airtren

Thanks for posting several articles that provide very useful information about flying an A/C of this kind.

One element that drew my attention in the last article you've posted was the mentioning that the A/C reaction to pitch and roll commands is amplified at high altitude.
...

Regarding the climb from FL350 to FL380, there are several elements in the BEA text (marked in italic, and/or color) that attracted my attention, and perhaps are worth mentioning:

Sometime between 1:59:32 and 2:01:46, the PF said, “…turbulence that you just saw…. We’re in the cloud layer unfortunately we can’t climb much… because the temperature is falling more slowly than forecast… and the logon with Dakar failed”.

The text marked in blue can be considered as implying that going to a higher flight level, above FL350, was considered as a possible solution, had the air temperature and the Dakar logon been OK.

At 2:08:07 PNF said “you can maybe go… to the left” airplane …. change ….about 12 degrees possibly because the increasing turbulence …. The level of turbulence increased … the crew reduce the speed to about Mach 0.8.

At the moment the A/P and A/THR disconnected, at 2:10:05, the A/C needed a correction command, and I think it is also possible that the PF thought, that it is worth trying to go at a higher flight level - we don't know if the air temperature may have decreased?

The BEA text indicates that the A/C climbed (from FL 350 and speed 275 kt) while rolling left and right between 12 and 10 degrees to FL 375, at which time the speed on the Left indicator increased (came back) to 215 kt, Mach 0.68, and the AoA was of 4 degrees (with stall warning stopped).

Based on the vertical speed of 7000ft/min mentioned by the BEA's text, the A/C climbed the 2500 ft to FL 375 in about 20 seconds, which left about another 20 seconds of flying approximately at this FL375 and A0A of 4 degrees, before the stall warning was triggered again at 2:10:51.

Note the left speed indicator seems to have been back OK right before the stall warning was triggered again at 2:10:51.

Did the PF, at this moment of stall warning again, decide to go a bit further up, as gaining altitude seemed to him to help with the turbulence, but also be a help with the coming back of the speed indicator? We don't know what he saw through the windshield - ice? - that may have been another contributor to the decision.

....

Recently, on a cross continental flight, as passenger, during the heavy storm season, at about ½ way into the flight, at cruise altitude, and clouds way bellow, out of nowhere, the A/C entered a high altitude cloud, and hit heavy turbulence. After a couple of seconds in the cloud and turbulence, the plane climbed, and I could tell, as soon as it came out of the cloud, after not too long, that it was at least several hundred feet higher.

airtren

Your reasonably can be interpreted as having the thought that other things could be done.

Based on elements pointed out on the AF 447 threads, there could be for instance:

a) provide a "better redundancy" of the sensors, as at the moment, they are all of the same kind, and positioned quite closely to each other, and thus providing a high probability of sharing the same failure fate, in similar conditions.

b) resolving the "lack of", or "confusing information" provided by the "A/C to Pilot Information Interface", by diversifying the parameters used to calculate certain extreme dangerous/fatal conditions, like Stall, and provide a separate and distinct "approach to Stall", and a "A/C is Stalled" Warnings.

The important resources dedicated by the French Government, Airbus, Air France, and others for two years... .to find and recover all what was left of AF 447, for a good understanding of what happened, and what caused it, seem to show the commitment and determination in adopting a wide range of solutions to avoid a repetition of an AF 447 type accident in the future.

Dehaene

ChristiaanJ :For those interested the report has leaked here:
http://jonathan2.blog.lemonde.fr/fil...se-Externe.pdf

Regards

Lonewolf_50

airtren, I am puzzled at one of your suggestions.

I am also intrigued by your trying to follow a reasoning process based on what we know, the idea that the PF was keen to change altitude.
Hadn't considered that line of thought previously.
But wouldn't he have added power with his pitch up input if it was his intention to climb two or three thousand feet?
But wouldn't he have added power to climb in the first place? Cruise climbs typically are a change in both power and attitude. Is there evidence that he assumed A/T would follow his stick input (nose up) and that he noticed (late?) that the A/T had not followed his nose up for a climb command? I cannot recall that having been covered in the BEA report. Is that another reason that the pilots noted "Alternate Law?" If so, why not comment on what the auto throttle was, or wasn't, doing?

