It would be important to assess different characteristics airframe to airframe, crew response, etc. do you know if any in-depth analysis is ongoing?

Machinbird

For most operators UAS ist NOT a reportable item and therefore the NTSB would not know about it either. To write it in plain languague. UAS is existing in aviation since the introduction of speed measurement and has not been a real problem since the effects were (and I assume still are) part of basic training, starting very early in the training of the most basic aircraft. It is not over 50 cases, it is thousands of cases. But they were not reported since they are a non-event.

I wonder if the Colonel Xavier MULOT is the same one who is on now on the staff of the French Embassy in Qatar? or is it a coincidence?? I had a google but didn't find any specific on his 'demission' - different from limoge (fired)....(accents missing in the french words).

More conspiracy stuff??

I would agree if the aircraft has natural positive dynamic stability, then it is a non event.
If left alone after a disturbance, it will naturally seek its trimmed angle of attack.

For an aircraft with neutral static stability, then it is a problem.
Any deviation must be recognised and corrected early. Once AF447 had deviated by that much Altitude, it didn't matter how hard they pulled trying to regain FL 350 - it would't work.

Edit: Typo: changed dynamic to static.
Thanks to Clandestino for pointing it out so tactfully.

It has certainly been promoted .. this is normal .. even the U.S. that also happens ... the morons responsible for security the 9-11 were promoted to a higher level :)
More conspiracy stuff?? :8

Highly debatable - not appropriate for discussion here - go to JB - Japan Earthquake and Tsunami where this was discussed in detail.
Very, very good observation, I think this will/is being looked at, particularly the valid data correlation.
Nonsense, see above plus I suggested this to you a few threads ago.
Thanks for spotting my error, got my "I" mixed up with my "D" on the keyboard.
However you want to look at it, there are both millions of flights as well as flight hours. The occurrence of UAS is a small number from which all crews managed to recover and fly on, except for one.
If a crew can't stabilize at 2.5-5º nose up how can they better stabilize in a "shallow descent? "crazy speed" was a result of pitot icing so how can there be less chance of this going down? And, how does going down result in less stress on the airframe or engines verses going up, particularly if sidestick management is heavy handed? explain?
Luckily, for all concerned, you don't build airliners.

That question has been asked on an earlier thread. I believe the answer was that the FADEC of the GE engine receives its environmental data from ADIRU 1 & 2.

Note that in the Air Caraibes UAS event the discrepancy between the aircraft pitot pressure and the engine P2 caused the ECAM message "ENG 1(2) EPR MODE FAULT". The GE engine is N1-controlled.

Hi Hazelnuts39,

Your memory regarding the FADEC & ADIRUs 1 & 2 is correct. The suggestion of somehow using an array of pitot tubes in the engine nacelle as a backup to the normal 3 fuselage mounted pitots would apply to future developed aircraft and engines. I would guess it would depend on the ability to both correlate and then integrate them into the overall aircraft monitoring system. It would require extensive testing to determine if this "backup" system would be operational and not develop icing should the normal pitots fail for openers. I do suspect searching for a solution is being worked in the industry to prevent pitot problems leading to instances of UAS on aircraft being developed or in the conception stage.

Control/trim law bias for AoA or speed
 

Thanks Turbine for the 777 poop.

Seems Boeing likes a plane that trims for speed/AoA versus one gee corrected for attitude/climb angle. And the pilot has to command a different trim speed/AoA if I read the data correctly. No automatic THS to maintain commanded gee.

Interesting that pulling/pushing the stick ( stick/yoke, what the hell) against the trim setting has increased force. So there is an artificial force feedback, huh?

I was also impressed with a fairly simple reversion sequence when the primary laws go away.

The stall protection implementation also seems very intuitive to pilots that did not grow up learning to "monitor" the Airbus system do its thing. Hmmmmm.....

Again, thanks Turbine.

A pilot should be able to fly any aircraft without needing training. Yes the training is good to teach the differences but no competent pilot should be required to know how to recognize and recover from a stall. That was taught in the first 5 hours of instruction. It is so basic, lower the nose and regain airspeed. AF had two pilots who couldn't do that. I am sure the captain could have but by the time he entered the cockpit the PF had screwed it up so bad he was even confused.

