|
.. as a sideline, should anyone be wondering why I haven't started the next thread, I'm leaving it until the report comes out .. as I suspect that the posts will be coming fast and furious for several weeks after that ..
|
Originally Posted by HN39
In my search for a correlation between side stick angle, pitch rate and normal acceleration, based on the C* control law, I started comparing the elevator positions to the side stick commands, and am surprised to find that the elevator seems to be leading the side stick:
|
I have never used a HUD so don't know if it would have helped them or not. Attitude indicators, altimiters, Vertical speed indicators and stall warnings didn't, so doubt if HUD would have helped either. They just needed an experienced pilot flying, not them. Sorry. That is how I see it. Monitoring an autopilot for thousands of hours does not make you a pilot.
|
HN39
In the first extreme, the stick follows acquired angle of elevator by eight seconds? What is wit that? Mach... Or a lead in the elevator data? If it is real, what could cause such a discrepancy? Was the a/c hunting, the pilot chasing? Sounds like an abnormal. |
In resp. to mm43
Thanks for the link to the Desdemona simulator project. I noted a link hidden in the article leads to an EU Research & Innovation page that includes a comprehensive write-up and video. Some may be interested. Mr. 43, (Since nobody has remarked on this)-- Thanks, that was superb. The soundtrack of the video is the same as the article text. A large download people, but highly recommended! The new simulator really is a centrifuge. :yuk: Stupendous. |
Originally Posted by Machinbird
That sounds like a data reduction problem with the original data to me. Something likely caused a delay artifact in the side stick position data.
|
Originally Posted by HazelNuts39
(Post 7267912)
In the simulation also?
|
HN In the simulation also? the time delay can and will be a non accurate start-time in the simulation or in the transfer from the simulation to the report, they searched for bigger effects than you |
I don't get it. If you do a simulation with the side stick as input and the elevator as output, how can the elevator get ahead of the side stick? If there was a delay artifact in the elevator or side stick position data, wouldn't the simulation have revealed it?
Yes, I'm looking forward to seeing that explained in the final report. |
In one specific hypothetical case, over a given period of time nose high somewhere in that 6-15 degree pitch range, airspeed decaying, if you were to graph a hands-off 'neutral' sidestick, would that not be a 0 degree deflection integrated over a particular time period (flat line)?
But you would end up with a constantly increasing value of nose up elevator deflection over time attempting to hold the FP which I guess in a way could be considered as 'elevator leading sidestick'. Now the SS is physically moved nose-up... The same existing pitch rate (=elevator position) required for airspeed decay and in effect for the flight path is continually input over a range of increasing SS angles as the deflected elevator holds the FP until the SS rate command catches up? Would this give the appearance of elevator leading SS? This may not be what you're getting at. :) |
HN what is your surce for the integral of the elevator position??? the graph on s.41 of the interimreport(en), capter 1.16.4.2 ???
|
grity,
No, it's the blue line on page 42, section 1.16.5.1. With thanks to free Engauge Digitizer software. |
HN
"Airbus conducted a simulation of the aircraft behaviour based on the theoretical model and on the actions of the PF (sidestick and thrust)" (s.41) "2 h 10 min 23 The N1 start to increase and reach around 104 % in 12 seconds." (s.90) and (s.113) is there any automatismus for the elevator to reakt against the moment (--->pull) of the increasing engines ??? |
Final AF447 report set to re-ignite safety feud
French investigation authority BEA appears likely to rekindle the smouldering conflict over the loss of Air France flight AF447 when it releases the final report into the accident on 5 July.