OK, then answer me this: why was TOGA applied when it was applied? See the timeline a few pages back?

Also, if I get a stall warning, is my first thought "I need to climb a bit to avoid ice?"
You are able, in pax mode, to measure/sense at cruise altitude a change in a few hundred feet of altitude?

jcjeant

Hi,

Seem's AF adopted already a measure
Some time after AF447 event AF made a general recall of the pilots for simulator training for such situation as AF447 was involved
So .. one can ask if it was refresh trainings or a completely new training ?
Again .. I suggest to read the external audit report for better comprehension ....
http://jonathan2.blog.lemonde.fr/fil...se-Externe.pdf

bearfoil

lonewolf

The initial NU I take to be PF directed. The Left Roll command as well. So does BEA. So the a/c was ND, Rolling Right at the switch? Logical?

As to the Rolling (L,R, between 12 and ten degrees). It would be interesting to know which direction the Rolls were. If one was consistently of different input than the other, one could infer an asym configuration of some kind.

On the other hand, it may have been an attempt to slow down, due drag.

Also BEA are not clear about the timing of "Continued ND inputs". When were these? After entering this climb? As written, the Stall is linked to the climb, initiated (?) by the Pilot.

The Stall could have easily been the result of the PF trying to recover the a/c from the climb.

The PF knew what was going on. The BEA know what was going on.

WE don't know what was going on. I am trying to come up with a way to understand what happened, by entertaining possibilities. BEA knows. BEA is not giving it up (at their discretion, no problem).

I am not trying to predict the Truth, I am trying to keep as wide as possible the discussion. Not least to keep and encourage an open mind.

Mostly, after expression of surprise and disgust at the "reported" conditions, the opinion here is too often too harsh and too conclusive (!) re: the PF performance.

Fine aircraft, fine Pilots. Always my starting point. What happened?

I do not know the motive of BEA with their note. Their distinct challenge if being devious with it, is to continue to withold data except the bare minimum to support a finding that is suitable. Cynical? Yes.

airtren

1) at least subliminally, the PF words indicate what he may have or would consider, 2) BEA's mentioning of those words, among a quite careful and succinct "selection" of "word exchanges" between pilots, must have a significance.
....
I think both pilots understood the relationship between the cloud/turbulence, possibly ice in contact with the windshield, and the loss of speed, and considered the first Stall Warning at FL 350 in light of that, and possible the one following at approx FL375, as only the left speed was showing a reasonable speed, as the ISIS came back in sync with the left speed indicator only a minute and some 10 seconds or so later.

Note: this is within the limits of the interpretation of the correspondence between actions/events and time scale in the BEA text,

Measure? SURE NOT, I didn't have on me any measuring device.

Sense? Yes, of course.

It was not only the clear sense that the plane was climbing, during its short climbing, but also the clear difference of the level of clouds with many holes, which was bellow the flight level before, and after the exit of the short presence in the high cloud, heavy turbulence.

ChristiaanJ

Dehaene, jcjeant,
Many thanks for the link to the report.
Haven't quite finished reading it yet, especially since it needs an awful amount of "reading between the lines".

Lonewolf_50

airtren: ah, visual cues.
OK ... but ... if the intent is to climb, where in the sequence is the initial power and pitch change to climb from 350 to 370/375?
Consider: they had recently slowed down to turb air penetration speed. (I presume by using A/P functions).

That is why I asked: do you believe that the nose was used to climb on the assumption that auto throttle would pitch in on time and allow the aircraft to climb at appropriate airspeed/Mach/energy state, rather than by trading airspeed for altitude?

bear:
Maybe, but if there was a roll/nose drop at AP disconnect, would not the FDR give BEA a hint of that?
Configuration asym ... such as ... what control surface(es)?
What? Use wing roll to slow down?
They have a throttle quadrant.
They have nose attitude control.
I don't see rolling as a deliberate "slow down" maneuver, no.
I wonder. They are trying to piece it back together.
As above, not sure what they know, and what they've been able to infer to fill in the holes where facts are not available.
Yet.

