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AF 447 Search to resume

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AF 447 Search to resume

Old 17th Jun 2010, 18:37
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Originally Posted by gums
Fer chrissakes, point the plane best you can using the ADI or stby gyro and keep power where it would normally be. NO AUTOPILOT in turbulence. Let the jet fly as it was designed to and she'll prolly do just fine
Originally Posted by bearfoil
Can't fly pitch and power w/o AH and throttles, though. The AH is an option, only luddites would want one.
What do you mean by that, Bearfoil, in response to gums? (See also Smilin' Ed's comment on power/attitude flying).

I do not understand the A330 cockpit and AFCS degraded modes, but there are some basics that seem to me applicable regardless of aircraft model.

As I have read this thread, I kept getting the idea in the back of my head that, with AirSpeed signal lost due to iced pitot tubes (let's call that a necessary assumption for the moment) one could maintain Straight and level within the air mass with power (roughly what you'd had set just a moment ago) attitude (nose and wing) , and a reference to VSI (basically, a partial panel scan/crosscheck).

Granted, VSI is a static instrument, so if static ports are also iced up my idea is at least partly dead in the water, particularly if you ride the downdraft inside a turbulent airmass all the way down to the ocean ...

But why did you imply that it would not work?

I have understood that were they at stall already, unwittingly, that maintaining power and attitude would not do much to get out of a stall.

EDIT: sorry, that was some weird cut and paste for quoting, have tried to clean it up.
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Old 17th Jun 2010, 20:30
  #1522 (permalink)  
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Lonewolf 50

Hello. The Airbus in the conditions imagined for 447 can be a handful. Automatics and FBW are two distinct subjects, suffice to say that Airbus trains reliance on the a/c and systems such that in the commercial cockpit, it morphs into dependence, and not all the Pilots fault, certainly not here. ACARS is not a flight tool, it is a maintenance convenience to save money (and very valuable in that regard). We are reading delayed messages meant for mechanics, not for flight support.

I personally believe that this dependence on auto played a very real part in this tragic accident. Even after AP dropout, the ECAM prompts a/c solutions for the computers, not avoidance of, or recovery from, upset. The manual must be consulted before action? Evidently, since Pitch and Power as a solution appears on the fourth page. Dark, bumpy cockpit, Captain most likely absent or due to relieve, there was no time for sequencing, prioritizing, or effecting control by hand.

The Airbus, (this one) has no Artificial Horizon, and Throttle lever position doesn't communicate truthfully the power status. At the cusp of upset, the computer and its trained for approach to flight does NOT entertain heroic manual efforts, the concept is foreign to the designer and flight support. What it does instead is steadily degrade pursuant to its own timetable and program.

gums is dead on, but his old fashion style (mine also) has no place in this modern cockpit. There is an Artificial Horizon (gyro) available for this model, it is an option and here it was not selected.

I don't accept necessarily that the pitots malfunctioned. In a cell, airspeed can realistically get bizarre; it is in some cases actual airspeed, but not accepted by the flying pilot because it doesn't make sense. Neither is a three way discrepancy unheard of in wide bodies, each ias being actual, subject to turbulence. Why is the windshear alarm not attracting more attention?

Neither is it known what RTLU fail meant. BEA assures us it meant only that the Rudder was captured by limits provided for >272knots.

regds,Bear

Last edited by bearfoil; 17th Jun 2010 at 20:41.
 
Old 17th Jun 2010, 20:52
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Bearfoil

First off, thanks for the reply.
The Airbus in the conditions imagined for 447 can be a handful. Automatics and FBW are two distinct subjects.
Understood.
I personally believe that this dependence on auto played a very real part in this tragic accident.
Roger.
Even after AP dropout, the ECAM prompts a/c solutions for the computers, not avoidance of, or recovery from, upset.

The manual must be consulted before action?

Evidently, since Pitch and Power as a solution appears on the fourth page.
This got my attention. It is also foreign to my understanding of flying any sort of aircraft.

