OK465;
Real question is, 'where would you find it?'. http://www.smugmug.com/photos/i-Qjmb...QjmbNFp-X2.jpg |
Originally Posted by jcjeant
(Post 7413129)
This speculation seems to still be the most plausible
In fact it is supported by the fact that the pilot continues pulling on the stick despite the stall alarm and the remarks of the PNF Added to this, both F/Os are on the CVR shortly before the start of the accident sequence discussing the fact that they're about as high as they can safely go for the conditions - as such, it's fairly unlikely that the PF would have consciously been pulling up - my personal opinon for all it's worth is that it was an unintentional control input initiated by the startle factor. If the PF believed that the protections would allow them to pitch up and climb safely then the whole conversation about altitude was moot.
Originally Posted by CONF iture
(Post 7414572)
What I find disturbing is that the system takes the decision to disconnect the AP and switch to ALT LAW based on its analysis of the ADRs outputs but does not think as necessary to keep the crew informed about the reason it took that very decision ?
I was under the impression that troubleshooting via ECAM was intended for when the aircraft is stable rather than during an attempt to regain control. It's also possible that IAS DISAGREE/ADR FAULT was bumped off the ECAM when the ADR DISAGREE appeared, as OK465 attests to. The ACARS timings are very vague - the final report contains more accurate timings which I'd imagine came from the DFDR. |
Originally Posted by gums
(Post 7416686)
The big thing was I never used the sucker as a routine way of doing business except on long flights and at constant altitude/heading.
Now... hat, coat... ;) |
Originally Posted by Lyman
(Post 7413530)
... a term like nugget is demeaning, and serves in the long run to cement a conclusion that may not be accurate, that the PF was some kind of flustered 'rookie'.
Originally Posted by UNCTUOUS
(Post 7414609)
When abstract and abstruse technology runs amok, it needs to be immediately apparent to a flight crew that anything (or everything?) in technoville is becoming unstuck.... or even just on its way out. Fortunately there is (prospectively) a digital way to do that - to "in your face" alert the crew of an imminent GIGO fiasco (GIGO = garbage in/ Garbage out). But more on that in a moment.....
Originally Posted by RR_NDB
(Post 7414672)
So, SURPRISES to the crew must be reduced to a minimum. Why not to ALERT CREW IMMEDIATELY when the System will face UAS? This is particularly important because there are risks of GIGO.
Originally Posted by Lyman
(Post 7413628)
On a basic level, perhaps a more critical look at the parameters of autopilot in Turbulence?
|
If the PF believed that the protections would allow them to pitch up and climb safely then the whole conversation about altitude was moot. If a problem occur (too much altitude) .. protections will act Why not try ... Those 4 minutes (yes .. they were startled for 4 minutes ..a long time for experienced pilots .. no ? ) were just ...the game " trying anything and we will see " ... They just not try one thing ... push .. push forward the stick .... Again .. the "surprise" effect ... ? |
Originally Posted by TTex600
My original point was this, it's dam#$%^$ near impossible for a sim instructor to configure a sim in a way to force direct law without also removing control surfaces from the pilots usage. And therefore it's quite difficult for a pilot to experience true direct law in the training environment.
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Originally Posted by jcjeant
(Post 7421249)
The conversation about the altitude does not prevent the pilot think he can easily take more altitude .. if it has the protections active ..
Those 4 minutes (yes .. they were startled for 4 minutes .. long time .. no ? ) were just ...the game " trying anything and we will see " ... They just not try one thing ... push .. push forward the stick .... Again .. the "surprise" effect ... ? |
Originally Posted by Dozy
The big red X on the speed tape
and the disappearance of the Vx indicators should have been a significant clue, no? It's also possible that IAS DISAGREE/ADR FAULT was bumped off the ECAM when the ADR DISAGREE appeared, as OK465 attests to. Also, it is not what OK465 was attesting. The ACARS timings are very vague - the final report contains more accurate timings which I'd imagine came from the DFDR. |
Originally Posted by Dozy
The fact that the CVR transcript has the PNF reporting no speeds at 02:10:15, despite the NAV ADR DISAGREE message not appearing until past 02:12 implies that at least half the crew on the flight deck were well aware what the problem was.
This flatly contradicts any assertion that the systems were not providing the relevant information to the crew. |
Originally Posted by CONF iture
(Post 7421280)
Is it again something of your own making ?
Originally Posted by Hunter58
(Post 7408184)
I would think a big red cross over thecspeed tape to be quite a visual indicator...
No - The disappearance of some characteristic speeds is NOT a positive signal of UAS. No - First a IAS DISAGREE ECAM MSG does not exist and second such message or its equivalence would have been part of the FDR if it had appeared even momentarily. The PNF's reference to losing the speeds is at approx. 02:10:15.
