How safe is (airbus) fly by wire? Airbus A330/340 and A320 family emergency AD

[DozyWannabe]

@BOAC - A "Dual Input" rumbler would have worked just as well in that situation - equally, as I said, the CVR suggests that the PNF was aware of what the PF was doing, but felt unable to take control, instead electing to wait for the Captain to return - by which time the situation was arguably irrecoverable.

And this is but a single incident - one in which the PF acted contrary to procedure and basic airmanship and the level of CRM on the flight deck was insufficient to catch it - an anomaly as opposed to a pattern.

@RunSick - I understand where you're coming from, but on the other hand you're supposed to trust your colleague, no? The instruments are in front of a monitoring pilot telling him or her exactly what the aircraft is doing. Is "Following through" with PFC inputs not something that only really belongs in training?

[Chris Scott]

Quotes from DozyWannabe, in answer to BOAC's suggestion that the PF's sidestick position might be displayed on the PFD in flight, not just on the ground:

(1) "Again - to what benefit? Adding more data to the visual perception channel risks overloading it."

Yes, it couldn't be on the PFD, IMHO. But there might be an argument for a separate, small display. But this would be of little help to the PNF when the aircraft is near the ground, and the PF is struggling. In the latter case, tactile is the only way.

(2) "Why the need to know precisely and at all times what your opposite number is doing with the PFC when only one pilot is supposed to be PF?"

Only someone with command experience in a two-pilot cockpit can really appreciate the desirability of this traditional feature. (See my previous post of Jan 02 @1959Z.) It's particularly so when a trainee, or inexperienced copilot, is the PF.

[DozyWannabe]

Originally Posted by Chris Scott

Only someone with command experience in a two-pilot cockpit can really appreciate the desirability of this traditional feature. (See my previous post of Jan 02 @1959Z.) It's particularly so when a trainee, or inexperienced copilot, is the PF.

Understood, but please humour me and try to explain. I'm not debating the desirability in this instance, I'm just not convinced - and it seems neither were the pilot engineering team at Airbus - that it's a necessity. I'm fairly well-versed in the Airbus perspective, all I'm asking is help in understanding the other side.

[Lyman]

ASKED (I assume in genuine sincerity)....by Dozy

"I swear I'm not being facetious - I really want to know why it's such a big deal for some."


ANSWERED (By a Captain, in type, with extensive experience, and great respect locally.)

Only someone with command experience in a two-pilot cockpit can really appreciate the desirability of this traditional feature. (See my previous post of Jan 02 @1959Z.) It's particularly so when a trainee, or inexperienced copilot, is the PF.

I have tried, and couldn't possibly put it better.....Especially so since Dozy and yours truly should really defer...

[jcjeant]

The information I have suggests that BZ's engineering title was more of an honorific

?

Bernard Ziegler (born March 12, 1933) is the former Airbus senior vice president for engineering. He is well known for his evangelical zeal for the application of the fly-by-wire system in the Airbuses. He is the son of the former Airbus CEO, Henri Ziegler.
Bernard Ziegler was born in Boulogne sur Seine, France. He was educated in the École Polytechnique (1954), as an engineer and École de l'Air (1955), for his pilot training and military commission.
In 1961, he continued his studies and joined the National School of Aeronautics and Space (SUPAERO) and then at the School aircrew testing and reception (EPNER) - School of test pilots. He then entered the flight test center in 1968 and became chief test pilot of the Dassault Mirage G1.
Mr. Ziegler began his career as a fighter pilot in the French air force. He saw action in the Algerian War and was decorated twice. Principal medals and decorations received include the Officier de l’Ordre National du Mérite, Médaille de l'Aéronautique, Croix de la Valeur Militaire and Officier de la Légion d'honneur.

It's seems to me that BZ have more than a "honorific tittle" of engineer ...
Honorific are his list of medals ... engineer tittle .. certainly not.
He was certainly not considered in the Airbus project as a "honorific guest engineer" ...

