nothing more than that.

This comes from which manual please?

Piloting 101 (or Air Training Corps Leading Cadet exam c. 1992).

When stalled, the airflow over the wings is insufficiently stable to allow the ailerons to behave in a stable and predictable way. The only way to stabilise roll when stalled is to use the rudder.

Dozy


Quote:
Roll was mastered as Machinbird has eloquently posted.


He spent a long time on PIO roll. The PF did control Roll in DIRECT in the climb...

By using aileron, spoilers.......

"When stalled, the airflow over the wings is insufficiently stable to allow the ailerons to behave in a stable and predictable way. The only way to stabilise roll when stalled is to use the rudder."

Or spin, careful........

Whether the PF started to get control of the roll in the climb or not is neither here nor there - the point is that the pitch inputs were all wrong from beginning to end. As CONF iture likes to point out, I have no line experience at all - and yet I did not inadvertantly add roll input to my pitch control during the sequence (in fact I had to work hard to do so), despite trying to settle the roll with the ailerons during the climb.

It took the TRE shouting at me to control the roll with rudder post-stall to make me do so (sadly I forgot a lot of what I once knew), but even then we managed to recover.

Spinning is hard to induce in a swept-wing design - they tend to develop a spiral dive instead. Birgenair 301 *did* spin towards the end of the sequence, but the DFDR proved that was caused by an asymmetric engine compressor stall rather than flight control input.

Hi jcjeant,

If you live in the USA and watch the early 1/2 hour evening national news, you agonize through 6-8 pharmaceutical commercials in the non-political season. The first 15 seconds extol the benefits of the product, the next 45 seconds is a legal disclaimer listing all the things that could go wrong up to and including death. It is what is known as "legal speak". It protects the pharmaceutical company from damages should you die taking their product, because they told you so. So the FAA and EASA develops wording (legal speak) defining "unsafe condition" or proposing a PAD for a condition for which there is no 100% remedy, now or in the future (our lifetime). This is legal speak to relieve themselves of responsibility should and when the next event occurs and at least one person dies. It is the way things work these days. Lets say you are zooming down the unregulated speed section of the autobahn in you BMW or Porsche at 240 KPH and you suffer LOC. Your estate will not be able to sue the government as they somewhere have a disclaimer (travel at your own risk). However, your estate may be able to sue BMW or Porsche for designing and building a car that goes so fast thereby causing your LOC. Such is the state of the legal business in the Western world. If either the FAA or EASA were really concerned they would have addressed this problem years ago, in fact they are not because there isn't a solution. A substantial part of my career was spent working with lawyers, supporting lawyers or working against lawyers. I know how the system works, at least in the US.

These guys need to be careful what they advocate.

Post stall "beta'' effects in a Level D simulator at this point in time are essentially worthless.

A quote from Captain William Wainright, Chief Pilot Airbus Industry

USE OF RUDDER We also spent a lot of time dis-cussing the use of rudder. The exist-ing training courses all emphasised using rudder for roll control at low speeds. It is true that the rudder re-mains effective down to very low speeds, and fighter pilots are accustomed to using it for “scissor” e v asive ma-noeuvres when flying not far from the stall. But large airlin-ers, with all the inertias that they pos-sess, are not like fighter aircraft. Based on our experience as test pilots we are very wary of using rudder close to the stall. It is the best way to provoke a loss of control if not used very carefully, particularly with flaps out. We finally got the training managers to agree to play down the use of rudder in their existing courses. But we do not say never use the rudder at low speed. We say that, if necessary, the aileron inputs can be assisted by coordinated rudder in the direction of the desired roll. However, we also caution that “ex-cessive rudder can cause excessive sideslip, which could lead to departure from controlled flight”.

End quote.

That can be found in FAST #24, a discussion of aircraft upset.

If rudder is the best way to " provoke a loss of control" in an upset, how could it be beneficial in the stall? I do agree with you were we discussing straight wing low speed trainers, but not large swept wing turbojets.

As we all know, roll wasn't the problem, pulling up into a stall was. Never pull up into a 15 degree pitch angle in any airliner and expect the ailerons to work once you stall. Only very inexperienced pilots would attempt this at FL350 because you will stall and ailerons are the least of your worries.

Autotrim OVERALL bad feature ?
No – Quote me please.

Autotrim should withdraw in case of known dubious data ?
Absolutely.

The guys did not trim in the 737 when they should have – Fair enough – Pretty sure they have learned the lesson and everybody smart enough to read their adventure will have also.
But what I like is the unambiguous rule : If manual flight trim is on you (the PF).

To the contrary on the Airbus confusion is around (Airplane talking) :

• If manual flight trim is on me
• Sometimes I won’t trim for you but I will advise
• But sometimes I may forget …
• Or some other times I will trim when I should not
• Or I won’t even if I should.

