Peter H

D/W The point I was making was that you don't need to know the specifics as far as Alternate Law is concerned
- fly the thing as you would normally fly it, just don't expect the protections to be there.

Please forgive a non-flying lurker his ignorance of A/B details.

My impression is that the application of protections is intended to be "transparent" to the pilot. If so:

How do pilots learn where the protection limits are? [In normal law, aren't protections just transparently
enforced when the pilot's command actions try to take the aircraft outside the permitted envelope?]

How are pilots expected to know where the protection limits "should be" when flying outside normal law?



... or are you just saying that outside normal law you should intentionally stay well within the a/c's
performance envelope? In the expectation/hope that that that will keep you out of trouble.

DozyWannabe

Got it in one.

Organfreak

It appears to me (from my comfortable armchair) that the problem may not have been 'not knowing which law they were in,' but rather knowing exactly what each law entails. I agree with the statement that the actual law details are quite complicated, and it behooves anyone flying one of these things to know the law details backwards and forwards.

Yeah yeah DW, "Why did he pull?" is at the crux of the problem, but there is certainly more to this than that. Stop apologizing for the AB, b/c nothing is perfect, and truth is complicated. And I really am gobsmacked that you dare to argue with actual line pilots! With all due respect.

I await, with horrified trepidation, the next Airbus crash.

DozyWannabe

Hammondfan, the point I was making (as Peter put more eloquently above) is that at a base level, all you need to know is to take care to stay within the flight envelope outside of Normal Law - anything more than that is a bonus.

As for arguing with line pilots - jeez, it's a discussion forum. I'll argue the toss if I disagree with anyone, pilot or no. Some of the anti-Airbus brigade tend to talk as though they speak for all pilots when they are in fact a minority, albeit a vocal one.

I apologise for or on behalf of no-one other than myself. If you want to take the fact that I will ruthlessly fact-check and counter politically-motivated assertions as me defending Airbus then that's your call, not mine.

Organfreak

DW:
And how did you arrive at this "fact"? Shall we dismiss every contention posted by a pilot if it is negative to AB?

DW:
Nope, it's not my call because you're defining the terms ("politically-motivated") in a way that isn't at all apparent to me. And, you state plenty of things that aren't facts, but rather opinions, and you have been contradicted by line pilots more times than I'd count. It rolls right off of you.

Bottom line, you almost invariably defend Airbus at the slightest opening. It's clearly biased. Very clearly. It is time to adopt a less arrogant attitude. Sorry for the harsh feedback on how you come off!

"Hammondfan." I like it.

rudderrudderrat

Hi DozyWannabe,

I agree.

Unfortunately I think some pilots may rely on the Normal flight law protection too much. As Bruce Dickinson says in his video you posted on post#170 "Airbus Trepidation - convince me otherwise," at time 5:35
"Full back stick - panic stations" is exactly what PF seems to have done.

It's a pity Airbus don't preach sensible aircraft handling and use the protections as the "belt and braces". I'd personally like to see the removal of advice such as:
"This includes the use of Full Back stick if required" during the windshear recovery. On previous aircraft types, we simply flew sensible pitch attitudes and never mentioned "Full Back" anything.

RetiredF4

Nothing got lost in translation. I´m not a native english speaker, but i live with that language since more than 35 years in talking, writing and reading. All the books i read for entertainment are written in english, meanwhile they fill the cabinets of a whole room. Im not perfect and without fault´, but i get along. I do not translate, when reading, and not when writing, i understand english like a native speaker would do without translation.

You may twist my comment around like you will, your statement is wrong in all three parts

Even the last part is misleading, because in the different sublaws of alternate law there might be all protections lost or only some of them, and the stage of degradation might influence the behaviour of the aircraft caused by the computers and might influence the necessary behaviour of the pilots.

Just be a man and accept, that your statement is not only gravely simplified, but that its BS. Arguing with semantics against it doesn´t make it true.


edit after i read the follow up post:
I do not agree on that one at all. It´s even a more ridiculous statement than the one before, and i´m going to tell you why.

it sure should be
" all you need to do is to take care..... "
or maybe
"all you need to know is how to take care..."

To be able to do that, one needs to know the point of degradation of the system and what system functions are still available, otherwise one will not be able to take care to stay within the flight envelope and the mishandling would kick one out of the flightenvelope.

By the way, that has nothing at all to do with FBW or Airbus or Boing, its basically common sense and applies for all parts of flying.

