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AF 447 Search to resume

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AF 447 Search to resume

Old 23rd Apr 2011, 16:37
  #3861 (permalink)  
 
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there are at least two reliable, solid indications that the guys up front were active right in the middle of the ACARS message stream, that is between 0210 and 0214.
True. But if (and I say if) they were less than fully awake prior to upset, then they sure would have woke up with the upset. So you would expect some evidence of pilot activity post-upset - irrespective of what they were doing prior to upset.

So I agree with you. However to me this does not shed any light on what was happening immediately prior to upset.

It is hard to escape the conclusion that these guys were caught out somehow. Despite a significant weather system in their path. And despite (I presume) a degree of radio traffic that other aircraft were diverging from their track.

I don't have an ax to grind. I really don't. I am merely trying to keep an open mind and consider all the facts.
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Old 23rd Apr 2011, 16:47
  #3862 (permalink)  
bearfoil
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slats11

From the lack of sparks, I for one can see you are not grinding an axe.

Isn't UAS sufficient explanation for "caught out" ?? There is ample precedent, the conditions were prime for a disastrous bout of "catch up" after loss of airdata, etc.?? Sleep occupies a distant position, imho. Here are seasoned professionals, familiar, flying a first rate ship for a Flag carrier. It was not mundane, whatever it was, notwithstanding msr. Gourgeon's accusations of "Lack of good fortune with the Radars."
 
Old 23rd Apr 2011, 17:10
  #3863 (permalink)  
 
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A/P ON

Gentlemen,

it is obviously difficult for most internet-age people to read beyond a few lines of text with any effectiveness. Please sweat a little with me.

Autopilot was turned back ON by 02:13 as attested by a late maintenance message where AutoFlight System (the Autopilot) detected a fault in FMGEC1.

A/P cannot be reengaged in the middle of an upset.

Which means no upset before that time 0213Z.

The UAS was apparently over by then, at least for the pilots, but perhaps not for the system. Remember the Airworthiness Directive regarding A/P reengagement after an UAS : "Unsafe Condition", "unwanted pitch commands"... It cannot be clearer than that, short of an outright confession.

And how caught up would anyone be, right after reengaging the A/P after a 3 minute nasty bout of night-time UAS live training in the ITCZ, if the aircraft suddenly went pitch-wild ?

Think More...
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Old 23rd Apr 2011, 17:23
  #3864 (permalink)  
bearfoil
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An early poster, will fraser, opined very early that it was auto flight that upset the a/c, he took much grief, poor fella.
 
Old 23rd Apr 2011, 18:21
  #3865 (permalink)  
 
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I was confused before but now............A few pages back there was lots of discussion about whether the pilots were awake at 2:00, now they have dealt with some sort of upset pt1 by 2:13. How is it this AFS message is being discussed for the first time at this late stage ?
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Old 23rd Apr 2011, 18:28
  #3866 (permalink)  
 
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bearfoil

An early poster, will fraser, opined very early that it was auto flight that upset the a/c, he took much grief, poor fella.
Funny you should remember that
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Old 23rd Apr 2011, 18:28
  #3867 (permalink)  
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So ACARS is transmitted by either of two antennas (systems). One in the VS, one the Satcom, on the dorsal Fuselage, flush. Did all Tx (ACARS) arrivee via FIN?? Or was the last one, the Cabin Speed, tx by the Fuselage, after the famous gap in ACARS, the loss of the Fin causing the Bus to switch to SATCOM?? If so, that explains the gap in tx, and would explain the possible loss of the Fin at altitude, coinciding with a depressurization, a hull rupture, and the possible loss of some cabin contents, explaining the lack of damage to the Galley structure, when the recovered cabin liner right next to it was utterly destroyed.

Trajectory?? if some bits were lost prior to impact, that would explain a disparate debris field of surface items, and a concentration of heavier debris. There were two debris fields, one containing everything that impacted at the as yet unknown impact zone, and the rest, the discovered things, spread due currents and wind. Where was the VS by interpolation relative to the field on the bottom??

The dramatic differences in damage evident on discovery suggests a trajectory of at least two descriptions.

lomapaseo.
 
