AF 447 Thread No. 9
Join Date: Jun 2011
Location: france
Posts: 760
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by CONF_iture
It is unacceptable the BEA simply ignores the matter
Then they have to manage it, to learn it. That is new, wise and safe.
Please, Machinbird, could you tell us the five possibilities to enter in that PIO who was in continuity with the "aparent neutral static stability" -did anybody find the exact definition ?) ?
The Bea was not so far ...
Join Date: Jan 2005
Location: W of 30W
Posts: 1,916
Likes: 0
Received 0 Likes
on
0 Posts
DW, thank you for quoting my opinion.
I would not change a word of it.
Where does it say that 'my objective is to force Airbus to go back to back-driven yokes as a PFC' ?
Another search maybe ... ?
I would not change a word of it.
Where does it say that 'my objective is to force Airbus to go back to back-driven yokes as a PFC' ?
Another search maybe ... ?
Last edited by CONF iture; 3rd Aug 2012 at 21:08.
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
having transitioned to fully Stalled with no change in Angle of Attack
It is what you wish would happen, is it not?
Last edited by DozyWannabe; 3rd Aug 2012 at 21:14.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
Quote Lyman
having transitioned to fully Stalled with no change in Angle of Attack
Quote Dozy Wannabe
An aircraft wing cannot transition from unstalled to fully stalled without a change in AoA.
You are correct. The AOA was increasing, my point is that the a/c retained a similar and extreme AOA to and through the STALL....the entry was gentle, the last portion of the climb was due momentum, not lift, nor power.
May I replace "no change" with "no palpable change" ?
having transitioned to fully Stalled with no change in Angle of Attack
Quote Dozy Wannabe
An aircraft wing cannot transition from unstalled to fully stalled without a change in AoA.
You are correct. The AOA was increasing, my point is that the a/c retained a similar and extreme AOA to and through the STALL....the entry was gentle, the last portion of the climb was due momentum, not lift, nor power.
May I replace "no change" with "no palpable change" ?
Last edited by Lyman; 3rd Aug 2012 at 21:25.
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
You may say what you like, although the transition to a rapidly-unwinding altimeter despite the nose-high attitude should have provided a clue (to say nothing of the Stall Warning blaring in their ears and Master Caution flashing in front of them). The THS setting did not have an immediate effect, and did not disguise the presence of stall. It contributed to the immediate return to a nose-high attitude once the nose had dropped and speed built up, but this in itself goes right back to the fact that stall was never diagnosed by the flight crew.
Sustained nose-down on the sidestick from the moment Stall Warning sounded would have been more than enough to recover.
Sustained nose-down on the sidestick from the moment Stall Warning sounded would have been more than enough to recover.
Join Date: Jan 2005
Location: W of 30W
Posts: 1,916
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by DW
It is what you wish would happen, is it not?
No luck with the search ... ?
Originally Posted by Lyman
I cannot prove it but I do not think the THS made the STALL severe ...
See you later.
Join Date: Dec 2010
Location: Middle America
Age: 84
Posts: 1,167
Likes: 0
Received 0 Likes
on
0 Posts
To help the current discussion along for everyone (for better or worse) regarding FBW controls, that is FBW-A & FBW-B, go here to review FBW-B (777).
B777 Flight Controls
B777 Flight Controls
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
I'm not mind-reading, I'm asking you to answer an honest question. Do you want to see Airbus go back to yokes? You don't have to explain why if you don't want to.
Which they did.
That's a factual account of the THS behaviour - and the limit of what the BEA can say.
That was the BEA job to analyse the operation and the influence of the THS ...
Originally Posted by BEA Final Report (English) p.22-23
At 2 h 10 min 51, the stall warning triggered again, in a continuous manner. The thrust levers were positioned in the TO/GA detent and the PF made nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) began a nose-up movement and moved from 3 to 13 degrees pitch-up in about 1 minute and remained in the latter position until the end of the flight.
Last edited by DozyWannabe; 3rd Aug 2012 at 22:03.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
CONFiture
Thank you for responding....
Originally Posted by Lyman
"I cannot prove it but I do not think the THS made the STALL severe ..."
You say...
"That was the BEA job to analyse the operation and the influence of the THS ... but a flight control behavior does not apparently deserve attention in the AF447 case. Of course I'd like to discuss further, but I have to go now."
Part of what I write is meant to publish in purposeful ignorance of the report, it is not closely re-examined, by me in part, It is protest.