[DozyWannabe]

Originally Posted by jcjeant

[Ziegler] was educated in the École Polytechnique (1954), as an engineer

That was his education, but his profession was as a pilot - he was not an engineering pilot from what I've been told. While still at the ARB, Gordon Corps had been working with the technology from the original Concorde "minimanche" experiments in the late '70s where the aspects of the design were refined - that was why Airbus hired him. This all happened before the A320 project was formally begun, and before BZ ever entered the picture.

[jcjeant]

That was his education, but his profession was as a pilot - he was not an engineering pilot from what I've been told. While still at the ARB, Gordon Corps had been working with the technology from the original Concorde "minimanche" experiments in the late '70s where the aspects of the design were refined - that was why Airbus hired him. This all happened before the A320 project was formally begun, and before BZ ever entered the picture.

I wonder why many people want to minimize the role of BZ in the genesis of the Airbus project ?
Maybe because his proselytizing without limitation about this project which has proven to be in a certain way damaging for the "Airbus image" ? (my concierge can fly it )

[jcjeant]

Lyman

"Climb, then!" ..... "(), But I have hald aft stick for some time now!"

DW

@Lyman - To what benefit? In airliner operation the PNF/PM is supposed to be monitoring the aircraft, not the other pilot.

[DozyWannabe]

jcj - It's not about minimising, it's about an honest appraisal of what went on. BZ's role was that of a product evangelist and publicist and for better or worse, his approach rubbed many people up the wrong way.

He did not have the relevant contemporary qualifications or practical experience to make decisions on implementation detail. He did, however, have confidence in the teams under him - but the way he went about expressing it was arguably counter-productive for some.

As an aside, the Space Shuttle programme was pitched to NASA as a "space truck", but at no point did the veteran astronaut crews take umbrage at the term, nor did they consider it demeaning to their role and skillset.

[RetiredF4]

Awareness of PNF

All bolding by me

DozyWannabe
@BOAC - A "Dual Input" rumbler would have worked just as well in that situation - equally, as I said, the CVR suggests that the PNF was aware of what the PF was doing, but felt unable to take control, instead electing to wait for the Captain to return - by which time the situation was arguably irrecoverable.

It is helpful, to reread the report. Your above assumption is just that, an unfounded assumption.

Four seconds after the autopilot disconnection, the rapid increase in nose-up attitude resulted in the triggering of the STALL 1 warning. This warning only appeared to provoke a small aeroplane handling reaction from the PF. The PNF asked “What is that?” which may refer to the stall warning. It is possible that the PNF, faced with a short, truncated warning, did not identify it. However, rather than indicating his failure to recognise the warning, this question seems to mean that the PNF did not consider the warning to be relevant in the context of the fact that he was not necessarily aware of:

ˆˆ- The PF’s significant nose-up inputs that generated an increased angle of attack;
-ˆˆThe relative proximity of a flight envelope limit;
-ˆˆThe reconfiguration to alternate law (which he only called out later): if he thought they were still in normal law, the warning could have seemed to be irrelevant.

It would also seem unlikely that the PNF could have determined the PF’s flight path stabilisation targets. It is worth noting that the inputs applied to a sidestick by one pilot cannot be observed easily by the other one.....

later on...

The PNF had noticed the need to stabilise the flight path, and the need for moderate aeroplane handling inputs. He probably considered that the reduction in pitch and the vertical acceleration sensed was a sufficient sign that the PF would correct the flight path to allow him to devote himself once again to identifying the failure.

he had to consider, but could not confirm what his partner was doing at all.


the following speaks for itself, still no awareness...

The crew never referred either to the stall warning or the buffet that they had likely felt. This prompts the question of whether the two co-pilots were aware that the aeroplane was in a stall situation.

And finally...

When STALL 2 warning triggered and buffet appeared, the PNF was faced with an increasing incomprehension of the situation.
The PNF’s strategy was then above all to call the Captain, which occupied a large part of his resources. Since he was anxiously waiting for him to return, it is possible that the phenomenon of attention selectivity reduced his ability to perceive the STALL warning.

And to top it...

At about 2 h 11 min 38, after the PF said “I don’t have control of the plane at all“, the PNF called out “controls to the left“, took priority and made two lateral left inputs to the stop. The aeroplane was then rolling to the left.

Still no correction of the pitch!

Hell Dozy, from where does your above statement come from?