Air France and the main French pilots' union, SNPL, have previously clashed with Airbus over the circumstances of the crash and whether the fundamental reason for the loss centred on pilot competence or the design of the Airbus A330's flight-control and warning systems. As expected, Airbus has submitted substantial comment to the inquiry following the release of the draft version of the report. SNPL has already reiterated its concerns over aircraft functions and the alerts given to the crew, in a document published in February. Airbus declines to comment on the AF447 report ahead of publication, but has previously strongly defended its aircraft and pointed out that three pilots appeared unable – despite clear warnings – to recognise the aerodynamic stall which downed the jet in June 2009. Although the draft did not include recommendations it featured analysis by a human factors panel established to look into the crew's response to the stall. But a source familiar with the situation indicates that the airframer is concerned whether the conclusions will focus too narrowly on the human-machine interface. "If there are things to improve on the aircraft, [Airbus] won't try to escape in any way," says the source, but adds that the manufacturer “would like to see a report in which all the issues are being dealt with”. The source also suggests that Airbus is likely to "become vocal" if it feels the breadth of the report is too narrow. Former BEA deputy chief Jean Pariès - who heads human factors consultancy Dédale and took part in an Air France safety review - told an operations forum in Oslo in April that current safety models assume pilots will recognise and identify abnormal situations, then implement relevant procedures. However in reality, he said, emergency situations generate surprise, causing momentary loss of cognitive control as well as resistance to recognising a loss of comprehension. Pariès cited 16 events similar to AF447, all of which showed poor understanding, rare implementation of unreliable airspeed procedures and stall warnings which were "perceived but mostly not believed". He suggests the problem cannot simply be reduced to "automation complacency" or loss of basic skills. Pariès claims crew training aims to prepare pilots for anticipated emergencies, not the unexpected, and highlights the irony that the competencies needed to cope with the unexpected "are those that are lost in a continuous effort to anticipate and respond to all potential threats". Investigations into a strikingly similar event to AF447, involving an Air France A340 in July 2011, recommended that pilot training include shock and surprise elements. |
Hi,
Investigations into a strikingly similar event to AF447, involving an Air France A340 in July 2011, recommended that pilot training include shock and surprise elements. |
Hi HN39,
I was reading an old post by Chris Scott (#1060 7/9/11 AF447 Thread #4) I don’t think much would happen to the THS during the initial rotation from level flight, as it would have required little up-elevator to enter the climb. Once the 7000ft/min had been achieved, the trajectory would be maintained by the EFCS even with no back-stick. As the speed started to drop, more up-elevator would need to be introduced by the EFCS to maintain 1g, and it would then start to trim the THS a bit to retain full elevator authority. Once the aircraft got on to the back end of the drag curve, however, this process would proceed rapidly. In fact the PF arrested most of the climb at FL375, by “nose down control inputs...”, so some down-elevator may have been used briefly by the EFCS at this point. This partial recovery was to be short-lived, as the PF seems to have reacted to a stall warning by selecting TOGA (causing a pitch-up) and resuming “nose-up inputs”. Resuming the climb at that point, on the wrong side of the drag curve, was when the EFCS had to start using up-elevator and nose-up trim (THS) in earnest, in order to try and maintain the trajectory it thought the PF wanted. |
Turbine D,
No, it doesn't. But thanks anyway. |
Hi jcjeant,
