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AF447

Old 22nd Jun 2009, 01:17
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qantas / PHC fault

from the preliminary report on qantas 72 flight:

Based on an examination of the FDR data, the aircraft manufacturer recommended removing ADIRU 1 and the number-1 probe heat computer (PHC)21 before conducting any data downloads or testing of the aircraft’s systems.
21 A PHC fault was recorded on an initial download of maintenance data. On further analysis of the available information, this indicated fault was considered spurious.
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Old 22nd Jun 2009, 02:28
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"Probe heat computer
Some of the PFR messages indicated a potential fault with the number-1 probe heat computer (PHC). Those messages could be generated by either a PHC fault or by an ADIRU fault. The PHC (serial number 2083) was tested by an authorised agency and no fault was found. Based on a review of available information, the messages related to the PHC were considered to be spurious."

http://www.atsb.gov.au/publications/...70_interim.pdf
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Old 22nd Jun 2009, 03:29
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quaeler;
AFAIK, the "middle" overhead bin structure is mounted in all cabins, J through Y, "5 through 42" so we don't know which cabin it's from, from the photographs. Seat/row numbers are on the structure just below the bins (in the small lights that extinguish when the cabin doors are all closed in the installation I'm familiar with). That piece of wreckage on board ship, is by the galley bins (O2 masks etc), separated from the overhead bins so we don't know if they are associated.

I understand that the search for pieces etc is being wound down so we won't likely see much more than what we have already. I understand that the underwater search continues.

ELAC - absolutely superb summary of the nature of assessing, and of assesed, evidence.
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Old 22nd Jun 2009, 05:44
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Thank you SaturnV for the posting and comments.

I first did not take into account the findings of the Brazilian SAR before they recovered AF 447's first body and wreckage because this sequence of events was badly documented and I could not rely on clear reports. Too many contradictory news were published about the first findings. So, my presentation was only based on post 06 June facts without taking into account anything before.

But now that you are showing us the 06-06-2009 reports of Brazilian SAR,
a much closer look at the 02 June Brazilian researches become obvious if we are taking into account where the crash location could be roughly infered by the 06-10 June surface sea drift.

Here is the picture again without SAR zones of 02 June:



The three items discovered were:
1. Poltrona = seat
2. Pedaços de metal = piece of metal
3. Mancha de combustível = strain of gazoline

They were spotted from the sky and, as no ship was close enough, they could not be recovered. Then, the following days, the bad weather made the SAR difficult and this specific stuff could not be located again. Other 'wreckage' was spotted and identified as sea garbage (orange buoy, fuel traces, wood palet, etc) but we can see also that it was far away from this place on the other pictures. I remember well the contradictory declarations from the authorities about the first findings, some were positive (I guess the spotting crew), and others doubted about it because nothing was recovered (specifically the blue seat). So, maybe this air crew was mocked for no reasons as this map is showing now:



An estimation of the coordinates based on sea relief for those three items give:
- seat (2.077, -29.800)
- metal piece (1.895, -30.080)
- gazoline (1.745, -30.035)

I picked the seat:
a) this is the best described item unlikely to be something else if spoted from a recon aircraft. Beside, there was several 'fuel strain' and 'piece of metal' spoted in several other places which were not from AF 447.
b) If other items would belong to AF 447, their specifics won't match very well the drift of the bodies.
c) An aircraft seat will match pretty close a body in water as it will be nearly fully submerged and won't be affected that much by the winds.

The distance from d06 to the seat is 180 km. As an approximation, (no spotting hour is available) four days between the spotting and d06 recovery which make an average 0.52 m/s drift. This is in the range of possible following the SHOM tables:

This map is showing a slice of the drift at 30.5W 2.5N to 30.5W 3.5N on 04-06-2009 from 1.000 meters deep to the surface (vert. axis) and the distance in km is on the horizontal axis. It is a slice of the sea at this point in the red circle shown on the second map. This one is maping the surface drift. As we can see, the 'surface' drift is fairly deep, it is not only a few meters deep layer.



Using the same method as before, it is now possible to roughly estimate a new possible crash zone 24NM farther (24 hrs @ 0.52 m/s). The heading will be @ 336 to d06.
- second hypothesis crash zone coordinates (1.708, -29.630)



Now, adding a new course (yellow) from S. Peter Rocks crossing the crash zone, it bring us directly to the 0214Z flightplan spot. I didn't change the U-turn as nobody knows actually what was the real course after 0210Z and the turn back could have started from this point or later, so its shape is fairly unknow and all this above is purely hypothetical, only based on the wreckage spots, and not on what happened really on board. It would be too early to speculate with the little information we have.

