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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 20th May 2011, 19:50
  #1961 (permalink)  
 
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Pressure Piling on BEA

@ Squawk_ident

Hi Squawk_ident.

With regard to your posting above concerning the pressure that is being piled up from " ...political and economic power...", let's please not forget that everybody in this forum who is participating in the discussion about AF447's accident cause, including me, is contributing to this pressure as well, which is in many perspectives a very positive development, compared to e.g. 15 years ago.

Of course there are limits and BEA's work must not be compromised by false accusations or by loading them with supplementary PR work in order to keep the conspiracy theorists at bay and away from naive press colleagues. But we can be sure that they as well follow this thread in order to think out of the box and at the same time this community also represents a sort of legislative power, as the media would be picking up any major cries of foul from this community - we make a contribution as well.

This represents a very positive development in my eyes and improves accountability and transparency to most stakeholders. They are being paid to do their jobs and this includes dealing with public and societal and whatever else pressure.

Being the technician in charge or not, it is part of his job and I bet that most pilots would frankly claim their daily responsibility and respectively pressure to be feeling much bigger indeed.

So don't become too touched by their efforts. They will for sure earn our respect and credit in this investigation, as well as in others (e.g. Air Caraibes), but they have to deliver first.
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Old 20th May 2011, 20:06
  #1962 (permalink)  
 
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Thanks, Mods

This is to recognize and thank John Tullamarine and other Tech Mods for their patience in monitoring, and apparently culling so few posts. It was very frustrating to me in the first thread in R&N that my posts regarding Wx radar were summarily deleted without explanation.
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Old 20th May 2011, 20:22
  #1963 (permalink)  
 
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Cool

Hi,

I respectfully disagree with your second reading and criticisms of the BEA and their response to this news article. They made somethings crystal clear:

1. They and they alone have the responsibility to release information concerning the AF447 investigation.

2. The BEA reserves the right to confirm information published from an external source as being accurate and true.

3. The BEA investigation has not reached the stage of determining cause of the accident.

and,

4. Articles, such as this one, does the families of those who perished no good and could cause harm as it is not information either released or concurred by the BEA.
Your answer has nothing to do with my critics about the BEA.
My critics about the BEA are about his right to be a moral judge of what the press released.
It's not his role to decide if a press release can be harm for families victims etc ...
If they want reply to press articles they must be factual and not emotional.
They have to publish a strong denial or a strong approval.
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Old 20th May 2011, 20:24
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My position is that life is inherently dangerous and we are constantly tossing the dice, aside from sitting in the middle of a large field for your entire existence, there is a level of risk that may lead to harm when we do anything, and in particular any human construct can and at some point will fail in some way and possibly cause harm to someone (buildings fall down, dams fail, cars crash, airplanes stop flying). What Airbus has tried to do is prevent most of the obvious bad things from being allowed, through control laws, but as with any control system, once you exceed the design limits, well, bad things may occur.

It's clear that Airbus has done a pretty good job - there are thousands flying. Obviously this is not to say things cannot be improved. Of course improvements are possible.
To be specific, we are trying to push the envelope.
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Old 20th May 2011, 20:33
  #1965 (permalink)  
 
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Whether it is then appropriate to blame the computers for not saving the day seems unfair.
Garage Years

I think the concern is for when the computer becomes an obstacle to the pilots recovering from a situation. The worry that The Shadow raised is the case of the computer masking a situation that is trending toward dangerous, leaving the pilots to play "catch-up" when they have to take control.

Aside: If you have ever, as an instructor, let the student pilot "go a bit further afield" as he makes an error, you are aware that the further he strays from desired performance without correction, the more work it is to get things back in order.

I think that on these boards, it is axiomatic that getting behind the aircraft rarely turns out well ...

snowfalcon, thanks! I'd guess that a checklist or something like an ECAMS resource in the cockpit would walk the pilots through the step by step if such a realighment/recaging were necessary inflight.

Perhaps not, perhaps fixed only on the ground.
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Old 20th May 2011, 20:37
  #1966 (permalink)  
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The BEA have the authority, in fact, are compelled to make findings. It is bad luck they incur criticisms. They are professionals, and must remain isolate from politics, and public opinion. Not to do so is a condemnation of their very role. That they responded to the Press at all is incompetent. To make moral judgments re: people's feelings, freedom of opinion, and what is proper in the culture is inexcusable. Their credibility is damaged greatly, jcjeant is on the money here.

