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Old 21st Dec 2012, 18:56   #81 (permalink)
 
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Quote:
Originally Posted by DOZY
I'm a little fuzzy on what "taking over" constitutes - Alpha Prot should not command significantly opposite the input it is given as that is not the way it is designed to work.
Which part is that confusing for you in the A330 AIRPLANE FLIGHT MANUAL :

At any time, if the aircraft goes to an unmanageable pitch down attitude despite a continuous deflection of the sidestick in the full backward position : APPLY THE EMERGENCY PROCEDURE
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Old 21st Dec 2012, 19:08   #82 (permalink)


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In a recent memo:

"The trouble shooting efforts of the flight crew ( they had turned off the 3 ADR systems) eventually placed the aircraft into ‘Alternate law’ which allowed the Pilots to override the Alpha protection and recover control although in a degraded state."

Why do airbus insist on regarding alternate and direct law "degraded"

Every aircraft I've flown prior to this airborne Citroen has been flown in "Direct" Law. Flying in Direct law is a non event really & I love the paradox in the above statement. Flying with the controls in a degraded state allowed the recovery of an aircraft flying in a degraded state???
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Old 21st Dec 2012, 19:40   #83 (permalink)
 
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Quote:
Why do airbus insist on regarding alternate and direct law "degraded"
For Airbus the way to fly this aircraft is "Normal law"
When the aircraft is no more flying in the "Normal law" .. he is flying in a "degraded" (Airbus phraseology) state (all the other "laws" kindly made available by Airbus ) IMHO
In a word .. for save your soul (and souls of the back cargo) sometime it's better to fly in "degraded" law ... if the pilot know how ...

Last edited by jcjeant; 21st Dec 2012 at 19:48.
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Old 21st Dec 2012, 19:46   #84 (permalink)
 
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@GG:

Quote:
"The trouble shooting efforts of the flight crew ( they had turned off the 3 ADR systems) eventually placed the aircraft into ‘Alternate law’ which allowed the Pilots to override the Alpha protection and recover control although in a degraded state."
That is 1 ADR to much....

'Degraded' because one will loose more than the AoA protection only in alternate.
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Old 21st Dec 2012, 21:01   #85 (permalink)
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Quote:
At any time, if the aircraft goes to an unmanageable pitch down attitude despite a continuous deflection of the sidestick in the full backward position : APPLY THE EMERGENCY PROCEDURE
- in the old days it would have been:
At any time, if the aircraft goes to an unmanageable pitch down attitude despite a continuous deflection of the sidestick in the full backward position : EJECT.
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Old 22nd Dec 2012, 02:47   #86 (permalink)
 
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Quote:
Originally Posted by Lyman View Post
Did the pilots get your memo?
The airframes and mods affected are explicitly listed in the EAD. It only takes a little research to realise that this mod is very recent - being applied from earlier this year. The after-market and custom order Thales AA pitot tube fitting was being done for years before problems were noted.

Quote:
Originally Posted by CONF iture View Post
Which part is that confusing for you in the A330 AIRPLANE FLIGHT MANUAL :

At any time, if the aircraft goes to an unmanageable pitch down attitude despite a continuous deflection of the sidestick in the full backward position : APPLY THE EMERGENCY PROCEDURE
I suspect the translation's a little off there, but that doesn't really matter. The point is that based on the way Alpha Prot works (explained in a lovely concise manner by BPalmer here : How safe is (airbus) fly by wire? Airbus A330/340 and A320 family emergency AD ), it will take some time for a significant pitch-down attitude to develop from the normal attitude, which is usually nose-up to some extent.

Quote:
Originally Posted by Greek God View Post
Why do airbus insist on regarding alternate and direct law "degraded"
Because that's the way it was designed to operate. It was designed to operate that way because technology had progressed to a point where the de facto "traditional" control set up (itself a product of the limits of pre-war technology) was due a revision. With the move to all-hydraulic actuation in the '60s, a lot of effort was put into effectively faking similar behaviour to the old cable-driven designs - so the question was at what point did all this work and the complex machinery involved to implement it become more hassle than it was worth? Airbus decided it was time for a clean-sheet approach and whatever you, I or anyone else may think of it personally, it's been very successful and statistically as safe as anything else.
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Old 22nd Dec 2012, 03:30   #87 (permalink)
 
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Quote:
Originally Posted by Lyman View Post
"Nomal Law" with all protections, gets a grade of "A". Anything else, missing one or more "protections" is sub standard in quality, iow, unprotected, the dummy flying can now make a blunder that the system will have prevented in "A" mode.
With equal respect, such an opinion can only be advanced if one believes that the design of the system was predicated on limiting human involvement in flying the aircraft. While it seems to be a difficult notion to shift in some quarters, the fact is that it is utterly untrue.

