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AF447 final crew conversation - Thread No. 1

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AF447 final crew conversation - Thread No. 1

Old 3rd Jan 2012, 19:42
  #1041 (permalink)  
 
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Be careful of SPA83. You asked for established facts. He's offering you a fair dose of opinion. I didn't say biased, you make up your own mind.
Yes, I'm not looking for anyone's own research or opinions, as I'm working on a Wikipedia-article. The absolute truth is not the aim, but anything stated need to be verifiable. So, prefer to write less and accurate, basically anything originating from official or otherwise trustworthy sources.
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Old 3rd Jan 2012, 19:54
  #1042 (permalink)  
 
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Caygill

This is official:

http://www.bea.aero/docspa/2009/f-cp...90601e3.en.pdf
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Old 3rd Jan 2012, 22:33
  #1043 (permalink)  
 
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Originally Posted by HN39
What would the FD command have been between 2:10:47 and 2:11:38?
According to the SELECTED VERTICAL SPEED trace on page 111, FD command was for a 1000 feet/min climb.
For that time period the actual V/S has fluctuated between +3000 and -8000 ft/min ... the horizontal FD bar has shown some push commands as well as pull ones.

When FD 1 and 2 disappeared, the airplane was passing through FL350 in descent ... so maybe the PF, and also PNF for an instant, were trying to not let go the initial assigned flight level with a full nose up command ... ?

Last edited by CONF iture; 4th Jan 2012 at 02:17.
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Old 4th Jan 2012, 05:42
  #1044 (permalink)  
 
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FD command was for a 1000 feet/min climb.
Wouldn't that depend on the selected AP/FD vertical mode?
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Old 4th Jan 2012, 07:31
  #1045 (permalink)  
 
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Maybe not completely fitting here but there are two facts I am astonished at by the plane and its performance:
Throughout the ordeal it remained stable to a certain extent, just some rolling oscillations that were possible to correct by either the pilot or A/P.
In my opinion this is the result of new building techniques.
Older built planes never had wings that were absolutely identical, there was just too much spread in machining techniques. So they ended up with different lifting values, and most likely also weight differences.
That would have meant the plane will drop a wing and enter a spin when flown like this. MAYBE the crew would then had been able to get it out of its death track, given enough altitude.

That does not mean I am advocating to build wings a-symmetrical....
But it is like our new navigation/airdata systems, You can have a head on between 30 and 40W with planes flying opposite tracks at the same altitude. Something just shy of impossible in the old days.

The other unbelievable performance was of the engines and cowling design.
Delivering full power in thin air at flow angles of over 60 degrees is just mind boggling. No engine manufacturer or test pilot would have envisaged the engine would not stall. Older designs certainly would have stalled, thus forcing the nose down.

When still in my flying days I was cautious in selecting full power during a crosswind T/O. (OK, a sideways flow is possibly less favourable as one coming directly from below, plus the fuse blanking the wind).
But obviously modern engines are less vulnerable to off optimum airflows as we have thought they were.....

Anyway, when reading the whole story I am reluctant to say that I would have acted different as a captain, I would also not have realised, expected nor seen that the PF was giving full aft stick all the time.

I am happy to have reached my retirement age without any issue hitting the headlines... I can only recommend everyone to try this too.....
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Old 4th Jan 2012, 08:12
  #1046 (permalink)  
 
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@HN39:

FDR trace (page 107 BEA Interim #3) shows HDG/VS selected all the time,
or is this a wrong conclusion?


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Old 4th Jan 2012, 09:26
  #1047 (permalink)  
 
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AB33Zab,

I must admit I know nothing about the AP/FD functioning and am just trying to understand. The FCU vertical control area has an altitude window and a VS / FPA window. The pushbutton toggles the latter window between V/S and FPA. My understanding is that the FD guides toward the selected altitude or the selected VS/FPA, depending on the active AP/FD vertical mode, which in cruise (I think) would normally be "ALT CRZ", unless "V/S or FPA" was specifically selected. Am I wrong?

Last edited by HazelNuts39; 4th Jan 2012 at 09:42.
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Old 4th Jan 2012, 10:41
  #1048 (permalink)  
 
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Double Back

"Older built planes never had wings that were absolutely identical, there was just too much spread in machining techniques. So they ended up with different lifting values"

You also could have mentioned that the Airbus fly-by-wire planes, by eliminating flying control cables and pulleys, also eliminate the need for rigging. Within reasonable limits, the fbw doesn't care about small left-right build differences.

