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AF 447 Thread No. 5

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AF 447 Thread No. 5

Old 30th Jul 2011, 04:04
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bearfoil claims the plane hit 30 degrees pitch up.

BEA claims:
The airplane’s pitch attitude did not exceed 15 degrees...
and later on:
...pitch attitude of 16.2 degrees nose-up...

They did declare AoA never got BELOW 35 degrees once it had stalled.

(And I see from news reports training is getting a dose of blame. The aircraft should earn a dose, too, for the way stall warnings are handled and the utter lack if cross feed into the ADIRUs from the GPS and Intertial systems, IMAO.)
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Old 30th Jul 2011, 04:14
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airtren The Vertical Speed Curve shows continuous variations during the fall, indicating that the fall was very bumpy, and not at constant speed.
have no problems with side 47.....

the vitesse vertical on s114 is inconsistent after 2:12:45 like a lot of other parameters too
at this moment the "incident par le iris 1,2,3" (what must be the AoA???) climb over 30 deg
I think with more than 30 deg AoA a lot of the sensors are not longer in a clean flow and they will show also the turbulences of the flow at the bottom of the fuselage, so I do not think that it is the true vitesse vertical.....


p.s. what means "vitesse vertical selecte" also s.114)

Last edited by grity; 30th Jul 2011 at 04:31.
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Old 30th Jul 2011, 05:23
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Originally Posted by takata
Having a camera showing all the displays and crew actions (postions/attitudes) would be very helpful rather than having to derive something from recorded data which doesn't give any hint about what can NOT be derived. (e.g. was the PNF reading silently the documentation? was he scanning the displays? looking at the PF actions? did they exchange meaningful regards?)
That may require just a whole lot of large disk space for fully readable displays from about ceiling height mid console. Decent HD width video requires about 100 megabits per second or more. Poor quality is about 13 megabits/second. Displays may be visible and gross features may be readable. YouTube video tends to be under 6 megabits/second even for 1080 resolution. So you can figure for yourself about readability with a vibrating cockpit. (That will make compression harder and video readability worse.)

8 megabits/second is a megabyte per second. One hour is 3.6 gigabytes. This is within the size limits for well established solid state disk technology such as could be repackaged into a Honeywell box with modified interfacing. Getting the signal back to the position in the tail will require a new wire, probably using Ethernet, for the data to be store. If Ethernet is used well established backup disk software can be repurposed.

They might be able to get this working in a few months and certified in a couple years. It would be a good idea. And I'd use a larger disk and perhaps 1/2 hour recording time before old is overwritten. Then higher resolution for more readability could be applied. With a 100 gigabyte solid state disk they could record three or four channels at quite respectable resolutions. They might need to be using gigabit Ethernet or even a pair of gigabit Ethernet connections to pass all the data. So four or more new cables might be needed to get the data back to the recorders. That's probably the most difficult to sell part of the concept.
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Old 30th Jul 2011, 05:30
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HN39,

Red, yellow, and green is needed. Red is means, "If' it's in this region and the plane is not resting on its landing gear then it is stalled no matter what." Yellow or perhaps orange means "You're stalled in this region if the air speed is above 60kts." That region gets adjusted for air speed. Green is "not yellow/orange/red" meaning you're probably OK but be paranoid if it's not neatly within the central region of green.

An AoA above 30 degrees is stalled. I am sure the 30 degrees can be set a little lower. In the case of AF447 any sane set of AoA display parameters would have been a clue. Whether the pilots would have had a clue what to do is up for grabs, after things that BEA said. Oy!

I rather wish they'd had words about AB's choice to shut off stall warnings with air speeds below 60kts no matter where the plane is. That's "bogus". It seems pretty obvious these pilots were not well enough aware of this counter intuitive trait.
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Old 30th Jul 2011, 05:38
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badgerh, regarding recoverability of the stall note that the instance a recovery was made does not mention the THS at its "up" limit as AF447 had. It would have taken over 5000' for the THS to become neutral and another who knows how much for it to go "down" enough to matter. Then could it be returned to neutral fast enough for the plane to fly out of the recovery. It'd be real close at 10000', I bet.

(grin) Anyone here willing to try?
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Old 30th Jul 2011, 05:58
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An enhanced (engineered) version of the air temperature trace.

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Old 30th Jul 2011, 06:39
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Alber Ratman, I'm not even sure an AoA indication would have helped them at all. They were so hopelessly disoriented I'm sitting here with tears in my eyes.

The PNF should have trusted his hunches and pushed the stick forward to recover from the stall. His abiding by proper procedures cost him his life.

Oh God!
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Old 30th Jul 2011, 06:49
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vanHork, "Further on I keep seeing that the captain is trying to make sense of what are apparently continuously divergent readings."

And apparently they never looked at the inertial instrument readings for either velocity, pitch, or altitude. It was not even mentioned. WTF is it even in the cockpit if the crew are not trained to use it? And why in (totally censored) are they NOT taught how to use it?

