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-   -   AF 447 Thread No. 10 (https://www.pprune.org/tech-log/493472-af-447-thread-no-10-a.html)

bubbers44 26th Aug 2012 04:05

G27, the pilots didn't follow the AB manual and if they were above obstacles not do the low altitude procedure but do the cruise prosedure of just hold present attitude for level flight and get out the UAS check list. They were new and inexperienced. They needed the only qualified pilot in the airplane to be in the cockpit but he was taking his break and they couldn't handle it. Hiring 300 hr pilots on automatic airplanes is not safe.

BOAC 26th Aug 2012 08:57

Flap flap flap:mad:

They were new and inexperienced.
- no they were not (for the fithtieth time). They were not '300hr' pilots (for the thirtieth time..

They needed the only qualified pilot in the airplane
- they WERE 'qualified'.

For g27

I understand the panic in severe turb.
- there was NO severe turb

Either of you read the report?
B44 page 29 et seq
G27 page 60

Give it a break?

Mr Optimistic 26th Aug 2012 10:21

This sidestick visibility thing is all well and good but I do not understand why the cpt didn't at least ASK the pf what he was doing never mind instruct him as to control inputs. There were enough pax behind him, situation didn't need one more.

CONF iture 26th Aug 2012 14:28


Originally Posted by HN39
Considering the inertia of the airplane, I'm not so sure of that. Perhaps you should try it in your next simulator opportunity.

Every rotation is done in direct law, and any undesirable erratic movement would be immediately evident due the instantaneous response of the aircraft.


I suppose you mean that there is no autotrim and that you assume that the PF would not have trimmed manually. At 02:11:35 he seemed pretty desperate to keep the nose up, and in direct law "USE MAN PITCH TRIM" is displayed on the PFD.
Did he try to trim up to the FULL stop of 14 degrees ... ?
If the pilot wanted to trim up, let him make such a silly thing himself, Please. We really don’t need any automation to do it for him.
If the guy had done it himself, I would not show up here to defend his action.


In the two instances that the PF released the stick, the elevator responded and the airplane promptly pitched ND.
And nothing to compare with what would have been obtain in direct law in terms of ND movement and AoA reducing in order to achieve stall exit.


While it is probable that the stall warning would have been uninterrupted in direct law, that is not certain.
If you think you can get below 60 knots on elevators only, it is your call. What I want to see is the BEA calling the shot. That should be detailed already.


I have earlier expressed my opinion on the visibility of the sidestick. Seeing the control pulled to the back stop might have added another clue that might have pointed the PNF and particularly the captain towards a correct diagnosis of the situation.
So we agree.
It was the duty of the BEA to make recommendations to Airbus to include in their documentation how the sidestick concept does not permit the same type of supervision allowed by more conventional flight control commands.

The crews operating the Airbus must be made aware of such characteristic.


Perhaps you would care to justify that opinion considering that BEA's investigations "are conducted with the sole objective of improving aviation safety and are not intended to apportion blame or liability."
That's something we can keep for later, but for now I could resume it that way : Do not write too much in the technical as the judiciary could be too well at ease to use it afterwards …

CONF iture 26th Aug 2012 14:34


Originally Posted by Mr Optimistic
This sidestick visibility thing is all well and good but I do not understand why the cpt didn't at least ASK the pf what he was doing never mind instruct him as to control inputs. There were enough pax behind him, situation didn't need one more.

As soon as the captain is back, the stall warning quits. For him a stall has been properly exited. He has no clue the stall warning can quit for other reasons than a stall exit. The Airbus documentation makes absolutely no mention of anything like it, and on the contrary it is specified that a stall warning won’t stop before a stall is actually exited, which follows both regulation and logic.

This stall warning thing puts everything up side down for the captain ability to properly evaluate the situation.

What do you want him to instruct if he cannot make sense himself of the situation ?

But it is a remarkable that the captain would need to ask the PF what he was doing, just because the sidestick concept deprives him to naturally know about the inputs made on the flight control commands.

jcjeant 26th Aug 2012 14:53

Interesting and neat report about AFR1896 (from the Moroccan investigation authority)
Only in french unfortunately
http://89.30.127.37/docspa/2011/f-xc...f-xc110808.pdf
The event is from last year
This show again a real problem at AF about CRM .. respect of the laws .. etc ...
Extracts (Google translator)


1. RENSEIGNEMENTS DE BASE

1.1.- Déroulement du vol

Le 08 août 2011, l’avion Airbus A320 de la compagnie Air France assurait le vol commercial
N° AFR1896, en provenance de l’aéroport Paris Charles-De-Gaulle (CDG) à destination de
l’aéroport de Casablanca Med V (CMMN) selon horaires suivants : Heure de départ : 5h30 UTC,
Heure d’arrivée : 8h24UTC

A 08h10mn05s, l’équipage du vol AFR1896 prend contact avec l’Approche GMMN. L’approche
lui notifie de procéder sur le point GODAM, de descendre au FL50 et de prévoir un guidage
pour la piste 35L. L’équipage accuse réception.

