FBW question

[JammedStab]

To quote....

"There is to be even greater innovation in the cockpit of the fly-by-wire G500 and G600, which will be the first Gulfstreams to feature active sidestick controls. According to Mark Kohler, Gulfstream vice president for advanced aircraft programs, the airframer was unwilling to make the shift to a sidestick control until BAE Systems adapted technology originally developed for fighters for civil use. “The system’s active force feedback provides a classic airplane feel, and it simulates the feel of mechanically linked sticks,'”


Does Airbus have this active force feedback that Gulfstream says they were waiting for?

[Denti]

No, they don't have that.

[Piltdown Man]

Airbuses and stalling.

As I understand it, in normal operation FBW Airbus aircraft are designed to prevent a stall from occurring. But what if it does? So firstly, how does an FBW Airbus (A320 type) announce that it is stalled? Secondly, how does it recover from a stall? Does it do this by itself ie. recognise that it is stalled and reduce the AoA, change the position of the elevator trim if inappropriate, apply thrust etc. or does it throw up its hands, change the active flight law (upgrade/downgrade) and let the pilots deal with the problem? Lastly, how often is this manoeuvre practiced?

[Radix]

..........

[NigelOnDraft]

PM:
Read up on Alpha Prot, Max and Floor.

There is, IMHO, rather a big deal being made on here about the difference between recovery from the approach to a Stall, and from an "actual" stall.

I cannot recall many types where the drills / actions required differ. Including the Airbus A320 series. Yes - the degree / magnitude of response required may differ but the "drill" remains the same.

When you apply FBW to it the software / automation will often degrade, if only since by definition, it either has a fault, or external circumstances out of it's control, if a stall occurs. The "degrade" basics are not just "throwing it's hands in the air", but ensuring inappropriate control inputs are not made due to the fault etc.

[PEI_3721]

Airbus does not currently use active force feedback; the technology was unavailable at the time of design. Airbus side-sticks have some force-feel about the null position.

Force (positon) feedback can provide an indication of the aircraft trim condition about a datum speed; this assumes that autotrim follow-up is not used.
Mechanical or similar hyd/elect technology enables cross coupled feel/positon from the other stick. However with any system the problem of a system jam/restriction has to be solved – in the stick, in the cross coupling, and elsewhere in the system. Airbus uses an elegant electronic solution, but this comes with novel aspects which require understanding – control priority/lockout. Fighter aircraft generally don't have a problem with cross coulping.

Some of the arguments for non-feedback systems assume a high degree of automatic flight, and particularly automation for speed control – where stick force is an indicator for trim speed. There was a further argument about speed displays, where if a speed tape was inferior to dials there would be greater dependency on automated speed control.

There may be some concern if sidesticks are used in smaller aircraft without A/T and/or weak speed displays; however Gulfstream’s philosophy appears to be aligned with the heavy jets, and notably their first tape speed scales were opposite to others in the industry.

Stall avoidance in FBW aircraft is part of the overall control system, but not directly associated with the stick design. Conventional systems provide some stall awareness / protection from stick position.

[RVF750]

I've often thought that some force feedback is the answer to Airbus' problem.

If the stick position is motored to show the summed flight surface movements, it would be easy to provide the means to show the uncoupling in jammed control conditions by making the individual sticks show the movement in that side only. Who needs a load of ECAM messages when one moves and the other doesn't!

Also, if a pressure sensor is used on the stick neck, as in some fighters, you push the stick to move it, but the force is sensed and fed to the FBW system. The actual movement is a feedback to you. Thus any interference of Alpha Floor, or similar can be felt directly as the stick not responding in a natural way. Also if they moved the bloody throttles as well, you'd actually be able to FEEL the plane flying for you and be in the loop if you disconnect on a windy day or whatever.

I suspect it's this lack of feedback to provide feel is why many like me really don't want to fly Airbus products anytime soon.....

[PEI_3721]

TD, Airbus does not have a problem, but some sections of the industry may have.
There are many myths and folk laws about FBW, often from basic training – ‘it can’t stall, thus no need to train that aspect”.

FBW is a particular technology primarily associated with the transmission of piloting input to control activation. The technology replaces or adds to the many restricting and aiding devices in conventional controls.
The industry problem is with the understanding of these aspects of the technology, its intended use, and limitations.

