in the early model A320s it was not uncommon to see a status message displayed without any associated warning or caution. The message was always Cat 3 dual inop. It took a bit of digging in tne manuals to discover that this related to an ADR disagree. After a few years these messages stopped appearing and. I have not seen one for at least ten years.

tubby linton
It is level 1 caution. It is loss of redundancy or system degradation, only requires crew monitoring. It is a caution message without procedure. It is still the same.

CONF iture

You are totally right!

The system of voting a computer when the other two agree can have potentially lethal results, and therefore it should be indicated to the crew when this happens, so that some procedure allows us to make sure that the voting of a computer is correct. if computers alone cannot do it, get the pilot involved in the process. No reason to keep it "transparent to the pilot".

THe ECAM you suggest should be accompanied by an AOA CHECK PROC APPLY blue line, or something like that.

A 'xxx DISCREPANCY' message is used if one display deviates from the other display.
e.g. NAV ATT DISCREPANCY or NAV IAS DISCREPANCY.

Latest standard A330 do have a NAV AOA DISAGREE msg but only if ALL AOA disagrees or
(after EFCS rejection of one) the - Cz estimation - on the other 2 deviates.

Don't know if this also applies to A320 and what 'Cz' estimation here exactly means.

But in this case displays were in agreement as was the value of AOA1 and AOA2 hence messages would not have triggered.

Discrepancy, disagreement, ... this is a topic for discussion when time permits but in the middle of the night all a crew wants to know is that something's going on with the AOA data and prepare accordingly before some protection could mess around ...

Vilas, it was not a level one. The only message was on status ,and it appeared as an inop.

A3Zab,

I think there was in A320 older msn's the NAV AOA DISAGREE msg, but not sure.

Newer versions have the NAV ADR DISAGREE msg which includes speed or alpha disagreement. However I thought that for this msg to come up would require an ADR firstly to have been failed or rejected by ELACs.

As for the DISCREPANCY msges, I am new in the bus, FCOM doesn't clarify this but makes a lot of sense. Do you know the tolerances for the IAS msg between PFD's? Thanks

A330
the NAV ADR DISAGREE (or the NAV AOA DISAGREE depending on the model) caution is necessary when one of the three ADR was already declared faulty or it was switched OFF and there is a disagreement between the two remaining ADRs (or AOAs, depending on the model).

This caution does not protect us from a treacherous failure of two ADRs or AOAs in such a way that their error is coincident and it has the effect of declaring faulty the only healthy ADR. It is a necessary caution, since with only two ADRs there is no possible voting.

What protects us is that, every time an ADR is declared faulty we have to be healthily paranoid and check that it is OK that ADR #x has been correctly rejected (or not). All the more if the reason of the rejection is a disagreement of one versus the other two. That is why I would appreciate to get that information.

Now I think that the best way to give this info could be a extra line below the NAV ADR FAULT caution (something like DUE ADR DISAGREE?) when the reason of rejecting is the result of a voting.

Bangalore
 

Actually they were well aware to be in open descent but didn't know how they ended up in such mode they did not desire. Instead of minding the overall situation and mainly the speed they put their energy on finding why they were on that OP DES mode and how they could leave it.
Instead of reverting to the fully manual solution, they were looking for a software solution (is it a consequence of the training where emphasis was probably more on understanding and managing a computerized system ... ?) but could not find it on such short notice for a System that was new for them.
For guys with their experience on HS748 and B737 it is surprising how they simply forgot about checking their speed, or how one can be easily distracted ...

Problem happened below 500ft. They had asked for visual approach how does it matter which aircraft or mode you are in. You just maintain speed and flight path angle and land. SFO and Bangalore both aircraft were flown visually without looking at speed. In SFO the conventional yoke, active feed back, Q feel, moving throttles but when basic norms are ignored or are absent nothing helps.

@Latirn:
 

IIRC it is 16kt for ?? sec. as detected by PRIM (FCPC) or if 'Pitot-icing' is detected (fast drop of Pt) by FCDC.

So the tolerance is the same as the discrepancy msg.
16kts or 0,05mach for 10secs.

Thank you

It matters so much that they have crashed.
They had no problem managing the basic only 6 months before but suddenly forget about it after acceding to the latest technology. It only tells that something big has been missing during the training for the transition.

Indeed, the golden rules are probably briefly noted, but the real importance of them seems to be usually lost, especially rule 1 and 2. And that is certainly a lack of the right training.

@OK465:

Thx for confirmation.

@ CONF iture / Microburst2002:

We have all the time here....


That's exactly what OEB 48(SR)/49(LR) and (previously OEB 45) is all about, Anticipate->Monitor->Prevent and Recover if the first 3 have been missed.

Hi tubby,
I still see this in late msn A/C, usually in turbulence status msg shows Cat 3 single only/ inop sys Cat 3 dual. Indeed due to adiru disagreement.