Last edited by kwateow; 4th Jan 2012 at 15:41.
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Old 4th Jan 2012, 12:58
  #1049 (permalink)  
 
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Vertical Tailplane Separation?

If this has already been reviewed, forgive me.

Is there the remotest possibility that the vertical tailplane separated due to an inappropriate full rudder input, while at FL350? (I believe the fin was recovered some distance from the site where the fuselage and wings lay).

This could account for the unusual oscillations and strange handling of the damaged aircraft. I have no idea whether the rudder inputs and outcomes were analysed on the FDR.

This is not a pet hypothesis, obviously, more a thought. Has this possibility been examined?
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Old 4th Jan 2012, 13:11
  #1050 (permalink)  
 
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Bloggs, you are not forgiven

Please do the bare minimum of research before posting.

This has been raised in dozens of posts, and the answer is NO, NO and NO.

It was attached when the plane hit the water.

P.S. the "strange handling" of the aircraft was done by the pilots. Before that the plane was fully flyable, if they could work out how.
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Old 4th Jan 2012, 13:24
  #1051 (permalink)  
 
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HN39:

Since the FD pushbuttons were not selected OFF, each time valid ADR data was recovered, the FD's would have reappeared, and the FD vertical mode at recovery would have defaulted to V/S and the FD vertical command cue would have commanded the vertical speed existing at that time. This V/S would also be displayed in the FCU window, just as if selected.

Deselection of the FD avoids this.
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Old 4th Jan 2012, 14:27
  #1052 (permalink)  
 
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Bird

ventus45,
Traces on page 107 and 108 do NOT show any bird selection.
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Old 4th Jan 2012, 14:29
  #1053 (permalink)  
 
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Originally Posted by OK465 View Post
Since the FD pushbuttons were not selected OFF, each time valid ADR data was recovered, the FD's would have reappeared...
Are you sure about that?

I'm not familiar enough with the FCS mode switching logic on the A330, but I would have expected the FD ENGAGED state to disappear (unlatch) on the occurrence of an ADR F/W - same as the AP 'dropping out' - and a 'new' push on the FD pushbuttton(s) to be required to re-engage the FD(s) and return the FD bars into view. *)

Also, since it appears not to be advisable to re-engage the AP too soon, I would have thought the same would have applied to the FD.... after all, AP and FD are mostly the same system, with the pilot in the 'control loop' in the case of the FD.

*) In "my" days, AP, FD, etc., were engaged by means of magnetically held levers, which indeed literally dropped in case of a fault (with a loud 'clack' added to the symphony orchestra from the CWS). So a positive action was required to re-engage them.
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Old 4th Jan 2012, 14:53
  #1054 (permalink)  
 
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Originally Posted by Ventus45
The aircraft turned slowly right 270 degrees during the event.
The turn started some 20 secs after the airplane stalled.
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Old 4th Jan 2012, 15:11
  #1055 (permalink)  
 
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@HN39:

I lack in depth knowledge too, but it's in the transcript pages:

2 h 10 min 08 The FD 1 and 2 become unavailable.

2 h 10 min 17 The FD 1 and 2 become available again; the active modes are HDG/ALT CRZ*.
The selected heading is 37°.
2 h 10 min 21 The FD 1 and 2 become unavailable.

2 h 10 min 26 The FD 1 and 2 become available again (HDG and V/S modes).
The vertical speed reached the maximum value of 6,900 ft/min.
2 h 10 min 36 The FD 1 and 2 are unavailable.

2 h 10 min 42 The FD 1 and 2 become transitionally available (HDG/VS modes).
The selected heading is 36°.
The vertical speed is 1,900 ft/min and the vertical speed selected is 1,300 ft/min.

2 h 10 min 47 The FD 1 and 2 become available again (modes HDG/ VS).
The selected heading is 34°.
The vertical speed is 1,500 ft/min.
2 h 11 min 40 The FD 1 and 2 become unavailable.

2 h 12 min 52 The FD 1 and 2 become available again (HDG V/S modes).
The selected vertical speed is -6,000 ft/min.
The selected heading is 197°.
2 h 12 min 58 The FD 1 and 2 become unavailable again.

2 h 13 min 57 The FD 1 and 2 become temporarily available again.
The selected vertical speed is 1900 ft/min.
The selected heading is 280°.

