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AF447

Old 13th Jun 2009, 08:27
  #1341 (permalink)  
 
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RWA - The ACARs messages go via any of one 4 (soon to be 7) operation Inmarsat sateliites (plus backups). The SATCOMs is continously tracking the satellite on which the A/C has logged-on. The Inmarsat Aero air-interface should allow any ACARS messages to be transmitted within a few seonds in normal circumstances and certainly in less than a minute if the Ground Earth Station is operating normally.
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Old 13th Jun 2009, 09:00
  #1342 (permalink)  
 
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I do know something about IT and can confirm that satellite internet connections are available with downlink speeds of 400 Mb/sec.
hmmm.... everyone seems to "know something about IT" these days.

Stuff like BGAN only does around 400kb/s. Even modern platforms such as "SPACEWAY" only get up to 30Mbps.

Believe me, it's going to be a looooong time before you see 400Mbps coming from a satellite !

Units .... units...... always verify your units !
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Old 13th Jun 2009, 09:59
  #1343 (permalink)  
 
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I have taught emergency procedures training for 15 years. Interesting photographs of a/c debris. Items of interest are liferaft survival kit including slideraft canopy/inflatable centre mast and flare kit. This is usually slung/attached to slide/raft. Wonder which door it comes from?
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Old 13th Jun 2009, 10:14
  #1344 (permalink)  

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RU4Real.
Agree.
There is also the orange/red pharmacy box. One of a number on board, placed close to an F/A position.
In my opinion, the jumpseats are from the aft bulkhead, as will Fraser noticed :
The jumpseats are most likely aft, since the radius of the perimeter of the bulkhead is small, and if that is a passage to the left of #3, that is a pair, possibly even on the aft pres bulkhead.
The jumpseats sem to have been unoccupied, the belts nicely stowed.
One reason could be that, four hours into the flight, half of the F/As would have been resting in the crew bunks.
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Old 13th Jun 2009, 10:32
  #1345 (permalink)  
 
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The jumpseats sem to have been unoccupied, the belts nicely stowed.
One reason could be that, four hours into the flight, half of the F/As would have been resting in the crew bunks.

Question: Is it a correct assumption that the F/A move from the bunks to the JS to be all hands available "incase" in a forseeable and developing critical situation?
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Old 13th Jun 2009, 10:42
  #1346 (permalink)  
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"RWA - The ACARs messages go via any of one 4 (soon to be 7) operation Inmarsat sateliites (plus backups). The SATCOMs is continously tracking the satellite on which the A/C has logged-on."

Thanks, and welcome, Dan Air UK - only meant in fun, but I can't resist quoting a WW2 divisional commander (forget which one) who once said at a briefing, "The next fellow who fires an obscure acronym at me is going to find himself bloody RIP........"

I'm pretty sure that 'SATCOMs' means 'Satellite Communications,' and also that you mean the ones fitted to the aeroplane, not the satellite itself or the ground station. But I can't be sure, given that the only serious radio I've ever used is military Radio Telephony.

'.........should allow any ACARS messages to be transmitted within a few seonds in normal circumstances and certainly in less than a minute if the Ground Earth Station is operating normally.'

My question was, could the fact that (as far as I can tell from the transcripts) the ACARS (sorry for the acronym ) messages appear to have come in batches about one minute apart mean that the aeroplane was bucking about a fair bit and the aircraft antenna kept 'losing its line' and having to line up and' re-connect again?

The reason I ask is that, if that's so, it suggests that, for the four-minute period we're discussing, the aeroplane was flying more or less normally. Maybe bucking about a bit, but certainly not upside down or in a vertical dive, because the satellite antenna would have had 'NFC' (No 'Ejaculative' Chance' ) of lining up at all if that were so.

The reason that it's important to me is that, as far as any of us know, the signals ended either because the aeroplane had either dived straight down into the sea (at a descent rate of the order of 8,000 feet per minute) in that four-minute period, or had a catastrophic event (like a high-altitude break-up) which cut off all communications?

Hope you don't mind me pulling your leg. Return the compliment any time. But I guess that you can see why I'd like to know for certain.........