Dark, bumpy cockpit, Captain most likely absent or due to relieve, there was no time for sequencing, prioritizing, or effecting control by hand
Could happen to anyone, it's why airline pilots make the big bucks. Got to fly the bird as best you can.
The Airbus, (this one) has no Artificial Horizon, and Throttle lever position doesn't communicate truthfully the power status.


At the cusp of upset, the computer and its trained for approach to flight does NOT entertain heroic manual efforts, the concept is foreign to the designer and flight support. What it does instead is steadily degrade pursuant to its own timetable and program.
While my gut instinct is to recoil at this concept, my brain tells me that the pilot of the A330 must know his robot, and its habits, inside and out, or the chance of a robot and a human brain working at cross purposes poses some scary ( to me ) problems.
gums is dead on, but his old fashion style (mine also) has no place in this modern cockpit. There is an Artificial Horizon (gyro) available for this model, it is an option and here it was not selected.
Not selected for purchase, or not selected as an option by the crew from a menu of choices? I think you mean the former, did I guess correctly?
I don't accept necessarily that the pitots malfunctioned. In a cell, airspeed can realistically get bizarre; it is in some cases actual airspeed, but not accepted by the flying pilot because it doesn't make sense.
Roger. One reason (among many) to avoid cells wherever one can.
Neither is a three way discrepancy unheard of in wide bodies, each ias being actual, subject to turbulence. Why is the windshear alarm not attracting more attention?
Neither is it known what RTLU fail meant. BEA assures us it meant only that the Rudder was captured by limits provided for >272knots.
Again, thanks for the insight. This thread has been an eye opener.

Change of sub topic for a moment?

For anyone still intersted in search, and a tool referenced a few pages back, MAD.

I don't see MAD as of any use. For airborne use, slant range too great given presumed depth of target, and mass of target.

For a submersible, order of magnitude too slow, and target mass too low, to get a useful signature.

MAD working versus a submarine (consider how much steel/iron is in even a small one) has a few orders of magnitude more signal to try and achieve, but it is the rate of change in mag field that gives useful indications, which is a function of airpseed (or water speed?) of MAD and the size of the target. (Orientation as well, but let's not get too far into the weeds).

Lots of words to say: MAD, not what will find what you are looking for.

I tried to find an F-16 (the assumption was maybe the engine would register if we flew over it) with MAD off the coast of Turkey, in coastal/shallow water, with a reasonably well established datum. Nothing doing. Not a sniff. Was eventually found by other means.

Last edited by Lonewolf_50; 17th Jun 2010 at 21:04.
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Old 17th Jun 2010, 21:22
  #1524 (permalink)  
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The Falcon is mostly Resin, Aluminum, Stainless, and Titanium, all non-magnetic.


MAD is expected to not work here?

Is Mass density important, or just ferric structures? As in Magnetic Resonance Imaging, where iron is a nono.

bear

OT The Airbus is a triangle, not a duality. The Triangle is the strongest stucture in engineering; in aviation, it must be FBW, Pilot, And Automatics. All three must be interdependent, and easily understood, one and the other TWO. This tragic accident may be partially explained by hubris, ego, and politics, among other more direct causes.

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Old 17th Jun 2010, 21:48
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What MAD is good at picking up is a change in the density/amount of iron/steel material due to its magnetic characteristics. The amount of iron/steel plays a big part in making a big enough mag field change to pick up: signal to noise ratio issue. (I'd need to look up a few bits from long, deep memory, but I do recall there being degaussing ranges our subs used to run through to reduce mag signature ... memory very fuzzy). HY 80 and HY100 steels were what a lot of US subs were built with, but that's very old news. I think they have more exotic alloys in the newer stuff.

Russian Alpha class, all Titanium, was not something MAD would pick up ... did find a Tango once, though. Good day for us.

As to A330, I presume the engines have lots of steel alloys in them, which is what I was hoping for with that F-16. Again, more than an order of magnitude less steel/iron than a standard submarine ...

Just out of curiousity, has A330 got titanium in the wing boxes?
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Old 17th Jun 2010, 22:16
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bearfoil, Lonewolf_50,

I thought MAD (in this context...) stood for "Magnetic Anomaly Detection".
I thought it 'could' work for bl**dy great subs with a lot of steel at a few hundred meters depth.

