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AF447 final crew conversation - Thread No. 2

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AF447 final crew conversation - Thread No. 2

Old 12th Mar 2012, 19:37
  #161 (permalink)  
 
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Roll surface damage?

CONF iture:

Here it was the rudder but what about one or more ailerons on AF447
?


RR_NDB:

It is technically feasible (and not costly) to detect this type of failure
(on the fly ).



Looking at the aileron & spoiler traces:


If NOT in A/P control the outboard ailerons are centered (active zeroed) at speeds above 190Kts. (Active zero =1.4[/FONT] up)[/COLOR]

(In A/P control or certain failure modes outboard. ailerons can be controlled up to 300Kts)

This transition is visible @ 02:10:05 at A/P drop off.

The trace shows also the outboard ailerons remain centered all the way down even when the CAS was well below 190Kts.

This could be another protection from the PRIMS (due to rejection of ADIRU's?)

The position is sensed by the LVDT inside the servo actuator and not the actual surface position.

There is no separate surface position RVDT like in the elevator and rudderdesign.

However the adjacent servo-actuator (while in dampening mode) is still monitored and since this one is driven by the aileron it reflects the actual surface position.

If there is any difference between the active and the dampening servo a fault message will be triggered. (And aileron faults were NOT present)

There were NO outboard aileron commands from PRIM and because there were also NO aileron fault messages present, we can conclude the surface was still attached.

However we CANNOT conclude nor exclude the outboard aileron surfaces were completely undamaged.

The inboard ailerons did receive commands, A/C did respond to these commands and failures were absent.

***

From the spoiler trace:

In ALT 2 spoiler (roll function) 2, 3 and 6 are inhibited.

The only glitch you will find in the FDR trace is after ~02:13:35.

Traces of spoiler 5 (cyan) & 6 (amber) shows peaks thereafter, this could be the moment the PRIM 1 and SEC 1 were switched off.

#5 is controlled by PRIM 1 and #6 is controlled by SEC 1.

If the peaks are caused by aerodynamic loads we can conclude the surface(partly?) was still connected to the servo. (Spoiler position is also derived from the servo-actuator LVDT).

Last edited by A33Zab; 12th Mar 2012 at 19:55.
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Old 12th Mar 2012, 20:34
  #162 (permalink)  
 
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Surfaces damage

Hi,

A33Zab,

Fine biz,

Kind rgds.
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Old 13th Mar 2012, 02:15
  #163 (permalink)  
 
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Originally Posted by A33Zab
The trace shows also the outboard ailerons remain centered all the way down even when the CAS was well below 190Kts.
This could be another protection from the PRIMS (due to rejection of ADIRU's?)
That question should be addressed by the BEA ... let's wait and see.
The SECs should have taken over, no ?

Originally Posted by AZR
I remain very surprised at your (and other's) "eagerness" to find (potentially catastrophic) failure with the aircraft.
My only eagerness is to make sure the victim's families have access to all the data, not only part of them. There is no excuse for the Judge not to include them in the proceeding. We want to know what happened, everything, not only what the crew did wrong.
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Old 13th Mar 2012, 11:00
  #164 (permalink)  
 
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Originally Posted by CONF iture
Originally Posted by A33Zab
The trace shows also the outboard ailerons remain centered all the way down even when the CAS was well below 190Kts.
This could be another protection from the PRIMS (due to rejection of ADIRU's?)
That question should be addressed by the BEA ... let's wait and see.
The SECs should have taken over, no ?
No. SECs don't take over valid PRIMs. In case of unreliable airspeed many protections remain as for a last valid speed.

Originally Posted by CONF iture
Originally Posted by AZR
I remain very surprised at your (and other's) "eagerness" to find (potentially catastrophic) failure with the aircraft.
My only eagerness is to make sure the victim's families have access to all the data, not only part of them. There is no excuse for the Judge not to include them in the proceeding. We want to know what happened, everything, not only what the crew did wrong.
But wild speculation does not bring families closer to truth, it only decreases signal to noise ratio. You want the data not a garbage.

This was addressed by BEA in interim reports that both wreckage as well as FDR recording indicate no structural failure up to the impact. Plane was responding to stick deflections, and was symmetric aerodynamically (otherwise it would not fall flat, wings level at such extreme AoA). It was (for many) surprisingly stable (many planes would need to enter flat spin to fall wings level from fl370 down to the .

