Discussion:
Air France 447 crash
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JF Mezei
2009-06-06 07:04:42 UTC
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Ok, not trying to speculate here, but it is human nature...

Has anyone found a reliable source of information on the exact nature of
the ACARS messages sent by the aircraft before/during the accident ?

I have heard a variety of speculation with regards to ice on pitots,
cabin depresssurisation, incoherent speed readings. I have heard that
the messages spanned a period of 3 minutes from one source, 4 minutes
from another.


I've looked at the french site
http://www.bea.aero (click on the "fr" button below the
letterhead/header to choose english).


as well as the brasilian site:
http://www.anac.gov.br/ (use google to translate from portugese to english)


But could not find any hard factual information.

It appears that there may be some credibility to the airspeed indicators
being dysfunctional as there is apparently some AD going out to pilots
telling them to disregard airspeed indicators if they go nuts. (wouldn't
that be part of basic pilot training ?)

However, getting the exact order and timing of those messages would be
important to get some educated guesses in (which the media seem so
incapable of doing). Having cabin pressure drop first before altitude
drops would be quite different from having cabin pressure drop at the
end, after the aircraft has floored the engines and pointed the nose
straight down and aircraft went supersonic before breaking up.


On a computer aircraft such as the 330, should the pitot cease to
provide good data during level flight under autopilot control, would the
computer go nuts and floor the trhottle to try to increase airspeed ?
Would it think there is a stall condition and immediatly point the nose
down to try to regain airspeed, and since airspeed would not go up,
would point nose down even more until the aircraft is going vertical?

Would an aircraft such as this 330 flighing a long ETOPS route be
equipped with GPS and whatever the equivalent of what used to be called
FANS-1 navigation ? Would the computer consider the ground speed given
by the GPS when checking for airspeed validity ?


Also, doesn't ACARS automatically include aircraft's position in its
reports ? Or are those omitted ? Seems to me that this should be made a
prerequisite.
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JF Mezei
2009-06-16 06:34:36 UTC
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Spoke with a recently retired pilot who had flown the 330/340.

If all 3 pitots fail, the computer realises the anomaly and won't take
any harsh actions. But he did said that this probablty never happened
before (that all 3 would fail at same time). Computer also has INS and
GPS to add to the information given by the pitots.

He said that aircraft always have enough fuel to avoid a line of
thunderstorms and there would be no excuse for pilots to knowingly enter
a thunderstorm.

Explosion can't be ruled out.

He was not sure whether the ACARS system is backed up by battery in the
cockpit (essential systems) or if it runs only on normal and/or RAT
power. (normally, power from engines or APU, then backup to RAT, then
backup to cockpit batteries for bare minimum).


The french BEA will hold a press conference this wednesday at Le
Bourget, so this ought to have plenty of press coverage.

And to show just how pervasive Google has become, they reconsitituted
the flight plan using Google Earth.

Loading Image...



The "International Business Times" reported that none of the 49 bodies
recovered so far showed signs of water in lungs, suggesting people died
before reaching water, leading to speculation place broke apart while at
altitude. Not sure how authoritative this news would be.

The brasilian military has now begun to use the term "mortal remains"
instead of "bodies" to denote body parts they are recovering.

The military's web site is at:
https://www.defesa.gov.br/ (their SSL certificate is invalid, you need
to accept it to get to their site).


The brasilian airforce seems to have more information:
http://www.fab.mil.br/portal/capa/index.php?page=voo447

There are some videos and photos including pictures of recovered debris.

There is part of a port bulkhead with the 2 FA seats that are "up".

There is one flap. It floats because it core is some sort of foam.


And good pictures of the tail fin which is in remarkably good shape
considering the rest of the recovered debris is rather small. The rudder
is still attached to it. The lower part of the rudder has some damage,
but the fin itself appears to have had a relatively clean separation
from the fuselage.

There is a picture of what appears to be a crew rest compartment. Would
this have been a container in the cargo hold ?
Loading Image...

There is a lavatory door in apparently good shape.



QUESTION:

Shouldn't FDR/CVR be installed in the tail ? Seems tails have a tendency
to survive crashes and float when there is a crash over ocean.
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JF Mezei
2009-06-20 02:28:51 UTC
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http://www.fab.mil.br/portal/capa/index.php?page=voo447

They have added a few more pictures.

Notably a galley partition complete with some of the meal containers

If you look at:
Loading Image...

I wonder if they can conclude that this galley fell from the sky (due to
the fact that the cavity where trolleys woudld be stored apepars to be
mostly dry) as opposed to having risen from a sunken wreck.

Normally, any object where flotation happens because of foam would not
rise from the depths because there, the foam will be compressed/crushed
by the water pressure and thus not give much bouyancy.


And a few tidbits from the Bureau des Enquêtes et d'Analyses (french NTSB):
http://www.bea.aero/fr/enquetes/vol.af.447/com17juin2009.php

or for english:

http://www.bea.aero/anglaise/actualite/actu.htm

BTW, when they say flight level 350, shouldn't that be flight level 35 ?