DozyWannabe

Not at all - rudderrudderrat makes a valid point above that some of Airbus's training is a bit blase about relying on the protections. I'd be inclined to think that using full back stick in windshear escape is using the tools provided well, but he's right that the trainng should include the caveat that full deflection should be used as an emergency measure only, and only when the control law has not degraded.

You weren't a member when CONF iture joined, and along with a now-defunct poster known as "the shrimp", proceeded to blanket Airbus-related threads with links to Norbert Jacquet's website. The Jacquet case is nothing if not political.

I've got at least as many agreeing with me as those who disagree (both in public and via PM). As far as I'm aware, the only line pilot making a meal out of our interactions of late is CONF iture. Every opinion I put forward is based on the evidence I've accumulated over the years.

To you, maybe - to others, not so much. I'm not defending Airbus, but if I see a blatant bit of misinformation, myth presented as fact, or a conclusion derived entirely from internal bias, then I will call it. The problem is that there's a lot more misinformation out there regarding Airbus than other manufacturers - so it will tend to look that way if you're not used to it.

Here's a short list of things that came up on this thread and it's predecessors - none of them true, but nevertheless fervently believed by those who posted them

To be clear - all of the below assertions are provably false

• Airbus have weaker vertical stabiliser attachments than other mfrs
• The Airbus FBW flight deck was designed as the first step towards pilotless airliners
• The infamous Habsheim A320 crashed because the computer thought it was in landing mode
• With a connected yoke, pilots will automatically see poor handling and take control
• Airbus pushed hard for more automation, and their airliners are more automated than any other types of the same vintage
• The Airbus A320 was designed by engineers and computer geeks with little or no pilot input
• Airbus FBW computers will command an attitude change opposite that of pilot input
• The Boeing FBW design is simpler than that of Airbus
• The BEA deliberately steer investigations to protect Airbus

The last one came up recently, with the poster lamenting that the BEA is not an NGO - but neither is the UK AAIB - and the US NTSB, while nominally independent, remains a government agency.

Someone referred to you as "Orangefreak" in an earlier reply - I figured I'd make the "Organ" aspect clearer. (see also: "Farfisanut", "Voxadorer" etc. )

@Franzl - in Alternate Law, all the "hard" protections are lost (Alternate Law's "soft" protections can be overridden by pilot input). If you don't know exactly what systems have failed to put you in Alternate, then you can still fly safely by staying within the envelope (which you should be doing anyway), and assuming that all protections are gone. The whole point of grouping complex failure modes - of which there are thousands - into a small number of flight laws is to make life easier for the pilot, because they don't have a flight engineer anymore.

jcjeant

Hi,

DW
I do not understand why you put my comment on the BEA under your heading "false asssertions"
What I said is true .. BEA is not an NGO
AAIB or NTSB are indeed governement agency or controled .. monitored by governement ...
EG AAIB
And that's the same for the BEA ....
but for be "independent" this would be better than all these organizations are NGO

Clandestino

Folks, do you know who killed MacMillan?

Google does.

DozyWannabe

@jcjeant:

The "false assertion" is that the BEA tries to avoid attaching responsibility to Airbus - which is indeed untrue, but distinct (to some extent) from the point you made about the BEA not being an NGO (which is true).

France may be traditionally associated as the major player in Airbus, but there are other countries involved too. Like the AAIB and NTSB, the BEA is a government agency - but crucially it is completely distinct from the regulator (the equivalents of which would be the UK CAA, US FAA and the French DGAC). Certainly in the last two decades, the BEA has treated Airbus as it would any other manufacturer.

OK465

Oi Suzy...!

gums

Hey, Doze!

I sure hope I am not one of those that assert the 'bus FBW system and laws were soley designed by computer geeks with no pilot inputs.

I do question how many of the pilots had previously flown a pure FBW system while the control laws and so-called "protections" were being implemented. I also question how many tweaks and changes were made during the prototype phase and such - those suggested or even demanded by said pilots after actually flying the beast at the limits of those "protections" ( how I absolutely hate that term - grrrr).

Folks can point out that my ancient jet was not designed for the same operational needs and requirements as a commercial airliner. Nevertheless, just divide our "limits" by certain values and you get the 'bus "limits". And BTW, we had less ability to override those limits than the 'bus drivers. only thing we could do was manually lower flaps and, if HAL let us, we could use the pitch override switch to command horizontal tail movement ( HAL would not let us unless AoA was above 30 degrees).

We did not have four distinct reversion modes and a fifth if you count manual THS commands and I guess rudder. Fer chrissakes, look at the 'bus reversion chart in the manual! 26 footnotes! AoA alone has three, plus note (a).