Wild and unfounded (and in fact contrafactual) speculations were plenty here. When BEA said that fracture analysis of found rudder indicates almost flat impact with little forward speed and small roll to the left many here dismissed it and continued to speculate about plane disintegrating mid air. Then "black boxes" were found and read and surprise - they perfectly agree with that early rudder analysis. Yet still some contrafactual speculations surface all the time
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Old 13th Mar 2012, 16:58
  #165 (permalink)  
 
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Cool

Hi,

You want the data not a garbage
Indeed ....
Google Traduction
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Old 13th Mar 2012, 20:03
  #166 (permalink)  
 
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Originally Posted by sebaska
In case of unreliable airspeed many protections remain as for a last valid speed.
Except for the RTLU, that is new information and it would be helpful if you could elaborate on that.

According to BEA's Interim Report #3 p.27 (English version):
The calibrated airspeed recorded in the FDR is that displayed on the left-hand PFD, unless it is invalid (if the speed is less than 30 kt, in which case the SPD flag replaces the speed scale).
The recorded airspeeds remained above 30 kt until at least 02:11:45.

Perhaps it one should distinguish "invalid" from "erroneous". At least one airspeed value became erroneous at 02:10:04.6. The ECAM message NAV ADR DISAGREE was generated after 02:12:00, so until that time at least two of the three airspeed values must have been within tolerance of each other, erroneous or not, but still 'valid' until 02:11:45.
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Old 13th Mar 2012, 20:40
  #167 (permalink)  
 
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Can anyone explain why there is a SPD flag on the left PFD between 02:11:40 and 02:11:45? (p. 44 of I.R.#3 EN)

Last edited by HazelNuts39; 13th Mar 2012 at 21:19. Reason: typo
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Old 13th Mar 2012, 20:43
  #168 (permalink)  
 
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Could those have been two (incorrect, but consonant) speeds upon which PF based his "Overspeed"? Plugged Drains only? Hence the continued PULL?

For that matter, if reading high, wouldn't A/P have input NU, and for how long prior to loss of reliable speeds?

Don't mind me.
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Old 13th Mar 2012, 21:04
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Originally Posted by Lyman
Could those have been two (incorrect, but consonant) speeds upon which PF based his "Overspeed"?
No, the speed from ADR2 that was not recorded would have been close to either ADR1 or ADR3 (when different) which were recorded. Note also that the right PFD was showing the speed from ADR3 between 02:10:40 and 02:12:17.

Since the CAPT pitot and the F/O pitot are mounted in exactly identical symmetrically opposite positions on the forward fuselage, while the STBY pitot position is below the CAPT's and therefore in a slightly different airflow, I would expect ADR2 closer to ADR1 than to ADR3.

Last edited by HazelNuts39; 13th Mar 2012 at 22:09. Reason: italics
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Old 13th Mar 2012, 21:08
  #170 (permalink)  
 
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@HN39:


Can anyone explain why there is a SPD flag on the left PFD between 02:10:40
and 02:10:45? (p. 44 of I.R.#3 EN)
My copy of (p. 44 I.R.#3 EN) shows speed flag @ 02:11:40 not @ 02:10:40.
Is my copy again outdated? or do you need to increase the font size a little bit

while the STBY pitot position is below the F/O's
Minor correction, STBY is below Capt. probe, to be exact 60 below datumline (Z=0) while Capt and F/O are @42.


Last edited by A33Zab; 13th Mar 2012 at 21:28.
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Old 13th Mar 2012, 21:22
  #171 (permalink)  
 
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A33Zab;

You are correct on both counts, thanks for pointing that out. I've edited my post to correct the errors.

Last edited by HazelNuts39; 13th Mar 2012 at 21:48.
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Old 13th Mar 2012, 21:40
  #172 (permalink)  
 
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@HN39:

No thx,

BTW, very good observation! I don't have an answer.
Airspeed acc. graph was still above 30Kts.

Confirmed by the CVR transcript pages @ 02:11:40:

The CAS is 106 kt and the CAS ISIS 112 kt.

But this is contradictionary with:
The FD 1 and FD 2 become unavailable.
The angles of attack 1 and 2 become invalid (NCD status)
Which implies CAS 1 AND 2 are <60 kt.

Last edited by A33Zab; 14th Mar 2012 at 00:15.
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Old 14th Mar 2012, 00:36
  #173 (permalink)  
 
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Originally Posted by sebaska
No. SECs don't take over valid PRIMs. In case of unreliable airspeed many protections remain as for a last valid speed.
Outboard ailerons did not move when they should have. If there is a logical explanation, and there could be one, I would like to hear about it ...