A general view of the wreckage is more telling and of course, the drift is vectorized as the flow may be much more turbulent in reality than pictured by this:



I'll answer other questions later about the bodies sinking or not. Beside, sorry for the typos and grammar (I need to add a 'h' to hypothesis and 't' to spotted on my maps!) due to my poor English skills.

S~
Olivier

Last edited by takata; 22nd Jun 2009 at 06:03.
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Old 22nd Jun 2009, 05:47
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Remains identified

"Officials in Brazil have identified the first 11 of 50 bodies recovered from the Air France disaster in which 228 people died three weeks ago."

Full story at:

BBC NEWS | Americas | Atlantic crash bodies identified
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Old 22nd Jun 2009, 05:49
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quaeler

It's not from the middle of the cabin, I admit, but they do have part of the crew rest container, which is located just aft of the wing centre section.
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Old 22nd Jun 2009, 06:25
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PHC/Pitots

"Probe heat computer
Some of the PFR messages indicated a potential fault with the number-1 probe heat computer (PHC). Those messages could be generated by either a PHC fault or by an ADIRU fault. The PHC (serial number 2083) was tested by an authorised agency and no fault was found. Based on a review of available information, the messages related to the PHC were considered to be spurious."
Is there any relationship between those messages and anything regarding pitot malfunctions ? Does it prove that pitots status is INDIRECTLY verified by ADR data ?
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Old 22nd Jun 2009, 06:26
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The light blue/azure colour in tataka's current map also shows the thermocline.

The deepest part is about 600 feet and the shallower at about 350. Whilst the thermocline marks the difference between temperature profile is is also almost a 'hard' surface for buoyant objects. It is also the layer most affected by wind and wave action. Below that things remain faily constant.

IIRC sink rates for heavy objects would be about 40 seconds per thousand feet so for 10k feet it would take some 6-7 minutes. There would be sub-surface drift but it would be insignficant for an object sinking to the bottom.
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Old 22nd Jun 2009, 06:55
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Has there been any news yes on the recovary of the two "Black Boxes"

It's all gone very quiet from a news piont of view.
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Old 22nd Jun 2009, 08:08
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Drift plots posted by Takata 06.44 Monday 22 June

I seem to recall that a freighter picked up a spoiler about 45 km NW of StPeter & St Pauls. This matches Takatas latest Hypothesis but doesnt show on his plot.
It also seems to support a more consistent and constant rate of drift from the discovery point of the first most southerly items

(The report came on PPrune after the VS was first picked up, but I havent been find it . There is a post #1325 June 13 which has a pic of freighter and spoiler, but I cant find any seperate report text now,)

Last edited by wilyflier; 22nd Jun 2009 at 09:02.
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Old 22nd Jun 2009, 09:39
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Now it's quietened down I must observe that the contribution of takata seems to be pulling it all together. My only obsevation is that the tragectory he shows surely involves enough time for a life jacket request from the crew and there seems no evidence of their use yet. It also does not prove that the aircraft was under the control of the crew if it 'flew' this direction. Can I ask if the fact that the recovered bodies were intact indicates that they did not have seat belts fastened?
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Old 22nd Jun 2009, 09:48
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Olivier / Takata

You bear all the signs of an Airbus insider and since you seem to know what you're talking about I'd like to know how many incidents DIRECTLY related to the probes happened with other A330 operators.
Surely, it can't be a FRENCH curse, can it ? What are the, let's say 20 AF A330 compared to the rest of the world's fleet ?

One thing I can tell about Airbus is that in a way it sucks !!
I flew the 320 for 4 years, really enjoying it but totally unaware of the consequences of pitot problems. Yet, that's where it all started, on the 320 fleet.

I'm now on the 777 and I can tell you it is a very comforting thought to know the Primary flight computer switch off button is right above my head. A flick of a switch and I fly a " basic " airplane again.
This probably saved Malaysian over Australia in 2005 and could have allowed Qantas 072 their second dive.
Do you think Airbus would / will come up with such a feature ??? That would imply tons of humility, quality they've proved to be rather short of.
On the Airbus, you have to cope with whatever the aircraft decides to give you. That sucks big time.
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Old 22nd Jun 2009, 10:07
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Me Myself

Just for my understanding, what is that "basic airplane" you're getting? I thought you would still be using the control column to provide inputs to the fly-by-wire computers. I didn't think the 777 had direct mechanical linkages to all control surfaces.
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Old 22nd Jun 2009, 10:18
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Takata's analysis is very thorough and looks conclusive.