I can't possibly see how it could work for a debris field of largely non-ferrous (non-magnetic) material at 3000+ meters....

But I suppose this already has been mentioned in this thread before.

CJ
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Old 17th Jun 2010, 22:46
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Bearfoil,
The Airbus, (this one) has no Artificial Horizon
You seem to be implying things which are aimed at misleading.
In this Version of the 'Bus the Artficial Horizon is provided by the IR Part of the ADIRU, shown on the PFD's plus the Horizon provided by ISIS.

Yes it doesn't have a mechanical one but three electronic ones and none of the ACARS messages suggests they were u/s.
Ans a mechanical one is much more prone to tumbling in turbulence or upset than the Ring Laser gyros.

I still have some difficulties understanding what you are trying to achieve here ?!
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Old 18th Jun 2010, 00:04
  #1528 (permalink)  
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I am trying to contribute to this thread and keep current. It is extremely important to keep this accident in public view; as one who is familiar with the mission and method of investigative bodies ennabled by Public Authority, I can provide an insight into how they work. I have been a member, a Director, and an investigator for many different bodies, though all in my native tongue, and Politic.

My memory of ACARS is that both PFDs crapped out, and IRU is dependent on AD, and that at a critical time in the sequence, the pilots had not a clue about Pitch, nor did they about Power, and this at a time when all automatics had left. In leaving, they ignorantly displayed their mischief on the panel, taking up crucial time for the pilots to catch up with real behaviour.of their aircraft. If the auto is inop and unavailable, I frankly do not give a fig about troubleshooting the system ahead of maintaining (or recovering) controlled flight with pilotage relative to a manually controlled aircraft.

That is my background, and my motive, along with trying to defend this flight crew against well financed and powerful story tellers who have taken advantage of dead pilots before. What is your purpose here?

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Old 18th Jun 2010, 01:31
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Henra - "In this Version of the 'Bus the Artficial Horizon is provided by the IR Part of the ADIRU, shown on the PFD's plus the Horizon provided by ISIS."

But what happens if the electrics fail ?
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Old 18th Jun 2010, 03:20
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what happens if the electrics fail ?
What do you expect to happen in a fly-by-wire aircraft if the electrics fail?
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Old 18th Jun 2010, 06:14
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Originally posted by Backoffice ...

But what happens if the electrics fail?
Providing the a/c is still in one piece, the Essential Systems Service buss (ESS) will have at its disposal AC and DC power required for flight control, navigation and communication. If primary sources, e.g. main engine generators fail, the APU is available, then the Emergency generator (RAT) and then Battery banks for DC buss and an Inverter for essential AC buss powered equipment. There are alternative AC and DC buss supplies also available.

Electrical supply is not an issue.

mm43
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Old 18th Jun 2010, 08:10
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Hi,

the APU is available
How much time (start sequence etc ..) for have the APU connected (providing electric power) to the buss bars ?
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Old 18th Jun 2010, 09:40
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Originally Posted by SomeGuyOnTheDeck
What do you expect to happen in a fly-by-wire aircraft if the electrics fail?
Well, I wouldn't expect the ACARS transmissions to continue for a start...
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Old 18th Jun 2010, 12:18
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As I have said before, and still believe, the event started with a sudden, unprepared and unexpected upset which promplt escalated in uncontrolled flight agravated by time as the flight continued. Most likely, all acars were a spin off and a result of the initial event, not a contributor to the actual cause. I agree, electric had nothing to do with it.
ww
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Old 18th Jun 2010, 15:42
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Christiaan: yes, about MAD not being useful in this case, I was trying to explain why. Size of metal/iron object not big enough, nor speed of search vehicle, nor slant range within parameters. Because of how MAD works, or doesn't, this scenario is not MAD suitable for detecting desired object: engines.

Gentlemen, please forgive an old pilot ... I am unclear on the AH/AI/Attitude Gyro equipment on the A330.

First off, I understand it is part of the usual glass cockpit, not the old ball in a box I first flew with back when dirt was new ... thanks for the laser ring gyro point.