08h15mn59s : l’Approche demande à l’équipage de descendre à 3000 pieds QNH 1013.

08h18mn27s : l’équipage AF1896 annonce qu’il est en vue des installations pour une approche
à vue. L’approche approuve et demande à l’équipage de continuer à vue pour une finale 35L.

08h19mn56s : l’approche demande à AFR1896 de tourner en final 35 L et de contacter la Tour
sur 118.5.

08h20mn08s : après prise de contact avec la Tour, celle-ci demande à l’équipage du vol
AFR1896 de rappeler en finale 35 L.


08h22mn05s : AFR1896 confirme qu’il est « Autorisé à atterrir sur la 35 Gauche »

08h24mn24s : Une autre station annonce pour information qu’un avion d’Air France a atterri
sur la piste 35 droite.

08h24mn46s : AFR1896 confirme l’information : « Oui 1896 on vous a bien reçu, et on espérant
l’approche à vue, effectivement on s’est trompé de piste en approche à vue merci. »

1. BACKGROUND

1.1. - History of Flight

August 08, 2011, the Airbus A320 of Air France operated the flight business
No AFR1896, from the Paris Charles De Gaulle (CDG) to
Airport Casablanca Med V (CMMN) according to the following schedule: Start Time: 5:30 UTC
Arrival: 8h24UTC

A 08h10mn05s, the flight crew will contact AFR1896 Approach GMMN. The approach
it shall proceed Godam about to descend to FL50 and provide guidance
track for 35L. The crew acknowledged.

08h15mn59s: Approach asked the crew to descend to 3000 feet QNH 1013.

08h18mn27s: AF1896 crew announces that it is to approach facilities
sight. The approach approve and asked the crew to continue to a final 35L for.

08h19mn56s: the approach requires AFR1896 final turn of 35 L and contact the Tour
of 118.5.

08h20mn08s: after making contact with the tower, it asks the flight crew
AFR1896 to recall the final 35 L.


08h22mn05s: AFR1896 confirms that it is "authorized to land on 35 Left"

08h24mn24s: Another station announcement information for Air France plane that landed
on runway 35 right.

08h24mn46s: AFR1896 information confirms: "Yes, in 1896 you were well received, and we hope
visual approach, it is actually the wrong track approach to thank you. '

1.13.3 Témoin oculaire :

Le Commandant de bord du vol N°AT560 a remarqué au cours du son roulage que
l’avion assurant le vol AF1896 était haut sur le plan et mal aligné sur la 35L. Il a donc
décidé de ne pas traverser la 35R pour s'aligner sur la 35L malgré l'autorisation initiale
de la TWR/GMMN.

A la suite de l'atterrissage de l’avion de la compagnie Air France (Vol N°AF1896) sur la
piste 35R, le CDB du vol AT560, qui était au point d'attente 35R, a informé la TWR de cet
événement.
1.13.3 Eyewitness:

Commander of flight AT560 No. noticed during his driving that
the aircraft on the flight AF1896 was high on the plan and misaligned on the 35L. He therefore
decided not to cross the line to 35R 35L despite the initial authorization
the TWR / GMMN.

After landing the plane of Air France (AF1896 Flight No.) on
runway 35R, flight AT560 the CBD, which was at the holding point 35R, informed the TWR this
event.


1.10 Enregistreurs de paramètres de vol
1.10.1 Cockpit Voice Recorder (CVR) :
Le CDB n’a pas appliqué les consignes de la compagnie Air France (AF) dans le cas d’un
incident grave, ce qui n’a pas permis d’exploiter les données CVR de l’avion en question
au moment opportun.
1.10 Recorders flight parameters
1.10.1 Cockpit Voice Recorder (CVR):
The CBD has not applied the instructions of Air France (AF) in the case of a
serious incident, which did not exploit the CVR of the aircraft in question
timely.