As In: Pushed to respond to a mere gnat, (The Press), imagine how anxious they will be whilst composing their Final. Politics and Economics make the Figaro as a small barking chien.

Last edited by bearfoil; 20th May 2011 at 20:48.
 
Old 20th May 2011, 20:41
  #1967 (permalink)  
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Flight control laws

Salute!

Thank you Garage, thank you, thank you, thank you!!!

The "Direct Law" in the 'bus is not much different than the basic Viper control laws. Closest relation is on the ground and with WOW switch depressed.

- There was no direct relationship between control stick input and control surface deflection or rate of deflection.

Here's the roll command function:



But wait!!!! There's more!!! That was only the "command". Between the "command" and actual control surface movement the computers blended AoA, body rates, etc. The end result was still the same - the jet tried to achieve your command.

+++++++++++++++++++++++++++

So we roll back the clock to late 40's and early 50's. Hydraulic augmentation or even direct control of the ailerons, elevator, rudder. No direct feedback from cables or pushrods. Wow! The dinosaurs bitched. We new kids on the block didn't know any better. I, personally, learned in Champs, Luscombes and Taylorcraft taildraggers. But when I went to USAF pilot training our first plane had mechanical controls!! I could "feel" the burble and lack of response at the edge of the envelope. And then on to the fighters.

Wow! No direct mechanical connection to the elevons in the F-102. Then same for the F-101B. We had springs and dampening gizmos to keep us from commanding full deflection at any speed. Elevator in the VooDoo and Phantom had a pneumatic bellows that "stiffened" the stick the faster we went. VooDoo even had AoA protection that included rate limits - this was back in mid-60's.

Biggest change in flight controls was in 1973. You guessed it. Lightweight Fighter program. GD introduced us to the "electric jet".

The initial impression to all of us was that we didn't move a hydraulic valve with the stick or rudder. Hell, we just sent a signal to the actuators on the wing or tail and voila!!! NOPE!!!! And nope big time.

The designers tried to make the jet "feel" like the ones from the old days. They also figured we didn't need to pull hard at slow speed to 60 degrees AoA, then recover from the stall or whatever. Hornet violates this design consideration, BTW. Then they added gee protection, blended AoA and gee command and pitch rate when landing gear was down. And the beat went on......

The electronics did not simply convert stick deflection to surface movement. Along the way, the computers applied all kindsa functions and limits. To be honest, the jet felt like all the others except the relics that had mechanical connections ( pre-60's except for the big jets most here have flown or heard about). The engineers did a great job on the Viper, but that same team did not work on the Airbus. We also did not have much of an autopilot connection to the flight control system. It was not quad-redundant and had limited functions. More like a pilot's stick input.

more later, as I wanted to "set the stage".
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Old 20th May 2011, 20:46
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Anectodotal input for you here, gums. 25-30 years ago.

Picked up an A-7 pilot from one ship, taking him to the Carrier. He'd been doing some staff function with the Anti Air boss on the Cruiser. We had a chance to talk about that magic new jet, the F-18. He'd had a chance to fly it, I think at Pax River. He told us that flying straight and level, he could look out at his wings and (I think this was at slower speeds) watch the very small corrections being made without any movement of the stick. Also said the plane flew as smooth as silk.
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Old 20th May 2011, 20:51
  #1969 (permalink)  
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I think when the Hornet is departed, the pilot is required to let go. Feel the force, Luke. Likewise on the cat, launch is "Don't touch". Pilot grabs the right handhold, so the guy with the thing can go poosh.
 
Old 20th May 2011, 20:54
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jcjeant,

The BEA's response to the le Figaro article was not only correct and fully justified; it would have been seen to be neglectful not to have issued it in the circumstances.

Your constant, carping, biased criticisms of the BEA are becoming... ennuyeuse. Condemning their press release is surreal. Give it a rest - unless you wish totally to discredit your arguments?
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Old 20th May 2011, 20:59
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Originally Posted by gums
The engineers did a great job on the Viper, but that same team did not work on the Airbus.
Well, to be fair it's a completely different design consideration :

Originally Posted by DozyWannabe
The implementation of FBW on the F-16 was intended to solve a very different problem than that of the A320 series. The F-16 was one of the most maneouverable fighters of it's day, but the way General Dynamics achieved that was by having an aerodynamically unstable airframe that *required* constant computer correction to keep her airborne and going in a straight line. The A320 was designed to be as aerodynamically stable as any other airliner, but the FBW was simply designed to assist the pilot by easing the workload when it came to actually controlling the thing, as well as provide safety features as backstops when things got hairy.
Going from memory here, so please correct me if so, but as I understood it the F/A-18 was more of a hybrid of the advanced setup in the F-16 and more traditional control methodolgies - in a not dissimilar way to how FBW is implemented in the B777 vs the A32/3/4/80 series.
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Old 20th May 2011, 21:36
  #1972 (permalink)  
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Hornet aero

Salute1

Well, Dozy, the Hornet and her prototype - the YF-17, were "conventional" in terms of static stability. Still are.

