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AF447

Old 13th Jun 2009, 13:07
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I'm not sure we can assume that water bottles would rupture on depressurization. They handle the pressure drop from sea level to 8000 feet (about 4PSI) without any obvious stress. 8000 to 30,000 feet is about another 7PSI. It's by no means unlikley that the bottles that can handle 4 PSI differential would rupture 11. But it's not self evident either.

In fact, if you've ever made a "rocket" from a 2-liter soda bottle, you'd know you can pump several atmoshperes of air into it with a bicycle pump without rupture.
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Old 13th Jun 2009, 13:16
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[quote] "From the incomplete data that I have seen, it is clear that SATCOMS transmissions are regular and consistent with an A/C that is tracking the satellite reasonably well up to the last transmission at 02:14."/QUOTE]

Many thanks, Dan Air UK. Can I take it that your opinion (as someone who genuinely knows a lot about satellite communication) and mine (as no more than a 1960s 'seat of the pants' light aeroplane pilot) largely coincide?

That the aeroplane was under reasonable control (flightpath-wise) for plus or minus four minutes. And then 'blacked out' - among other things, losing all communication with the satellite. Suggesting either a catastrophic systems failure or an 'Extreme Flight Path Irregularity' - like the aeroplane standing on its nose and heading for the deck at Mach. speed?
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Old 13th Jun 2009, 13:27
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RWA Everything depends on the provenance of the ACARS copy and the lack of additional similar information. If the transmission terminated at the top of page two, and there is no more, it would tend to support a theory similar to yours. 'Absence' of evidence is not 'Evidence' of absence. The data is proprietary, AF has behaved 'erratically' (my term) in this event.
Who knows?
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Old 13th Jun 2009, 14:25
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In fact, if you've ever made a "rocket" from a 2-liter soda bottle, you'd know you can pump several atmoshperes of air into it with a bicycle pump without rupture.
Good point Chu-Chu. Looked it up, the 2-liter soda bottles are good to 50 psi.
Cabin differential pressure at 35k ft is 9 psi. Can't be as confident as before, but those clear water bottles in the photo are more flimsy than the 2-litter ones. Might do a little experiment in the hangar later.
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Old 13th Jun 2009, 14:31
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The other 'news' is that (since the FDRs of the time recorded pedal movement and rudder movement, but were not able to 'say' whether the pedals moved the rudder or vice versa) AA587 may well not have been pilot error at all.
1) I find that very hard to believe... low frequency flutter on powreed controls?

2) If true, then where are the ADs? A very serious problem indeed with immense ramifications, which surely couldn't be covered up - requiring fundamental control system redesign.

1) & 2) taken together make it sound more of a conspiracy theory - so solid evidence please
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Old 13th Jun 2009, 15:07
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RE those jumpseats and the pharm box

Something that has to be considered now is the simple failure of the aft pressure bulkhead as in JAL123. That could certainly knock the tail section off.

-drl
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Old 13th Jun 2009, 15:19
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In particular, the vertical stabiliser is missing from the items being displayed. Simply because it has not yet made it to land or was it withheld from the display for some reason?

http://www.pprune.org/4994299-post1367.html
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Old 13th Jun 2009, 15:34
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Debris - crew seats

As far as I am aware, no cabin seats are attached to the aft bulkhead. In my opinion the seats photographed may have come from the front face of the right-side aft galley or from a left-hand partition such as at door 2 or 3. I do not know the precise AFR configuration for cabin attendant seats.
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Old 13th Jun 2009, 15:40
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General seating chart for an AF 332:
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Old 13th Jun 2009, 15:46
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Debris - crew seats

... or door 2 rh but probably not door 3 lh.
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Old 13th Jun 2009, 16:07
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1
) I find that very hard to believe... low frequency flutter on powreed controls?

2) If true, then where are the ADs? A very serious problem indeed with immense ramifications, which surely couldn't be covered up - requiring fundamental control system redesign.

1) & 2) taken together make it sound more of a conspiracy theory - so solid evidence please
I'm sure that no offence was intended, Harry Mann. Nor was any percepted. But I'm not in the habit of telling lies, or even 'inaccuracies', on the Net or anywhere else. And I'm sure that you feel exactly the same.

The rudder controls on AA587 were conventionally-linked. No Airbus-style FBW..........

Please read this whole NTSB report through. And then get back to me, and we can have a fully-informed discussion.

NTSB Abstract AAR-04/04

Last edited by RWA; 13th Jun 2009 at 16:34.
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Old 13th Jun 2009, 16:11
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Rob21,
Interesting point. I all my many years of transatlantic crossing it has always been difficult to get 2 particular carriers to talk on 123,45 on 128.95 to discuss anything pertinent, ie, turbulence, or levels they will be requesting for onward planning purposes.
Those carriers are Air France and Lufthansa.
Don't know why...and this is my personal experience only. I always thought it to be because I am a pom!
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Old 13th Jun 2009, 16:16
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Other flights in the area

As previously reported, there were indeed other airplanes nearby, even in the same route.