To my understanding one type of alternate law would not have trimmed further as the AoA reached a critical value, but the alternate law on which was AF447 just kept trimming … Go and figure ?

Perpignan and AF447 were not exactly conventional planes either …

Play the ball, not the man ... what I think too.
The man fully deserves that little extra and don’t worry he’s very much able to take it, but pathetic I am ... you may be right.

Actually, that's not what I meant to convey. What I wanted to point out is that the crew that has lost situational awareness and is unable to regain it will make a mess out of flying no matter if flying FBW, conventional or "conventional" aeroplane. Manual or automatic trim also doesn't have much impact if the pilots don't know what is going on and what they need to do.

True, with a bunch of caveats. I'll just list two I find the most important:

1. It is easy for you, it was easy for me (while it lasted) and is supposed to be easy for anyone earning sustenance by plowing the atmosphere in Airbus. Catch is that to get to the point where we started considering it to be easy it took some inborn ability, a lot of dedication, hard work and time. It's quite usual to concentrate on the present and forget the efforts that went into getting where we are now.

2. Easy to fly in everyday operation doesn't automatically translate into easy to fly when things go rough, but factor here is pilot who gets distracted by the fear into forgetting the basics of control maintenance, not the aeroplane. So no amount of handflying form ToD to touchdown can prepare you to handfly when AP quits out of its own accord in not quite optimal circumstances. Thanks to much better engineered and maintained aeroplanes, today we have a bunch of pilots that retired without ever having an emergency but we also have few who were so excited by their first occurrence late in their careers they have turned it into disaster and many an observer was puzzled by what was superficially labelled as "beginner's mistake" e.g. being so obsessed by need to prepare the cabin for landing with unsafe gear as to allow the aeroplane to run out of fuel. So neither experience or handflying practice by themselves can prevent future AF447-like accidents.

I think that is still unsubstantiated.

Can I read it with my fingers in my ears? :}

I liked this preceding post and it points up the problem of how to maintain control of yourself and your emotions when suddenly stressed.

I learned the flying game in a much more hazardous environment than is currently accepted. By the time I had a few hundred hours, I'd had the experience of flying into a fog bank after a night takeoff, inadvertent IFR in mountainous terrain, landing under extreme crosswinds (in a taildragger), iced up pitot tube, being rolled by wake turbulence to 90 degrees bank against full opposite aileron, control restriction (due maintenance error) during landing flare, numerous near midair collisions, observing a spin and ejection by a wingman, and still more that do not come readily to mind. The thing that prepared me for this was an intensive training program, strong internal motivation, and extensive 'hangar flying' with numerous instructors and fellow students.

The key is to remain thinking and analyzing despite the adrenalin shot. To remain in full control of your actions despite the adrenalin. I know that eventually, I developed the ability to override what was happening to my body and remain in mental control.
Example: When the G-suit inflated after I had saluted the catapult officer and before the catapult fired, I was able to ignore the crushing force on my lower body and fly the aircraft through the catapult shot and cleanup after takeoff. ( I know this seems funny, but if you have not experienced it-you have no idea of what is involved.) Others faced with that same emergency have stabbed themselves with a knife trying to deflate the g-suit.

How to develop this ability to retain mental control under stress is the question. Certainly simulators can help develop this mental toughness, but at some point, you realize it is just a simulator, and if you crash, it is just a learning situation. Some means of triggering the adrenalin response is necessary for the full training benefit. That is what is really meant by the startle effect.

PIO
 

Hi Maching Bird,

Lyman is right but I also remember your last Thread 8 post, just before the final report release (Jul 5. 2012), you evocated five possibilities to start that PIO, and you were wainting the spoilers and ailerons traces. In your post you also did a graph with the roll rate calculated from the roll traces, with the HN39 software. You mentioned this post at the beginning of the thread 9.

As the BEA report started, a new reflexion on heavy facts basis started, but let many of us frustrated with the many descriptions of the last part of the flight AF447 done by different BEA teams, with different methods, we just have to save the thing ! and start our own PPRuNe analyse from all the released official data now and "report" ! :O Everybody is ready on the deck !

To start with the roll oscillation (after the both normal law and PA loss), and seeing the spoilers and the ailerons traces which do not show (to me !) some anomaly, we still have 3 possibilities :

1. Alternate 2B itself
2. Impulsion due to starting the manual flight at PA loss
3. Impulsion due to law change

Am I correct for you Machinbird ? If it is or if not, how do you analyse that PIO after the release of the spoilers and ailerons traces, and of the final report who give importance at different pages of the report to that PIO ?

