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Old 5th Dec 2012, 09:10   #1 (permalink)
 
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A330/A340 EAD (AoA PROBES)

An EAD has just been released following an issue experienced by an A330 crew:

The EAD includes the narrative:

Quote:
An A330 aeroplane experienced a blockage of all Angle Of Attack (AOA) probes during climb leading to Autopilot (AP) disconnection and activation of the alpha protection (Alpha Prot) when Mach number increased.

The blockage of two or three AOA probes at the same angle may cause the Apha Prot of the normal law to activate.
Alors, qu'est que c'est un 'blockage' of an AOA probe? Does that mean blocked with foreign matter / ice / whatever, or is it some quaint Franglais referring to a stuck probe?

The EAD also states:

Quote:
Under normal flight conditions (in normal law), if the Alpha Prot activates and Mach number increases, the flight control laws order a pitch down of the aeroplane that the flight crew may not be able to counteract with a sidestick deflection, even in the full backward position.
Followed by the "No Sh*t, Sherlock" statement:

Quote:
This condition, if not corrected, could result in reduced control of the aeroplane.
You don't say!

Another piece of Froggldegook comes in the actual procedure and states:

Quote:
CAUTION RISK OF UNDUE STALL WARNING
I've heard of spurious stall warnings and have even experienced spurious stall ident and stick push at 500 ft in a much older 4-jet, I've taught 'incipient' stall recoveries and 'fully developed' stall recoveries, but never in 40 years have I ever heard of an 'undue' stall warning....

Just WTF do they mean?
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Old 5th Dec 2012, 09:39   #2 (permalink)
 
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Once again it becomes clear that every Airbua FBW aircraft pilot should know how to get out of the normal law.
As it seems the only safe way out of such mess.
Regrettably Airbus will continue to refuse to tell us.
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Old 5th Dec 2012, 10:17   #3 (permalink)
 
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Easy, reach up and turn off all 3 PRIMS.

You're now in in direct mode via the 2 remaining SECS.

However that would be a last ditch effort!!
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Old 5th Dec 2012, 10:42   #4 (permalink)
swh

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Quote:
An EAD has just been released following an issue experienced by an A330 crew:
This only applies to the newer aircraft with the new AoA probe that is mounted on a raised area away from the skin.

Quote:
I've heard of spurious stall warnings and have even experienced spurious stall ident and stick push at 500 ft in a much older 4-jet, I've taught 'incipient' stall recoveries and 'fully developed' stall recoveries, but never in 40 years have I ever heard of an 'undue' stall warning....
Considering every aircraft flying is at risk of undue stall warnings, I am surprised that you have not heard of it (sensor issue, radome damage, bird strike, ADC issue etc). An example would be the 777 incident out of Perth https://www.atsb.gov.au/media/24550/...503722_001.pdf
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Old 5th Dec 2012, 12:41   #5 (permalink)
 
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Safelife - I sincerely hope you are not a A3xx driver! You have multiple way's of getting the machine into Alt or Direct law easily within a few seconds, all of which you can find in the FCOM.

As stated in the above post - Switch of multiple PRIMS or ELACS, or FAC 1+2

Not ideal in the slightest however not some big AB secret and something you should most definitely already know...

Last edited by NOLAND3; 5th Dec 2012 at 12:43.
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Old 5th Dec 2012, 13:45   #6 (permalink)
 
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'Undue' is defined as 'to a level which is more than is necessary, acceptable or reasonable'. As in 'use of undue force'

So, is an 'undue stall warning' something which meets this definition? Or is it yet another froggldegook mangling of English in this context?

I presume they mean a 'spurious' stall warning?
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Old 5th Dec 2012, 17:28   #7 (permalink)
 
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'Undue' is also defined as 'unwarranted'. Doesn't seem a huge leap of logic to suggest, therefore that an unwarranted stall warning is one which doesn't actually mean the aircraft is stalling...nothing to do with Froggledigook.
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Old 5th Dec 2012, 17:34   #8 (permalink)
 
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Regardless of the derivation of the word...

Does anyone seriously not understand what it's saying?

If so, you should probably not be in command of anything more dangerous than a pencil sharpener.
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Old 6th Dec 2012, 09:17   #9 (permalink)
 
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I have been following this shimmering thread that expands and contracts with time, with interest. There seems to be an almost obdurate unwillingness to understand the text of the EAD and of the Airbus concept of design and operation of aircraft. I have no problem with either, but then I operate Airbus aircraft and have done so for many years, and am familiar with the way they do things. It's not difficult, nor is it inherently dangerous, it is comprehensible and is designed to be so worldwide.
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Old 6th Dec 2012, 10:42   #10 (permalink)
 
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Quote:
Originally Posted by swh
Considering every aircraft flying is at risk of undue stall warnings, I am surprise that you have not heard of it (sensor issue, radome damage, bird strike, ADC issue etc). An example would be the 777 incident out of Perth
I do agree with your comment, except that, if i read correctly the report, the activation of the stall warning and stick shaker devices was justified in the Perth 777 case.