I can't seem to get these tears out of my eyes.
{o.o}
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Old 30th Jul 2011, 07:09
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Originally posted by ventus45 ...
.... unswerving belief in, "the gospel according to Toulouse
No. They didn't understand it. Wrong faith!

It's their belief in Air France that brought them down ... and it shouldn't have.
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Old 30th Jul 2011, 07:12
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Hello Grity
p.s. what means "vitesse vertical selecte" also s.114)

It seems to me that On glaresheld : FPA/VS knob was selected VS 0
Take care of you and happy landing
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Old 30th Jul 2011, 08:01
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Takata;

Re your message #999:
Originally Posted by ACARS
.1/FLR/FR090601 0210 279334 06
EFCS1 X2,EFCS2X,,,,,,
FCPC2 (2CE2) /WRG:ADIRU1 BUS ADR1-2 TO FCPC2,HARD
About Svarin's concerns in relation to this "wiring fault".
It seems to be simply due to PNF selection of ADR3 in place of its own ADR1 displayed. Hence, he switched to ADR3 (wrong) shortly before ADR1 returned "good" again. A while later, it seems that ADR+IR 3 was switched for ADR+IR 2 on PF display.
Yes, possibly. But I wonder if the explanation is more straightforward? From the AMM:

(3) Fault detection and analysis (except for the internal FWS computer faults)
As soon as an internal or external fault is isolated, it is considered as being at DETECTED status.

The FWS computer which detected the fault must confirm it.

The fault duration affecting ARINC bus links is:

- 2 s for a label with its SSM coded FW or FT FLIGHT, for the SDACs
- 2 s + maximum of 500 ms or 5 cycles for a label not refreshed or if its parity is incorrect , for the SDACs and for the FWCs
- 2 s + 5 cycles for a label if its SSM is coded FW or FT FLIGHT, for the FWCs.

Then, the fault is at DECLARED status.

A declared fault must be sent to the CMC.

A DECLARED fault is then consolidated. This consolidation is performed by the computer which declared the fault. It consists in checking the duration of the fault or its recurrence.

If the fault is still present after 10 seconds or if it occurs 3 or more times during the flight, it is consolidated.

A fault which is declared not consolidated is transmitted to the CMC as being a TRANSIENT fault, with bit 19 of label 356 at 0 (INTERMITTENT).

A fault which is declared consolidated is transmitted to the CMC as being a PERMANENT fault with bit 19 of label 356 at 1 (HARD).

A declared fault, whether it is consolidated or not, is transmitted for correlation:
- a fault declared by a SDAC is transmitted to the FWCs,
- a fault declared by a FWC is transmitted to the opposite FWC,
- an ECAM control panel fault is transmitted to the FWCs.

The correlated message which is transmitted in any case to the CMC by the FWC 1 is stored in each FWC.

NOTE : Very few LRUs connected to the FWS, are not checked at the
BITE level but remain checked at the operational level.

(4) Correlation principle
In addition to one fault detection, each FWC starts a correlation process.

This correlation is only possible because every LRU which is acquired by the FWS is connected at least to two computers of the FWS.

This correlation is performed on the buses and on the analog data.

The correlation enables a greater precision on the origin of the fault.

- Example of a message not correlated:
If a fault is detected only by one FWS computer, the associated message will be:
FWCi(1WWi)/WRG:FMGECn BUS E GEN TO FWCi

- Example of a correlated message:
If the same fault is detected by two computers of the FWS, the associated message will be:
FMGECn(1CAn) BUS E GEN


The correlation process which is performed by the FWCs can be initiated only after the consolidation.
grity;

Yes, it means "Vertical Speed Selector", on the FCU - it also doubles as the FPA selector when the mode is in TRK-FPA.

An observation - (one of many, I suspect); Just so everyone is clear on this, the "MAX REC" on the MCDU is not displayed in red font as shown in the BEA Report. I suspect this is for emphasis only. The MAX REC is not a limitation but an advisory based upon both crew-entered TROP heights, and current weights and temperatures, (SAT). One doesn't attempt to climb above it but it wouldn't be a "limitation" in the same sense that the service ceiling of the aircraft is a certification limitation.

Thus far, in my reading of the Report, I cannot find clear comments on why the initial pitch-up occurred. The stick movement was brisk - 7deg (almost half-stick aft movement) in one second. As I posted earlier, I thought it might have been 4 to 5 degrees, which equated to about 3cm of aft stick movement or about roughly about six inches on a standard control column. This aft movement is far greater than that. We can understand a bit better why the aft stick movement during the cockpit confusion, but not the initial movement.

Still reading.