I have stated my opinion re: the Final report. In this matter, it is partial, brief, incomplete, and unsatisfactory.
These bureaus are deserving of respect partially in relationship to their product.
I do respect them, but here they have failed, and not in the least due only their lack of inquiry into the Autotrim issue. Well and good they ignore post Stall, I do so myself, and am on record as saying the Stall and after is interesting, but what caused it is the important thing; the THS articulated upwards to and through the exit of envelope.
I don't quibble with the importance of Stall, but any Stall is severe, I think it more important to emphasize how and why the Stall was unusual, and gentle, unnoticed.....initially.
Dozy... What do you think of the BEA language "The THS began a Nose Up movement"? Do you think that is misleading, technically?
Also, they say "And remained in that position to the end of the flight". Why would the THS do that? Doesn't it follow the elevators command? Towards the end, the PITCH reached 10 degrees up, the Captain said that, it was the last of the CVR. Why would the THS remain planted in 13.2 degrees A/C NOSE UP, when the elevators were set to ND, and for a decent length of time, enough to reduce the ROD by 50 per cent?
Thank you for responding....
Originally Posted by Lyman
"I cannot prove it but I do not think the THS made the STALL severe ..."
You say...
"That was the BEA job to analyse the operation and the influence of the THS ... but a flight control behavior does not apparently deserve attention in the AF447 case. Of course I'd like to discuss further, but I have to go now."
Part of what I write is meant to publish in purposeful ignorance of the report, it is not closely re-examined, by me in part, It is protest.
I have stated my opinion re: the Final report. In this matter, it is partial, brief, incomplete, and unsatisfactory.
These bureaus are deserving of respect partially in relationship to their product.
I do respect them, but here they have failed, and not in the least due only their lack of inquiry into the Autotrim issue. Well and good they ignore post Stall, I do so myself, and am on record as saying the Stall and after is interesting, but what caused it is the important thing; the THS articulated upwards to and through the exit of envelope.
I don't quibble with the importance of Stall, but any Stall is severe, I think it more important to emphasize how and why the Stall was unusual, and gentle, unnoticed.....initially.
Dozy... What do you think of the BEA language "The THS began a Nose Up movement"? Do you think that is misleading, technically?
Also, they say "And remained in that position to the end of the flight". Why would the THS do that? Doesn't it follow the elevators command? Towards the end, the PITCH reached 10 degrees up, the Captain said that, it was the last of the CVR. Why would the THS remain planted in 13.2 degrees A/C NOSE UP, when the elevators were set to ND, and for a decent length of time, enough to reduce the ROD by 50 per cent?
Last edited by Lyman; 3rd Aug 2012 at 22:42.
Join Date: Oct 2011
Location: Lower Skunk Cabbageland, WA
Age: 74
Posts: 354
Likes: 0
Received 0 Likes
on
0 Posts
DW:
So flippin' what if he does? I do. So sue me. BFD. This has gotten really tiresome to the point that I'm ready to bail. Not liking side-sticks/un-linked operation is a perfectly legitimate opinion to hold. I'm gonna block your posts, thus reading the threads twice as fast, without the constant aggravation. Seen ya!
I'm not mind-reading, I'm asking you to answer an honest question. Do you want to see Airbus go back to yokes? You don't have to explain why if you don't want to.
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
But I'm not saying it's not a legitimate position to hold (despite disagreeing vehemently with that position), I'm simply asking on what basis - a question to which I have not had a satisfactory evidence-based answer in the best part of a decade on here.
It's no skin off my nose, but I'll miss your snark.
[Not to mention a mean count of 4 posts a day since the start of August, two of which I didn't post on at all, is a funny definition of "constant aggravation"...]
Last edited by DozyWannabe; 3rd Aug 2012 at 22:30.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
CONFiture...
I have changed my post to better reflect my meaning, to wit:
I cannot prove it but I do not think the THS made the STALL more severe, so much as it made the STALL Entry different....,
I have changed my post to better reflect my meaning, to wit:
I cannot prove it but I do not think the THS made the STALL more severe, so much as it made the STALL Entry different....,
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
Dozy...
"You may say what you like, although the transition to a rapidly-unwinding altimeter despite the nose-high attitude should have provided a clue"
Knock it off. I am discussing transition through apogee, and the crew have already experienced 1.65 g in the ascent... An acceleration back to 1g from what had been a decreasing ascent, does NOT qualify as airframe STALL WARN, especially,as before, when the nose remains at Extremely high AOA....