The latest technology enabling a force feedback side stick offers opportunity for improvement, but it is not an essential aspect to cure ill formed biases.
Many aspects of manoeuvring flight don’t require force feedback or even sick movement, but for aiding awareness of flight, protections, etc, then the stick provides a means of feedback. But if you haven’t got your hands on the stick, then how is this awareness to be provided, and if provided, seen and used?
Thats a real problem, but it doesn’t involve FBW directly.

[Denti]

Airbus does not currently use active force feedback; the technology was unavailable at the time of design.

No, the technology was available, but it was deemed to complicated and failure prone to incorporate it into the FBW system.

I guess the main issue why many pilots would like some force feedback is a position feedback of the other stick, not necessarily of flight control positions.

[RVF750]

...which is what I was aiming at. Not force feedback but position feedback. I do feel the force feedback comes from the need to show the position of the flight surfaces. Thus if it moves less at higher speed, or the trim is out, etc, you would feel more resistance to your hand.

It's putting the pilot back in the loop, something Airbus neglected from the start. We start as small aircraft students and if you move to a large airliner too soon, you never develop the skills and feel.....I came up the traditional way, and so many companies look down their noses at people from this route. When it comes down to it, the absolute basic reversion is pitch power and feel. If you never had it, you never will. Sully has it in spades and many others too. Just my opinion, of course. I'm just arguing that AB doesn't value Pilot skills enough despite many crashes that may have been prevented if they had. It's the philosophy of flying. The hardware can make a difference!

Edited to say I do appreciate there are many very skilled and capable pilots out there flying Airbus products! I also know there are many operators who value these skills and tailor courses to keep them.

I just don't like the lifeless nature of the stick and throttles- it's very off putting! It's purely this that tells me what Airbus think of pilots!

[Clandestino]

Validation of pilot skills lies strictly with the operator and local licencing authority. It is no Airbus' fault if some of them go with whatever they can get away with nor it should take any credit for my 320 type rating training starting with five sessions of flying in Direct law, no flight director, autopilot nor autothrust. Also it is no coincidence that a classmate of mine that started in A320 RHS at the tender TT of 200, had aposlutey no problems 9 years and 6000 hours later with conversion to the left seat of Q400.

Stories about Airbus not requiring skilled pilot or Boeing being natural pilot's aeroplane are just black marketing rumours, usually perpetuated by the good folks clueless about either product.

Having flown 320 and being current in 737NG, I know which one I prefer.


The one that pays better.

[DozyWannabe]

Airbus does not currently use active force feedback; the technology was unavailable at the time of design.
With respect, you are incorrect on the latter point. The technology was available, but to use it would have added extra technological complexity in the first instance, and in the second it would have undermined one of the design goals - namely that the Airbus FBW fleet should appear to handle in a more-or-less identical fashion regardless of whether the specific type being flown was a short-haul narrowbody or a long-haul widebody.

If the stick position is motored to show the summed flight surface movements, it would be easy to provide the means to show the uncoupling in jammed control conditions by making the individual sticks show the movement in that side only.
But that undermines another positive aspect of passive flight controls - namely that by being able to override the opposite control and not have to physically work against the deflection, control of the aircraft becomes easier (think EgyptAir 990).

It's putting the pilot back in the loop, something Airbus neglected from the start.
Not only incorrect, but blatant prejudice. By making the sidesticks passive, all Airbus was doing was acknowledging the fact that since the advent of hydraulically-powered controls, the "tactile" feedback through the column was a simulation only, and a simulation which risked misleading pilots if the systems driving the feedback suffered a malfunction.

[glendalegoon]

clandestino...nope, the one with more days off and nicer over nights

[Cough]

I think the force feedback idea needs revisiting by Airbus...

Take the training environment, this is from here, under simulator assessment (http://www.aaib.gov.uk/cms_resources.cfm?file=/Bulletin%2012-2008.pdf)

In the first of these ‘unusual’ approaches, a manual approach was flown with autothrust, but the ‘trainee’ ceased to make sidestick inputs at 50 ft RA. The TRE(A) was unable to intervene in time and the aircraft struck the runway without a flare. In other ‘unusual’ approaches, the TRE(A) was again unable to intervene, or intervened too late, to prevent a hard landing.

For me, that summarises what has been said for years on the line about monitoring Airbus approaches...