Shock and surprise are virtually impossible in a simulation cession ... unless you make suddenly appear on top of the dashboard .. a tarantula or a poisonous snake or even a mouse when female pilots on training ...:) Actually, I have a family member who is working on the development and installation of two new nuclear reactors for electrical power generation here in the US. In order to take in account human psychological factors when things go wrong, they have a computer program they follow as it relates to S & S. She calls it Human Risk Analysis, and they use an HRA calculator from EPRI as the tool. They go through plant operating procedures and identify human actions that could be a pre-initiator to an event or a post-initiator that could inhibit mitigating systems. They also identify operator actions necessary to mitigate an accident. They can quantify Human Error Probability (HEP) with the HRA calculator knowing various environmental factors, the approximated stress level of the operator/operators, the complexity of the procedures that must be followed, and the time window available to perform the action. All of these inputs are combined using various statistical methods in the HRA calculator, resulting in in a human error probability. If the analysis depicts a high HEP, the controls, control panels and procedures are reviewed and reworked to lower the HEP within acceptable levels. She thinks that responses to aircraft accident scenarios are also highly proceduralized and imagines that similar methods could also be used in the aviation industry. Just some food for thought.... |
Things that have never happened before happen all the time
#1453
Former BEA deputy chief Jean Paries - who heads human factors consultancy Dedale and took part in an Air France safety review - told an operations forum in Oslo in April that current safety models assume pilots will recognise and identify abnormal situations, then implement relevant procedures. However in reality, he said, emergency situations generate surprise, causing momentary loss of cognitive control as well as resistance to recognising a loss of comprehension. Some details here |
Hi HN39
In my search for a correlation between side stick angle, pitch rate and normal acceleration, based on the C* control law, I started comparing the elevator positions to the side stick commands, and am surprised to find that the elevator seems to be leading the side stick: A sidestick movement commands a 'g' level and the control system moves the elevators as much as it thinks is needed to fulfill that command. If the stick is held at a constant position the elevators will still move until that 'g' level is acheived - i.e. they will 'lead' the sidestick. If the 'g' is not what the pilot wanted then he would add more stick and the process would continue. Seems to me that is what was happening here. |
Hi Owain G,
Thank you for your explanation, I'll go along with that. Didn't read that in Turbine D's post though. BTW, speaking about the C* law, if anyone is still interested, I did another exercise. The graph below shows the calculated side stick angle to maintain a constant pitch rate of 1°/second from 2.4° to 12° pitch attitude, with nz feedback, and compares it to the AF447 DFDR side stick angles averaged over 2-second intervals. http://i.imgur.com/VJFeO.gif?1 |
@HN39:
|
A33Zab,
Yes, I agree with you, Thank you. The curve of integrated elevator angle gives a misleading impression because: (a) At 02:10:18 the elevator changes from nose-up to nose-down while the side stick is still nose-up, (b) At 02:10:40 the elevator changes from nose-down to nose-up while the side stick is approximately neutral, (c) The elevator is slightly nose-up between 02:10:00 and 02:10:06,5, i.e. prior to any side stick action, and (d) The graphical scales presenting the two parameters. I've accepted Owain Glyndwr's explanation for (a) and (b) and am hoping to get an explanation for (c). I've edited post #1439 to rectify (d). Apologies for causing "a storm in a glass of water" (as we say in dutch). |
(c) The elevator is slightly nose-up between 02:10:00 and 02:10:06,5, i.e. prior to any side stick action. elevator was up-down-up in this time ??? |
grity,
the elevator positions controlled by the autopilot are the purple dots. They do not seem to be part of the simulation which assumes zero turbulence. Perhaps I should have included the variations in AoA and normal acceleration in my item (c). |
IMO the intention for the simulation was just to control if the flightpath of the climb and stall was controled (consistent) from the action of PF and system, or from outside like broken wing or elevator, extrem turbulences, hand of the lord, rocket or metorit...
not more |
@HN39:
"Don't sit down by the packages":ok: (another dutch saying)
From the C* schematic below (Don't know the airliner it belongs to, but in principle it is valid for any FBW airliner) the SAS control has a inner f/b loop based on qmeas (thru wash out filter and Kq gain). http://i474.photobucket.com/albums/r...999/C_Star.jpg |
A Small Peek at The BEA Report
The majority of you must have missed this since there was a distraction about pitch control.:) You would be talking about it otherwise.