You want the data not a garbage.
Exactly my point. Full data to the families. FDR especially.
Airbus has full access to the data, which makes sense, naturally the families should also, why not ? What's the problem ?
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Old 14th Mar 2012, 01:05
  #174 (permalink)  
 
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Originally Posted by CONF iture
Outboard ailerons did not move when they should have.
They should not have moved. The EFCS retains the configuration associated with the last known good speeds. When the ADR monitoring began, the flight control configuration was locked, including RTLU and ailerons.

The rest is pure politics and anyone can spin that as they please.
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Old 14th Mar 2012, 01:38
  #175 (permalink)  
 
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Also THS? Flap? RTLU froze the Rudder. Does the lock remain locked? Also, do spoilers remain inhibited, and for how long? If speeds return, are controls all available? Also, if ailerons inhibited, how did ROLL DIRECT retain so much authority, without the outers?

Thanks for info sir.

Last edited by Lyman; 14th Mar 2012 at 01:54.
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Old 14th Mar 2012, 08:56
  #176 (permalink)  
 
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Originally Posted by A33Zab
But this is contradictionary with:
Quote:
The FD 1 and FD 2 become unavailable.
The angles of attack 1 and 2 become invalid (NCD status)
A drop of 30 kt in 1s of either the median or the mean IAS around 02:11:40 could again have triggered the monitoring of the airspeeds by the FMGEC and the EFCS. That would explain the loss of the FD's, but not that the AoA's became NCD.
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Old 14th Mar 2012, 13:03
  #177 (permalink)  
 
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@HN39:

The ADR monitoring of FMGEC is a continuous process and rather complicated...
simplified it needs at least 2 valid sources for the command side, OWN ADR and ADR 3, with OWN ADR as default.
But the monitoring side takes all 3 ADRs (if valid) in account.
Don't know the exact influence of F/O switching to ADR 3 on monitoring logic.

Anyway:
@02:10:40 CAS (#1) seems to be in same range as ISIS trace (~ADR3).
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Old 14th Mar 2012, 13:30
  #178 (permalink)  
 
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Originally Posted by HN39
That would explain the loss of the FD's, but not that the AoA's became NCD.
02:11:40 CAS measurements are still above 60kt but not 5 sec later.

Originally Posted by Hamburt Spinkleman
When the ADR monitoring began, the flight control configuration was locked, including RTLU and ailerons.
RTLU was initially stuck then non available, but what is your reference for the ailerons ?
Please quote ...
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Old 14th Mar 2012, 15:07
  #179 (permalink)  
 
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Clearly, many here are conversant with the 330's systems, and its pilotage. I certainly am not. So I am curious as to some things.

When the ADR's begin to be interrogated by the computers, as to reliability, isn't this ongoing? Or is this 'suspicion' the result of already sensed anomaly? Because if it involves locking of control limits (certainly not locking controls, that would be crazy), are the pilots on board with the 'suspicion'?

Most certainly, right? Wouldn't the flight crew be apprised instantly if A/S was thought sour?

As in: "Monsieur, the computer is interrogating our displays, heads up..."

Would that be the cue to start UAS protocol? Certainly. So Bonin was informed at the outset of the 'beginning' of UAS? At least its possibility?

Now, since H. Spinkleman has stated the controls' limits are locked at the beginning of such interrogation, may we assume the THS stopped trimming shortly after? It is shown, FDR, the THS remains at 3.5 degrees until just at apogee? Bonin knew this of course, he was without trim to PITCH.

Another has said, essentially, that all control surfaces were acounted for until late in the game. I differ, here. Since the ailerons reporting is accomplished by its actuator, the aileron 'need not be present' to be accounted for? Similarly, an elevator is in the same situation? Is there a tickle conductor to the Trailing edge, so, if its continuity is interrupted by surface separation, it is known in the cockpit/ACARS? I have not heard of one.

The "Aircraft handled in predicted response per the FDR". That's nice, but it does not account for all controls' surfaces to the strictest extent. The recovered spoiler separated at its attach to its actuator; the recovered elevator, at its hinge line. It is acknowledged that to entertain control surface separation may be difficult, even fearful, but thus far, we have BEA saying that the a/c impacted "......complete". They did not say "Completely intact, whole".
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Old 14th Mar 2012, 15:29
  #180 (permalink)  
 
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Lyman, I know lawyers speak the way you speak all the time, but would you mind writing in simple un-convoluted English for a change. It might help present your points more clearly. Choose simple words instead of the $5.00 words please.
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