##
- The airplane was in cruise at flight level 350 (about 10,500 metres).

- No messages indicating problems were received on the air traffic
control radio frequencies.

- Close to the planned route of the airplane above the Atlantic there
were significant convective cells characteristic of the equatorial regions;

- The last position message from the airplane was broadcast by the ACARS
automatic system at 2 h 10 UTC.

- Between 2 h 10 and 2 h 14 UTC, 24 maintenance messages were
transmitted by the ACARS, including 14 between 2 h 10 and 2 h 11.

- Analysis of these messages shows inconsistencies between the various
speeds measured. Most of the messages appear to result from these
inconsistencies; they correspond to the loss of several flight
assistance systems.

##

Based on what I was told by the ex pilot, the above would seem logical:
subsystems would detect data input problems and put themselves offline
instead of taking action based on data known to be faulty.

I guess for legal reasons, they don't want to describe those
inconsistant speed readings. For instance, did the 3 pitots go wacko,
while GPS and Inertial; speeds were OK, or were they all OK ?

Or were instruments all showing same speeds, but aircraft was stuck in a
powerful storm where airspeed would go all over the place because of
very strong wind gusts that would, 1 sencond be with teh aircraft
(reducing airspeed) and the next second be against it (increa1sing
airspeed) ?
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JF Mezei
2009-06-23 08:44:51 UTC
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Le Monde reports this morning that the french submarine ahs located the
black box pingers. They will now work to get a small ROV to take a look
at the area.

This has not yet been confirmed.
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w***@googlemail.com
2009-07-01 14:53:49 UTC
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Post by JF Mezei
Le Monde reports this morning that the french submarine ahs located the
black box pingers. They will now work to get a small ROV to take a look
at the area.
This has not yet been confirmed.
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This could either have some real basis or it is
the legal vultures doing a bit of reality engineering:
http://www.timesonline.co.uk/tol/news/world/europe/article6612165.ece
http://timescorrespondents.typepad.com/charles_bremner/2009/07/fantasy-and-facts-over-airbus-disasters.html

statistics:
airbus-crash 6.5 million hits on google
boeing-crash 0.8 million hits ...

wid
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Roland Perry
2009-07-01 18:55:22 UTC
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In message
Post by w***@googlemail.com
airbus-crash 6.5 million hits on google
boeing-crash 0.8 million hits ...
That's because Airbus is the name of a plane, but Boeing is the name of
a manufacturer.

777 crash 1,620,000
767 crash 1,140,000
757 crash 1,060,000
747 crash 1,590,000
737 crash 1,490,000
727 crash 1,050,000

total 7.9 million hits.
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Roland Perry
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DevilsPGD
2009-07-02 18:59:02 UTC
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Post by Roland Perry
In message
Post by w***@googlemail.com
airbus-crash 6.5 million hits on google
boeing-crash 0.8 million hits ...
That's because Airbus is the name of a plane, but Boeing is the name of
a manufacturer.
Really? I thought that Airbus was a manufacturer. I wonder who makes
the A300/310 family, A320, A330/A340, etc?

I should look that up.
Post by Roland Perry
777 crash 1,620,000
767 crash 1,140,000
757 crash 1,060,000
747 crash 1,590,000
737 crash 1,490,000
727 crash 1,050,000
total 7.9 million hits.
If we're counting hits (which is a very silly way to do it), then

A300 crash 3,970,000
A330 crash 6,840,000

I trust your math skills are sufficient that I don't need to point out
that 3.9+6.8 is greater then 7.9, right?
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Roland Perry
2009-07-03 14:47:59 UTC
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Post by DevilsPGD
Post by Roland Perry
Post by w***@googlemail.com
airbus-crash 6.5 million hits on google
boeing-crash 0.8 million hits ...
That's because Airbus is the name of a plane, but Boeing is the name of
a manufacturer.
Really?
It's most popularly the name of a plane - as in "Easyjet has a fleet of
Airbuses".
Post by DevilsPGD
I thought that Airbus was a manufacturer.
The manufacturer is called "Airbus Industrie"
Post by DevilsPGD
Post by Roland Perry
777 crash 1,620,000
767 crash 1,140,000
757 crash 1,060,000
747 crash 1,590,000
737 crash 1,490,000
727 crash 1,050,000
total 7.9 million hits.
If we're counting hits (which is a very silly way to do it),
It seemed to start with someone saying:

#airbus-crash 6.5 million hits on google
#boeing-crash 0.8 million hits ...

I see that you agree with me that it was a silly way to try to prove
anything.
Post by DevilsPGD
then
A300 crash 3,970,000
A330 crash 6,840,000
I trust your math skills are sufficient that I don't need to point out
that 3.9+6.8 is greater then 7.9, right?
But silly, as you agree above.
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JF Mezei
2009-07-25 07:52:26 UTC
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Just a quick update.

The debris from AF 447 is starting to arrive in Toulouse France for
analysis. They have about 1000 parts total (600 have arrived).