Originally Posted by CONF iture
(Post 7409086)
If the guys knew, why the PNF would have said :
Fais attention à ta vitesse - Fais attention à ta vitesse I just don't see how an argument that the crew were unaware of an air data/speed problem until the ECAM displayed NAV ADR DISAGREE at 02:12:44 can stand up in the face of a clear reference to speed being unavailable at 02:10:15. Fundamentally I have no problem with a hypothesis whereby there was a technical issue that misled the crew - however if you want that hypothesis taken seriously then you must work forward from the evidence at hand to support your hypothesis. Throwing mud in the form of unsupported assertions because you've already decided that the aircraft and its design must be at fault is unlikely to convince anyone other than those who already share your views. |
Several questions regarding the NAV ADR DISAGREE message have been lingering in my mind. The ACARS message was time-stamped 0212 and it was received by the ground station at 02:12:51. The 3rd interim report lets it appear on the ECAM at 02:12:XX and the final report at 02:12:44. What new information permitted the more precise timing?
What caused the message at this point in time? The Air Caraibes memo states the thresholds for rejection of the first ADR as: Altitude 3000 ft during 1 second, Mach 0.05 / 10 s, CAS 16 kt / 10 s, TAS 16 kt / 10 s, AoA 3.6° / 1 s, total pressure 20 hPa / 10 s, static pressure 5 hPa / 1 s. The thresholds for rejection of the two remaining ADRs are the same except that the time is always 1 second. Then the ECAM message (final report, page 99): NAV ADR DISAGREE - AIR SPD ...... X CHECK - IF NO SPD DISAGREE -AOA DISCREPANCY - IF SPD DISAGREE -ADR CHECK PROC ... APPLY Isn't it odd that the system asks the crew to find out what caused the system to generate that message? If there is NO SPD DISAGREE, the crew is to suspect AOA DISCREPANCY? |
I know this will go 'against the grain' for all those 'affectionados' of total computer control etc, but if my idea of a spring-loaded boxing glove in the panel is discarded, what is really need is a soft, HAL-like message:
"Dave - I'm sorry - I really don't know what is happening here. Would you mind being a pilot for a short time?" As long as we have 'pilots' at the controls we will then be ok. |
I know this will go 'against the grain' for all those 'affectionados' of total computer control etc, but if my idea of a spring-loaded boxing glove in the panel is discarded, what is really need is a soft, HAL-like message: "Dave - I'm sorry - I really don't know what is happening here. Would you mind being a pilot for a short time?" As long as we have 'pilots' at the controls we will then be ok. One is a constant "Dave - I'm sorry" :) The other is a variable "As long" :uhoh: Not so sure that the result will always be good :sad: |
Hazelnuts39
The computer is trying to determine if the ADR disagree is induced by NAV (sic) Maneuvering? Eg slip/skid, asymmetric, etc. |
Originally Posted by DozyWannabe
Throwing mud in the form of unsupported assertions because you've already decided that the aircraft and its design must be at fault is unlikely to convince anyone other than those who already share your views.
Hunter58 must be working for the BEA after all … no need to check. Do you only make the difference between characteristic speeds and speed tapes ? Unsupported assertions and mud … look in your own garden Dozy. |
Originally Posted by Lyman
(Post 7421937)
The computer is trying to determine if the ADR disagree is induced by NAV (sic) Maneuvering? Eg slip/skid, asymmetric, etc.
Chapter*10.*Navigation
Originally Posted by BOAC
(Post 7421717)
... all those 'affectionados' of total computer control etc
@CONF - coming from someone who's still convinced that Asseline's stuff-up was the fault of the aircraft I wouldn't be throwing stones. Hunter states something that contradicts your hypothesis, so you automatically assume he must be part of the conspiracy. |
UAS early warning
Hi,
Because it's one of the most difficult situations to reliably work out - as has been stated previously. This is feasible, should be done long time ago and the approach used by Airbus SAS showed in the earlier mentioned paper from the Design group is IMHO an ERROR. To diagnose UAS just by "System output" is DANGEROUS and a good example of K.I.C.S. (*) This flatly contradicts any assertion that the systems were not providing the relevant information to the crew. ...at least half the crew on the flight deck were well aware what the problem was. (*) Keep It Complex Stupid |
ACARS
From page 98 of the final:
This correlation confirmed the preliminary analyses written up in the interim reports. Study of the transmission times between the computers that identified the triggering of the monitoring and the CMC also made it possible to explain and check the order in which the messages were sent by ACARS. This order may differ from the order of appearance of the ECAM messages. message-timing by the CMC is accurate to within one minute, the order in which these messages are transmitted does not necessarily correspond to the associated sequence of events, |
Originally Posted by RR_NDB
(Post 7422250)
This is feasible, should be done long time ago and the approach used by Airbus SAS showed in the earlier mentioned paper from the Design group is IMHO an ERROR.
To diagnose UAS just by "System output" is DANGEROUS and a good example of K.I.C.S. (*) The System provided a lot of information including processed garbage. A good man-machine interface could provide to 100% of the crew (including Capt) reliable information. Remember that when the Captain returned, the airspeed was back online, so he was facing a different set of problems than the initial situation confronting the F/Os. For what it's worth I think that the initial UAS problem was quickly overtaken by the concern over the aircraft attitude caused by the PF's control inputs as far as the PNF and Captain were concerned. |
Originally Posted by OK465
- the order in which these messages are transmitted does not necessarily correspond to the associated sequence of events
F/CTRL NAV MAINTENANCE etc.. The ECAM and ACARS sequencing will both vary accordingly, and in the case of ACARS the shuffling shows up when a lot is going on. |
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