Old 23rd Apr 2011, 18:31
  #3868 (permalink)  
 
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Engine Monitoring

bearfoil & BOAC

Like Rolls Royce, GE has a real time engine monitoring program called "On Point." The CF6-80E engines on AF447 were being monitored with data being fed to both GE & AF. As the BEA Interim Report states:
The engines were subject to real-time monitoring in the framework of the engine condition monitoring program. Examination of the data recorded, including the data transmitted on the day of the accident, shows that both engines were functioning normally.
This data is another part of the mosaic. I would suspect the BEA has more relevant data from this source beyond their disclosed comment. For example, they may know the power settings at the time of the incident, how they may have changed by input from the A/P or pilots and exactly when the settings changed. They probably have overlaid this data overtop of the ACARS to gain insight as to what was happening and when.
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Old 23rd Apr 2011, 18:40
  #3869 (permalink)  
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TurbineD

BEA know a vast amount that is not disclosed. The engines would be a virtual second by second log of the events right up to loss of antenna, no?? BPR (a/c attitude), vibration (airloads). What do you think could be known other than "The engines were functioning" ??
 
Old 23rd Apr 2011, 18:42
  #3870 (permalink)  
 
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bizman, in the case in front of us or anything similar there is not much that would have gotten searching started much sooner. The area was enveloped in a heavy storm. And that's very likely one of the conditions necessary to have made this plane fall out of the sky.

It is also probably coincidence that the plane dropped out of the air with as many ACARS messages as we see. And there seems to be nothing in the ACARS messages to prompt a person to assume the plane hit the surface except the cryptic cabin pressure message. You'd have to have some VERY expensive software involved to get maybe a 20% to 40% detection ratio. You'd have to have a very well trained and analytically minded person sitting feeling his brain ooze out from between his ears from boredom scanning the incoming ACARS messages and trying to guess which one means plane prematurely contacted horizontal surface. (You don't have enough money to get me to do that more than one day. An airline might be able to find enough money to pay me for maybe three weeks. (It would be broke afterwards.) I might do it for four weeks if I came out of it as unquestioned dictator for the entire world. So I don't see it happening.)

There is a practicality gap here. There is an effectiveness gap here. There is a huge cost benefit gap here.
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Old 23rd Apr 2011, 18:46
  #3871 (permalink)  
 
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Confusion

Mr Optimistic wrote :

I was confused before but now............A few pages back there was lots of discussion about whether the pilots were awake at 2:00, now they have dealt with some sort of upset pt1 by 2:13. How is it this AFS message is being discussed for the first time at this late stage ?
Why ? Because people who want to know without access to all necessary, proprietary, well-hidden documents, with a job to do besides, against all "obvious" theorizing, will need time to think through a paradoxical and heavily interest-loaded issue.
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Old 23rd Apr 2011, 18:47
  #3872 (permalink)  
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Mr. Optimiistic

This is not the first time that the pilots' actions have been discussed. FPV, Flight Path Visualization, was selected well into ACARS, an act that requires volition of a conscious and attentive pilot. My guess at the time was to suggest that in addition to flying Pitch and Power due to loss of Pitch cueing, the Pilot Flying wanted the "bird", an object on the screen that can cue flight data in real time. At the time, there was argument whether there should should even be back up Attitude display, even with known episodes of UAS.
 
Old 23rd Apr 2011, 18:52
  #3873 (permalink)  
 
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NoD
"Ummm, have you ever used HF? It's hard to enough to talk over, passing data I would think impossible. Just listen to the bandwidth of SELCAL for data transfer - maybe 1 or 2 chs /sec AFAIK ACARS works over VHF (los) or Satcom (when VHF unavailable)."


HF ACARS is possible, works, and is still in use, I just received this message.

[MPDU 17:41:04 AIR CO1495 SLOT 4 300 BPS ]
Nr LPDUs = 1 Ground station ID SAN FRANCISCO - CALIFORNIA NOT SYNCHED
Aircraft ID AC
Slots Requested medium = 0 Low = 0
Max Bit rate 600 bps U(R) = 0 UR(R)vect = 0
[LPDU UNNUMBERED DATA FM AIR CO1495 TO GND]
[HFNPDU PERFORMANCE]
17:41:02 UTC Flight ID = CO1495 LAT 33 58 59 N LON 117 55 27 W
Performance version 138
Flight Leg 76
GS SAN FRANCISCO - CALIFORNIA


While ACARS is effective the tracking functions might be better served by a version of ADS-B Automatic dependent surveillance-broadcast - Wikipedia, the free encyclopedia which brings as a side effect such sites as http://www.flightradar24.com/

I was hoping some of the pilots here could comment on how/when HF ACARS is used as at least in my area it seems a minority of planes use it.
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Old 23rd Apr 2011, 18:55
  #3874 (permalink)  
 
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Gringobr, are we ready for this, yet?