ChristiaanJ

"Corporate Culture" at AF hasn't changed, audit or no audit.
CC on strike the coming weekend, pilots the weekend after.

Holiday departure/return weekends especially for France.
Classic ploy.

takata

This isn't related to the famous AF "internal audit";

[Edit:] Sorry, disregard my above statement (I had too many open windows and messed up with another report) , this one is related with AF "external audit", not with the other one I'm talking below which is another report from "Judicial Experts":
See report (in French) here: rapport d'expertise Rio-Paris

this "expertise report" (linked) is from the Justice inquiry which is in charge of the procedure. Anyway, they interwieved 22 crews from 9 flights belonging to Air France about those previous UAS events - and that's what I was trying to translate in English. Too bad, all annexes are lacking in this linked report.

Flights:
#01 10-05-2008 A340 AF675 PPT-LAX F-xxxx Papeete -> Los Angeles
#02 14-07-2008 A340 AF279 NRT-CDG F-xxxx Tokyo -> Paris
#03 16-08-2008 A340 AF908 CDG-TNR F-GNIH Paris -> Tananarive
#04 20-08-2008 A340 AF101 CAN-CDG F-xxxx Guangzhou -> Paris
#05 10-09-2008 A340 AF488 CDG-SXM F-xxxx Paris -> St Maarten
#06 31-10-2008 A340 AF012 CDG-JFK F-GLZN Paris -> New York
#07 30-03-2009 A330 AF459 GRU-CDG F-GZCB Sao Paulo -> Paris
#08 07-08-2008 A340 AF422 CDG-BOG F-xxxx Paris -> Bogota
#09 30-03-2009 A340 AF607 CAY-ORY F-GLZH Cayenne -> Paris

xcitation

@PJ2
Would you pick any of these?

The list was in reference to the stick backs during the stall rather than in the flying zoom climb earlier. The stick back during the stall is harder to explain IMHO. The zoom climb could be explained by many reasons e.g. PF wishing to climb out of the warm air he spoke of in the BEA report.

Reasons Why "Generally" Stick Back for Final Mintues?

1. Failure to recognize stall condition (PF responded correctly to the first stall but not subsequent stall).
2. Correcting for perceived overspeed/dive.
3. Ignored flight attitude data.
4. THS trim interferance?
5. Pilots executed wrong stall recovery procedure although they did it right the first time ???
6. Failed flight attitude data on PFDs, no backup steam guage style AI instrument installed. [A330 ADIRU failures: 21 May 2009 Miami-Sao Paulo TAM Flight 8091 registered as PT-MVB and on a 23 June 2009 Hong Kong-Tokyo Northwest Airlines Flight 8 registered as N805NW]
7. Sidestick input fault with nose up bias. Failure to diagnose and overide.

PJ2

CJ;
Having seen this kind of report before, I think that this kind of writing is well within what is usually done.

If I may comment generally...- a 'reading between the lines' here isn't intended to diffuse or obscure meaning, (I know you know this...I'm writing generally).

Rather, the Report is expressed in terms that clearly indicate that it is not intended to be specifically linked with any accident. This team did not do a "safety audit" and left large areas of AF unexamined. A safety audit is quite a different thing than an operational safety review.

I think the report accomplishes what it sets out to do, which is to honestly, bluntly, examine areas that work and areas that need change, some "quickly". To me the report's language only appears "soft" - it most certainly isn't but it does not "criticize" either. It is substantively "frank".

The group is a blue-ribbon panel of experts on flight safety processes and I trust their work in this Report. This is a courageous piece of work on the part of Air France when it didn't have to be done. I am completely familiar with many of the organizational issues which the report discusses including "siloing" of departments, lack of respect for others' capabilities, complexity of processes, inability to effectively assess, highlight, communicate and use safety and risk information gathered through programs such as FDM, and so on.

These issues are not unique to Air France and the caution from the authors not to link the report with any one accident is wise and appropriate.

In fact, connecting parts of the Report or linking the Report to one accident would be the same as linking, say, one runway or a specific route, to an accident and concluding that, "we shouldn't use that runway, or fly that route anymore". The Report is far broader than this.