Last edited by A33Zab; 4th Jan 2012 at 15:50.
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Old 4th Jan 2012, 15:45
  #1056 (permalink)  
 
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A33Zab

Which is confusing, but only if AF abnormal procedures for Unreliable Airspeed are not followed (FD 1 and 2 ..... OFF)

Last edited by kwateow; 4th Jan 2012 at 15:56.
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Old 4th Jan 2012, 15:46
  #1057 (permalink)  
 
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@Conf:

Traces on page 107 and 108 do NOT show any bird selection.
I had the same conclusion:
FDR trace (page 107 BEA Interim #3) shows HDG/VS selected all the time,
or is this a wrong conclusion?

however:

BEA Interim #3 - 1.16.6.3 Page 47.

The presence of the “FLAG FPV ON PFD CAPT (F/O)” message indicates that TRK-FPA
(Flight Mode Annunciator) mode was selected by the crew during minute 2 h 11, but that the
FPV was unavailable (see interim report 2 for details on the conditions of availability). Based
on a study of the other relevant parameters it may be concluded that the FPV was selected
between 2 h 11 min 48 and 2 h 11 min 54.

BEA Interim #2 - 1.16.2.4.1Page 35/36.
FLAG ON CAPT PFD FPV and FLAG ON F/O PFD FPV (2 h 11)
Symptoms:
Disappearance of the FPV (bird) on the PFDs, Captain and First Officer sides,
and display of the corresponding flag.
Meaning:
This message indicates that the flight path vector (FPV) function is selected but
unavailable. In order to lose completely this function, which is elaborated by
the three IRs, in a way that is compatible with the CFR, one of the following
three conditions must be met for each ADR:
barometric vertical speed higher, as an absolute value, than 20,000 ft/min,
true air speed higher than 599 kt,
measured calibrated airspeed lower than 60 kt.
Once the operating conditions are satisfied again, the FPVs reappear on the
PFD (if TRK/FPA mode is still selected).
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Old 4th Jan 2012, 17:11
  #1058 (permalink)  
 
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@kwateow:

Which is confusing, but only if AF abnormal procedures for Unreliable Airspeed are not followed (FD 1 and 2 ..... OFF)
The ECAM ADR CHECK PROC drill came only after 02:12:xx and at that time they were already in deep trouble.

When AP disconnected @ 02:10:05 the UAS (iced pitots) must have been lasted NOT longer dan 10 sec. otherwise this ADR ECAM Message would have been triggered.
(This ADR CHECK ECAM message has higher priority (116) above other present level 2 messages,
so would have been in view)

"If two ADR outputs are erroneous, but different, and the remaining ADR is correct, or if all three are erroneous, but different
The autopilot and the autothrust are disconnected by the FE (whichever autopilot is engaged).
If the disagree lasts for more than 10 seconds, the PRIM triggers the ADR DISAGREE ECAM
caution.
It reverts to Alternate 2 law (without high and low speed protection).
On both PFD, “SPD LIM” flag is shown, no VLS and no VSW is displayed.
This situation is latched, until a PRIM reset is performed on the ground without any hydraulic
pressure.

However, if the anomaly was only transient, the autopilot and the autothrust can be re-engaged when

the disagree has disappeared."

Last edited by Jetdriver; 4th Jan 2012 at 21:07.
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Old 4th Jan 2012, 17:50
  #1059 (permalink)  
 
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I think it's possible, even likely, that many pilots would deselect the FD's if they observed a blank black airspeed tape on the PFD, not necessarily only in response to a particular ECAM message.

And if they chose not to, they would, as a minimum, disregard any FD commands until things were sorted out and FMA modes were confirmed as those warranting use of the FD.

CJ: Yes. (I've flown those older type aircraft too. They are different. )

(BTW: V/S is the default restored initialization for the vertical mode, but if you're within capture parameters for the selected altitude, the mode may jump right to ALT* or ALT CRZ*.)
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Old 5th Jan 2012, 03:09
  #1060 (permalink)  
 
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A33Zab,
It then appears paragraph 1.16.6.3 on Page 47 and VS/FPA mode trace on Page 107-108 could be in better agreement ... ?
The AP/FD vertical mode trace is also dearly missing especially in regard to the nature of the selected vertical speed just before the event. What kind of internal conflict was already taking place ... ?
Haven't we heard very recently how spikes could trigger some very wild behavior ?
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