2.3. Procédures Air France en cas d’incidents grave :
Le Manuel d’exploitation de la compagnie Air France précise les mesures à
entreprendre par le CDB responsable du vol dans le cas d’incident grave, notamment
en ce qui concerne la protection des données de CVR. Il est mentionné dans le manuel
de la compagnie Air France qu’une fois l'avion immobilisé au sol, il faut tirer et baguer
les disjoncteurs correspondants aux différents enregistreurs selon les consignes du
MANEX B, et le mentionner sur I'ATL, chose qui n’a pas été faite par le CDB de ce vol, ce
qui n’a pas permis aux enquêteurs de vérifier toutes les communications dans le
cockpit durant l’approche et l’atterrissage.
Il est à noter que le règlement en vigueur classe cet événement comme incident grave,
par conséquent, l’équipage de conduite devrait le traite comme tel.
Par ailleurs, le responsable de l’escale d’Air France, à l’aéroport de Casablanca
Mohammed V, s’est contenté d’accompagner le CDB du vol AFR1896 au bureau de
piste pour la rédaction du relevé d’infraction et d’en conserver une copie.
2.3. Air France procedures in case of serious incidents:
Operations Manual for Air France specifies the measures to
undertaken by the CBD responsible for the theft in the case of a serious incident, including
regarding data protection CVR. It is mentioned in the manual
of the Air France plane that once grounded, pull and band
breakers corresponding to different recorders according to the instructions of the
MANEX B, and the mention of I'ATL, something that has not been made ​​by the CBD that flight
which did not allow investigators to verify all communications in
cockpit during the approach and landing.
It should be noted that the regulation in force class this as a serious incident,
therefore, the flight crew should treat it as such.
In addition, the head of Air France station at Casablanca airport
Mohammed V, was content to accompany the flight AFR1896 CBD office
track record of drafting the offense and keep a copy.
timely
.

3.1 Faits établis :
.......
· L’avion était haut et rapide par rapport à la trajectoire nominale d’approche.
· L’absence des enregistrements des conversations dans le poste de pilotage pendant cet
incident n’a pas permis de clarifier certains détails de l’événement, notamment la tenue
de briefing avant l’approche ;
· L’attitude du CDB n’était pas en cohérence avec les bonnes pratiques en matière de
gestion des ressources dans le poste de pilotage.
· L’avion a atterri sur une piste non assignée (la piste 35 R au lieu et place de la piste 35L);
· Le CDB n’a pas appliqué les consignes de la compagnie Air France (AF) dans le cas d’un
incident gave ce qui n’a pas permis d’exploiter les données du CVR en temps opportun.
3.1 Findings:
.......
· The aircraft was high and fast compared to the nominal trajectory approach.
· The absence of recordings of conversations in the cockpit during this
incident has not helped to clarify some details of the event, including the holding
briefing before the approach;
· The attitude of the CBD was not consistent with good practices
resource management in the cockpit.

· The plane landed on a runway unassigned (runway 35 R in lieu of runway 35L);
· The CBD has not applied the instructions of Air France (AF) in the case of a
incident which gave no license to operate the CVR timely
.

bubbers44 26th Aug 2012 15:06

BOAC, for the 50th time, they were hired with low time and monitored Airbus autopilots for years until their actual piloting skills were required with no autopilot and they failed. They could not hand fly.

BOAC 26th Aug 2012 17:37


they were hired with low time
- I've heard tell a lot of pilots start with 'low time', and in the 21st Century where most of us live, they then monitor autopilots for years (including the AF447 Captain).

They were NOT 'new and inexperienced' - get your terminology right - unless, of course, you consider 10 years on AB, 39 SA route rotations and 6500 hrs 'new and inexperienced'?

It seems you may have dozed off for a decade or two. Exactly WHAT do you expect a crew to have as minimum 'experience'?

"They could not hand fly." That much is obvious, but I would add for accuracy "They could not hand fly an AB340 in Alt Law.". How they would have fared in a different a/c we will never know.

bubbers44 26th Aug 2012 19:17

I guess this is a waste of time but in my 23,000 hrs my airline never required me to be on autopilot and monitor it 95 % of the time and only take off and some times land manually. I always hand flew enough to know I could do what the autopilot quit doing. These two couldn't and what they did by pulling up into a full stall shows what automation does if you don't maintain basic flying skills.

bubbers44 26th Aug 2012 19:32

BOAC, you are wrong even though you have 10 times the posts I have. No pilot should depend on automation if he can't do it himself. Yes I am in the 21st Century too but letting automation make you a monitor and not handle a simple situation like they had, UAS, isn't the answer. If the automatic stuff quits it is no big deal unless you don't know how to fly.

jcjeant 26th Aug 2012 19:37

I think whoever said (Ziegler) that Airbus could be controlled ( monitored ? ) by his concierge was right
He just forgot to say that it was the plane had to be configured on autopilot and normal law

RetiredF4 26th Aug 2012 19:52


Quote CONFiture
Any release of the stick, not to talk about push command, would have provoked an immediate ND change in the attitude.
Direct law would not have allowed to go that easily to the stall and would have favorized an exit from that stall.

