AF 447 Search to resume (part2)

[ChristiaanJ]

Originally Posted by RR_NDB

BTW, What is "wiring fault" (Hard) mentioned in some earlier posts regarding ACARS sent. I am curious to understand this.

Knowing how difficult it can be to find a wiring fault or failure in the "real" world, I'm still totally baffled by this ACARS message too.
I suspect it probably translates to a "lack of signal" condition, but I would still like to know, too.

[RR_NDB]

EMI/EMC issue?

Hi,

Question:

2:13:08 FLR/FR0906010211 34220006ISIS 1,,,,,,,ISIS(22FN-10FC) SPEED OR MACH FUNCTION,HARD
2:13:14 FLR/FR0906010211 34123406IR2 1,EFCS1X,IR1,IR3,,,,ADIRU2 (1FP2),HARD
2:13:16 ~ 2:13:41 Possible "Loss of Signal" with satellite

Could be this facts be associated to Lightning? And subsequently:

2:13:45 WRN/WN0906010213 279002506F/CTL PRIM 1 FAULT
2:13:51 WRN/WN0906010213 279004006F/CTL SEC 1 FAULT

A very strong "interference" can even reset a System and in extreme cases damage buses ("connections" between sub systems), etc. I know Airbus SAS redundancy is also on the physical location of critical modules. And i know the a/c interior is protected (inside a Faraday shield). And also the lightning activity at that night was reported as "low" at the region.

[Safety Concerns]

mm43, do you fly A340 and not A330?

some of your comments do not apply to the A330.

[MountainBear]

This puzzles me a bit. Decades ago when I was a student at Navy Test Pilot School, <snip> I preferred minimal stick motion with aircraft response determined by stick forces. Nello informed me that the vast majority of pilots also preferred that configuration.

I wonder if you would still feel that way today.

One of the realities that plague video game designers is the fact that as we age one of the first skills that is lost is what is known as "fine motor control," especially in the hands. FMC does not refer to reaction time; it has to do with the ability to make small, discrete movements as opposed to large sweeping ones. People who suffer from poor FMC often appear to be "overreacting" physically to the stimulus but it's not a reaction problem.

I have long wondered if poor FMC isn't the true explanation behind this crash:

American Airlines Flight 587 - Wikipedia, the free encyclopedia

I'd bet my bottom dollar that if your old teacher put a group of 45 year olds who had never piloted before in that test,he'd get very different results.

[DozyWannabe]

Originally Posted by RR_NDB

To say you what happens to me when i realize the "circuitry" amount and complexity used (required) in highly complex FBW a/c.

The complexity is mitigated by redundancy, as you state - and the components themselves (derived from the 80186) were obsolete in computing terms in the late '80s, but highly predictable and easy to understand at a circuit level. To compare that to the incredibly dense multi-pipelined designs used in consumer level computers even 10 years ago is like comparing a trusty old pick-up truck engine (powerful enough to do the job, but reliable over long periods of time) to that of a Formula 1 racer (Immensely powerful, but prone to frequent failure).

Just a detail: You need to use 3X (acting as 5X) redundancy. Approaching the one used in the STS fleet now retiring.

They used 68000s in some of those STS systems. Again - relatively obsolete technology, but comparatively simple and predictable.

I agree 100%. And will use this to ask: Whatīs your feeling (on this issue) on the Revolution (rdware and Software/algorithms[/]) EA introduced using DFBW technology (for the first time in non military planes)? With itīs big implications. Why US didnīt introduce "in parallel"? But this is for another post or even another thread.

I think it was as valid a direction to take when designing the next generation of airliners as any - especially given the accidents that happened in the '70s and '80s with mechanical/hydraulic systems failing due to damage. I studied Software Engineering under Peter Mellor, who you'll see in the Risks archives occasionally, especially relating to the A320 - and what I learned was that the process that they went through designing the systems was utterly exhaustive. Whatever the naysayers profess when it comes to "Keeping it simple", the fact is that the hydraulic systems required for widebody airliners and the artificial feel required to make such controls make sense to a pilot are anything but simple.