[autoflight]

There is a relatively minor problem with sidestick feel. The aileron detent (if I can call it that) operates in the exact same position regardless of the fore and aft movement of the sidestick. Since the stick fore and aft movement is to the side of each pilot, pitch control is not a straight pressure towards the pilot. In ordinary flying conditions this is easy to get used to.

During a missed approach, especially from a low height, there is a pitch feel requiring additional rearward force on the sidestick. This increased force has a desensing effect for the feel of the aileron "detent", often resulting in a small unintended right turn for captain as PF, or a small left turn for FO an PF. This small turn and a correction to desired heading is evident on simulator tracking history.

The point is, that when larger than normal back pressure is required, the lateral feel should also be increased.

[Uplinker]

I have flown C172, PA28, Zlin, PA34, SD360, Q400, A320/321 and A330.

Given that my day job is commercial passenger flying - involving many aspects of flight in busy airspace, or at the tail end of an 8 hour transatlantic crossing, I am happy to let the FBW do some of the donkey work; trimming and prevent overstresses etc. while we monitor and 'conduct' the flight. One soon develops a "feel" for what is going on without having to have an actual 'feel' through the side stick. I can see what is going on by scanning my instruments. If I want to actually FLY an aircraft, and trim it etc., I could always go back to the Zlin !

Like any system, FBW is not perfect and has its gotcha's. e.g. AF447 et al. I personally think we should have more training rather than the minimum required. I think we should be actively encouraged to hand fly more often - like recording LVP approaches, and I think the side sticks should physically follow each other so we both can see or feel what the other pilot is doing. Obviously there would then need to be a disconnect system, but the one in the Q400 seemed to work very well, (albeit they use mechanical yokes not side sticks).

Just my 2p worth.

[Goldenrivett]

Hi John,
Anyone who feels 'out of the loop' flying an Airbus FBW product needs to take a look at themselves rather than the aeroplane design.
Have the authors of this paper got it completely wrong then?
Pilots in the loop? Airbus and the FBW side stick « Critical Uncertainties (http://criticaluncertainties.com/2011/09/16/pilots-in-the-loop-airbus-and-the-fbw-side-stick/)

"A key cognitive engineering flaw

The decision to use passive controllers unfortunately introduced a cognitive engineering design error in the form of the absence of tactile feedback to the pilots. This in turn transferred the behavioural cue from the tactile (hands on stick) to the visual channel of the pilots, with the design implementation further translating the cue from an analog kinaesthetic to visual symbolic form, which in turn requires higher levels of cognitive processing. This visual cue then competes for attentional resources in the visual channel and requires additional ‘mental bandwidth’ (e.g. symbology requires abstract processing) to handle. The net result an ineffective coordination mechanism under high stress conditions."

There is no feed back through the Thrust Levers in auto thrust or TOGA LOCK. More competition for 'mental bandwidth'.

[vilas]

john_smith bluntly put it and Goldenrivett has retorted with some evidence. I think the truth is in between. What JS is saying is that the airbus FBW is not a big deal and I agree with him. An average pilot can easily adjust to its design. The adverse opinions about AB FBW are because it is a departure from other airplanes pilots fly. You develop certain habits, feels and clues and once on Airbus you need to relocate a few things differently. There are pilots out there who switched to Airbus straight out of flying schools and they have been flying it without fuss. They may find it difficult to adapt to conventional airplanes and not vice versa. It is a very easy airplane to fly does not demand high levels of stick rudder skills. Majority of flights get conducted routinely and even many careers end without having faced any serious abnormality and Airbus is a very good airplane for that. It has had few quirks in its protections mainly the high angle of attack protections but Airbus FBW is too good a concept to discard totally. It has its followers and popularity and there can be no doubt that Airbus is here to stay.

[Amadis of Gaul]

Come now, john, the authors put that paper on the internet, and we all know everything on the internet is true!

[safetypee]

j s, it’s a little harsh to state that the authors are ‘wrong’; they have an opinion which should be respected.
However, I agree that the article is of little value because it appears to be biased by hindsight and tailored towards a particular agenda.
A meaningful discussion requires an understanding of the design principles and objectives of many years ago, the assumptions made about piloting skills, education, training, and procedures. These should be compared with today’s standards and expectations.
Many of the ‘problems’ stated in recent times stem for this gap in understanding; - different points of view, different operational environment, training standards, social expectations, etc.

j s, vilas, :ok:

[Amadis of Gaul]

j s, it’s a little harsh to state that the authors are ‘wrong’; they have an opinion which should be respected.