As the System already knows something is incorrect with primary data, why shouldn't it simply inform the crew ... ?
Anticipation part done !

... but then you can only publish a red OEB and put everything on the concierge's shoulders ...

The self identified ADR failure cannot be simulated. To give ADR disagree scenario you need to fail one which is indicated to the crew before making other two disagree .

Thank you for your post b215. I have only ever seen it in an A320 not in an A321.

In 16th Operational and Performance Conference Airbus had indicated a change to ECAM alert NAV AOA DISAGREE and in status page they added RISK OF UNDUE STALL WARNING. It was supposed to be effective in FWC H2F5 MOD 37871 date of completion Jun 2009.

In the latest revision of the FCOM, the OEB on the abnormal alpha prot has been removed. Does anyone know if any modifications were done, if not on what basis was it decided that it no longer applies? Can't find any info on this.

Any ideas why on one of the three scenarios you can't use the FPV but on the other two you can?

FPV utilization
 

You can use FPV and vertical speed IF ALTITUDE INFO IS RELIABLE. Need to cross check with GPS altitude, as depicted in QRH.

FPA is Vzbi or Baro inertial vertical speed. When the baro part is lost the bird could not be used. But after Modification No.153528 after loss of ADRs the FPA is calculated using hybrid vertical parameters based on GPIRS. The procedure for all ADRs off now is to use FPV is available.

If you have a look at the OEB there are three scenarios listed. The first is for a continuous nose down pitch.
One ADR - Keep on
Two ADRs - OFF

But in this scenario it doesn't say to use the FPV.
My guess is that it's a dynamic situation so the FPV might be erroneous in this situation.

PilotJames
This topic was discussed in the following thread:


A320 OEB Blocked AOA probes 25/12/2012

Actually this is only AOA locked without any problem with Pitot Static system. So the speed and bird are not affected. The first scenario is immediate action in case of uncontrolled descent and the remaining two possible displays on the PFD. The bird should be usable for all the situations.
You can see the explanation from below reference:
http://mes-transferts.lescigales.org...PROT%20320.pdf

Yes it's not an unreliable airspeed indication.

Bird using IR data, usable but not sure how it will be very helpful.

The aim is to get out of normal law. After that's done when you loose FD, the bird surely is a help to maintain flight path. Also speed indication is correct.

As an amateur as i am, can you explain how the FDs are not reliable in alternate law when the situation is stabilized?

Because this particular OEB says so.
The AP and FDs are lost for remainder of the flight.

And you also need to include the Turkish Airlines crash at Amsterdam. I think this statement is closer to the mark regarding recent crashes.

Everybody loves Mr Ziegler :)
https://en.wikipedia.org/wiki/Bernard_Ziegler

KayPam
clunckdriver is a rabid airbus hater who no doubt was an early airbus pilot but who seem to have gone in hibernation since then and after suddenly coming back to life started voicing same prejudices while the rest of the world has moved on. Likes and dislikes are part of human psyche but it should not be completely divorced from reality. The airbus FBW order book as on 31/01/2017 stands at 16268 aircraft. There are hundreds of airlines that operate them and thousands of pilots like them. No one pilot or an airline can claim to be smarter than everybody else. Boeing also has moved on to FBW and they were not at all keen to extend the only non FBW 737 but for South west their biggest customer demanding an immediate equivalent to A320 Neo or else threatening to buy the Neo. Airbus FBW is different but it is here to stay and thriving not just surviving. Outside the US A320 Neo is outselling 737 by a margin. As you may have noticed some PPL/CPL or non airbus pilots use such posts to have pot shots at airbus. Other than that they are a waste of time.

The OEB 48 is cancelled provided that the aircraft is equipped with at least two Thales AoA probes (PN C16291AB or AA with repetitive check of the heating element) and ELAC standard L97+ or higher (A320) or L99 or higher on A319/A321. Sadly the information we got didn't elaborate what was changed on those ELAC versions, just that it solves the problem.

Is there any guidance or thoughts on which two ADRs to turn off...ie does it matter which you turn off? Are there any implications which may influence your choice. I have heard some pilots discuss that turning off certain ADRs may require a manual gear extension later on.

Doesnt specify, PF's data should stay on.

If you turn off 2 ADRs you will lose Flight directors, Autopilot and autothrust.

If you turn off 1&3 you will need to manually extend the gear and will be in direct law for remainder of the flight once gear down, gear will not come up on a go around.

If you have no prior ADR failure turning off 2&3 would surely be a sensible course of action to allow the capt to become PF for the upcoming alternate law raw data man thrust approach to direct law approach, landing and possible go around. Not saying FOs wont be able to, but personally I would prefer to take that on.

EVA AIR AOA