Edited to add:
Corporate culture takes almost a generation to change, unless done with a heavy hand informed by an unusual ability to comprehend the issues and go beyond mere commercial priorities. I know about the issues between management and union having lived with them for 35 years and won't comment further in public except to say that only one can lead and that "soft" responses to safety matters do no one any favours in the long run, but getting there can be extremely difficult depending upon the cultural milieu in which the organization functions. It is easier in Singapore to get something done "quickly" than it is, say, in France, Canada, Italy or even the US, but what is given up in the exchange?

PJ2

xcitation;
No, I wouldn't pick any of those, not because they may or may not apply but because there is no single "cause" and we can't stop at answer a, b, or c yet.

In these discussions about climbing, there is something that has been missed in airtren's and others' here of "climbing out of warm air", etc etc.

An aircraft on a routing which has been flight planned is not just climbed out of one altitude for another. One needs an ATC clearance to do so, as one needs an ATC clearance to deviate off course. It is not mentioned in the BEA Update that the crew obtained a clearance either to deviate from course or later, to climb out of FL350. You simply don't deviate from your flight planned routing and altitude without an ATC clearance unless it is a dire emergency, which, given all available information including the loss of airspeed information, this was not an emergency.

This relates to my earlier point about SOPs. While we do not have all the information, the BEA Update does not indicate any standard communications with ATC took place (for the climb), nor does the Update indicate that the crew followed SOPs for an Abnormal or Emergency event. The PF just started the climb, essentially on his own without coordination with the PNF, and the PNF appeared to just follow along. Now this may not be the case at all but it is what the BEA Update either says or leaves out from which we must draw interim notions. One simply never, ever "launches" into an abnormal or emergency drill on one's own, period. I have discussed this at length elsewhere.

The discussion between the two/three crew members about altitudes and temperatures is pretty ordinary stuff for flight crews and, if I may, I think airtren and others may be reading far too much into the communication/discussion...they're parsing it far too finely and perhaps looking for justifications of the pitch-up and climb where there are none. I've had such discussions many times and while an operational decision (to climb or not), it isn't unusual, ominous or even significant that they decided not to climb at that moment.

True, the ICAO Flight Plan (available in the Appendices of the First BEA Interim Report and reproduced below), indicates that after NTL the routing was UN873 INTOL/M0.82 @ FL350, then SALPU at which a climb to FL370 was flight planned, with the Mach remaining at M0.82, (see the ICAO Flt Pln below).

Standard procedure is to cross the waypoint at which the higher altitude is planned, AT the higher altitude (vice beginning the climb at the waypoint).

They were relatively heavy (not "too" heavy...the discussion was a recognition that it was a bit too warm to climb even though I suspect they could have...I've done it sometimes, when it's close but still operationally doable because if one doesn't take the higher altitude one may not get it for the balance of the trip - it's as much a judgement call as it is an operational one).

Their clearance at that moment was to maintain FL350 and they would not climb to/maintain FL370 without ATC clearance to do so even if the Flight Plan indicated such - one simply doesn't climb without a clearance unless it is a dire emergency when communication with ATC is not possible in the time available. Again, this was not the case at this point in the flight, (prior to SALPU). That climbing to FL370 was on their minds was obvious but there was nothing unusual in that - it was on the flight plan and they were assessing the need for the climb and, at that point, were content to stay at FL350, with a possible request to climb to FL370 a bit later than flight planned.

My sense of their discussion is, therefore, that it was about managing the flight, not about any concern about altitude and weather or temperature. I think things were "ordinary" in the sense that there was weather around and they were doing what everyone else was likely doing - discussing it, and deviating where necessary and monitoring temperature for their climbs.

PJ2


ICAO Flight Plan from the 1rst BEA Report:

takata

Hi xcitation,
PF responded correctly?
Do you mean that climbing at 7,000 ft/mn could have been a correct answer to stall warnings at FL350? A correct reaction seems to me to descent to lower flight level, not a try to out climb the weather.

There is no certaincy about the reason causing the stall warnings to sound due to BEA narrative style (was it at 0210:05 or slightly later?); Consequently, there is only two possibilities:
1. Caused by switch to Alternate Law and subsequent change of Stall Warnings threshold.
2. Pull up by the pilot => g-load induced warning by his first sidestick order.