I disagree, not every opinion necessarily merits respect.

[DozyWannabe]

Have the authors of this paper got it completely wrong then?

While john_smith makes an (IMO quite correct) one-word response, it might be worth (yet again) trying to parse what's being said. For one thing the article posted (which is a blog post - not a peer-reviewed paper) is very hit and miss with its use of sources (including an article from 1987 - a year before the A320 even went into service). For another, it makes assumptions about the reasoning behind design decisions which are at best speculative.

Furthermore it makes this statement:
...in an emergency with a traditional yoke control the instinctual grab by the PNF is something that is clearly visible and also inherently self resolves the control contention...

which is fundamentally incorrect. In an aircraft with direct cable control, the aircraft will respond based on whichever of the two inputs is physically dominant (which is not necessarily the right thing to do), and in more complex modern aircraft with apparently "traditional" controls, the response may not be immediately obvious. An example would be the all-hydraulic B767 controls of EgyptAir 990. As it turned out, with one crew member pushing forward on the yoke and the other pulling back, the result was a split elevator condition which exacerbated the aircraft's departure from controlled flight.

In fact, a lot of the potential objections made by a subset of the piloting community around the launch of the A320 were based on the (as it turns out, incorrect) assumption on the part of those pilots that they knew what the response of their current aircraft types would be when presented with control-based edge cases.

The Boeing FBW system in the B777 retained (or to be more precise, reimplemented) the tactile feedback, but this came at an engineering cost - namely that the hardware and software required to provide this feedback was as complex again as the entirety of the Airbus EFCS. The sole reason the Boeing system requires a physical bypass control and the Airbus system does not relates solely to the potential scenario whereby the feedback system itself develops a problem.

The fundamental principle of the Airbus design involved confronting a basic truth that had been around for some time - namely that with hydraulically-assisted or all-hydraulic controls, the tactile feedback the pilots were getting was itself an electro-mechanical simulation, and as such open to potential failures and complexities that weren't really necessary.

As a postscript, it's worth noting that the naysayers the blog post refers to were predicting a slew of accidents caused by the change in control system philosophy - and to this date there have been precisely zero accidents attributed to the change.

[Microburst2002]

flight path stable fbw is inherently incompatible with any force feedback. (the case of airbus fbw)

speed stable fbw is another story (the case of boeing fbw, and gulfstream it seems)

[CriticalUncertainty]

Ehem,

I'm the author (there's just one of me) of the work quoted by GoldenRivett above, and I'll clarify that the quoted conclusion relates strictly to the mechanisms that are used to resolve dual input scenarios. On that function there is IMO sufficient evidence in the form of ATSB and NTSB reports to indicate that it is a less than effective implementation, for the reasons stated. I'd note that at the time I wrote it I hadn't seen the AF447 final report, which is why it's not referenced, again in that incident we see the same behaviour.

By resolve 'control contention' DozyWannnabe I mean the PF knows the PNF has his hands on the controls and can either tell him to get his hands off or relinquish control. Dozy you're reading more into it that statement than there is, but that's probably because of how I worded it (thanks).

Regarding FBW and displacement rather than force feedback, the reason that displacement is viable is that the protection laws can prevent you over-stressing the airframe. Hence there's no need for force feedback to tell the pilot to ease off. As Airbus point out you can get rid of a whole lot of complication and reliability problems by not providing force feedback, I agree and that too is in the quoted post. There are other reasons why it's essential to have protection laws on an Airbus, but I won't bore you with a discussion of C* based feedback flight control laws and FAA regulations.

As far as source data, I conducted what I consider to be a solid literature search, I'd note that the references quoted go from 1987 through to 2007. The use of side-stick controllers was a hot topic back in the 70s and 80s, and the US DoD was funding a lot of research into it that resulted in the USAF's F-16 side-stick controller (as an example). Their conclusions are still pertinent and I see nothing that has rebutted them. I also cautioned about drawing too general conclusions from work in the lab, my experience is that when you get into field trials things can often be very different from a human factors perspective.

I'd also note that the work by Corps (1988) was written by an insider to the Airbus program about the Airbus teams experiences with FBW and side-stick controller, you cannot really get a more contemporaneous and pertinent source than that. I summarise from that report how Airbus developed their dual input resolution functionality, it took several iterations and some incidents in the field before they settled on the final form. The paper by Corps is still good read, I recommend it.