We need to not let automated airplanes make pilots monitors. They both forgot how to fly watching the magenta line.

Bubbers, stop being dismayed about the pilots and start being outraged at the system that trained them and placed them there.

TT, I agree with your statement. This wasn't a problem when I started flying. It is now. Competent pilots were the only people hired when I was. Now with automation competent pilots are too expensive so they hire the cheapest pilots out of pilot school they can find. Sad but true.

Embry Riddle pumps out pilots with no experience as soon as Daddy can pay for it. Now they are qualified for a 24,000 a year job with a mere 200,000 help from Daddy. A friend of mine just funded this exact thing.

TD....

Quote:
Originally posted by Lyman - Different airstream, dependent on demand, not ambient velocity.
"Nonsense, see above plus I suggested this to you a few threads ago."


"The suggestion of somehow using an array of pitot tubes in the engine NACELLE as a backup to the normal 3 fuselage mounted pitots would apply to FUTURE developed aircraft and engines. I would guess it would depend on the ability to both correlate and then integrate them into the overall aircraft monitoring system. It would require extensive testing to determine if this "backup" system would be operational and not develop icing should the normal pitots fail for openers/B]

Are you so eager to utilize the word "nonsense", that you miss the accuracy contained in my post?

By the way, I did not correct your spelling of the word "intent". The word was spelled correctly. I merely asked if you had meant "Detent" instead....

My original comment was based on data you enlarge in your retort to my succinct post. I am full of nonsense, but you think enough of it to widen the prose used to expand on it?

What's up widdat...?

It is a safe procedure as long there's nobody below.
It has been done by a few crews.
Idle + pitch on the horizon or slighly below do just fine.
Absolutely no risk of overspeed.
Just like a normal descent from cruise level.

To follow directions or switch to a memory item, you need first to understand what you are facing. For them the first signal was the alarm and the red ecam for AP disconnect - Probably also a sudden drop of indicated altitude - I don't think they realized they had to deal with an UAS scenario - Among the reported events, is it possible no one called for the UAS memory item, and no one deselected the FD ?

When it was getting obvious that UAS events in altitude were adding up, it would have been very wise to simulate such scenario during recurrent training : This, is what you may encounter, there are all the associated ecam and alarms, that's what your PFD may look like : THIS IS WHAT YOU NEED TO DO.

I am a bit disapointed we still have not done it in my outfit

Everything is so much easier when you have been properly demonstrated once.

Why climb or descend with UAS? Why not stay level, use the altimiter and VSI to maintain altitude? Why bust through everybody elses altitude? I only flew Boeings and MD's but no procedure required changing altitude in cruise because of UAS. Every aircraft has an UAS checklist, get it out and stay level. Just my opinion because I stayed away from the Airbus.

Is it possible that a pilot sees the IAS drop from 274 kt to 52 kt in a matter of seconds, and not consider the IAS to be unreliable?

From the Air Caraibes memo (my translation):

"Phase 4, crew reaction
Starting at 22:22:59 during 1m26s the indications of CAS, Mach and altitude are not reliable. The PF flies manually without FD, without FPV, and without A/THR. In that period the various warnings on ECAM, Master Warning, Master Caution, Cavalry Charge, Single Chime, and STALL are numerous. In this extremely charged context, the crew concentrates thus on the piloting of F-OFDF and the application of the checklist QRH 2.21 UNRELIABLE SPEED INDICATION. (...). "

Agreed. It is difficult to understand that this is still not being addressed in training.

It is not being addressed in training as their are no algorithm's in the sims for high altitude handling. ( most only up to 14000ft) which risks negative training.

no algorithm's in the sims for high altitude handling

.. a matter of tweaking the box's software.

But do we know what IAS2 was displaying ... ?

The last time we did practice a scenario of UAS at low level, the initial clue that something was wrong came under the warning : WINDSHEAR WINDSHEAR WINDSHEAR
My airspeed was getting in the red, which made sense to me in case of windshear.
As per SOP my call was "WINDSHEAR TOGA" which implies to follow the FD, not to turn them OFF.
That's only when I heard the instructor word : "eh guys ..." that I took a quick look at the other PFD and could remember that one of the exercises for the day was UAS not WINDSHEAR ... The appropriate call was then only made : "UNRELIABLE SPEED"

This is how things can get confusing sometimes.