Any subsequent sidestick nose down order was only applied between 0210:16 and 0210:49. Moreover, not enough ND was applied to stop the climb as she climbed again 500 ft after this point. Hence, this is hard to believe that it would be a reaction to those previous stall warnings, and it seems to be confirmed by the second reaction.

bearfoil

Lonewolf

Asym config. At first blush, a jammed or unstowed spoiler. Consistent with a RL input at handoff. Or an hung aileron. Rudder issue?

Isn't it possible? Also, BEA do not state much of anything re: aspect at handoff. There is perhaps nothing of note to report, or there is, and it remains unreported. Nodata. "No soup for you........"

The Path shows a chronic right biased descent, and BEA in first Interim state a "rotation right" at impact. I think it is early to foreclose on all mechanical issues.

If PF input "SLOW" (turbulence pen speed) to auto pilot, it would be in NORMAL LAW. As such, at a/p drop, He would be in NORMAL LAW. As such, if he input NURL, he HAS Protections in PITCH and ROLL. In ROLL to 30 degrees, and Pitch to STALL nibble. The approved recovery from CFIT is full BACK and full ROLL (And full THROTTLE). Not suggesting CFIT, only to demonstrate the LAW in effect at a/p LOSS. If I was expecting STALL protection with my Pitch UP, the dual chirp of STALLSTALL would be more reassuring than worrying.......Remember, at this point NORMAL LAW.

It is here, during the last ten seconds of a/p, and the first ten seconds of Hand flight, I believe the a/c was lost.

BEA state the a/c did not begin to climb until she was passing through ten degrees NU. (PITCH). So there was a lag in response to PF's "First Input".

Did he become impatient, and just as she started to rotate, input everything the Stick had left? The elevator responds faster than THS, did he have too little back stick with his first input? As the THS caught up, she "overrotated"? Is there a STALL WRN on the THS? Because this climb wants to tell us that ND (at least 'effectively'), was unavailable for the time she was zoomed?

takata

Please, could we have a quote from those flight reports showing an Attitude data failed on PFDs?
Where did you get that? Those are UAS reports, no trace of IR faults.
No backup steam gauge? Well there is an ISIS, which is the 4th source of Attitude indication! (considering that the backup ADIRU3 may be displayed in either PFD in case of 1 or 2 IR channel failure)

takata

You could save the bold for something sensical, it's so embarrassing.
Quite simply, AP would not go OFF while EFCS would stay in NORMAL law.
When AP kicked off, it was ALTERNATE 2. Before, it was NORMAL, right?

Hence, when the pilot entered Mach 0.80, this was between 0208:07 and 0210:04... so, call it before event (NORMAL) with autopilot ON... while at 0210:05, it was ALTERNATE 2, after event, with autopilot OFF!
Get it?

Event = UAS.

In Normal law, if something happened (attitude, speed) protections will kick in and EFCS will set itself in "protected" law (high Alpha, High Speed, bank angle, pitch attitude...) without any need of pilot imputs, the aircraft will recover automatically. They won't be "STALL STALL" sounding if entering the high Alpha mode (Alpha-lock) because the aircraft would not go as far by itself (pilot needs to help up to Alpha_Max, where it doesn't sound either).

After EFCS dropped NORMAL for ALTERNATE 2, anything could happen as protections won't kick, and everything would have to be done manually.

It looks like a motto!
BEA is covering up that, at 0210:05, she was at 90° bank angle, while "starting" to roll to its right... or was at -90° pitch down while "starting" to climb at 7000 ft/mn!

jcjeant

Hi,

More and more I read this BEA"note"(french or english language) and more and more it make non sens for me (for many reasons and principally a erratic chronology and a syntax of bad first grade student)
Best is to stay stick with the two first interim reports and wait the FDR (I don't think the CVR is crucial)
Unfortunately I think (personnal feeling) the next interim report will not include any FDR parts ...

bearfoil

takata. Thank you for the data. I appreciate that you respond, and your response is important. The invective and attitude is wasteful, though. I am old enough to have learned to smile instead of frown. No offense taken, but save your upset, it must be unpleasant for you. It isn't to me!