DFBW was proven in military terms for a decade before the A320 started carrying passengers, and I think that was a more than reasonable lead time. The US did not openly develop FBW airliners in tandem, but the B777 followed hot on the heels of the A320 - as such I suspect that something similar was on the drawing board as the A320 progressed from the testing phase to production and service. The only difference between the latest generation of Boeing aircraft and that of Airbus is that Airbus developed a new control philosophy based around the new systems, whereas Boeing had their FBW systems drive a facsimile of a "traditional" flight deck environment. The "ain't Boeing, ain't going" crowd like to say that they don't trust computers in charge of their aircraft, but the B777 (and presumably the B787) is as reliant on it's computers as any Airbus FBW model.

[HarryMann]

the right answer is: it is impossible to extrapolate the direction of a turbulent flow....
but why they do not started this experiment one year earlier ?

That is not a correct use of the term 'turbulent flow'.

[Smilin_Ed]

Fine Motor Control

MountainBear:
I wonder if you would still feel that way today.

One of the realities that plague video game designers is the fact that as we age one of the first skills that is lost is what is known as "fine motor control," especially in the hands. FMC does not refer to reaction time; it has to do with the ability to make small, discrete movements as opposed to large sweeping ones. People who suffer from poor FMC often appear to be "overreacting" physically to the stimulus but it's not a reaction problem.

I think I would. Landing on a carrier, which was my most demanding task, demands small precise control movements, not sweeping ones. At my age, 74, I clearly do not have the same ability to do fine work such as drawing with a pencil but I believe that I still have the same ability to sense pressure. I don't play computer games nor do I even have a "joy stick" on any of my computers but the very few times I tried one, I found it difficult because the stick moved and I had no tactile feedback. For the same reason, I have always disliked a mouse.

[RR_NDB]

Failures (BEA rprt #2, pg 36)

Hi,

"lack of signal" condition

The sub systems "interact in a completely safe way" (protocols, CRC, etc.)

A (HARD) failure as mentioned strongly motivates me to go deeper in the issue.

NAV TCAS FAULT (2 h 10): ... it could be the consequence of an electrical power supply problem or of an external failure.

F/CTL PRIM 1 FAULT (2 h 13): ...or be the result of a failure.

F/CTL SEC 1 FAULT (2 h 13)...or be the result of a failure.

1.16.2.4.3. Interruption of the messages:

... loss of one or more system(s) essential for the generation and routing of messages in the aircraft: ATSU / SDU / antenna... or loss of electrical power supply: this would imply the simultaneous loss of the two main sources of electrical power generation.

Intriguing: A redundant System possibly hit by multiple failures.

Question: What kind of "external stimuli" (to a redundant "electric/electronic" System) has the ability to make it (possibly) fail in that way?

Note: BEA analysis on above msgs. show first other possible reasons and is not conclusive (by lack of further info.; ACARS is for other purpose).

[Lemurian]

jcjeant,

.. this material (the black boxes) are exhibits to the prosecution of the court process.
The BEA report (the result of their analysis) is not an exhibit.
It therefore not falls under the same sections of law protecting the exhibits.
That's the point I want to put emphasis (BEA report is not part of the judicial process)

You are really something, you are !.
And very sneaky, too : By that one sentence, you now have everything for criticizing the french system, the BEA independence, the weakness of the French judicial conclusions and penalties involved (they have nothing to prove anything!)...Unfortunately for you, it's also an absolute
BULLSHIT !
This is an excerpt of the bill instituting the BEA and its duties and priviledges :

L. 1621-5
Le procureur de la République reįoit copie du rapport
d’enquęte technique en cas d’ouverture d’une procédure
judiciaire.

(The Prosecutor for the Republic is to receive a copy of the technical investigation report in case of the opening a prosecution case).Which is, btw, what has happened as Air France and Airbus are in a manslaughter lawsuit.

Try again

[bearfoil]

Lemurian

I was trying my best to figure that one out. Thanks for the ennabling legislation.
Do you have more of the Law ? Maybe I'll just withdraw from the discussion, I didn't get much of the Concorde proceedings, either.

[DenisG]

ACARS / Satellite Signal Failure

Hi folks.

As to the ACARS, we know for sure that at least one message would have been sent by the aircraft (60 seconds after preceding event) that should have been received between 2h15m00s and 2h15m14s. (BEA Report, 17-12-2009, p 36ff)

At least BEA will know by now (FDR), whether this non-occurrence of the expected class 2 fault message is due to (1) the sudden end of the flight at that point in time or due to (2) satellite communication issues in the storm or even (3) fatal electronic failures in the aircraft.