When flying the A330 in standard configuration, does the flying pilot normally have on his display the pitch and bank indications that an attitude gyro/artificial horizon usually provide in aircraft as I was used to? I would assume "yes," and be surprised if the answer is "no."

I was led to believe, though I may have read incorrectly, that there was no AH either selected (or even equipped ??? makes no sense now) in the A330 model being flown by Air France flight 447.

If I have misunderstood, please help me.

I think I understand one estimate being that AH was for X time unreliable, but I do not grasp what in the ACARS pointed to that estimate or conclusion.

Thanks for any enlightenment you can shed. Perhaps the acronyms, and my unfamiliarity with them, hold the answers that are right in front of my face.

Last edited by Lonewolf_50; 18th Jun 2010 at 15:56.
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Old 18th Jun 2010, 16:00
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LoneWolf said: While my gut instinct is to recoil at this concept, my brain tells me that the pilot of the A330 must know his robot, and its habits, inside and out, or the chance of a robot and a human brain working at cross purposes poses some scary ( to me ) problems.
That really got my attention. I heard a NASA/JPL robotics-expert lecturer define a robot as a machine that can make autonomous decisions, and the A330 and its kin are certainly that - surely the largest and likely most 'intelligent' robots man has built so far. I wonder if it helps the cockpit to think of it that way.
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Old 18th Jun 2010, 16:34
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poorjohn, it helps me, and has been an aid in better understanding what I have learned from some superb PPrune commentary on the Hudson River landing, this lost flight, and other mishap discussions. The explanation of normal law, degraded modes and Alt Law, and the sorts of decisions IF/THEN rules result in -- actions by the software/hardware package (robot ) -- makes the state of the art autopilot a hell of a lot more complex than the old George who'd keep airspeed and altitude for you at cruise conditions.

The good thing about robots, so far, is that you can know what programming parameters are, and limits, as robots built to date tend to be rule-driven machines. But you do have to know in order to get the most out of it, and not expect more out of it than it can deliver ... like most machines.

FWIW, I understand that learning machines with AI that is beyond simple rule structure have been in development for some time, but am not current enough on that matter to comment further.

Last edited by Lonewolf_50; 18th Jun 2010 at 19:09.
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Old 18th Jun 2010, 17:52
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Bearfoil
My memory of ACARS is that both PFDs crapped out, and IRU is dependent on AD,
If you read back into the old Thread plus BEA's analysis the common understanding seems to be that there is no inidcation the PFD's were u/s.
Also the IR part is not dependent on the AD part.
Only the other way round, if there is no IR, then AD is blanked out on the PFD's as well.
None of the ACARS messages indicated that attitude information was lost.

BTW. thanks for the explanation of your motivation.
I can follow that logic and it's OK for me unless it would be mainly used to spin the public opinion in the wake of a lawsuit.
Keeping the public interest up and keeping the spotlight on this accident should be in the ineterst of all involved in aviation.
But I would be grateful if you could avoid oversimplifications which could imply things which are not meant to be.
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Old 20th Jun 2010, 05:18
  #1539 (permalink)  
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Thanks for your kind reply, henra. I have revisited the Preliminary, and take note of pp51 forward to 02:13. Initially the PFD's (display) are denied FD (director), it was selected but unavailable. Next comes the failure of the FPV (bird), and all orientation by PFD is eliminated. This implies to me that all attitude (and airspeed) values are not transmitted to the screen; the discrepant pitots are minimally reacting to a decrease in a/s of thirty knots from the medianed number, so none can be seen. BUSS (back up speed system) is an expensive option, and was not chosen for this aircraft. I am lacking the perception of an available value for attitude, of any kind, airspeed likewise. Add to this the need to know power, either by throttle lever position, or a displayed value by N1 (or epr). What am I missing? Lay it on, I have thick skin.

thanks again

bear
 
Old 20th Jun 2010, 06:19
  #1540 (permalink)  

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From the point of view of information presentation in real-time, I'd rather have a bunch of round-dials and scan-scan-scan as I was taught....

Should something unforseen happen rather fast, the thought of having to page through assorted displays to see the info that I need is disturbing.

Maybe going half-way back to a mix of the two would be a thought.

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