Thank you for the new training program for airline pilots ... We need all the free military pilots as instructors :)

Chemical injection? :}

Focal MRI assessment.... Saves on speed. None of these responses are mysterious any longer. Select candidates by where they process data in the brain...

The aviation equivalent of "Minority Report".

Put your victims under the helmet whilst they "fly" your program, OK. You would know categorically what kind of pilot they are in the ess...

studi,
I think you can train it. I used to be a bit twitchy when I was just learning to fly. I think I largely overcame that tendency http://images.ibsrv.net/ibsrv/res/sr...s/badteeth.gif.
Don't rule out that thought, although there may be more ways to do that effect than direct injection.
The roll channel gains in ALT2B appear to be a bit on the high side which promotes roll instability. Things could be done to make it easier to avoid roll oscillation. For example, if the roll gain started at a lower level and ramped up to what the engineers believe to be a minimum mandatory level over a period of time (eg 15 seconds), then a guy who was starting off green would have a bit of time to get the feel of its sensitivity and avoiding overcontrol/PIO.

Due to the needs of running a business, I have not taken the time to analyze the final report data. I expect to do that eventually. That really was a nice analysis tool that HN39 provided:ok:.

Lyman:

I've been involved in some SIMULATOR testing where the pilot subjects were fully physiologically 'wired' and then subjected to various critical abnormal and emergency situations, chosen for the most intense sound and motion cues, and difficulty of assessing what was actually occurring, as well as subsequent physical strength requirements during recovery.

Except for verifying an occasional pre-disclosed heart anomaly, the preponderance of pilot actions and physiological responses were the epitome of the 'right stuff'.

It's a simulator, dude.

A waft of perfume perhaps?

You know the joke about Acute Angina.

Hi OK...

To be clear, I am discussing the brain map, not so much physiological, as neurological. Back driven, one can pilot an aircraft by 'thinking'. No kidding....

acute angina.... Better than an ugly one?

:)

"No son, you can't be a pilot. We've 'mapped' your brain, and all roads lead to some bar on the east side of town."

BTW one of the sim bays I worked in had lead lining and, at one time, an airlock system of lead lined doors.

It would have been a safe place to be in the event of nuclear war, let alone an instructor input malfunction. :}

(Never had an MRI)

Training versus the "right stuff"
 

@ Stud and 'bird:

I believe you can train folks to react to unexpected situations, although having a decent flying skills can be of great value. And you develop most of those via your training. I was given by a higher power decent "touch" or "feel" for flying, so basic maintaining altitude, heading and such wasn't a problem, and I could concentrate on making all the radio calls and clearing the airspace about me. But I know many great pilots that had to rely upon rote memory and standard procedures and having seen some unusual flight conditions during their training.

As 'bird has said, lottsa hangar flying and "what if's" in the flight shack can really help. In my case, I would sit in the barber chair or waiting room someplace and try to think of everything that could go wrong and develop my plan. Use the basic procedures but also think of cases where they would not completely correct the problem. My LEF emergency had no "procedures", so it came down to a decent FBW system and my own judgement whether to punch or stay with it as long as I had a semblance of control.

The military training exposes the newbies to many unusual attitudes and flight conditions that demonstrate that "there is a way". The war stories in the recreation bar also help, as in the case 'bird mentioned about the inadvertant gee-suit inflation or the pitot-static freezeup.

Serious training is essential to preparing the pilot for the known emergency conditions likely to be experienced and the unknown, but survivable ones. Helps to have some natural abilities such as being able to remain calm when everything is going to hell-in-a-handbasket, plus basic airmanship. But great training can supplement whatever natural abilities and such you already have.

That's the way i see it, but I didn't see it on AF447.

gums, you are absolutely correct.

Would the following, fictious, BEA recommendation have made everyone happy?

"...that Airbus redesign autotrim so that it cannot add nose-up trim while the stall warning is active."

Not really, since the stall warning was 'inactive' for a large part of the backstick event - due to a design deficiency.?

noske: I was advocating for such a change, but HN39 showed that as long as the elevators are not full nose-up, this wouldn't change anything. Therefore, is it useful (vs the added complexity)? I'm not so sure anymore. :oh:
I think other aspects are far more important/urgent to address than that.

BOAC: Isn't there already a recommendation re: S/W continuation? ;)

"BOAC: Isn't there already a recommendation re: S/W continuation?" -yes, but noske's addendum would need to be made conditional on the implementation of that..

The stall warning was inactive when the IAS dropped below 60 kts. The speed dropped below 60 kts when (and because) the AoA exceeded 40 degrees. If uptrim had stopped at SW, the AoA would probably not have reached such high values and the SW would not have stopped prematurely. Noske's proposal would make me happy.

PS.
Curiously the BEA never mentioned that IAS became inaccurate at extreme AoA.