"You may say what you like, although the transition to a rapidly-unwinding altimeter despite the nose-high attitude should have provided a clue"
Knock it off. I am discussing transition through apogee, and the crew have already experienced 1.65 g in the ascent... An acceleration back to 1g from what had been a decreasing ascent, does NOT qualify as airframe STALL WARN, especially,as before, when the nose remains at Extremely high AOA....
Last edited by Lyman; 3rd Aug 2012 at 22:39.
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
Jeez - the first thing you're taught in an Instrument Rating course is to ignore what you feel in your body and focus on the instruments to the exclusion of all else.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
I remain hopeful that you might get my point. I relate the inappropriate reaction to STALL to the lack of TWO palpable cues: Buffet (felt) and Nose Drop, (felt). Sensation is critical, do not get confused. In this cockpit, instrumentation is a crapshoot, in the eyes of the crew. The two cues heralding STALL are completely physical, and sensate. Confirmation can come from instruments (not here) but there is no instrument that has a big red arrow, and pinches one in the ass, even if visual...Though there is such a similar animal in non Airbii....
Last edited by Lyman; 3rd Aug 2012 at 23:03.
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
02:11:32 - Nose drops
02:11:45 - Nose drops
02:12:02 - Nose drops
02:12:32 - Nose drops
02:13:47 - Nose drops
02:14:12 - Nose drops
No it isn't - as the Flash Airlines report stated, sensation should always be ignored in favour of what the instruments are telling the crew.
Only in your mind - evidence suggests that airspeed data and only airspeed data was missing for a short period at the start of the sequence.
The aural Stall Warning was disregarded in this case, just as it was in the Birgenair crash - in the latter case even a stick-shaker didn't help.
02:11:45 - Nose drops
02:12:02 - Nose drops
02:12:32 - Nose drops
02:13:47 - Nose drops
02:14:12 - Nose drops
Sensation is critical, do not get confused.
In this cockpit, instrumentation is a crapshoot, in the eyes of the crew.
Though there is such a similar animal in non Airbii....
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
Dozy Wannabee,
You are confused. Post stall, the nose is responding to controls. At STALL ENTRY, the nose is supposed to drop on its own.
I think we're done. You do not read.....
You are confused. Post stall, the nose is responding to controls. At STALL ENTRY, the nose is supposed to drop on its own.
I think we're done. You do not read.....
Last edited by Lyman; 3rd Aug 2012 at 23:35.
Join Date: Jul 2009
Location: DFW
Age: 61
Posts: 221
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by TTex
Quote:
Originally Posted by TTex600
In this accident we have an aircraft designed to be flown by computers
Originally Posted by TTex600
In this accident we have an aircraft designed to be flown by computers
Originally Posted by DozyWannabe
Not so - the Airbus FBW series were intended to be no more reliant on automation than any other contenporary type.
Originally Posted by -TTex
that suffers a GIGO computer issue that convinces the computers to give up on their job.
Originally Posted by DozyWannabe
See Birgenair for an example of what happens when the automation does not know when to give up...
Originally Posted by TTex
Which leaves the pilots with a system designed to be flown by computer and they now have no computer or at least not all of the computer.
Originally Posted by DozyWannabe
See my first reply. The system is not designed to elevate the computer over the pilot(s) and never was.
Originally Posted by TTex
BUT, it still wants to be flown like it is a computer because only PART of the computer system gave up, the rest is still working and it only knows computer sense.
Originally Posted by DozyWannabe
Again, no - it wants to be flown like any other aircraft, with the caveat that the trim is automatic. In such circumstances, the only thing that needs to be remembered is that the trim is affected by the PFC inputs - if sustained for long enough.
Originally Posted by DozyWannabe
If these pilots went straight from instrument rating to ATPL - and their ATPL experience consisted entirely of Airbus FBW types - then autotrim is the norm. The habit of trimming manually grew out of technical limitations of aircraft of the postwar period - it does not necessarily follow that later designs should mandate manual trim when the flight management automation disconnects.
Join Date: Jul 2009
Location: DFW
Age: 61
Posts: 221
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Lyman
You are confused. Post stall, the nose is responding to controls. At STALL ENTRY, the nose is supposed to drop on its own.
I think we're done. You do not read.....
I think we're done. You do not read.....
Last edited by TTex600; 3rd Aug 2012 at 23:32.