However, being a skipper on the A330 myself, I have some doubts for operational reasons:
  • deciding to leave the track for a turnback is a serious matter and would be coordinated, if ever possible, with ATC.
  • If unable due to urgency or no contact, broadcasting the intention on 121.5 is certainly a high priority.
  • Assuming, the reason was for a crippled aircraft: VHF #1 is connected to the DC-essential bus and available in ELECTRICAL EMERGENCY CONFIG. Assuming there was no complete electrical loss at the time of a turnback-decision (which would render a turnback almost impossible because of flight in MECHANICAL BACKUP), another aircraft should have catched such a transmission.

I would also like to hint to funfly's conclusion with no signs of an ongoing preparation for an emergency in the cabin (e.g. deployed lifevests)

Thomas

Last edited by RealQuax; 22nd Jun 2009 at 11:32.
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Old 22nd Jun 2009, 10:56
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currents

There seems to have been a drifting buoy dumped into the crash area on 2009-Jun-15 1719. The area where it has been dumped seems to be more or less the same area that was identified by takata.

Ship Status Report: callsign 31998

Even though in the screen shot the track history is stated as 530 hours the track history actually begins on the above date. You can verify that by dumping the complete track history on the website. The depicted track represents 7 days worth of drift.

The orange triangles representing the last known position and TASIL where inserted by me.
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Old 22nd Jun 2009, 11:10
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Not facts just conjecture and a few questions....
Reclaimed bodies intact - no seatbelts?
No lifejackets - no time or no announcement?
Not many found - most remain within fuselage at time of impact?
Bodies found were generally unclothed - does this indicate leaving the aircraft at altitude or does it deny this?
Few pieces on the surface - Would an object the size and construction of the aircraft hit the surface at very high speed and not disintegrate.
Add to this the condition of the gallery component (it doesn't have the apearance of something that dropped a few thousand feet) and it is difficult to escape the feeling that the aircraft broke apart relatively near the surface of the sea and at a relatively low airspeed.
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Old 22nd Jun 2009, 11:16
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Fuel tanks & fuel?

ttcse:

Your remark about the fuel tanks just made me notice something peculiar....very early in the search for this plane, some wooden pallets and an oil slick were located, but these were quickly determined to be not from the plane but likely dumped (illegally?) from passing cargo ships.

So, does this mean that no trace of a fuel spill from the aircraft itself has been found? This plane was in the early portion of a long transatlantic flight, so surely it was carrying a significant fuel load. Yet (correct me if I'm wrong) I'm not aware of any reported sighting of a fuel slick from the plane along with the wreckage.

A question to anyone out there in the know: Could jet fuel dissipate so quickly in the ocean to have already disappeared?
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Old 22nd Jun 2009, 11:20
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Originally Posted by funfly
Can I ask if the fact that the recovered bodies were intact indicates that they did not have seat belts fastened?
This was answered in some detail earlier on in this thread. I believe it stated that injuries were indicative of seated passengers strapped in to their seats.

I would speculate that some at least those that had their seat belts fastened had them fastened on a relaxed manner as you might when trying to sleep. Others may have had them fastened more securely and this might account for the proportion of bodies recovered.

If that is true then it would acocunt for the lack of life vests.

Edited to accept harry mann's point about severe turbulence.

It is conceivable that although the seat belt light may have illumiated the FAs were in the process of waking passengers to ensure that seat belts were properly fastened. If they had not completed their checks it would account for FAs not being strapped in, for some passengers not being strapped in and for some to have slack seat belts.

One expects that there may or may not be evidence of seat belt injuries to supprt these possibilities.

Last edited by Wader2; 22nd Jun 2009 at 13:08.
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Old 22nd Jun 2009, 11:33
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Originally Posted by Orestes
Could jet fuel dissipate so quickly in the ocean to have already disappeared?
Yes.

You will recall that the early search period was hampered by bad weather. aviation fuel is considerably lighter and more volatile than furnace fuel oil or bunker oil from a ship. It would be dispersed quite quickly in heavy seas.

It is also conceivable that fuel in unruptured tanks would not be released and could still be trapped in the tanks at depth. Even if later released at depth it is unlikely to be visible on the surface.
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Old 22nd Jun 2009, 12:46
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Reclaimed bodies intact - no seatbelts?
Irrespective of speculation on mode of ejection, injuries etc.... it would be expected to a high probability that most/all would be seat-belted in 'strong turbulence', as reported shortly before.

We await details of whether many were FA's and where they all were seated, to draw any really valid conclusions?
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