PS - ex-Dan Air customer, used to fly a lot with them from Newcastle and Teesside.
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Old 13th Jun 2009, 10:51
  #1347 (permalink)  
 
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Her luck didn't last long

A woman who showed up late to the airport and missed the doomed Air France flight from Brazil died in a car crash a couple of days later, news services reported.

Johanna Ganthaler, an Italian senior citizen, was on vacation with her husband, Kurt, in Brazil and were ticketed to fly on Flight 447 to Paris.
The couple showed up late at Rio de Janeiro's airport and missed the flight on May 31.
All 228 people aboard were killed after the plane crashed into the Atlantic four hours into its flight to Paris.
The couple took another flight to Europe the next day and were driving to their home in Italy's Bolzano-Bozen province.
The ANSA news agency reported that Johanna Ganthaler died when their car veered across a road in Kufstein, Austria, and swerved into an oncoming truck.
Her husband was seriously injured.
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Old 13th Jun 2009, 11:36
  #1348 (permalink)  
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Looking at the photgraphs of the FA seats I don't think you can conclude anything except that there was no one strapped in them.

I don't think you could say they had not been in use during the incident. There are many reasons why they were unoccupied. They may not have had a full complement of FA but more likely, given what appears to have been a sudden emergency, they may have been attending to the passengers first.
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Old 13th Jun 2009, 11:44
  #1349 (permalink)  
 
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No liquid in the bottles

Would it have been removed, or should we assume they were empty? How does the decompression/recompression hypothesis flies if they were not empty?

Thanks- Gilles
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Old 13th Jun 2009, 11:48
  #1350 (permalink)  
 
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1. The ACARS messaging (if complete and accurate) up until 02h14 provides only a preamble of circumstances, circumstances that we are all aware could/would place the flight deck crew in an unenviable position for a whole host of reasons.
2. What we do not know with any certainty are the accompanying actual conditions such as Turbulence intensity, airmass movement and possible high level sheer (vertical and or lateral), Airframe Ice, Hail etc both before, and more particularly after 02h14.
3. We have some very good work by Meteorologist experts that ‘might’ indicate what they were faced with, nothing definite though, so apart from the ‘turbulence report’ there is nothing definitive beyond that.
4. We cannot draw any firm conclusions yet regarding the latent/possible connections between 1. 2. and 3. above


It is after 02h14 that the main destructive events occur of which we know very little


1. The Vertical Stab and Rudder became separated from the rest of the aircraft at some point after 02h14 (otherwise prior to 02h14 ACARS would likely have shot off other pertinent WARN and FAIL messages related to that structure, its integral systems and its operation)
2. Those recovered appear (if condition reports are accurate) to have left the aircraft structure sometime after 02h14, and most likely well before the fuselage section/sections met the surface
3. The small amount of debris (and its condition) recovered is suggestive of ejection (likely at high altitude and high speed) without high speed destructive impact with a solid surface such as other aircraft structures and/or the surface/water (NB: disputed, see below)


To glean anything further at this point is going to be difficult unless information such as:-


1. The seating positions of those recovered is known and published
2. The aircraft parts recovered are identified and their positions in the airframe confirmed and published


Even with that information, the dots are only very loosely drawn. It is my opinion that it is critical that retrieval (at any cost) of the FDR, CVR and the QAR (if it is not totally destroyed), as well as the aircraft structures is paramount. There may well be latent failure modes here that could develop without the preamble events as we suspect them to be, the only way those question marks can be eliminated or addressed is to know the actual events and behaviours. There is only one way to obtain the necessary information.

Last edited by The Chaser; 13th Jun 2009 at 13:36. Reason: Add NB and correct ACAS to ACARS
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Old 13th Jun 2009, 11:49
  #1351 (permalink)  
 
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RWA - The ACARs messages go via any of one 4 (soon to be 7) operation Inmarsat sateliites (plus backups). The SATCOMs is continously tracking the satellite on which the A/C has logged-on.

Inmarsat 3rd generation constellation, four satellites in geostationary orbit.
In that area, two birds cover the place, AOR-E (atlantic east) and AOR-W.
The a/c's antenna is "omnidirectional" (actually hemispheric), there is no tracking.

