AF447 final crew conversation - Thread No. 2
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Swear to God Mach, are you kidding? 5.00 words? Show me one, give me some direction. I'd be happy to edit.
sub Mach
Are the pilots 'told' instantly when the computer doubts the Speeds?
Did "control limit locking" involve THS?
Are surfaces linked to the computer, or just the actuator?
etc.?
sub Mach
Are the pilots 'told' instantly when the computer doubts the Speeds?
Did "control limit locking" involve THS?
Are surfaces linked to the computer, or just the actuator?
etc.?
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Originally Posted by A33Zab
The ADR monitoring of FMGEC is a continuous process and rather complicated...
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HN39
A decrese of 30knots/sec? Only? Not to include an increase of the same value?
Will someone say if the flying pilots are made aware of the urgency of the monitoring process post 30knot/sec. sensed? Are they "in the loop"? Or do they have to wait for the 'generic' cavalry charge and "MASTER CAUTION" without elucidation from the panel? My sinking feeling is that they are not made aware, that they have to await, in ignorance, the 'decision" of the Computer. No "Speeds" notation (verbal) exists until eleven seconds after a/p LOSS.
Did the AutoPilot quit at start of monitoring, and, ten seconds after its loss, the pilots were 'told'? Sounds impossible.
A decrese of 30knots/sec? Only? Not to include an increase of the same value?
Will someone say if the flying pilots are made aware of the urgency of the monitoring process post 30knot/sec. sensed? Are they "in the loop"? Or do they have to wait for the 'generic' cavalry charge and "MASTER CAUTION" without elucidation from the panel? My sinking feeling is that they are not made aware, that they have to await, in ignorance, the 'decision" of the Computer. No "Speeds" notation (verbal) exists until eleven seconds after a/p LOSS.
Did the AutoPilot quit at start of monitoring, and, ten seconds after its loss, the pilots were 'told'? Sounds impossible.
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@CONF iture:
RTLU was initially stuck then non available, but what is your reference for
the ailerons ?
this is a protection not a malfunction of the RTLU.
RTLU reset would have been accomplished upon S/F selection.
If anyone can find the reference for the OB ailerons he is most welcome, I couldn't find it in words, but its there in the traces and since the roll function of spoiler 2,3 & 6 in ALT2 are inhibited to decrease the roll rate it is obvious to zero the OB ailerons for the same reason.
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I ask again. The ailerons and spoilers inhibit remain in ALT 2? Where does she get her reputation for "twitchy"? And wouldn't this be counterintuitive, since Roll would then demand maximum from surfaces that were not intended to produce rapid Roll Rate?
Or are they limited to prevent excess YAW, the remaining Roll controls being closer to the longitudinal axis?
Or are they limited to prevent excess YAW, the remaining Roll controls being closer to the longitudinal axis?
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Open data
Originally Posted by CONF iture
My only eagerness is to make sure the victim's families have access to all the data, not only part of them. There is no excuse for the Judge not to include them in the proceeding. We want to know what happened, everything, not only what the crew did wrong.
It is independant from the trial who does his own enquery (yes !) They have their own experts...
We have access only to the BEA enquery results.
The family may ask to the Judge the result of the Justice enquiry two.
The reality is very different : it is totally impossible for the Justice to do an independant inquery. But you have two groups of experts (all are generaly friends or colleagues one of another)...
That is in France ...
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Originally Posted by A33Zab
RTLU was not stuck, as in jammed, it was freezed at the position it was.
this is a protection not a malfunction of the RTLU.
RTLU reset would have been accomplished upon S/F selection.
this is a protection not a malfunction of the RTLU.
RTLU reset would have been accomplished upon S/F selection.
As the role of the RTLU is to limit rudder and pedal deflection as a function of the speed, and the position of the rudder limiter was stuck, frozen since 02:10:06, why that limit was exceeded when the rudder was suddenly and generously applied after 02:13:00 ?
I have not heard about the slats being extended earlier ...
S/F selection and position is just another trace I'd like to see.
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"As the role of the RTLU is to limit rudder and pedal deflection as a function of the speed, and the position of the rudder limiter was stuck, frozen since 02:10:06, why that limit was exceeded when the rudder was suddenly and generously applied after 02:13:00 ?"
CONFiture. You will need to address the limit strength of the RUDDER actuator v. air loads. Just as the limit strength of the THS jackscrew is compared to the airloads on the THS. When takata posted the picture of the recovered jackscrew, I noted some damage at (near) the end (NU) limit of the screw. The rotation and torsional impetus of the jackscrew would be in opposition to the extreme airloading on the THS. If it failed, and trapped the collet in its near max. position of 13.2, that explains the nesting of the THS from apogee. Logic demands some movement post apogee with ND from PF. None is in evidence.