This is not so much about the handling, but how the avalanche of warnings can just mean that : UAS, and how the energy of the PF should go on maintaining a normal pitch attitude for cruise and the energy of the PNF should go on the monitoring the PF performance. The only actions the PNF could perform would be to kill the FD and set the thrust at a normal thrust setting for cruise.

All the concentration and energy on aviate - This is not necessarily easy as the multiple warnings don't seem to stop.

This could be like suddenly switching from a walk in the park to seat in a formula one at 300 km/h

IcePack:

What's your source for that statement?

CONF:

It may depend on how the instructor inputs the airspeed variation.

If the indicated aircraft speed is slewed directly, you'll get an effective windshear.

Check and see if you've got a 'Variable Airspeed Drift' malfunction available in the ADIRS section.

Using this malfunction can give a nice approximation of the Air Caraibes situation with appropriate ADR disagree messages and no windshear warning.

Sims are set up to meet the equivalent test schedule for the type. Most sims handle the same at 35000ft as they do at 14000ft which is definitely not the case for the aircraft. Sorry would have no idea of the source document for that.
Trouble with negative training is that it may be of benefit to get pilots to hold attitude & power but could lead them to believe that the handling is easy which in an A330 at height with an aft C of G due trim tank it is not. Hence in a surprise situation (in real a/c) they may over control or disbelieve the indications.
Whatever, the simulator industry needs to address this short coming IMHO.

Then how did you find out about this?

Question. The aircraft (F-GZCP) was in an airstream that was actively changing directions, from the VSI, her accelerations were brisk in the vertical. This was happening at 2:10:05, both sides. ( before and after). So since I've not seen an answer, let me ask again. The ACARS show a WindShear event of some description. Is there a possibility Bonin was reacting to this? Was there no W/S alert on the ECAM? Seems to me WindShear can cause discrepancies in Pitot reporting, sufficient to not only cause autopilot to drop out, but to degrade the Control Law as well....

Answers
 

Lyman,

Answers to your 4 questions:

NO
NO
NO
NO (actually the answer may be wrong, 'cause it might just be that to you it really seems so)

By the way, windshear cautions or warnings show up where they belong, on the pilots' Primary Flight Displays (same in Airbus as in Boeing).

IcePack,
I cannot tell about the 14000ft stuff, you may be right, but I can tell it is still pretty easy to over control at 35000ft in a simulator. IMO the handling would still require a LOT of attention.
For the record, despite the fuel in the tail, the CG for AF447 was still very much fwd compared to the ideal target for fuel saving.

OK365,
You are most probably correct.
I'm not too aware of the different possibilities for the sim as I have never occupied that back seat. What I can tell is that the instructor seemed surprised too.

The ACARS message you're referring to has the Meaning (ref. Interim#1, p.49):
"This message indicates unavailability of the reaction to windshear detection function"

Read it somewhere, however couldn´t find it. Stumbled on another pdf though.

Validation of stall recovery technique and training from Airbus March 2011

edit: another look from april 2012
aviation week

Where did I write inadequate ?
It is only a temporary fix where the pilot needs to be quicker than the malfunction to badly bite one more time.
But as usual you redirect the subject as you cannot assume your writing :

CONF iture
I can see the appeal of that (as I am very much a fan of stick and rudder flying). I think henra's response answers some of the "why" the system is as it is.

TTex
I understood you perfectly. :ok:
It makes sense to whomever bought the plane with the objective being a smooth ride in a modern airliner. I will suggest to you that, for the most part, as evidenced by most of the 228 casualties being strapped in, that even as it fell from the sky it was a smoother ride than one might expect for out of control flight. (Then again, many of those strapped in might have strapped in, and then dozed off, a buffet here or there not noticed, be it turb or stall ... )

The only question I'd have on that is: how often do you get to practice that?

Lyman
Gravity assisted flying! What will they think of next! :-)

Sorry for that, I could not resist.

Thank you for being nitpicky for me.

Neither do I. BEA is also unhappy but it issued no recommendation on fixing it. What you fail to understand is...