Last edited by PJ2; 30th Jul 2011 at 08:12.
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Old 30th Jul 2011, 08:16
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p.s. what means "vitesse vertical selecte" also s.114)

It seems to me that On glaresheld : FPA/VS knob was selected VS 0
but it has 3 values over the time, so it can not be a single knob ???
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Old 30th Jul 2011, 08:22
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mm43 your old calculations compares wery good with the outcoming

2 points I found:
they lost more energie in the first time, maybe du to the strong corections with ailerons

and the pitch was not constant high it moves up and down +16deg.....--8 deg
so the stall was not so stable, the stable flow must have braked down 2 or 3 times with a move to the front
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Old 30th Jul 2011, 08:40
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Originally Posted by JD-EE
They might need to be using gigabit Ethernet or even a pair of gigabit Ethernet connections to pass all the data. So four or more new cables might be needed to get the data back to the recorders. That's probably the most difficult to sell part of the concept.
I would even consider the wireless communication over a 60GHz band. It seems not to interfere with the existing standards and is expected to be widely available in the middle of this decade (IEEE Xplore - State of the Art in 60-GHz Integrated Circuits and Systems for Wireless Communications).
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Old 30th Jul 2011, 09:15
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dozy, thanks for the translation of that section of the report.

jcgeant, the answer to your 'bizarre' question is that the wife of the PF is back in the cabin, and they both are returning from a vacation in Brazil. The PF had apparently not previously flown with the captain before this flight. That's why the captain asks if he is qualified.

(You can check the passenger list and match her name with the name of the PF.)

Now one can ask whether it was prudent for the captain to take his rest while the flight is transiting a turbulent section of the ITCZ, and turning the flight over to a junior FO with whom he has never flown before.
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Old 30th Jul 2011, 09:15
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@Grity

Quote:
p.s. what means "vitesse vertical selecte" also s.114)

It seems to me that On glaresheld : FPA/VS knob was selected VS 0
but it has 3 values over the time, so it can not be a single knob ???
FCOM
1.31.40

INDICATIONS ON PFD

VERTICAL SPEED:

The displayed vertical speed information is normally based on both inertial and barometric data.
If inertial data is not available, it is automatically replaced by barometric information.
In this case, the window around the numerical value becomes amber.
---


3 values? on page 116 only 2 (ADR or IR)

Last edited by A33Zab; 30th Jul 2011 at 09:50.
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Old 30th Jul 2011, 09:40
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Initial stick movements

Sorry everybody, meant to send this as a PM. No disrespect intended to any pilot, living or dead.

PJ2
Thus far, in my reading of the Report, I cannot find clear comments on why the initial pitch-up occurred. The stick movement was brisk - 7deg (almost half-stick aft movement) in one second. As I posted earlier, I thought it might have been 4 to 5 degrees, which equated to about 3cm of aft stick movement or about roughly about six inches on a standard control column. This aft movement is far greater than that. We can understand a bit better why the aft stick movement during the cockpit confusion, but not the initial movement.

I share your confusion about why the pilot saw the need for the initial stick movement.

However I wonder if the magnitude of the input might be be the result of [trained?] poor piloting technique. If the full "protections" are there, a huge input simply says "give me all you can".

I have no idea if such a practice exists anywhere, but can see how the available pilot interface might encourage it to develop. Or at the least, not discourage its use.

Any opinion?
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Old 30th Jul 2011, 09:41
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Has anyone else gained the impression that PF actions, appear to assume 'Normal' law ? - despite acknowledgements of Alternate reversion soon after the AP disconnect sequence.

If so, does this indicate a stress reversion to Normal law ss inputs by PF, confused training, or lack of understanding just how sensitive the a/c is at cruise altitude to manual control...

I don't wish to criticise, but the focus on what this that or the other instrument was displaying, where this that or the other switch was set or not set, and what was being said is all but immaterial once you look at the gross insensitivity of manual flight control... and what appears to be an assumption, at least on the part of PF, that the answer to almmost everything has simply got to be stick back (and possibly more thrust)
... only when explicitly countermanded, did PF try anything else.

The meaning and dangers of MAX ALT (recommended) being exceeded were acknowledged by PNF & PF, but whereas coarse NU had been used to get there, only weak, tentative and ineffectual ND is observed as the response.

Here we have an extreme FEAR of any ND inputs (speed fear)
Here we have a seeming belief that NU inputs at the very edge of the High Alt flight envelope, in Alternate Law, are perfectly acceptable.

The 'speed fear' can perhaps be explained by the known UAS - the NU inputs as a response a serious failure by PF (and yes, its been said PNF should then & there taken firm control)

Let us also not forget that the 'silent & unobserved' Alternate Law THS movement - undoubtedly a big factor in the stability of the stalled pitch attitude, requiring large ND for long periods (many tens of seconds) to overcome...

I am glad the BEA have reported their concerns over this unfortunate oversight.

Last edited by HarryMann; 30th Jul 2011 at 10:21.
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Old 30th Jul 2011, 10:07
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HarryMann

I agree totally. The actions following the stall could suggest an "Alpha Floor" fixation. I don't think the PF understood the implications of the reversion to Alternate Law.

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Old 30th Jul 2011, 10:12
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...and I don't think you lot would have a clue as to what you are talking about!!
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