These questions are unaddressed here, and to my knowledge, not broached in the BEA reportage.
Best regards
CONFiture. You will need to address the limit strength of the RUDDER actuator v. air loads. Just as the limit strength of the THS jackscrew is compared to the airloads on the THS. When takata posted the picture of the recovered jackscrew, I noted some damage at (near) the end (NU) limit of the screw. The rotation and torsional impetus of the jackscrew would be in opposition to the extreme airloading on the THS. If it failed, and trapped the collet in its near max. position of 13.2, that explains the nesting of the THS from apogee. Logic demands some movement post apogee with ND from PF. None is in evidence.
These questions are unaddressed here, and to my knowledge, not broached in the BEA reportage.
Best regards
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Originally posted by Lyman ... Ref THS ...
Logic demands some movement post apogee with ND from PF. None is in evidence.
Logic demands some movement post apogee with ND from PF. None is in evidence.
Excerpt from Owain Glyndwr's explanation ...
For virtually the whole of the event, and certainly for the whole time the aircraft was stalled, the THS had a positive AOA so that it was generating upwards lift and a nose down pitching moment despite the fact that it was set at -13.5 degrees! This is consistent with it being a stable aeroplane as shown by that pitching moment curve. Of course the net HS lift was negative and the net pitching moment positive (nose up), but this was made up of a very large downwards lift from the elevators partly offloaded by the positive lift from the THS itself. If the elevator had been returned to neutral the THS lift would have given a ND pitch and attitude reduction. Look at the traces - that is exactly what happened!
The nose was being held up by the application of elevator.
For virtually the whole of the event, and certainly for the whole time the aircraft was stalled, the THS had a positive AOA so that it was generating upwards lift and a nose down pitching moment despite the fact that it was set at -13.5 degrees! This is consistent with it being a stable aeroplane as shown by that pitching moment curve. Of course the net HS lift was negative and the net pitching moment positive (nose up), but this was made up of a very large downwards lift from the elevators partly offloaded by the positive lift from the THS itself. If the elevator had been returned to neutral the THS lift would have given a ND pitch and attitude reduction. Look at the traces - that is exactly what happened!
The nose was being held up by the application of elevator.
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@CONF iture:
As the role of the RTLU is to limit rudder and pedal deflection as a function of
the speed, and the position of the rudder limiter was stuck, frozen since
02:10:06, why that limit was exceeded when the rudder was suddenly and
generously applied after 02:13:00 ?
the speed, and the position of the rudder limiter was stuck, frozen since
02:10:06, why that limit was exceeded when the rudder was suddenly and
generously applied after 02:13:00 ?
@~02:13:00 the pedal input was abrupt and full 8° while Yaw damper was deflecting the rudder in same direction max 4°.
So a little overshoot occured (and torsion on the inputshaft) because yaw damper was unable to compensate in time.
I have not heard about the slats being extended earlier ...
S/F selection
and position is just another trace I'd like to see.
S/F selection
and position is just another trace I'd like to see.
For lieman:
The LL (limit loads) are max loads expected in the normal flight envelope, the UL (Ultimate Loads) are 1.5 LL.
No breaking of the surface occurs before UL.
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For A33Zab
A question:
Is this an add-on made after the AA587 crash? You know, where the pilot got blamed for "excessive rudder input"? (tail broke off) 
Because the RTLU is not a Rudder DEFLECTION Limiter but a rudder INPUT limiter.
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@OF:
Is this an add-on made after the AA587 crash?
My ATA 27 pages with diagrams of RTLU and PTLU are dated APR 1993.
But AA587 was A300 isn't it?
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Originally Posted by A33Zab
Because the RTLU is not a Rudder DEFLECTION Limiter but a rudder INPUT limiter.
The RTLU set the position of the rudder limiter (physical limitation). In this case it was between 5 and 6 degrees according to the graph on page 112 of the third Interim Report, but 8 degrees after physical observation as stated in the second Interim Report ... why such difference btw ?
The RTLU ECAM MSG then indicates the unavailability for further rudder deflection limitation calculation function, but the position of the rudder limiter was already frozen.
Nevertheless, at 02:13:00 the rudder reached 10 degrees ... not 'a little overshoot'
Could it be the consequence of the limitation value being unfrozen following a slats extension command ... ?