Amadis, yeah everything on the interwebs is so true :) That's why I put my big smiling dial on my blog, tell everyone who I am, what my background is (system and aerospace safety, human factors etc) and give a list of my peer reviewed publications. All posts are open, I invite constructive comment, respect opinions other than my own and if I get a fact or conclusion wrong I correct it.

I hope all that helps in clarifying my position, which is that I am neither an Airbus-Boeing fan boy nor a hater, the real world's a little more nuanced than that.

Here's the link to the infamous post

Pilots in the loop? Airbus and the FBW side stick « Critical Uncertainties (http://criticaluncertainties.com/2011/09/16/pilots-in-the-loop-airbus-and-the-fbw-side-stick/)

[Clandestino]

Did you notice that the work you have quoted lists affiliation with Douglas Aircraft Company, builder of competing MD-80 design at the time?

[DozyWannabe]

I'm the author (there's just one of me) of the work quoted by GoldenRivett above
Welcome to the forum.

there is IMO sufficient evidence in the form of ATSB and NTSB reports to indicate that it is a less than effective implementation
I'd argue that the implementation is at least as effective as the alternatives for the reasons I mentioned above (particularly the unexpected side effects of dual input in the B767 as evidenced in EgyptAir 990).

I'd note that at the time I wrote it I hadn't seen the AF447 final report, which is why it's not referenced, again in that incident we see the same behaviour.
And yet there are other incidents involving aircraft with linked controls where the same thing happened (e.g. Birgenair 301, West Caribbean 708).

I'd also note that the work by Corps (1988) was written by an insider to the Airbus program about the Airbus teams experiences with FBW and side-stick controller, you cannot really get a more contemporaneous and pertinent source than that.
Indeed, but I'd argue you're quoting him out of context to make your point. If you were to take a look at my earlier posts, you'll see that I'm well aware who Gordon Corps was - in fact he's something of a hero of mine. His experience with the control setup actually goes all the way back to the Concorde "minimanche" experiments of the '70s and early '80s, when he was still at the ARB.

As far as the design of the Airbus FBW control system goes, the overriding ethos of the design was to use technological advancements to build a fleet of aircraft whose degree of similarity in terms of flight deck layout and handling characteristics would be unprecedentedly consistent across all types, from the short-haul narrowbody to the long-haul widebody. Because of the need to support legacy types, this was something that Boeing and MD couldn't hope to match, and in business terms, looking back across 27 years, it seems that Airbus were remarkably prescient.

The tendency for a group of pilots to react negatively to such changes is nothing new. If you go back to D.P. Davies' "Handling The Big Jets", he notes that a number of pilots fought the introduction of stick pushers tooth-and-nail. Hell, you can go all the way back to Eddie Rickenbacker's decision not to have autopilots fitted to Eastern's fleet at the time of their introduction - which ended up being rescinded very quickly!

[Cool Guys]

I dont think there is much disagreement regarding the advantages of the AB FBW/protections and uncoupled sidesticks. Some advantages that have just been mentioned are:

They are cheaper.
It is easier to implement commonality over fleet types.
And of course people can "get used" to the feel of the lack of tactle feed back.


However a key point with the "Pilots in the Loop" article is that tactile feed back requires less cognitive processing than visual. Hence:

Under heavy work load the pilot is likely to consume less of his cognitive resources on interpreting the machine interface and will have more left over to deal with what is actually going on with the plane.
And maybe there is a very small chance that an accident like AF477 would be less likely to occur.
I dont think anyone is implying accidents like AF477 would never never never never ocuur in a plane with more orthodoxed FBW/protections and connected yokes/sidesticks.

[Uplinker]

No, sadly there will always be accidents, but we must try to minimise them as much as possible. Not being able to see what the other pilot is doing with the controls is a major lack of important information, in my opinion. If that pilot is following SOPs all well and good, but if they do something totally odd and out of the blue and you can't see or detect that, then that is a problem.

But controls that move don't always help either. What about Asiana 214 that got slow on finals and crashed into SFO?

If you believe what the advocates say, thrust lever movement - or the lack of it - should apparently have been a big cue, but clearly wasn't.

[Jwscud]

Uplinker, it potentially wasn't a cue because PF was only about 20 approaches into flying a brand B after some years on the Airbus. The fact he was also holding 40 pounds of out of trim force suggests rather more basic issues.

Neither aircraft can save you from a basic inability to fly!