Transmissions are almost real-time.
In other words, during those four minutes the antenna "saw the sky".
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Old 13th Jun 2009, 11:55
  #1352 (permalink)  
 
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Chaser:
3. The small amount of debris (and its condition) recovered is suggestive of ejection (likely at high altitude and high speed) without high speed destructive impact with a solid surface such as other aircraft structures and/or the surface/water
If you researched at least 2 other Airbus into-water crashes and reviewed the floating debris recovered, you would want to retract this.
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Old 13th Jun 2009, 11:57
  #1353 (permalink)  
 
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As deSitter explained,rudder use(if it was used) may have been instinctive or even last-resort.
There has been no feedback whatsoever re what rudder deflection was available in ALT law:
-Ive heard TEN
-Ive heard FOUR(ie last cruise default)
-Could full deflection have been available if CAS was erroneous?

Naturally,one pilot would be PF during unreliable airspeed whilst the other attempts to read the procedure and recommendations.But lets assume this was unreliable airspeed with severe turbulence.The larger the upset becomes,the more likely the PNF would be tempted to input control.There is no control yoke in the Airbus,just 2 sidesticks.They dont "mirror" each other and in any case because of their position/size you,as PNF,wouldnt get an idea of what the PF was doing,even if they did.Fine in normal operations but what about in a full high alt jet upset?The possible "dangers" of the design are proven in x-wind landings(lufthansa 320 incident).Same applies here.

I read that the computer in this situation(control inputs from both pilots) takes the sum of the two inputs and gives the mean(if contradictory) or additive(if complimentary)value.Is this true in ALT LAW as it is in NORMAL?If so,the question now becomes does this design in any way make it more difficult/confusing for a succesful upset recovery(assuming the forces of nature were in fact recoverable on 447)?
You have two pilots with different experience levels and set of skills.One may recognize the importance of "ATT vs speed only" in an upset,the other may give equal importance to ALTITUDE/COURSE (this is an emergency..theyre irrelevant).
If the two minds thinkalike,can it lead to an over-control situation?I understand that G-LOAD protection is still available in ALT LAW?2.5g to -1g??
What about other protections though?
If the two minds are not in sync,the appropiate inputs may get diluted by the inappropiate ones.
The takeover button is supposed to address this "fight for control".Use of the "I have control" button in a x-wind landing by a training skipper is one thing but in a severe high-alt upset,reluctance and hesitation may creep in.

It is interesting to remember that during Egypt Air's suicide flight,the Captain remarked "Pull with me".He knew(because he could plainly see) what the FO was doing at all times.
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Old 13th Jun 2009, 12:08
  #1354 (permalink)  
 
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Chaser, review the photo of the Perpignan A320 on page 50 of this thread. Note the lack of large floating debris to be picked from the surface. Review the Armenian Airbus crash off Sochi into the Black Sea from a very low altitude and relatively low speed (much less than cruise) during a go-around in weather. Note the difficulty finding and retrieving floating debris.

RWA
as far as any of us know, the signals ended either because the aeroplane had either dived straight down into the sea (at a descent rate of the order of 8,000 feet per minute) in that four-minute period,
Few or none of those who know would believe this flight dove straight down (all the way) into the sea.
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Old 13th Jun 2009, 12:08
  #1355 (permalink)  
 
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debris and impact-location

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.

This two finding locations can be explained by a broke up in flight (see the New York Times 11 June) but 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. The westward flowing NSEC is situated between 1°N and the SEUC at 3°S-5°S.... Its velocity rarely exceeds 30 cm s-1. This velocity is also confirmed by the Brazilian Navy on 11 June: "the maritime current has changed from North to a Westerly direction, with a speed of around 1,1 kilometers per hour".
This western current is also influenced by the wind. The wind was on 1 June also from the east ( see the detailed meteorological analysis of Tim Vasquez)
So we can assume that the surface-current was about 25 km per day from east to west

The AF447 tailfin was found at 8 June. So this fin traveled 8 days with the NSEC current about 200 km (= 8 x 25 km).
If you want to find the impact-location of the tailfin then start on the finding location of the fin and follow the NSEC.
So it is reasonable to assume that the impact-location will be about 200km ( = 2 degrees) more to the east then the finding location.