Just a few:


BEAM ME UP!!!

Convince me that the AF447 PF was considering all those exceptions to the "rule".

DozyWannabe

I think I recall a few of them had been involved in the Concorde "minimanche" project. Concorde used an analogue FBW system rather than a digital one, but it was FBW nonetheless.

Probably several - but the process was not particularly antagonistic - remember that the prototype would have been flown in Direct initially and the test pilots would have confirmed those limits.

Why? "Limit" doesn't cover the functionality, and the best example of that is Alpha Floor, where the system commands maximum thrust to prevent stall.

In fact the only accident related to Airbus FBW occurred when the Captain turned the protection into a limit by permanently disabling the autothrust function.

Fair enough, but that doesn't change the fact that the fundamental requirements are different.

The specifics underpinning these modes do not need to be memorised in order to command the aircraft safely. The only rule that cannot be forgotten is the lack of hard protections (or "limits" if you prefer) outside of Normal Law. As far as I'm aware there have been zero incidents of ABNORMAL ATTITUDE or MAN PITCH TRIM ONLY on the line.

He didn't need to be - staying inside the envelope was all that was required.

Turbine D

Dozy,

Your continued rhetoric is becoming old, very old.
Your Quote:
These are not assertions that are provably false, they are simply Dozy's opinions that can be provably false in part or whole. Each can be challenged and debated and have been and will continue to be.


As an engineer speaking, there is no man-made aircraft, engine, control system, software or whatever, however you want to cut it, that can't be improved upon, period! And so goes it with Airbus and their FBW aircraft. In fact, the technology of the A-320 is old technology today (1984), if it hasn't been improved upon or changed from the original concept.

Your quote:
This is not the informative "technical" Dozy posting that were worth reading.

DozyWannabe

I deliberately avoided the "debatable" issues, and I can prove every one of those that make up that list (give me until tomorrow though - it's late).

I never said that wasn't the case - I just dispute some of the old canards which have been raised against the design since 1988.

As an engineer (albeit of the software persuasion) that maxim is something I live by on a daily basis!

That's pretty much exactly my position!

What gets my hackles up is the unquestioning assumption (and conclusions derived thereof) that the design was primarily based upon taking pilots "out of the loop", which is a brazen lie.

I've said several times that some of the assumptions made at the design stage need revisiting in the light of later experience, but the idea that the fundamental design was flawed is simply not borne out by the evidence.

The Airbus FBW design is a long way from perfect, but I don't believe that it is any further from perfect than the alternatives on offer today.

In case you didn't see me saying this earlier - *engineering is the art of compromise*. That some base their perception on the idea that the design decisions taken were based on the erroneous assumption that Airbus wanted to sideline pilots is not my fault.

Allow me a little light-heartedness. Interaction on this thread would be incredibly depressing otherwise.

Turbine D

Fair enough, why don't you start with this one, thinking back to 1984 when the A-320 was being designed as the first FBW commercial jetliner.

DozyWannabe

Going to bed in a second, but the basis of what I was saying is that FBW and automation are two very separate and distinct concepts.

The FMS on the A320 is roughly analogous to that available on the 757 and 767 - pretty sophisticated if compared to the old Sperry units in the second generation jetliners, but little to differentiate between them.

FBW as a concept relates to the flight surfaces being electronically actuated and managed as opposed to direct connection by cable or hydraulics. This allows for limits or protections being placed on the inputs, but it is not automation. Automation involves the aircraft's attitude being controlled mechanically or electronically regardless of manual input - FBW involves the flight surface controls being managed electronically regardless of whether the control input comes from a computer or a human pilot.

Airbus pioneered FBW in airliners, but the level of automation in those FBW airliners wasn't a great deal different from other manufacturer's designs of the same vintage (e.g. B757, B767, B737 Classic/NG, MD-11).

OK465

Finally found it. These 486's with dial-up can be slow.

MacMillan committed suicide and lived to tell about it. (Oi, Suzy!)

(Fortunately I had plenty of beer while wasting a few of those remaining hours I have left.)

CONF iture

Another misconception of your own making :
Alpha Floor does not command maximum thrust to prevent stall, but only to provide maximum performance in term of altitude gain when high AoA are reached and want to be maintained.

One day you'll get it :
You can permanently disable the autothrust function, and therefore lose Alpha Floor, but you can still maintain full back stick without stalling, IDLE thrust. The system will maintain Alpha Max for you - NO STALL - Going down YES - BUT NO STALL - STILL FLYING

Comprenez-vous à présent ?

Stop your disinformation please.