Chris ScottOnly
someone with command experience in a two-pilot cockpit can really appreciate the desirability of this traditional feature. (See my previous post of Jan 02 @1959Z.) It's particularly so when a trainee, or inexperienced copilot, is the PF.

DozyWannabe
Understood, but please humour me and try to explain. I'm not debating the desirability in this instance, I'm just not convinced

You need a mathematical formula to believe it?

[jcjeant]

jcj - It's not about minimising

When you write that a man who have the title of engineer is a "honorific engineer" you relegate the title .. you make it void .. so you minimize any engineering decisions of this man

[RetiredF4]

DozyWannabe
jcj - It's not about minimising, it's about an honest appraisal of what went on. BZ's role was that of a product evangelist and publicist and for better or worse, his approach rubbed many people up the wrong way.

He did not have the relevant contemporary qualifications or practical experience to make decisions on implementation detail. He did, however, have confidence in the teams under him - but the way he went about expressing it was arguably counter-productive for some.

Should be possible for you to produce a reference for that? Or is that your personal oppinion?

[DozyWannabe]

Originally Posted by RetiredF4

Should be possible for you to produce a reference for that? Or is that your personal oppinion?

I told you - I cannot talk about the info I have, or it's source, without permission from the person who told me. As I do not have that, my hands are tied and I'm sorry.

I'm not asking for a mathematical formula, just a reasoned explanation to aid my understanding.

@jcj - I used an analogy to explain the situation. Bill Gates' title at Microsoft is "Chief Software Architect", but that does not mean he is present at all of the meetings and doing the work of implementing and defining software architecture because he's been out of "the trenches" too long. He understands high-level concepts and acts as arbitrator where necessary - from what I was told BZ's role on the A320 project was similar.

[RetiredF4]

DozyWannabe
I told you - I cannot talk about the info I have, or it's source, without permission from the person who told me. As I do not have that, my hands are tied and I'm sorry.

That´s worthless. I know a lot of people who know something which was told by somebody who doesn´t want to be connect to his saying.....

DozyWannabe
I'm not asking for a mathematical formula, just a reasoned explanation to aid my understanding.

The problem is not, that nobody i trying to explain reasonably, but .........

[jcjeant]

Hi,

DW

I told you - I cannot talk about the info I have, or it's source, without permission from the person who told me. As I do not have that, my hands are tied and I'm sorry.

So .. it's seems that for you BZ was just spokesman for Airbus
But ...

Bernard Ziegler was the most influential figure in developing the cockpit design and fly-by-wire control system for the Airbus airliners. He proposed that numerous technological innovations be applied to Airbus aircraft; for example, using composites, twin-engine configuration for the A300, fly-by-wire and many others. He was the guiding force in the creation of the flight envelope protection, incorporated in the Airbus flight-control software. This innovation allows the pilot to apply the maximum control forces considered necessary, while preventing inadvertent inputs that could place the aircraft outside the safety margin. This feature is considered by many to be highly beneficial in avoiding unusual attitudes in flight and in safely maximizing the effectiveness of evasive maneuvers in response to GPWS warnings.
For his efforts in advancing the fly-by-wire cause, he was honoured by the Flight Safety Foundation in 1998. He retired from Airbus after 25 years of service in 1997.

It is a wonder why Airbus (and many stakeholders in the world of civil aviation) has always put forward (publicly) the role of BZ and not that of the famous test pilot and technical advisor
It is even BZ who receives the honors ...
Airbus was lucky (and BZ too) that his brilliant career was not stopped by this sad event

In August 1961 the Vallee Blanche Aerial Tramway was badly damaged when an aeroplane of the French Air Force piloted by Bernard Ziegler tore its hauling cable. Three cars crashed and six people were killed.[1]

[RetiredF4]

Bernhard Ziegler

July 2012: Bernard Ziegler receives the Flightglobal Lifetime Achievement Award.
From Airbus page Press center

[DozyWannabe]

@jcj - Precisely. High level concepts, not implementation detail.