One thing that comes out of the AF447 ACARS messages suggests that planes at least of the A330-200 vintage are absolutely not ready without a total electronics refit and some really exciting new developments. And even then it would not be guaranteed to be ready.

The one event is the involuntary handover from autopilot to meatpilot when the going got rough and airspeed went unknown. This is an especially poignant detail considering Thales is one of the sponsors of the cited initiative and their probes were the ones that delivered bad data for whatever reason.

That means the autopilot system would have to be made over dramatically. Or we'd have to accept much higher levels of fatal failures of flight hardware.

One exciting development in this regard is the Rockwell Collins work on recoverable flight control. They demonstrated it on a model aircraft by setting off a charge that broke an entire wing off the model. It performed the expected spiral dive and then managed to recover stable flight. I temper my enthusiasm because it was a model not a real aircraft. Models are in the "with enough power I can fly a brick" regime. They have the power to weight ratio to fly things as unaerodynamic as lawnmowers.

Thales - really? No thanks.
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Old 23rd Apr 2011, 19:00
  #3875 (permalink)  
 
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BOAC, my memory insists that in the case of AF447 the nominal captain was not necessarily the most experienced member of the cockpit crew. Does this change your assessment?
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Old 23rd Apr 2011, 19:05
  #3876 (permalink)  
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JD-EE

With respect, it now appears that the erm.... "Meatpilot" recovered the a/c from UAS, and in reselecting a/p, it was the a/p that may have destroyed the aircraft. Perhaps it needs a "refit" of broader description than you indicate.
 
Old 23rd Apr 2011, 19:20
  #3877 (permalink)  
 
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Nigel, there is a mode of communications used by ham radio operators that sends a puny 31.5 bits per second of data. You can fit 25 to 50 of them into one HF speech frequency allocation. And you can drag out 100% copy from signals you cannot hear with your ears in a normal SSB radio. (I have used it in the past to communicate with places like South Africa, Chile, and Europe from Southern California well after the 14 MHz ham band was close tighter than a drum for most other modes of communications.) I'd not worry about "too slow" as 63 bits per second and 128 bits per second variants exist. The latter would cut you down to 6 to 12 sub-channels per channel. An unencoded ACARS message would go through several times in 10 seconds or so on one subchannel. If planes are assigned "time slots" accommodating large numbers of planes would not be hard.

Now, to what benefit. It's not going to STOP a crash. It only tells you within 80 miles or so where the plane stopped transmitting. That's a LARGE area to search. So you've not bought much even for the postmortem search effort. And if the search area is socked in, as in this case, you still must patiently wait until you can get calm enough water that mostly submerged objects stand out to you when searching a thousand square miles or so.

(And the first time a massive search effort is triggered by a part in an ACARS radio gasping its last breath and shutting the radio down at the same time DAKAR is being derelict, again, the whole thing will be shut down.)

It might be more salubrious to lean on outfits like DAKAR and to a lesser extent ATLANTICO to invest a few more brain cells in their day to day operations.
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Old 23rd Apr 2011, 19:21
  #3878 (permalink)  
 
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Thanks Svarin: at least I read all the text

So let me get this straight: the pilots are awake and paying attention in the period 2:01 to 2:10. The air speed data becomes unreliable, the a/p and auto throttles kick out the crew manage the aircraft and get to a state were re-engagement of the a/p is a possibility in their minds, they then re-engage it, the system coughs up a fault message but even after the exciting preceding episode, they allow the air speed data and automatics betray them again ?
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Old 23rd Apr 2011, 19:24
  #3879 (permalink)  
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Originally Posted by JD
Does this change your assessment?
- no. It is his ship (no sick humour intended).
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Old 23rd Apr 2011, 19:26
  #3880 (permalink)  
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Mr.O

Well, it looks that way, but Airbus pilots are proud and dependent upon an almost universally safe a/c in the A330. It would not be unusual to defer to a/p once things had gotten 'safe' again.

Per the AD, and Savarin, when re-selected after UAS the a/p is known to command extraneous and dangerous Pitch excursions. Likely in this case to have instigated an unrecoverable upset, via Stall, overspeed, or Roll +.

sorry for barging in, I think Svarin has left the building,
 

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