Closest one was Iberia IB6024 (A340-300) which took off 7 minutes after the AF to a (geographically) similar destination on the same route. They briefly saluted and chatted with the AF crew while getting the flight ready earlier in the airport.

Press reports IB pilot declaring: "We flew about 10 minutes (~80 miles) directly behind the AF, at 35000'... being monitored by TCAS, noticed bad weather ahead and decided to deviate from it an unscheduled 30 miles to the east at about the same time the AF dissapeared from the radar forever..." They never had visual contact. They never picked up any transmissions from the AF around the time the accident is believed to have happened in any of the open frequencies.

He heard the repeated attempts of brasilian traffic controllers to contact the AF after its dissapearance from radars all the way to the entrance to Senegal air space". Iberia flight was totally uneventful otherwise, with nothing unusual about the weather etc (except that there were indeed patches of bad weather around the area at around that time worthit of circunvention).

Last edited by justme69; 13th Jun 2009 at 16:29.
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Old 13th Jun 2009, 16:49
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Originally Posted by justme69
Press reports IB pilot declaring: "We flew about 10 minutes (~80 miles) directly behind the AF, at 35000'... being monitored by TCAS, noticed bad weather ahead and decided to deviate from it an unscheduled 30 miles to the east at about the same time the AF dissapeared from the radar forever..."
Maximum range for the TCAS to display a target is only 40 NM ...
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Old 13th Jun 2009, 18:16
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"Maximum range for the TCAS to display a target is only 40 NM ..."

The airline I fly for has five A330s (sn 800s and 900s) that show TCAS targets up to about eighty miles ahead and about twenty behind.
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Old 13th Jun 2009, 18:30
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Hi RWA

At the risk of being completely wrong...

I don't think that the rudder would feedback force to the pedals. Even in a non FBW plane this big the controls are moved by hydraulic actuators. The pedal force feel is artificially generated (by the artificial feel box or Q-feel box) which simply converts a pedal position and dynamic pressure into a force.

On another point about composites, when I was at Airbus working on VTP structures we always used hot/wet testing (both heat and moisture degrade composite structural properties). I don't know about the fatigue work as I wasn't involved but I don't think it would have been done differently. Thats not the same as fluid getting into a sandwich structure, as with the rudder failures, which is a more serious problem.
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Old 13th Jun 2009, 18:31
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Ok, I didn't know that.
But I'm not sure that the IB A-343 are that new ?
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Old 13th Jun 2009, 19:14
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The twin jumpseats are located
-FWD, near L1
-AFT, at the far end of the back galley. You could say they mark the end of the cabin.
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Old 13th Jun 2009, 19:15
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Originally Posted by RuudA
The Brazilian Air Force released information on 9 June showing that bodies from flight af447 had been recovered from locations that were more than 50 miles apart..

. . can also be explained by the influence of the surface current: the Northern South Equatorial Current (NSEC).

This NSEC current is a westward flowing current that extends from the surface to a nominal depth of 100 m.
As I tried to post before, but it was deleted, the surface current moderated by the wind, will account for a significant distance between the point that debris entered the current and the point at which it was found.

The significant point in RuudA's post is surface. Debris is more likely to be released from the wreckage as the aircraft descends and breaks up at depth. Such debris will be affected by sub-surface currents until such time as it rises to the surface current zone.

There is no guarantee that all sub-surface release will occur at the same time or the same depth. It is as likely that the debris spread is from sub-surface release as from an airborne breakup.

PS, I believe this post-crash surfacing of debris was a feature of a RNlN Atlantic aircraft about 30 years ago.
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Old 13th Jun 2009, 19:26
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It seems to me that where these threads go wrong is when someone fixates on a single fact.

A single fact can disprove a theory, but it can never prove a theory. And a theory is only viable when it accounts for all the facts known.

An example: It was noted previously (multiple times - I'm not specifically responding to the immediately preceding posts) that the dispersal of the remains is not firm evidence of an in-flight breakup, because ocean currents could also play a role in the dispersal, or even account for it completely.

As far it goes that is reasonable. But it ignores other reported evidence - e.g. ocean currents do not account for the reports that some victims had all clothing ripped off, or had ceased to breath by the time they encountered water (no water in lungs).

But those other data points themselves do not "prove" in-flight breakup either. Other explanations are still open.

We have pictures of a VS no longer attached to the rest of the aircraft. A data point. I see no evidence one way or the other as to when the VS ceased to be attached: At 35,000 ft? At 15,000 ft? At 0 feet?

I see a VS in which the failure point appears to be in the aluminum-alloy supports, not the composite structure - but am perfectly prepared to be corrected on that.

As far as I'm concerned, there are only four clearly established facts in this tragedy: The plane departed radar range, the flight was in the vicinity of tropical convective weather, a series of maintenance/failure messages were sent, and remains have been found on the ocean.

What occured amidst and between those knowns is still a very large black hole bespeckled with a few dots of light.
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