It is clearly mentioned in the second Interim Report that the flaps were retracted but I have not seen a word on the slats ...
Extending the slats could be an attempt to regain control, kicking the rudder like it was done at 02:13:00 could be another one ...
roulishollandais,
The families are 'parties civiles' and should have full access to the data.
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Protections
I am studying carefully before posting part B and C on "Transient in feedback Systems II" and i have a question "hovering" in my mind. 
Why not to implement a protection against climbing above REC MAX?
Protections are designed to "protect". It is reasonable to allow a plane climb (at high ROC) towards a FL above this important limit?
Why not to implement a protection against climbing above REC MAX?
Protections are designed to "protect". It is reasonable to allow a plane climb (at high ROC) towards a FL above this important limit?
Last edited by Jetdriver; 18th Mar 2012 at 14:24.
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Hi,
CONF iture
Indeed .. as plaintiffs families are entitled to access to investigative files
But it's more complicated than that because the judge handling the case has not joined the FDR and CVR transcripts as exhibits to the investigation and therefore .. given the needs of the technical investigation .. BEA has given datas to Airbus and AF .. but not to families since they are not parts of the technical investigation .....
AFAIK
Dura Lex Sed Lex
CONF iture
roulishollandais,
The families are 'parties civiles' and should have full access to the data.
The families are 'parties civiles' and should have full access to the data.
But it's more complicated than that because the judge handling the case has not joined the FDR and CVR transcripts as exhibits to the investigation and therefore .. given the needs of the technical investigation .. BEA has given datas to Airbus and AF .. but not to families since they are not parts of the technical investigation .....
AFAIK
Dura Lex Sed Lex
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@CONF:
Originally Posted by A33Zab
Because the RTLU is not a Rudder DEFLECTION
Limiter but a rudder INPUT limiter.
The RTLU set the
position of the rudder limiter (physical limitation). In this case it was
between 5 and 6 degrees according to the graph on page 112 of the third Interim
Report, but 8 degrees after physical observation as stated in the second Interim
Report ... why such difference btw ?
Ref. mm43: RTLU GRAPH
Ref. PJ2: R/PTLU
When the RTLU is at minimal (0° RVDT angle) the RTLU limits the rudder input to 4°, to be accurate this is 3.7° (CMM).
Interpolating the low resolution TLU trace its value was ~4.2° (RVDT angle) just before @02:10:05.
4.2° + 3.7° ~ 7.9° at which it was freezed by PRIM at the start of the speed monitoring process.
The RTLU ECAM MSG then indicates the unavailability for further rudder
deflection limitation calculation function, but the position of the rudder
limiter was already frozen.
deflection limitation calculation function, but the position of the rudder
limiter was already frozen.
The PRIM freezed the RTLU at the start of the monitoring process, but it can not control it because the TLU electrical motors are driven by the SECs.
The PTLU and RTLU share the control relays but have separate driver circuits inside the SECs. (so far true)
If the SECs continue to drive the PTLU to 5.8° RVDT angle the limiting position of the PTLU will be 5.8°(RVDT angle) + 3.7° ~ 9.5°.
at that position it detected the RTLU is not following its command position and triggers the TLU NOT AVAIL signal and F/CTL RUD TRV LIM FAULLT @ 02:10:18.
Nevertheless, at 02:13:00 the rudder reached 10 degrees ... not 'a little overshoot
Taking free play in all swivels & hinges in account the rudder deflection can be a bit more than the RTLUs position. (Due to poor resolution I would say just before 10°......9.5°?)
Could it be the consequence of the limitation value being unfrozen following a slats extension command ... ?
It is clearly mentioned in the second Interim
Report that the flaps were retracted but I have not seen a word on the slats
Report that the flaps were retracted but I have not seen a word on the slats
No, Slat/Flap input is combined (1 S/F lever).
If this was TRUE, the R/PTLU would have been driven to allow max. rudder deflection (35°) within 30 sec.
After 30 sec. this backup circuit will be isolated.
Last edited by A33Zab; 19th Mar 2012 at 09:35.
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Originally Posted by A33Zab
If this was TRUE, the R/PTLU would have been driven to max. rudder deflection (35°) within 30 sec.
The rudder pedal position was 10 degrees off max, so was the rudder (page 112)
No, Slat/Flap input is combined (1 S/F lever)
But FLAPS 1 selection in the air for landing preparation provides only slats. It is called CONF 1
Many data are missing ...
The BEA has provided too little.
What the Judge is waiting for ?
Who are those lawyers who pretend to defend the families ... ?