In post 1453, A33Zab posted the content of a Flight Global article relating to the AF447 human factors. This was based on an April presentation by Former BEA deputy chief Jean Pariès who heads human factors consultancy Dédale. In post 1458, NeoFit posted a link to the actual presentation by Pariès but it was not particularly obvious. Here it is again:http://www.flyoperativtforum.no/Foredrag/FOF12/AF447%20accident%20-%20some%20deep%20lessons%20-%20Jean%20Paries.pdf The presentation is entitled AF 447 ACCIDENT: SOME DEEP LESSONS. Somehow I believe this will largely represent the BEA human factors thinking on this accident.;) |
Machinbird;
From the Jean Pariès paper - Underlying assumption of the current safety model
I somehow doubt that will happen overnight, but adaption of current technology will most likely be used to lessen the "startle factor" and lead/prompt for the correct response. If that doesn't work, then the "technology" might just have to vote the "HF" out of the loop.:} |
the SAS control has a inner f/b loop based on qmeas (thru wash out filter and Kq gain). |
Sim Shocks
Reading a number of PPRuNe threads it would appear that Simulators are used by a number of different airlines in different ways. One pilot commented that he had done the same series of routine checks on TWENTY different occasions. China Airlines use them to keep their F/Os in flying practice, because with their 747SPs flying their very long sectors ( which require four pilots) it must mean that each pilot would only have a limited number of opportunities of T/O or Landings available per month. There were some interesting contributions by FRYBURG on 8th June on the Humbling Sim Experience thread. I have never used/ seen a Simulator - they were not around, then ! I read of one where to keep the pilots alert, having found that the airfield was not getting closer at something like the right G/S, one found that the B737 was on short finals for an aircraft carrier. I might have been better with a " F/O Dead Drill", a one hour hold at Nantucket before landing at JFK. ( The F/O had been flooded with R/T from the replacement ATControllers, due to their industrial action. I took him to a briefing place before departure. He was all right.) A Simulator Check of "Engine failure on Overshoot" before it happened to me would have helped on a heavy twin. My Chief Pilot said that "It had never happened before..." Two months later it happened again... To a different crew, who were killed. After that, that system was switched OFF, except for heavy T/Os. |
Pariès
I have been very very estonished to read Mr.Pariès, heading the human factors consultancy "Dédale SAS France", and also the "Former BEA deputy chief"! in AF 447 ACCIDENT: SOME DEEP LESSONS !
Reading the text (april 2012), clearly concerning AF447 as Machinbird , mm43, A33Zab, Neofit, iself, have seen it, it was even worse.
Originally Posted by French criminal code Article 432-12
The fact of a person holding public authority or discharging a public service by a person or a public elective office, take, receive or retain, directly or indirectly, any interest in a company or in a transaction for which it has, at the time of the act, in whole or in part, responsible for providing supervision, administration, liquidation or payment, is punishable by five years imprisonment and 75,000 euros fine.
|
Hi roulishollandais,
Relative to your post #1471, I don't see how the French criminal code cited would have any bearing relative to Jean Paries. If he were still an official of the BEA and also CEO of Dedale, it certainly would. It seems to me that Mr. Paries is an expert in what he does (and has done) and besides the AF447 presentation he gave, he has given dozens of others to various audiences around the world pertaining to aircraft safety. If I were examining the human response aspects of the AF447 accident, I would want to hear him out on his thoughts, observations, recommendations and any other pertinent information that would be helpful in the analysis and/or recommendations offered going forward. There may not be many credible sources of this type of information to draw from, but I sure would like to hear from as many as possible leading to the final report out. Also, didn't most or the entire upper echelon of the BEA turn over prior to the AF447 accident? Isn't this a new BEA organization team doing the AF447 investigation? Just my opinion... |
Why i am waiting nothing coming from HFG
roulishollandais
I agree, absolutly Nowadays, it's very fashionable to appeal to external consultants :) I am so sorry coming back with Tarom event: If the conclusions of the 447 HFG are of the same order as that of the Tarom thesis (sponsored by the bea), then, obviously, I wait for nothing of 447 HFG := Tarom report (Engl.) or try also here Tarom HFG thesis (french) ('Fiche Nr 3 : incident A310 - Declenchement de la protection de vitesse en approche') |
Hi,
Turbine D Also, didn't most or the entire upper echelon of the BEA turn over prior to the AF447 accident? Isn't this a new BEA organization team doing the AF447 investigation? The only significant change after the AF447 event was the replacement of the BEA chairman (Paul-Louis Arslanian replaced by Troadec) and the depart of Arslanian was already scheduled prior the AF447 event http://i.imgur.com/Fc827.jpg Bouillard (left) and Arslanian http://i.imgur.com/nSw9y.jpg Troadec |
Originally Posted by NeoFit
(Post 7272350)
If the conclusions of the 447 HFG are of the same order as that of the Tarom thesis (sponsored by the bea), then, obviously, I wait for nothing of 447 HFG
An objective view of the evidence - even going back to 1988 - proves conclusively that BEA did *nothing* to protect or shield Airbus, and all accusations of such behaviour were lies concocted by the defence team of M. Asseline and those who followed him. |
? Investigator Bias ... misconduct ... fraud??