...the pressure that hit the total pressure sensor was not the real one due to clogging of the pitot, but such reduced pressure resulted in calculating airspeed of about 52 kt at the minimum and this is valid speed during t/o run or landing roll and cannot be rejected by simple algorithm! This is not readily identifiable to computer as a garbage! It can be identified as such only by someone who has a whole picture of the aeroplane state in his CPU and can recognize that sudden drop from 270 kt to 52 without aeroplane starting to fall or being torn apart in severe turbulence actually means speed display is totally wrong and we call that entity "a pilot". You just can't teach the computer to compare all the parameters and come to intelligent solution, if you try, you can only end up with set of instructions so convoluted its execution will be totally unreliable. Farthest Airbus came is displaying "CHECK GW" message when computer detects discrepancy between input weight, airspeed and AoA - it can not determine which is which so output is made to warn about the most common failure, to input wrong weight into FMGS. A lot of guesswork but it's best that can be done for the time being.

Question of adequate training is another can of worms. How come other AF crews dealt without much fuss with UAS if AF training is inadequate? It is not just about training, it is also about selection. Starting from the first flight in glider, ending when the logbook is closed for good.

Do you have a slightest idea who writes and approves the procedures?

So it would! So freaking what? Pilot who would seriously consider acting IAW overspeed warning in UAS situation must be totally "destructured", to use BEA term.

Panic, caused by sudden realization that something is wrong but one has no clue what it is or what should be done. So doing first thing that crosses his mind and disregarding absolutely every clue it wasn't good idea in the first place.

What situation?

I have read many a misconception about Airbus protection, this one goes into top tier. No altitude protection is offered ever on Airbus as AoA makes it irrelevant. No hard air data based protection is available in alternate laws as there's no sufficient redundancy to guard against the unwarranted activation of the protection.

How come other 36 crews went through UAS ordeal unscathed? Better training than yours?

So it is. No electronic part of the system failed in AF447 case. It just wasn't fed the right pressure.

Problem is that many a PPRuNer has noticed it is dangerous only when it resulted in 228 deaths and all of a sudden there are righteous demands, very similar to ones made by certain young F/O

At least he was so forthright to humour himself once the fright loosened his grip.

So what? I have flown aeroplane with single pitot and then it got blocked. There's always way out.

I have to warn everyone that trying to explain some aspect of Airbus FBW while not being versed in basic aerodynamics tends to produce entertaining, if not true or otherwise useful , results. What you are referring to is static stability and that airbus lacks it in normal and alternate law is total non-event.

What?!? AF447 did regain FL350 by pulling, if only fleetingly as it passed through it on her final descent! Now, if only they pushed...

If we assume that Airbus is dangerous by design, shouldn't we be praising the system for always putting the super-pilots in the cockpit that made it home and failing just once? Of course not.

You are right. How could they realize when they were suddenly faced with 200+ kt drop in IAS?



BEA does. 88, 93, 94.

Dear CONF iture, by know you should have really known better than assuming I would link to the report without reading it. So: 1. QF72 was single occurrence in 28 million hours of flight 2. temporary fix of switching off the faulty ADIRU was later supplemented by rewriting the FCPC algorithms. I will suggest you should stop burying yourself, just because I know you will not listen to me.

Another read i could find concerning Loss of Control in Flight
Training Foundations and Solutions.


Some bits out of it:

What Changed: Uncovering the Problem
Part of the predicament has nothing to do with LOC-I at all; in fact it is the reduction of other accident causes that left LOC-I as one of the last remaining causal factors to be “tamed”. To be clear, the overall number of accidents and fatalities due to LOC-I have not been increasing. It is the improvement in other accident categories that has resulted in the emergence of LOC-I as the leading cause of fatal accidents in air transportation worldwide. It’s as if when the “swamp” of the aviation accident pool was drained of other causal factors, the “snakes” of LOC-I were exposed. It is only in the past five years that LOC-I has overtaken Controlled Flight Into Terrain (CFIT) as the leading fatal accident category among airline
aircraft worldwide. While other accident areas have improved, LOC-I has stagnated at an unacceptable rate.

You should tell BEA. They obviously dont know about it.