Submarines still patrolling the seabed, looking for metal objects.

I find interesting that the BEA has repeated its "ruling out" of a
in-air breakup from the fact that it has seen upward deformation of
flooring on cargo deck. Seems to me that the tail could have broken off
in flight, and the rest of the plane broken un in some major segments,
some of which could have fallen flat on their belly, creating those
deformations.

If you have a section of the plane with heavy cargo on lower deck,
woudln't that tend to cause that section to remain right side up during
the fall since the bottom is heavier ?
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Uwe Klein
2009-07-25 09:01:16 UTC
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Post by JF Mezei
I find interesting that the BEA has repeated its "ruling out" of a
in-air breakup from the fact that it has seen upward deformation of
flooring on cargo deck. Seems to me that the tail could have broken off
in flight, and the rest of the plane broken un in some major segments,
some of which could have fallen flat on their belly, creating those
deformations.
The horizontal stabiliser seems to have ripped off from back to front
with a very slight offset to one side taking structure from the fuselage
around the attachment lugs with it.
( That was in the BEA report from ~3 weeks ago )

Yesterday on Airliners.net someone had images from the seating plan
with the "body found" places tagged.
They are randomly distributed over the seating area.
this could be interpreted towards the bodies found being representative?
( or just those that had no savetybelt attached (or it broke) and thus
would float free from the heavier than water debris )

uwe aka Wid
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JF Mezei
2009-07-31 05:05:35 UTC
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News today that Airbus will now require all 330/340 (about 200 are
involved) equiped with only Thales pitots to have at least 2 of the 3
changed to Goodrich pitots ASAP.

There was an "incident" on a routine flight between Rome and Paris last
week which made the news, and that aircraft had Thales sensors.
Passengers were unaware of the problem since aircraft continued to fly
normally. But once the media got hold of the story, the political
pressure to fix this rose.

Thales is a french company. So there would have been a good deal of
pressure to get customers to ditch 2/3s of their Thales sensors and buy
replacements from Goodrich.
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Uwe Klein
2009-07-31 07:36:59 UTC
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Post by JF Mezei
News today that Airbus will now require all 330/340 (about 200 are
involved) equiped with only Thales pitots to have at least 2 of the 3
changed to Goodrich pitots ASAP.
It looks like the trigger event happened with an already improved
Thales sensor.
( And I am uncertain if the Spiegel article shows a pitot tube,
an aoa sensor or a combi instrument
http://www.spiegel.de/wissenschaft/mensch/0,1518,639384,00.html
unclear if REUTERS provided a generic or specific image.
)

uwe
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JF Mezei
2009-07-31 05:05:35 UTC
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News today that Airbus will now require all 330/340 (about 200 are
involved) equiped with only Thales pitots to have at least 2 of the 3
changed to Goodrich pitots ASAP.

There was an "incident" on a routine flight between Rome and Paris last
week which made the news, and that aircraft had Thales sensors.
Passengers were unaware of the problem since aircraft continued to fly
normally. But once the media got hold of the story, the political
pressure to fix this rose.

Thales is a french company. So there would have been a good deal of
pressure to get customers to ditch 2/3s of their Thales sensors and buy
replacements from Goodrich.
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JF Mezei
2009-07-01 21:07:21 UTC
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Post by w***@googlemail.com
Post by JF Mezei
Le Monde reports this morning that the french submarine ahs located the
black box pingers.
BTW, that rumour was just that. The day after I had written this, they
confirmed it had NOT been found.
Post by w***@googlemail.com
This could either have some real basis or it is
http://www.timesonline.co.uk/tol/news/world/europe/article6612165.ece
http://timescorrespondents.typepad.com/charles_bremner/2009/07/fantasy-and-facts-over-airbus-disasters.html
There is nothing in those articles that impresses me. They are both
highly speculative.

Think about it, you are flying at 35kfeet, level flight, passengers
sleeping. If all 3 pitots cease to function, you get an alarm. Even if
the computer indicates you now have an airspeed of 0, you, an
experienced pilot, have not felt a sudden and violent deceleration from
600knots (or whatever) down to 0 and know you still have plenty of
airspeed to avoid a stall.


The computer, from what I was told, would detect the fault and put
off-line any systems that depend on this flawed data. Abd we know for a
fact that the computer detected flaw in airspeed ndicators since it
radioed this back to the AF maintenance base. So the aircraft would now
be flying in "manual".


These aircraft are also equipped with an INS and GPS which can provide
ground speed indication.

And pitot tubes would also not mess with the artificial horizon.


Yes, those pitots were known to be less than perfect and are being
changed. My opinion is that the failure of the pitots was a side effect
of the aircraft being drioven into a thunderstorm and the crash was
also a side effect of the aircraft being driven into a thunderstorm and
likely breaking up in the air.

Would an FDR provide any information on what their radar was showing ?
for instance, if the radar was not working properly and did not show a
big bad storm ahead, the pilots would not have gone around that storm
and by they time they realised it wasa bad storm it would be too late.
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