Another topic -- a new thread --
Above, in slots #1471 & #1473, there seems a skepticism about the _investigation_: So -- for that discussion of investigator-err, bias, misconduct, and fraud, see: http://www.pprune.org/safety-crm-qa-...ml#post7273383 |
Really, IGh - "Hoot" Gibson again? Didn't he retire sometime around the last Ice Age? (not to take anything away from him...)
|
From the briefing, I noted that there had been one or two stall warnings roughly a minute before the upset.
I hadn't grasped that before. It fits the vague idea I had that the pilots were initially, and in the end fatally, inclined to believe that the stall warnings were spurious, or perhaps as unreliable as the airspeed. |
DozyWannabe
Why? An objective view of the evidence - even going back to 1988 - proves conclusively that BEA did *nothing* to ... Did you never heard something about "The reasons of State" ? It has been discussed of Concorde on this (or a previous) AF447 thread. After one of the Concorde Washington tire event, you probably remember that NTSB sent a letter to BEA (links or scans available within some deadline). It others one terms, NTSB needed to open the umbrella and protect his back. Which was the answer of BEA? I summarize: everything is under control. Okay, no problem .... till Gonesse Concorde Crash. Now, what's new about pitot probes ? No problem (and don't take care with near of 50 previous UAS events?) :ugh: IGh Investigator Bias ... Another topic -- a new thread -- At the time I read it : only two posts ... but two Scuds ! Why Tarom report ? It and only an example to show the slowness. At last but not at least: Tarom from french BEA report: 4.2 Recommandation intermeiaire A la suite de plusieurs accidents pour lesquels le Bureau Enquetes-Accidents avait participe, la recommandation suivante a ete emise le 24 janvier 1995 : ... 4) Consequences: * la reaction des systemes automatiques de vol entraine des configurations potentiellement dangereuses : hors trim, poussee moteur(s) incompatible avec la trajectoire souhaitee par le pilote, ... * L euipage, soit ne se rend pas compte de la situation, et donc ne peut pas prendre les mesures correctrices, soit constate la configuration de l avion sans en comprendre les causes. Cette incomprehension (egalement liee a une connaissance limitee des systemes) entraine une perte de temps dans l analyse de la situation, voire une analyse erronee, generalement associees a un deficit de communication entre les membres d equipage 3 Un rapport preliminaire a ete publie le 3 novembre 1994. Ceci a entraine des attitudes tres dangereuses: assiettes ou roulis tres importants, perte de vitesse (jusqu au decrochage) ou vitesse excessive, etc. En consequence, le Bureau Enquetes-Accidents recommande: - qu une etude soit lancee pour que la priorite du pilote sur les systemes automatiques de vol soit maintenue en toutes circonstances. Ceci pourrait se traduire: a) par la deconnexion des systemes automatiques de vol (pilote automatique et auto-manette ou auto poussee) en cas d antagonisme entre les actions du pilote et celles du systeme automatique de vol ou du directeur de vol. b) et/ou par une information claire en cockpit (eventuellement une alarme) alertant l equipage d un tel antagonisme. |
| All times are GMT. The time now is 06:45. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.