HazelNuts39: In the two instances that the PF released the stick, the elevator responded and the airplane promptly pitched ND.

Quote CONFiture: And nothing to compare with what would have been obtain in direct law in terms of ND movement and AoA reducing in order to achieve stall exit.
@HazelNuts39
To emphasis CONFiture´s position: Elevator only reduced from full NU to 15° NU (time 02:12.46 and 02:13:55) after a significant time delay, whereas in direct law the elevators would have responded immidiately according to the SS position, meaning SS neutral, elevators neutral, SS Full ND (02:12:32, 02:13:40) elevators equivalent full ND. Just superimpose the SS command over the elevator position and the outcome is obvious.

HazelNuts39 26th Aug 2012 21:20

RetiredF4;

Thanks for emphasizing Confiture's position. I was aware of that when I wrote my reply. But would a brisker response of the airplane have altered what the PF was trying to achieve? Have you considered why he briefly released his pull on the stick? I submit he did because the airplane pitched up when he increased thrust. Nothing indicates that he had any intention to get the nose down to an angle that would have unstalled the airplane. When the attitude reached 8 degrees and stopped increasing he started pulling again and kept pulling for over a minute. Yes, the airplane would probably have responded more briskly in direct law, but it is somewhat of a stretch to say that that would have changed everything.

RetiredF4 26th Aug 2012 22:18


HazelNuts39
But would a brisker response of the airplane have altered what he was trying to achieve? Have you considered why he briefly released his pull on the stick?
To answer that question we would have to come to a conclusion, what PF tried to achieve firsthand. Neither BEA nor our efforts here come to a final result.

Several options had been discussed here, and can be grouped into the intentional climb and the unintentional climb. By that i refer mainly to the amount and intensity of the climb, not the climb as the opposite of the descent or the equivalent of an maintaining level. That the PF intended at least to correct the indicated altitude loss and the deviating pitch and VS should be agreed to. Everything else later on is not clear anymore.

If the climb in that intensity was intentional, then nothing would have influenced or changed the end result. But do we have ultimate proof of that theorie? I dont think so. When PNF told the PF to go down, he acknowledged to do so, he did not argue against the PNF, although he didn´t comply in deeds. Was he not willing to do so or was he not capable to do so (intention to do so was present, but the means to accomplish it were unsuitable)?

We know almost, that the manual flying expierience of the PF on the A330 was mainly accomplished during takeoff and landing. In T/O it´s afaik comparable to a direct law behaviour, and during landing phase when SS inputs are necessary close to ground it´s flare law. During flare law the PF is maintaining the trajectory by compensating the system induced ND force by a NU SS input, and to reduce the trajectory he just has to relax some of this NU SS input. The normal feeling on the SS from day to day flying therefore is holding some backpressure to maintain the flightpath during landing or to rotate and climb during T/O. The necessity of ND SS input and the required amount of ND SS input in normal daily operation therefore differed grossly to that one needed to correct this unintentional climb.

Additionally in day to day flying the roll channel doesn´t need much attention, except when a change of direction is desired, but otherwise the aircraft is stable in bank. PF was occupied by getting the wings back to level and maintaining them there, with roll law in direct a task he was not used to do. He might have associated the prooblems in achieving the correct pitch with the deviations in changing bank angles.

My position was from the beginning and still is, that the initial climb in the recorded intensity and duration was unitentional due to lack of manual handling at altitude and in degraded law. That PF was more occupied by roll control than pitch control, the last one may be doing by feel like he was used to during landing phase in flare mode. His corrective action to the announced and acknowledged deviation from altitude and pitch targets was ineffective from the beginning, leading only to a little decrease of VS without correcting the main problem, the beginning trajectory through the propulsion ceiling and the lift ceiling. Selecting TOGA in honour of the stall warning 2 made those inadequate amounts of SS relaxing useless, increased the pitch even more and led to the final stall.

From that point on the crew was helpless, as they did not know what brought them into this situation, what that situation actually was and therefore denied them the insight, what actions would bring them out of this situation. Therefore the SS inputs in that phase after the stall are no pointer to the initial intent.

In this assumed unintentional sequence the mentioned points by CONFiture are more than valid.

Machinbird 26th Aug 2012 23:27

Thankfully the other F-4 guy (Franzl) has more time to post than I do, but I'm in full agreement with his analysis.

Full nose up after the stall, was simply an attempt to stabilize the aircraft's pitch attitude by a pilot who didn't understand WTF was happening.