The reason for considering control laws outside Normal "degraded" is for no other reason than they were designed to come into effect in the event of a technical or structural failure in the aircraft and its systems. The concept is no different than older designs in the event of, say, partial hydraulic loss where the working systems provide a degree of control, albeit in a degraded manner.

In this case, the temporary workaround published by Airbus is in effect simulating dual ADR failure, which will cause the flight law to degrade to Alternate.

* - Hmm, seems like Lyman's post disappeared...

Last edited by DozyWannabe; 22nd Dec 2012 at 03:38.
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Old 22nd Dec 2012, 12:33   #88 (permalink)
 
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Quote:
Being an EAD bulletin, it's likely that the incident report is still in progress. I did have a hunt online, but nothing as yet. There are a couple of stories on Flight, but some are subscriber-only.
BEA answer to a question about the investigation of the Eva Air AOA incident:
Quote:
« La décision d'ouvrir et de conduire l'enquête de sécurité sur cet évènement appartient aux autorités japonaises (état d'occurrence) ou taïwanaises (éta
de l'opérateur). Celles-ci ont décidé de ne pas ouvrir d'enquête, c'est la raison pour laquelle vous ne trouvez pas trace de l'évènement sur le site Internet du BEA. »
Quote:
"The decision to open and conduct a safety investigation on this event belongs to the Japanese authorities (state of matter) or Taiwan (state operator). They have decided not to initiate an investigation, it is the reason why you can not find a trace of the event on the BEA website. '
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Old 22nd Dec 2012, 12:48   #89 (permalink)
 
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Quote:
I suspect the translation's a little off there, but that doesn't really matter. The point is that based on the way Alpha Prot works (explained in a lovely concise manner by BPalmer here : How safe is (airbus) fly by wire? Airbus A330/340 and A320 family emergency AD ), it will take some time for a significant pitch-down attitude to develop from the normal attitude, which is usually nose-up to some extent.
Which translation (?) ... there is none.
LOVE makes you blind DOZY - How hard is it to may have to admit some weaknesses in the Loved one - If you treat your wife the way you treat Airbus, she must be the happiest woman on earth really, but if you don't, she would have every reason to get jealous ...

Last edited by CONF iture; 22nd Dec 2012 at 13:52.
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Old 22nd Dec 2012, 15:39   #90 (permalink)
 
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CONF iture, I'm simply applying fairness and reason - I'm not the kind to get emotionally invested in aircraft (well - except maybe Concorde and the VC10 ).

Also, as far as I know Airbus documents are well-known for being written in French and translated into English, sometimes making them read slightly unusually to native English speakers.

Last edited by DozyWannabe; 22nd Dec 2012 at 16:55.
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Old 23rd Dec 2012, 02:10   #91 (permalink)
 
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Quote:
Originally Posted by DOZY
Also, as far as I know Airbus documents are well-known for being written in French and translated into English, sometimes making them read slightly unusually to native English speakers.
Why should they be written in French suddenly ?
Aren't you that very guy who likes to mention how Airbus is multi-national, not just French ?
Do not imagine translation issue where there is none.

Quote:
CONF iture, I'm simply applying fairness and reason - I'm not the kind to get emotionally invested in aircraft.
DOZY, what you're applying and so with brilliance, is intellectual dishonesty.
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Old 23rd Dec 2012, 02:18   #92 (permalink)
 
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I'm only repeating what I've been told and have read over the years regarding translation of Airbus documents.

As for honesty, intellectual or otherwise, I'm not the one trying to present what is clearly a quickly-remedied problem with a recent modification to AoA vanes as a deep and underlying problem with the FBW design.
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Old 23rd Dec 2012, 08:20   #93 (permalink)
 
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@ Confi & @ Dozy

There's a point about this dastardly translation business whereby I remember that the French version says in case of stall to "Afficher 5° d'assiette" whilst the English version says "Reduce...........".
There is a big difference in "Afficher" which means to display as opposed to "Reduce".
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Old 29th Dec 2012, 07:29   #94 (permalink)
 
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Hello to all of you,

Is there on PPRuNe any Eva Air pilot who can detail more precisely what happened on the A330 who recently lost its 3 AOA ?
We hear a lot of things about the reasons who led the pilots to disconnect 2 ADR :
1) that the aircraft was AOA indicators equipped and it is one of its related emergency procedures who led them to think about that ; or
2) that it's rather the "Unreliable Airspeed" procedure who...