BEA reported a minor technical issue with the radio management panel at takeoff from Rio, but it appears insignificant as it has not been followed up by further info (at least to my knowledge). (BEA Report, 02-07-2009, p. 70)

Perhaps we will find out during the announced press conference this upcoming week, why and how the flight met its tragic end only about 6nm from the LKP at 02h10m, despite the operations center receiving messages until 02h.14m.26s (important: we cannot conclude that it was transmitting until then!).

In fact, we know little more than three months ago, and the recovery of the CVR and FDR this close to the LKP has raised more questions than it provided answers. Based on the sea drifts, we know at least that the calculations with regard to the point of impact by the US Coast Guard, the Brazilian Navy and the US Navy (BEA Report 17-12-2009, p. 80) appear to have been very accurate back then.

[RR_NDB]

Testability issue

Hi,

Airbus developed a new control philosophy based around the new systems

Introduced more than FBW: a new control philosophy.

don't trust computers in charge of their aircraft

Good issue to be discussed later.

but the B777 (and presumably the B787) is as reliant on it's computers as any Airbus FBW model.

I will go deeper to later comment on that.

A question, regarding "predictability" of a complex "electric/electronic" a/c:

A test 787 (ZA001) was hit by a lightning bolt and survived. (landed). During the Test phase or Certification process, the airliners are "lightning tested"?

Or expressing in another way: Itīs really impossible (indeed near zero probability) to "reset" or even damage the wiring/buses if the a/c is hit by a powerful "cloud-cloud" bolt?

I know the several cases, Iran Air Force 747, JP case, IIRC a P3 in US, etc. that went down (for mech. reasons). My question is on the "Testability" issue on that specific subject.

An a/c after an UAS issue being hit in itīs nose section by a "very intense current" (thousands of amps), facing severe turbulence (with the crew in a "dark" cockpit, interior lights dim*) can become "faulty"? Or, What can cause "multiple failures" in a "redundant computer system"?

(*) No significant lightning activity that night.

old pick-up truck engine

I have it in my RV such engine, modified (fail safe fuel supply and redundant ignition) to be more reliable than the original.

They used 68000s in some of those STS systems. Again - relatively obsolete technology, but comparatively simple and predictable.

Right!

[gums]

Tactile feedback and "old" hands

I gotta go with Smilin' Ed.

Trouble with a small stick that moves 30 degrees or so off-axis is you really can't tell instinctively if you're commanding half or a third or three quarters or.... Larger sticks such as those on jet fighters are easier to figure out whether you are commanding max or half or...

If the small stick has a good "load" to it that requires greater and greater pounds of pressure along the way, then could be a player.

Viper stick moved zero originally. See the black-nosed Block I jets I flew in mid 1979. Block 5 modified the stick for 1/8 inch of movement. Breakout force to command gee or roll rate was same, but theoretically the stick stopped moving when you reached "X" pounds for pitch or roll. Apparently, someone thot we would then stop pulling more. Seems that a few guys were pulling over 100 pounds in a fight to ensure they were asking for all the jet could give!! I never noticed, to be honest, the ham fist I was.

I fly the online sim Warbirds and use a simple stick that is very stiff. The gimpy ones that move a lot and move easily are harder to use for fine corrections.

[mm43]

Safety Concerns

Some of your comments do not apply to the A330

Thanks for highlighting the matter.

Yes, rudder travel is limited as follows:--

A340 - 31.6° and 3.5°
A330 - 35° and 4°

A corrected RTLU graphic is at post #109. Not the only time I have made the mistake.

[DozyWannabe]

Originally Posted by RR_NDB

Introduced more than FBW: a new control philosophy.

Nothing wrong with that per se. Anyone used to driving a modern car would be completely at a loss trying to drive a Ford Model T. Also, the sidestick control method had been in use in military jets for some time before the A320 went into service, so it's not like they were springing a complete unknown into the pilot community.

A test 787 (ZA001) was hit by a lightning bolt and survived. (landed). During the Test phase or Certification process, the airliners are "lightning tested"?

I don't think so, but the laws of probability suggest that many a FBW Airbus model has been struck by lightning in one form or another in their 23 years of airline service and not one has fallen from the sky because of it.

