Lyman, I know lawyers speak the way you speak all the time, but would you mind writing in simple un-convoluted English for a change. It might help present your points more clearly. Choose simple words instead of the $5.00 words please.
The ADR monitoring of FMGEC is a continuous process and rather complicated...
I'm referring to the "10 seconds" speed monitoring process described on page 55 of BEA's Interim Report no.1 and again on page 40 of I.R.#3. It is triggered by a decrease of more than 30 kt in one second of the “polled” speed value. The polled speed value is the "median" or middle value of three valid ADR's or, if one ADR has been rejected, the mean of the two remaining values.
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.
RTLU was initially stuck then non available, but what is your reference for the ailerons ?
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.
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.
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?
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.
The BEA report is PUBLIC. Their report is said "administrative".
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)...
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.
I used 'stuck' as it is the word they used for the translation on page 40 of the third Interim Report, but am I missing something here : 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.
"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.
Logic demands some movement post apogee with ND from PF. None is in evidence.
Post apogee the Elevator was mostly at 30° NU and never came below 15° NU - short term. Why would the THS need to follow?
Quote:
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.
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 ?
Because the RTLU is not a Rudder DEFLECTION Limiter but a rudder INPUT limiter.
@~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.
Quote:
I have not heard about the slats being extended earlier ... S/F selection and position is just another trace I'd like to see.
Because they were not...
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.
No, RTLU is common on A320 series, (PTLU) was added to this system on A34/33 from the start....AFAK. My ATA 27 pages with diagrams of RTLU and PTLU are dated APR 1993.
Because the RTLU is not a Rudder DEFLECTION Limiter but a rudder INPUT limiter.
I feel a bit uneasy by this statement, I must say.
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.
roulishollandais, The families are 'parties civiles' and should have full access to the data.
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
Originally Posted by A33Zab Because the RTLU is not a Rudder DEFLECTION Limiter but a rudder INPUT limiter.
I feel a bit uneasy by this statement, I must say.
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 ?
IMO the TLU trace shows its RVDT angle ISO max. rudder deflection.
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.
Quote:
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.
The following is purely speculative since I am not able to prove with documentation.
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.
Quote:
Nevertheless, at 02:13:00 the rudder reached 10 degrees ... not 'a little overshoot
Quote:
The surface xdcr is placed at the lower side of the rudder, the lower servo is attached to the linkage before the RTLU, the upper and center input linkage after TLU.
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°?)
Quote:
Could it be the consequence of the limitation value being unfrozen following a slats extension command ... ?
Quote:
It is clearly mentioned in the second Interim
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.
Open data
For A33Zab
