glad rag

The AD certainly makes one stop and think, that's for sure.

Svarin

Clandestino wrote (about PIO/APC) :
Indeed, when the aircraft is fully stalled and mushing, and PF is holding full deflection left-up on his sidestick, and he is not touching the rudder pedals, yaw damper does give orders. After some time looking at these traces, I still cannot make sense of them. This is an area of interest which I hope will be investigated.

However, more akin to the APC definition which you suggest is the start of the sequence, right when PF takes control. Roll and yaw are mixed up in an oscillation, which appears to the pilots as a pure roll movement, but where in fact rudder is actuated and lateral accelerations are measured.

Surprisingly, no trace of gyros is provided. Yaw rate gyro would be interesting to look at. Heading traces are insufficiently detailed to extrapolate yaw rate from them.

Moreover, I am greatly interested in aileron authority and response to SS inputs. It appears that right inboard aileron maximum deflection remains limited to a modest amount. This maximum available deflection decreases significantly within the first seconds after A/P quit. Such limitation is surprising in the context of a Direct Roll flight law, which is part of Alternate 2B global flight law.

Interesting elements of comparison are available with the D-AXLA accident report. FDR traces show a large number of fascinating bits of information. Such are not provided in the 3rd interim report which is our subject matter. Maximum aileron deflection appears different in this report. However, the exact type of aircraft is different of course. Expert input welcome.

AlphaZuluRomeo

Well, perhaps A33Zab (or other knowledgable people) may help here. I would have thought that that kind of ECAM would also trigger an ACARS message, for the maintenance teams to check the vanes after the flight. Am I mistaken, here?
If not, given that we know there wasn't such an ACARS message, we may safely assume that the ECAM/warning was not triggered.

RetiredF4

I was answering upon DozyWannabes remark
and tried to find an explanation for it. It is not relevant for the start of the upset and stall, but it is relevant information, as it is a typical stall behaviour for a swept wing aircraft. Known to the crew it should have helped to recognize the stall (if they missed everything else) and to react more adequate to the rolling tendency by using manual rudder instead of aileron to roll wings level.

Yaw damping was active, also according to manual, but not side slip estimation.

Honestly i don´t know how this missing sideslip estimation influences the behaviour of the rudder in a stall, or how the functioning yaw damping influences it in a positive or negative way. But hopefully somebody can explain.

That compilation does not help, as it reflects the pitch attitude, the rudder position and the bank angle, but not the input from stick or rudder. Would be interesting to compile those with the input from SS and Rudder, the difference then would be the FCPC input (would do it myself, but am too dumb for it).

CONF iture

You’re not without noting that ADs are usually and conveniently not 'linked' to any accident …

Fully applying to the facts is actually my main purpose, but what do you imply by stating the BEA has changed ?
Is it how finally the awaited independency and transparency are upon them, so how do you see how things were managed 20 years back ?
I can’t remember you ever publicly doubting the official line …



This, is a relevant piece of observation that I could hardly refute.
Thanks A33Zab.

Mr Optimistic

Re 'verbalisation', is it still correct to think that BEA have not released all the cvr transcript so more may yet come ?

lomapaseo

CONF iture etal

I'm puzzled by the arguments involving ADs, DGAC and the BEA

ADs are specific and the responsibility of the regulator to enforce

Accident causes are general (multiple layers of swiss cheese) and the responsibility of the BEA to dissect

What am I missing in understanding the arguments ?

lack of ADs don't cause accidents, but the presence of ADs may minimize future accidents

xcitation

Good call. I lost sight of that. ALT LAW occurred at the outset when AP off.
PF immediately 3/4 stick back for no known reason. After 20 seconds PNF states "ALT LAW, Protections Lo"(st). By then the speed had decayed and they were dancing the edge of the flight envelope.
PF was over controlling from the get go. Large scale stick inputs, thrust set at TOGA and then idle, Air Brakes deployed. Ignoring PNF directions. Did he panic?
Sadly if PF had left the controls alone and sat on his hands it could have been a different story. Near the end he verbalizes his desire for max nose up thus confirming it was intentional SS input. This would fit him not being aware of ALT LAW or not understanding it.

xcitation

Can a french aviator clarify the extent of usage of the word "stall" in their training.
Is the english "stall" widely used in French aviation training or is the native "décrochage" used?
Is hearing "stall" a routine part of stall avoidance training in the sim?

rudderrudderrat

Hi xcitation,
If he'd done that - it would have continued to roll right wing down until it was inverted.
They were struggling to keep the wings level in ALT LAW from the outset.

Clandestino

I think that BEA should be informed about your concerns. There's a faint possibility they believe that two agreeing AoA probes outvoted the third. It is of utmost importance to discover which version is correct.
Yup, my mistake. It wasn't 32, it was 33 before and four between the accident and publication of interim 2. Thank you for pointing me towards the more reliable source.

Yup, because that made the difference between 37 happy landings and one crash. Other crews may not followed procedures, but they kept the aeroplane aloft.

If you look closer it seems that it's not just right inboard aileron. Left inboard aileron also goes only to about 5° up and no more. Is it normal to have ailerons with different maximum up and down deflection? Is it usual? Is it only Airbus specialty? We have the right to know!

Regarding the aileron authority: do you remember what aileron authority you had when stalling your first trainer? Widebody plummeting oceanwards at AoA higher than 35° is bound to have it even worse than that.

xcitation

Well maybe you hit the nail on the head. That is about the only thing they all focussed on. Forget speed, stall, attitude, THS and just focus on the roll. Amazing that they had such roll control once they stopped flying and became a falling 200 tonne piece of metal. If anything from all this the airbus is an awesome forgiving airplane at low speed. Would you expect to have control of liner at speed as low as 30kts in chop? If you asked me I would say it tumbles and break up.

PinkHarrier

Have I missed something? What would cause three pilots to know that the last thing they should do is put the nose down?

DozyWannabe

Are you sure? The initial roll could have just been a nasty bit of turbulence - everything after that could be PIO/ADC - the lateral control inputs from the PF certainly seem in excess of those required at cruise altitude.

HazelNuts39

The airplane rolled through seven degrees in two seconds, not really an alarming rate (the 'second' hand on your analogue wrist watch 'rolls' twice as fast). Upward gusts alternated with downward gusts about every five seconds.

OK465

I would not mind if someone would explain to me how releasing the SS in roll direct results in the aircraft rolling inverted, but more importantly explain this to the RAF who just sub-leased 2 of these aircraft and are probably not aware of this.

henra

Lookng at the likelyhood of the reasons for that tendency to roll it seems pretty obvious to me that we can assume that turbulence played a or the major role in this.
If that was the case the probability of a stable continued role to one side until inverted is rather low.
Looking at the outcome I'm with excitation on this one.

grity

even the interpretation of a medical monitor needs big experience, hehe we discuss since many weeks the lines of less minutos..... but in this case a trendline of the altitude, wouled helped the captain a lot to spot the situation (maby with a future-line calculation for different pitch or powers....?)

rudderrudderrat

Hi OK465, DW, henra,

Unless the aircraft was trimmed exactly to balance any asymmetric thrust (due TL moved in response to thrust lock), it would tend to roll one way and continue to roll, unless counteracted by pilot or Auto Pilot input.
Since it was in Alternate Law, there was no AP or FBW roll input - only pilot input.

At what attitude do you think it would stop rolling if left by itself?

bubbers44

I, by choice never flew the Airbus but friends that do say if you leave the plane in a bank it maintains it forever. Even in alternate law. If that is true it wouldn't roll inverted but I am sure a pilot would correct it if this information is wrong. I am so happy I only flew Boeings. They always do what you want.