Quote:
Originally Posted by NOLAND3
Safelife - I sincerely hope you are not a A3xx driver! You have multiple way's of getting the machine into Alt or Direct law easily within a few seconds, all of which you can find in the FCOM.
2 things i would like to see then :
  1. A published Memory Item to get rid of undesirable protection activation
  2. A single black guarded switch to trigger DIRECT LAW

Anyone to post the AD please ?
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Old 6th Dec 2012, 11:13   #11 (permalink)
 
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A330/A340 EAD (AoA PROBES)

In aviation it is frequently said that an experienced aviator is one that uses his exceptional knowledge in order to avoid having to use his exceptional skill.

The correlation to this thread is that I am able to understand (generally) what the people at airbus write, but I have to work at it sometimes.

The cynic in me suspects that it is not just a poor translation from French into technical English but a deliberate attempt to minimise adverse media coverage at the expense of clarity.

An undue warning seems much less emotive than a spurious warning when read as a newspaper headline!
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Old 6th Dec 2012, 13:28   #12 (permalink)
 
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''Anyone to post the AD please ? ''



http://www.caa.co.uk/docs/33/2012120...D20120258E.pdf
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Old 6th Dec 2012, 13:38   #13 (permalink)
 
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RISK OF UNDUE STALL WARNING is prompted by the ECAM in several malfunctions

The new bulletin tells us to switch off two ADRs to get in Alternate Law.

We don't want Direct law, direct law is dangerous
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Old 6th Dec 2012, 13:44   #14 (permalink)
 
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Amazing stuff, thank you.

Now, curions to read the exact :
"Blocked AOA probes" emergency procedure included in Airbus AFM A330 Temporary Revision (TR) TR293 issue 1 ?
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Old 6th Dec 2012, 22:02   #15 (permalink)
 
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Grrr bad day?

Quote:
Or is it yet another froggldegook mangling of English in this context?
Exactly what kind of English are you referring to?

spectacles or yoke?
tailplane or stabiliser?
throttle or thrust lever?
VAT or VREF?
coaming or glareshield?
to dump or jettison?

What does it matter whether the AoA probes are blocked or stuck? All the pilot needs to know is that they are not working the way they should.

RISK OF UNDUE STALL WARNING : with a little bit of imagination it is not difficult to figure that one out.

Last edited by Squawk7777; 6th Dec 2012 at 22:03.
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Old 7th Dec 2012, 03:35   #16 (permalink)
 
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@CONF iture;

Airbus A330/A340 AFM TRs can be found at:-

http://ad.easa.europa.eu/blob/TR293a..._2012-0258-E_2
http://ad.easa.europa.eu/blob/TR294a..._2012-0258-E_3
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Old 7th Dec 2012, 05:12   #17 (permalink)
 
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OK465

Roll direct is hardly a dangerous thing. Pitch alternate is Ok, no danger at all.

Pitch direct is dangerous, however. Many people thing that reverting to Direct law is like reverting to a conventional flight control system, but pitch direct is nowhere near conventional.
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Old 7th Dec 2012, 11:22   #18 (permalink)
 
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Thank you mm43.
I would be curious to hear more about the initial event and how the guys dealt with it ?

That Temporary Revision should also clearly specify how the procedure is meant to give back control to the pilots when protections do activate on unreliable data.
Give back credit to the pilots.

Quote:
Originally Posted by M2002
Many people thing that reverting to Direct law is like reverting to a conventional flight control system, but pitch direct is nowhere near conventional.
How is that different !?
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Old 7th Dec 2012, 11:35   #19 (permalink)
 
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Squawk7777, many of the items to which you refer have specific meanings and are not synonymous.

As for
Quote:
...with a little bit of imagination it is not difficult to figure that one out.
pilots should never need to do such a thing in response to QRH directions - which must be clear and unambiguous.

Last edited by BEagle; 7th Dec 2012 at 11:35.
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Old 7th Dec 2012, 13:58   #20 (permalink)
 
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Quote:
pilots should never need to do such a thing in response to QRH directions - which must be clear and unambiguous.
Ah but somewhere in all this the real world intervenes. Which is where common-sense (which in turn is based on experience) intervenes. I agree the QRH ought to be unambiguous, but, being written by mere humans, it occasionally is, no more so than for situations not dreamt of by the compositor. Which is where the Captain, using his experience, skill, judgement, imagination and flare, earns his money. And, should he survive, gets criticised by desk bound pedants.
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