You should have helped BEA with their report. They got it wrong again.

So, in the case of UAS, you could get a windshear warning and / or
a stall warning. Neither of which are correct. Wonder what else ?.

In the case of uas, one would think that the warning system would
at least consult the IRU and other available sources to correlate
the data before presenting it to the crew.

I guess that's all ok though, yes ?...http://images.ibsrv.net/ibsrv/res/sr...milies/eek.gif

I flew with pilots that would not have done what they did. I wouldn't. If we lost airspeed we would maintain pitch and cruise power as they should have. Get out the UAS checklist and press on. No stall, no panic, but they didn't. Experience helps when you didn't spend your whole short career monitoring an autopilot.

UAS diagnosis
 

Hi,

Clandestino:

Quote:

---

Originally Posted by RR NDB
I don´t like the approach to diagnose UAS by System output.

---

I put:

In an earlier post i observed:

IMHO this is dangerous. Digital signal processing of air speed analog data can inform UAS onset to the crew before System start to process garbage.

The recommendations will generate a better design. I hope an UAS DSP subsystem will be eventually used.

Please could you explain: "What you fail to understand is...". What you mean?


:ok:

Even morons could deal with UAS if are trained to use a DSP UAS detector. :)

(Air speed is important. Pitot´s seems obsolete. Thales version used in F-GZCP was obsolete)

Air speed anomalies are frequent and potentially affect the stability of the System. The current situation is not good.

The 3 redundant (Pitot´s and subsystems, CPT, FO and Stand By) System elements failed SIMULTANEOUSLY. No redundancy, therefore. Better to use a single element. :} :{

On the REC MAX protection please don´t consider it so seriously. Actually good pilots can unload the wing above REC MAX and save the day.

Hi,

bubbers44:

Quote:

---

Experience helps when you didn't spend your whole short career monitoring an autopilot.

---

:}

BEA...

"Thus, having identified the loss of airspeed information, the PNF turned his attention to the ECAM, undoubtedly in an attempt to refine his diagnosis and to monitor any actions displayed. He started to read the messages, and consequently called out the loss of autothrust and the reconfiguration to alternate law...."


In the prior paragraph, they reference a three second interval post a/p loss, and note the ECAM has not displayed the Law reconfig. It was sixteen seconds later the PNF called "Alternate Law".

Three seconds after the autopilot disconnection, the ECAM displays no information that is likely to point to a speed indication problem:

What is the point of This timeline, and the two time intervals? Thay mention the possibility of nose up, but make no inference other than, "possible confusion..."


The ECAM mentions a maximum speed that should not be exceeded but does not mention a minimum speed. This could lead crews to suppose that the main risk is overspeed. In the absence of any reliable speed indication, this might lead to a protective nose-up input that is more or less instinctive.


Sensory overload? The pilots? Or BEA? What a jumble...

Fault tolerance and graceful degradation
 

Quote:

---

BEA Final report 2.1.2.4 Identification of the situation
Three seconds after the autopilot disconnection, the ECAM displays no information that is likely to point to a speed indication problem:
The ECAM mentions a maximum speed that should not be exceeded but does not mention a minimum speed. This could lead crews to suppose that the main risk is overspeed. In the absence of any reliable speed indication, this might lead to a protective nose-up input that is more or less instinctive.

Thus, having identified the loss of airspeed information, the PNF turned his attention to the ECAM, undoubtedly in an attempt to refine his diagnosis and to monitor any actions displayed. He started to read the messages, and consequently called out the loss of autothrust and the reconfiguration to alternate law. The successive display of different messages probably added to the confusion experienced by the crew in its analysis and management.
In the absence of a specific message expressing detection of unreliable speed by the systems, the crew was unable to identify any logical link between the symptoms perceived and these ECAM messages. The impression of an accumulation of failures created as a result probably did not incite the crew to link the anomaly with a particular procedure, in this case the “Vol avec IAS douteuse” procedure.

---

K.I.S.S. has it counterpart: Keep It Complex Stupid :}

Question: How they could diagnose the UAS? (The so called, non event)

:mad:

We still today have two problems:

1) Important (redundant) elements prone to fail simultaneously
2) Diagnosability of UAS