[Uplinker]

Neither aircraft can save you from a basic inability to fly!

Agreed. He obviously was not looking at his instruments either, which is pretty fundamental.

[Derfred]

It could be argued that as a result of his being accustomed to a thrust lever that did not move, he was not alerted when it didn't!

[vilas]

Derfred
He was an experienced 747 captain. Where do you think he got used to non moving throttles? What they both got used to was total reliance on auto throttle and not monitoring speed.On approach you monitor speed and not throttles. On heavy jet with that inertia you don't drop 30KTS on approach unless you are doing stall recovery and what about standard call outs? -5 KTS should have elicited SPEED call, -10KTS should have been a scream. When you check someone you have to be on your toes. This accident is a mirror reflection of an accident in 1990 in Bangalore only the aircraft was Airbus 320.

[Derfred]

Of course.

How anyone could fly an approach without keeping a very close eye on their IAS is beyond my comprehension.

How anyone could let the other guy fly an approach without keeping a very close eye on his IAS is also beyond my comprehension.

But having thrust levers that move is a tactile feedback that the autothrottle is doing something. It is something that Boeing pilots appreciate and Airbus pilots have to learn to live without. In changing from an Airbus to a Boeing he had possibly learned to live without it so it could be put down to one of those many contributing factors.

[vilas]

Derfred
Captain under check was an experienced 747-400 captain where are you bringing in the Airbus and Airbus pilots don't sleep on approach they get into the habit of watching the thrust N1/EPR itself. Yet in 1990 Airbus crashed in Bangalore for the same reason. There also not single call out for speed even when speed dropped 27 KTS below VLS. There is only one way to fly an approach aircraft doesn't matter and no excuse for poor flying, period. Is there any tactile speed back for Air speed indicator.

[Derfred]

vilas

Captain under check was an experienced 747-400 captain where are you bringing in the Airbus

No, he wasn't. He had flown the 747-400 as an F/O. Prior to this accident he had spent something like 9 years on an A320.

[Goldenrivett]

vilas,
Is there any tactile speed back for Air speed indicator.
Obviously not. But according to the NTSB report, with more handling practice, the feeling for the need for pitch trim should alert the crew to falling airspeed.

"More manual flight for Asiana pilots. Asiana’s automation policy emphasized the full use of all automation and did not encourage manual flight during line operations. If the PF had been provided with more opportunity to manually fly the 777 during training, he would most likely have better used pitch trim, recognized that the airspeed was decaying, and taken the appropriate corrective action of adding power."
Crash of Asiana Flight 214 Accident Report Summary (http://www.ntsb.gov/news/events/Pages/2014_Asiana_BMG-Abstract.aspx)

[vilas]

Goldenrivett, Derfred
I quoted two accidents. 1990 Airbus no feed back in the stick, throttles static fully serviceable 3 year old aircraft unlimited visibility aircraft fatally crashed killing even the pilots. 2013 SFO Boeing 777 conventional yoke, tactile feed back moving thrust levers weather and aircraft same as Bangalore crashed on finals. The only similarity in the two is pilots did not monitor speed. Bangalore it was -27KTS in SFO -30KTS. There are two categories of pilots first category lost their raw data skill and scan over a period of time by over reliance on automation. They forgot that instrument scan is no different on auto pilot or manual flying, only difference on auto is pilot just monitors all parameters. Second category they never acquired the skill in the first place. I see some cases where an experienced captain is unable to fly raw data during type rating on a new aircraft. Why should that happen if your scan is intact? Same classic T is used in PFD of any aircraft. Faulty or insufficient training and non critical refresher and checking are main causes.

[Derfred]

As I said, I don't disagree with any of that.

[Microburst2002]

Airbus sidesticks could be enhanced with a stick shaker, I suppose, but nothing more. Stick force must be totally independent of speed.

However I think that a loud "STALL STALL STALL…" aural warning is enough, at least for me.

In the case of the AF I don't think that a Boeing style fbw would have made any difference. They would have just done the same, pull the yoke till death. The airplane was airworthy, although somewhat challenging to fly.

It is human factors that have to be addressed. They were taken by surprise and they never recovered for it. They were so "in the red" and the tunnel vision so so narrow that they became effectively incapacitaded. Both of them. I wonder what rol had fatigue, complacency, health, etc in that incapacitation.