The YF-16 could be flown with a "conventional" forward c.g., but allowing it to move aft provided a dramatic increase in several parameters. The Airbus utilizes it's FBW system to reduce trim drag, but that's about it. In the Viper, we saw a dramatic change in pitch rate when we had to balance fuel forward to reduce the chances of a deep stall. And BTW, none of we operational pukes had a deep stall the first year or so. The phenomena was discovered by the golden arms at Edwards after the flyoff and the YF-16 was selected.

The guys in our initial cadre had several pilots from the flyoff. They all liked the way the YF-17 "felt". OTOH, it could not maintain the same turn rate as the YF-16, failed the transonic acceleration requirement, and it was a gas guzzler.

Before I post "part two" of the changes in flight controls, here's a tidbit.

We have had pitch and yaw dampening augmentation since the 50's. By the end of the 60's, we began to have "augmentation". Clever devices "helped" us to fly smoother and have better control response without losing control. Good example was the A-7D and Navy model. We had "control aug". When following lead on the taxiway you could see the control surfaces jumping all over the place. The inertial inputs were moving the control surfaces to achieve the pilot's commands. Hmmmmm.

For all the active pilots here ( and recent pilots), tell me if you see the control surfaces jumping on that Airbus in front of you when it rolls over cracks in the concrete and such.

So much for "direct control". A true direct control would leave the control surfaces "frozen" unless the pilot moved the control stick.
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Old 20th May 2011, 22:13
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I don't think I've seen this particular link posted before, but those interested in the recent discussions about Sullenberger should read the flight crew interview material from the investigation report
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Old 20th May 2011, 22:31
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"Le circonstances" and the Friendly Flying Systems / "Wiring fault"

GY,

But, sadly I suspect (yes, this is WHOLLY opinion) this case will result in findings that indicate some sequence of poor human decisions leading to the aircraft being in a very bad place at entirely the wrong time
Defending vigorously his position you have a big and powerful conglomerate, with "State of the Art design capability" delivering "friendly" highly optimized Flying Systems in their a/c.

In another position you have the pilots being helped by "friendly flying systems" (that are "under continuous evolution"), and facing some "extremely complex scenarios" related to the richness of real world and mother nature and "enriched" by the sometimes highly complex behavior of their "friends".

In another position you have a govt. entity, BEA under intense pressures to "understand" factual information "recorded" in a/c debris, recorders and a/c occupants. And needing to work "together" the "designers" to be able to analyze the "complex mechanisms" of "highly complex systems", etc". And now clearly in a hurry that further complicates the task of their professionals. There are also other "players", as we know, in this "complex stage" contributing to the pressure.

The "circonstances report" to be issue soon can be aligned to the huge interests involved? To "construct" this question i just considered the facts that the a/c didn´t deviate earlier to a "important WX condition", the fact that the "friendly flying system" was eventually affected by UAS and considered that the System degraded creating additional factors for the a/c ability to exit the "important WX condition" the a/c entered (for any reason) and never left.

The report may fit well with the huge interests of the conglomerate and the French State. The timing of the Paris show (just one month from today) is a very important "time constraint". And we may ask: Which player(s) should be "strategically preserved"? The conglomerate, the carrier or the pilots?
Time will tell
Who has the bigger responsibility for the navigation since monday? IMO, no longer BEA. It seems came from the "player" that fed Le Figaro and is carefully "assembling" the near future environment along the BEA´s analysis.

The turbulences we are observing, i commented in an earlier post, impossible to avoid, are dangerous to all players. As a technician i yet felt how difficult they are. And it´s threat to properly emphasize in the "highest profile phase" (during next days) what is really most important. *

Svarin,

02:11:55 EFCS1 X2,EFCS2X,,,,,,,FCPC2 (2CE2) / WRG:ADIRU1 BUS ADR1-2 TO FCPC2, HARD

This is definitely a wiring fault, where FCPC2 and ADR1 lose their connection.
What kind of cause can create such wiring fault.