An a/c after an UAS issue being hit in itīs nose section by a "very intense current" (thousands of amps), facing severe turbulence (with the crew in a "dark" cockpit, interior lights dim*) can become "faulty"? Or, What can cause "multiple failures" in a "redundant computer system"?

I don't know, and neither does anyone else - which is why I'm waiting for the report to come out. At this point we don't even know if the computer system had anything to do with the loss of the aircraft, so we're into heavy speculation by even bringing it up!

Right!

And the 80186 used in the A320 is of similar vintage, so why consider one to be more suspect than the other?

(Nerdy aside : I know that the 68k series was much more friendly to program at assembler level than the 8086 series, but that's not really relevant here...)

Originally Posted by gums

If the small stick has a good "load" to it that requires greater and greater pounds of pressure along the way, then could be a player.

IIRC the Airbus FBW stick does so via a simple spring mechanism.

I fly the online sim Warbirds and use a simple stick that is very stiff. The gimpy ones that move a lot and move easily are harder to use for fine corrections.

As a flight-obsessed kid I used to play F/A-18 Interceptor on my old Amiga 500* with a digital joystick (either rate was commanded or it wasn't). Lots of fun, but I'm unsure of the relevance. As an aside, that 23-year-old piece of entertainment software had the best sound FX of any sim I've used since...

* - Hence why I know about the 68k

[jcjeant]

Hi,

(The Prosecutor for the Republic is to receive a copy of the technical investigation report in case of the opening a prosecution case).Which is, btw, what has happened as Air France and Airbus are in a manslaughter lawsuit.

Dunno where we go with that ... for me it's nowhere.
The copy of the investigation report (who is also public) it's just a information document and can't be used by prosecutors for point any responsible or irresponsible people or corporation
The only reports used will be those show at the court by the experts named for this case.
Those can be interrogated also by the judge of instruction and will also be called by the judge in the court when the trial run.
The BEA can also be interrogated by the judge of instruction or at the trial ... but the BEA report is not a exhibit for the court ...
Only will be exhibit .. the judiciary experts reports ... even if it's a conform copy of the BEA report.
BEA experts are not judiciary experts (otherwise .. how BEA can be independent of justice?)
Again refer to the last trial in France about aviation accident (the Concorde trial who is even not yet closed as AF and Continental are going in appeal)
Wait for the AF447 trial ... (in how many years ??) .........

[CogSim]

At this point we don't even know if the computer system had anything to do with the loss of the aircraft, so we're into heavy speculation by even bringing it up!

UAS->ALTN2->LOSA(loss of situational awareness)->LOC1->Recovery?->LOC2?->Recovery?->EOFLT(end of flight)

seems to be the simplest chain without invoking gremlins.

[deSitter]

Smilin_Ed said

One configuration was to have the stick (or yoke, I can't remember which) move large distances for small control surface movements but with little force required. The opposite configuration was to have the stick "locked in concrete" and all control surface movements responding only to stick forces. My instructor, Nello Infanti, asked which I preferred. I preferred minimal stick motion with aircraft response determined by stick forces. Nello informed me that the vast majority of pilots also preferred that configuration. I would think that, when finding it necessary to fly current FBW aircraft using the stick, that precise control would be more difficult using stick deflection rather than stick forces.

This is very fascinating and reminds me of riding a fast motorcycle. This is a subtle physico-mental thing that cannot be described, but is very instinctual for a experienced rider. There is no question in my mind that the airplane should respond to physical force so that a pilot can "feel" it in his own structure. There is probably a fancy medical word - is it proprioception? Astronauts in weightlessness lose track of their limbs unless they can see them. The lack of physical stress on the body divorces the mind from it in a very strange way. One astronaut experienced a strange glowing watch floating before his eyes while half-asleep in orbit, only to discover somewhat later that it was his own arm he was seeing.

The control input should match the physical stress of acceleration, because the pilot has to "feel" how to fly the airplane based on what it's doing to his body.

[mm43]

Originally posted by RR_NDB ...

NAV TCAS FAULT (2 h 10): ... it could be the consequence of an electrical power supply problem or of an external failure.

The BEA later rectified that comment, and the TCAS was found to have a self checking function that sampled all values and tested to see if they matched reality. Apparently they didn't, and the TCAS was inhibited to prevent the potential for mayhem. Note the graphic showing the cause, e.g. Cockpit effect messages without fault ... now incorrect and added in red.

[deSitter]

Where is the TCAS antenna?