[CONF iture]

In the case of the AF I don't think that a Boeing style fbw would have made any difference. They would have just done the same, pull the yoke till death.
Little chance that the right seater could have maintained the yoke on his stomach for a 30 sec period just as the captain came back ... What a HUGE input for both the captain and the left seater on what's going on ...

[Microburst2002]

Maybe, but I think they were incapacitated, otherwise, the other pilot would have prompted the PF to pitch down. You don't just sit there silent while such a mess is going on. They lost their ability to manage the situation.

In the Boeing they would probably have pulled both together from the yoke when the other pilot noticed that the PF had difficulties in pulling.

[CONF iture]

In the Boeing they would probably have pulled both together from the yoke when the other pilot noticed that the PF had difficulties in pulling.
I doubt that as the first action the left seater did when he grabbed the stick was to push on it.
Never he or the captain realized the right seater was maintaining full back stick for a 30 sec period.
They had lost confidence in the FCS to the point to shut down some computers.

When the left hand has no idea what the right one is doing ...

[DozyWannabe]

What computers did they "turn off"? to the best of my knowledge, there's no evidence of that...

[CONF iture]

http://www.pprune.org/7382441-post158.html
http://www.pprune.org/7383280-post164.html

[DozyWannabe]

Hold up - that's not proof, those are two of your own posts in which you seem to have derived your own theory based on your interpretation of flight surface deflection.

To the best of my knowledge there's nothing in the DFDR/CVR evidence which explicitly suggests any of the FCCs were turned off. Without either of those as supporting evidence, it must be considered as a strong possibility that your suggested disabling of FCCs did not in fact happen.

[EDIT : Some discussion went on on the next page of the thread - AZR wondered if the PRIM1/SEC1 FAULT messages tallied with the CVR (albeit very late in the sequence and not as a consequence of following any kind of procedure). I guess the question for me is whether manually turning them off would result in a FAULT ECAM message or whether it would say something different.]

[EDIT 2 : In fact, I'll quote AlphaZuluRomeo's response:

2 h 13 min 28,2
PNF : essaye de trouver ce que tu peux faire avec tes commandes là-haut (my note: the PRIM/SEC commands are on the overhead panel)
2 h 13 min 30,4
PNF : les primaires et cetera (my note: "primaires etc." may refer to the PRIMary and other computers)
CPT : (* fera rien)
2 h 13 min 31,5
CPT : on (fera /verra) rien

And then:
2 h 13 min 45 F/CTL PRIM 1 FAULT
2 h 13 min 51 F/CTL SEC 1 FAULT
...
The transcript show the PNF to want to "try" something with the "primary" (computers?) then the captain answering it will be no use, then the PRIM1 & SEC1 to be switched OFF.

Even that interpretation is vague enough to raise questions. If the PNF wanted to "try" something, was it simply turning PRIM1 and SEC1 off, or did he mean to attempt a reset (i.e. switch them off and back on)? In any case, all of this happened well after 02:12:30, which is the probable last timestamp in which recovery might have been possible given the aircraft's scenario.

[Linktrained]

"10,000 ft."
Was this said as a matter of routine... Or with surprise, when cruising over the Atlantic ? It appears to be the first recognition of the direction of travel recorded on the DVD.


No comment that the THS was only moving in one direction, NU, steadily. Would this be likely, when the aircraft would normally be in nearlv level flight.


I was a newby Second Officer, doing "my hour" of hand flying at night, as the A/P was u/s. I flew into an unseen Cb. The Captain told me to "Fly reasonably straight and reasonably level." Which I did. ( We had heard of someone who had tried something else with bad effect.)


Rain soaked through the unpressurised windscreen and wet my knees.


(Radar did not come, for me, for a dozen more years.)

[NeoFit]

DZ wrote
What computers did they "turn off"? to the best of my knowledge, there's no evidence of that...

Not really, in fact but ....

27 F/CTL PRIM 1 FAULT 2:13
27 F/CTL SEC 1 FAULT 2:13

----> Flight controls computers set OFF or reset

2012_ISASI_Airbus_presentations.pdf ( link (http://www.ntsb.gov/news/events/Documents/2012_ISASI_Airbus_presentations.pdf) )

[c100driver]

May I respectfully ask if you want to specifically argue the AF447 issues you move it to the AF447 thread please.

[vilas]

AF447 is like a hydra headed monster. You chop one another one pops up. It appears to me that dragging any airbus topic to AF447 is a favorite past time of some participants.