Originally Posted by jcjeant

It is a wonder why Airbus (and many stakeholders in the world of civil aviation) has always put forward (publicly) the role of BZ and not that of the famous test pilot and technical advisor

There's an annual lecture in the latter's name at the Toulouse Branch of the RAES. From what I'm told he wasn't much for self-aggrandisement - the same cannot be said of BZ.

Toulouse Branch Gordon Corps lecture | Branches | The Royal Aeronautical Society

[hoggsnortrupert]

Twin Otter Pilot:

I have never flown anything as complex as a fly by wire system, but!

I do wonder! Can someone give me the answer to this question:

Does Air Bus acknowledge that its machinery is flown by PILOTS, or are they SYSTEM MONITORS:

Authorities and some Air Lines have now recognized the very real threat that their PILOTS have lost their basic airman-ship flying skills, which is what alot of people in the industry, along with myself, have seen happening for the last twenty years:

I have reed the report on AF 447: (Talk about a shinning example of CRM, & Leadership)

In my opinion the system can have all the bells and whistles, and colored lights, nice female voices, & coffee on tap! but give the PILOTS, the means to IMMEDIATELY BE ABLE TO PUSH A BIG RED BUTTON:

But if it goes pear shaped at 500 ft on take off in hard IMC, and you have to analyze, recognize, then shut down the ADR's, is in my opinion a big ask, of any crew:

In my opinion A/B is ignorant of HUMAN FACTORS:

Now I will twaddle off into my Twin Otter office with 8 sectors, and all my manual flying:

Chr's
H/Snort

PS: exercise for you all, trawl through all this guff from the first posting, and read and sit back and think about what you are discussing! it is quite disturbing:

Let the clubbing and beatings commence:

[A33Zab]

@BOAC:

Why not, as an interim measure, enable the stick position display in flight (I understand it displays only on the ground)? I wonder if an obvious nose up demand from PF would then have been visible to the Captain when he re-entered the cockpit?

X-channel on monitoring pilots display only, red/amber on both displays when dual input. shouldn't be to difficult to adopt for current fleet.

But it is up to Airbus pilots to demand for such a system.

Other solutions Interlinking/tactile FB/ Decoupling/ Summation/Disabling adds complexity and far more failure possibilities.

[Chris Scott]

Quote from DozyWanabee:
"Understood, but please humour me and try to explain. I'm not debating the desirability in this instance, I'm just not convinced - and it seems neither were the pilot engineering team at Airbus - that it's a necessity. I'm fairly well-versed in the Airbus perspective, all I'm asking is help in understanding the other side."

Fair enough, and I'll do my best! But please also read my post of January 02 @ 1959Z.

There are, I guess, two advantages to the traditional interconnection.

1) Tactile feedback to the PNF for monitoring, but that only applies if he/she is touching the stick. That needs to be done very gently and carefully, as it can make hard work for the PF. In practice, therefore, we tend not to do it unless we are contemplating a sudden takeover of control. (However, I do remember once or twice, as a PNF trainee, being invited to “follow through” the training captain as he demonstrated the PF job.) This care would be particularly necessary with the sidestick, which the PF best handles with fingers and thumb: NOT the gripped hand. The advantage of the conventional yoke (and this also applies to old-fashioned joysticks in tandem cockpits), is that (peripheral) vision of its movements gives the PNF some idea of what’s going on.

2) The ability of the PNF to takeover control without pushing a button. Pilots are very reluctant to do that, because it would be a clear expression of no-confidence in the PF‘s handling. However, without pushing the button of your Airbus sidestick, you cannot counter a full-deflection on the other stick; only neutralise it. And that would be a recipe for loss-of-control.

Must finish by pointing out that these tricky situations are rare on a well-trained pilot fleet, but not unknown. The reluctance of the PNF to interfere applies on traditional types also (see above). The frailty of the human condition is not unique to Airbus cockpits! But momentary intervention (like correcting an undesired wing-drop on a gusty, crosswind landing) is easier on traditional types. Having said that, the Airbus in Normal Law is, IMHO, a more forgiving aircraft to fly “manually” than most of those. Can’t (and won’t) second-guess the Boeing version.

That's my take on it. Can current pilots comment?

In 14 years of line flying the A320, starting from type-certification, I never found myself in other than Normal Law.