There is sufficient reason to attribute the initial nose up leading to the stall as coming from the roll instability leading to inadvertent nose up inputs and the tendency of the aircraft's pitch channel to mathematically integrate those inputs. (For those who did not take calculus, it means add them all together). When did the initial nose up occur? Answer: When PF was fighting the roll problem the hardest. Did he have time to formulate a strategy of setting a nose up attitude? I doubt it. His computing power had to be focused on the roll problem.

Why doesn't the aircraft stop trimming in Alt2 Law when approaching the stall like it does in Normal Law?

More than likely, the engineers couldn't figure out a reliable way to do it. With stall AOA a function of Mach and gross weight/configuration, they didn't know how to make the Mach correction without airspeed inputs. They really should re-examine this more closely.
  1. You can likely make a fairly good Mach approximation from inertial data. With that data, altitude data, and a safety factor, they could stop the trim from running up to the limits.
  2. By considering alternate sensors for determining a stall state, they could probably stop trim from running up despite what would seem to be reasonable AOA at lower altitudes. What happens to the airflow over a wing during a stall anyway? Don't you think we can make a sensor to detect that state? I do.

HazelNuts39 26th Aug 2012 23:47


Originally Posted by RetF4
The normal feeling on the SS from day to day flying therefore is holding some backpressure to maintain the flightpath during landing or to rotate and climb during T/O. The necessity of ND SS input and the required amount of ND SS input in normal daily operation therefore differed grossly to that one needed to correct this unintentional climb.

A tendency to pull rather than push, combined with a concern for overspeed, in direct law as in alternate law, that sums it up nicely.

jcjeant 27th Aug 2012 00:16

RetiredF4

To answer that question we would have to come to a conclusion, what PF tried to achieve firsthand. Neither BEA nor our efforts here come to a final result.
The BEA report includes a exaggerated number of
Probably
Likely
If
Maybe

In the technical and human factors sections
It is rare to see a report containing so many conditional , uncertainties and inaccuracies while investigators have all the records (CVR-FDR) in perfect condition and many visual ( material - physical ) evidences
How aviation safety can be enhanced with the findings and recommendations originating from :
Probably
Likely
If
Maybe
That I do not know ...

gums 27th Aug 2012 00:58

Good analysis Retired and 'bird.

Without a "brain recording" we shall never know why the pilot kept pulling back. And I don't agree with 'bird about roll PIO and such. May have been there, but not to any serious influence versus the constant back stick.

If there is one good thing about the 'bus and our primitive system in the Viper, it was that HAL would use every control surface available to achieve the trimmed gee ( ours could be trimmed, but the 'bus was one gee all the time, corrected for pitch attitude). So simply relaxing the stick pressure would let HAL do what he was supposed to, allowing you to figure out what the hell was going on.

Another poster provided an excellent discussion of AoA WRT mach and altitude and such. But I am personally here to tell you that our primitive system handled the problem really well. We never exceeded the AoA limits while hard maneuvering, and the only way we got into a true "deep stall" was to hold a high pitch attitude as our energy decayed faster than the control system could get the nose down. Sound familiar?

Gotta go. Dodging hurricane in Florida.

Addendum:

It still distrubs me to see some pilots here that don't seem to understand how their jet flies. The new jets, with all the augmentation and such, may appear to be real easy to fly. Then you look into all the control laws and such and see what HAL is doing.

What do you do when HAL gives up?

I can't find one commercial jet with FBW or basic/advanced augmentation that doesn't fly like we old dinosaurs were used to.

As several here have pointed out, the 'bus is a basic "direct law" until well up in the air or in the "flare" ( not sure what the flare mode does, but whatthehell).

Ours was "direct" until weight off wheels. Then it was blended AoA, pitch rate and gee command until gear was fully up. Worked for me, and thousands of fighter pilots that have flown the jet since 1973.

I have a lot more confidence as a SLF after reading some of the "war stories" here from the professional pilots than I had three years ago. But make no mistake! If I am on board and you are the PF/PIC/AC or whatever, I shall be back there analyzing every move you make, heh heh.

Organfreak 27th Aug 2012 02:44

Huzah
 
The Peanut Gallery heartily endorses the views of Misters F4 and Birds.

:D:D:D:D:D

EEG for all pilots? A horrible idea whose time may have come.

:E

rudderrudderrat 27th Aug 2012 05:07

Hi Gums,

we shall never know why the pilot kept pulling back
I agree. He may have been attempting to out climb the CB in front of him - I have heard of other pilots who would attempt to fly over the top of a CB rather than through it despite being far to close to their ceiling.


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