The importance to me is not related to what this "wiring fault" could make to a redundant architecture.

I would like to understand what can create a "wiring fault". Other than a Kapton issue.


(*) I must mention that i consider most of conspiracy theories too simplistic and never taken into account the global picture. Eg. TWA800 shot by a missile and other similar ones.
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Old 20th May 2011, 22:34
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question ...

I did my 320 type rating some years ago .. (the real one with 6 real circuits !!.. haven't used it since though, so in the real world call it sim time) .. coming from another more basic type I was advised in clear language "IT" will maintain 1g and zero roll rate IF you leave "IT" alone.

Simplistic perhaps, with an upset more so, subtract the layers of protections quietly withdrawing from the game; my question to those who actually fly the thing day to day is ... does this hold true ?

Whatever happens will "IT" try to maintain 1g zero roll rate and fly away ?
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Old 20th May 2011, 22:38
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Barking chien or "instrument"?

Politics and Economics make the Figaro as a small barking chien.
Or a "useful instrument" In the right timing?

Who "is in control" now?
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Old 20th May 2011, 23:02
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Cheap memories

JD-EE

My point is:

Sound recording in cockpit can be HIFI at a LOW PRICE.

I posted microphones. I didn´t mention headset microphones.

Last edited by RR_NDB; 21st May 2011 at 04:06.
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Old 20th May 2011, 23:33
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The A330 has a ground mode of Normal Law, which I believe requires a SS input to deflect the control surfaces during the taxi (proportionally to the SS command). Control surface deflection can be monitored on the SD Flt Control page. You don’t need to be in another aircraft to tell if they’re moving. You are not "technically" in Direct Law as such on the ground anyway unless you landed that way. I’ve never noticed if the control surfaces are moving independently during taxi; the priority naturally is that the SS inputs result in the expected movement. You are of course able to command full deflection of each surface in the Normal Law ground mode. No g or roll rate logic involved.

As to DozyWannabe's earlier mention of “manual reversion”, the term itself can apply to a number of different solutions to degraded flight control systems. The earlier Boeing non-FBW aircraft that I’m familiar with do not have direct linkages to the primary control surfaces. In the event of multiple hydraulic system failures, linkage to both the aileron and elevator trim tabs is unlocked and the pilot inputs are to the trim tabs which eventually result in movement of the primary control surface after some excruciating delay. This is probably why a system like this is aircraft size (inertia) limited. A backup electric pump and separate dedicated hydraulic system provides rudder control however. Either electric or at a minimum manual stabilizer trim is always available, barring a jam.

If I recall correctly, the DC-9/MD-80 elevators were unpowered anyway. The MD-90 elevator was unpowered unless the aircraft was stalled and then it was automatically powered to assist recovery. I think the hydraulic pump came on when the shaker did.

All other conditions equal, I would much rather be in ALT 2 or Direct Law in an A330 than in manual reversion in a B727/737. Time marches on. Unique systems with unique problems require unique solutions and there’s always room for refinement.

More knowledgeable Airbus types may correct any of my errors at their leisure.

(I've filed it away to check control surface movement on the ground and FPV functionality the next time I get a chance.)
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Old 21st May 2011, 00:13
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Cool

Hi,

jcjeant,

The BEA's response to the le Figaro article was not only correct and fully justified; it would have been seen to be neglectful not to have issued it in the circumstances.

Your constant, carping, biased criticisms of the BEA are becoming... ennuyeuse. Condemning their press release is surreal. Give it a rest unless you wish totally to discredit your arguments?
I reiterate my firm position on the unnecessary comments and void in their response to the press

To read:
Google Vertaling

Asked by Reuters, the Office of Inquiry and Analysis (BEA), responsible for examining the black boxes, were willing to make "no comment" on that information.
The BEA does become more cautious in his responses to the press?

Original link:
FENVAC
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Old 21st May 2011, 00:18
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OK465

When I first began flying,one thing I recall most was:

"There are Rules and there are Laws. The Rules are made by men who think that they know better how to fly your airplane than you.
Laws (of Physics) were ordained by nature. You can, and sometimes should, suspend the Rules but you can never suspend the Laws."

I am now retired, after a host of years in the pointed end of my office. Perhaps I recalled well.
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