Is somebody able to answer these question ?
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Old 29th Dec 2012, 16:41   #95 (permalink)
 
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Let me ask the question another way...

Since no AOA display exists for the pilots, and AoA is critical to the flight path, how is "UnreliableAoA" not a far more problematic abnormal than "UAS"? Further, once somehow established on the flight deck that AoA is corrupt, how does initiating a UAS failure equate to an acceptable solution?

Two abnormals equal a "NORMAL"?

With apologies to Will Fraser: UAI Unreliable Angle of Incidence....

Last edited by Lyman; 29th Dec 2012 at 16:44.
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Old 29th Dec 2012, 20:03   #96 (permalink)
 
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@ Philemon:

Quote:
We hear a lot of things about the reasons who led the pilots to disconnect 2 ADR :
1) that the aircraft was AOA indicators equipped and it is one of its related emergency procedures who led them to think about that ; or
2) that it's rather the "Unreliable Airspeed" procedure who...
No EVA source however:

From another topic about the subject, it was said they switched off all 3 ADR i.s.o. 2, if equipped with 'BUSS' that will display the BackUp SpeedScale and AoA pointer.

if they re-select any or all ADR it will revert to the 'normal' speed display while alternate law (without AoA protection) remains.

In a reaction Thales submitted the aircraft involved was not Thales AoA vanes equipped and they where not responsible for the conical plate.

So Goodrich 0816ED vanes must have been installed....

Conical plates are physically different (Thales has flat circular cutout while Goodrich has a countersunk and lemon shaped cutout).....

Did they fitted 'thales' plates on goodrich vanes? conical plate on top of original flat plate?

Last edited by A33Zab; 29th Dec 2012 at 20:09.
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Old 29th Dec 2012, 20:20   #97 (permalink)
 
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All I can say , 5 pages into this thread, is Thank God I still fly a Dinosaur, which, whilst far from perfect, tends to go up at the rate I ask, down in a similar fashion ( with Left & Right similarly easily defined.)

I think, as a teenager , I saw straight through the Bernard Zeigler bullsh1t. . . adulthood & a life flying commercialy (predominantdly Boeing) have reinforced my wet behind the ears beliefs.

Don't, and never will, trust them.

Whenever I am in one, I am just that few () % points less comfortable than I would be in a more "conventional" aircraft &, you know what, I can spend all day arguing my point of view to anyone calling me a luddite, and I think I may on most occasions win the argument.
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Old 29th Dec 2012, 20:51   #98 (permalink)
 
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Originally Posted by captplaystation View Post
I think, as a teenager , I saw straight through the Bernard Zeigler bullsh1t. . .

Don't, and never will, trust them.
It was a major tragedy that Gordon Corps (who was the real engineering pilot behind Airbus FBW) died when he did, not only because he was the public counterbalance to BZ's flights of fancy, but also because he had a knack of explaining and proving the systems in public in a way that pilots could get behind (and as DP Davies' successor at the ARB before he joined Airbus, Corps had the "old-school" clout to make people listen).

Quote:
Whenever I am in one, I am just that few () % points less comfortable than I would be in a more "conventional" aircraft &, you know what, I can spend all day arguing my point of view to anyone calling me a luddite, and I think I may on most occasions win the argument.
I'd never go so far as to call you or anyone else a Luddite for what you believe - it's a perfectly rational position and unfortunately with the loss of Capt. Corps the Airbus message did get somewhat muddled in the late '80s, so an opportunity to reassure you and others who are of this position was sadly lost.
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Old 29th Dec 2012, 20:59   #99 (permalink)
 
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Quote:
All I can say , 5 pages into this thread, is Thank God I still fly a Dinosaur, which, whilst far from perfect, tends to go up at the rate I ask, down in a similar fashion ( with Left & Right similarly easily defined.)
Well that's deeply concerning; may I ask who you fly for so I can avoid them?

If you're only qualified for a mythical type that suffers no equipment failures or malfunctions whatsoever, on which you are happy to place total reliance, I would suggest a certain amount of complacency had set in.


I hope you're not representative, in which case I thank God for pilots who know their type well enough to understand what to do when their aircraft doesn't do what it's 'tended to' since Pterodactyls ruled the skies.
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Old 29th Dec 2012, 21:25   #100 (permalink)
 
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@SLFandProud - Come on, let's not get into another argument on that again - he's said his peace, best leave it be.
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