This drift of 200km from the impact-location to the finding-location can also explain why on two locations bodies were found.
On the impact-location the surface-currents are diverging. The south-part is going west-northwest and the north-part drifts more to the north.




You can see this surface-currents at: The North Brazil Current

So if the plane made debris on two different moments, then small differences in time (or place) at the impact location can give after 8 days bigger differences at the finding locations.

The next scenario gives an explanation of the two separated debris locations:
Assume that the impact started with a tail-break and the first loss of bodies and debris from the tail-section (this explains the finding of the crew container, the laval door and jumpseats).
Then some moments later during the sinking of the plane a second wave of bodies and debris was going to the surface. From this second location there can be a debris-trail from the impact-location to the second finding-location.

The consequence of an impact location 200km eastwards of the finding locations (or Tasil) is that the plane was 200km in the air after the last ACARS messages.

Last edited by RuudA; 17th Jun 2009 at 18:25.
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Old 13th Jun 2009, 12:11
  #1356 (permalink)  
 
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Stuff like BGAN only does around 400kb/s. Even modern platforms such as "SPACEWAY" only get up to 30Mbps.

Believe me, it's going to be a looooong time before you see 400Mbps coming from a satellite


This is an operator's choice with respect to its business case, not a technical limitation by the satellite.
The bird carries 30-40 transponders (Ku band), each has a bandwidth of about 50MHz.
A 50MHz pipe, with compression, can deliver very high speeds....but there is price to pay.

BGAN tops at 512kbps (IP mode).
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Old 13th Jun 2009, 12:16
  #1357 (permalink)  
 
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ttcse

Agreed!

1. The XL Fuselage was intact on impact (all inertia contained) Correct???
2. The Armenian Fuselage was intact on impact (all inertia contained) Correct???

Thus my view that:- The small amount of debris (and its condition) recovered is suggestive of ejection (likely at high altitude and high speed) without high speed destructive impact with a solid surface such as other aircraft structures and/or the surface/water
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Old 13th Jun 2009, 12:25
  #1358 (permalink)  
 
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Chaser
Thus my view that:- The small amount of debris (and its condition) recovered is suggestive of ejection (likely at high altitude and high speed) without high speed destructive impact with a solid surface such as other aircraft structures and/or the surface/water
I wouldn't argue FOR a high-speed impact. But you might also consider that this debris could have resulted from airframe subsections breaking upon impact at less than a high speed. Keep in mind we have no clue the condition of debris which sank.

If the aircraft largley disintegrated at altitude I would think many more floating items would be found.
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Old 13th Jun 2009, 12:35
  #1359 (permalink)  

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There is also the orange/red pharmacy box. One of a number on board, placed close to an F/A position.
-The orange one is the Doctor's kit, and there's only one on board, stowed in proximity of door 2R. The FAK which are near the CC stations are clear plastic, and none is in the pictures.
-The 2 jumpseat could come either from doors 1 or 4. There are twin jumpseats at each of these locations (my bet would be doors 4 for the ones in the pictures by looking at the wall partition they are attached).
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Old 13th Jun 2009, 12:40
  #1360 (permalink)  
 
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ttcse

Again agreed!

There are other examples (beyond the two you cite) where an intact airframe has structurally failed on impact with water at various speeds.

The thing that sticks in my mind (although I would be happy to be challenged as an open mind is critical in such circumstances) is that most all structurally intact fuselage's retain most of the items within during impact save for the odd bit of non-structural cowling doors etc. Sure, some small unsecured items onboard might be ejected intact through fuselage breaches during deceleration and remain largelly undamaged. I would at first glance (and that is all it is at this point) suggest an almost complete unoccupied (seats) partition bulkhead would not fit this description, nor is the reported condition of those found.


I agree that if the fuselage has been breached at altitude (for whatever reason), it would have to breach in a fairly localised fashion for this type of debris footprint, which is possible of course, given the first breach will have to deal with the pressure differential outflow if it occured at high level. The remainder of the fuse may have remained intact, or, later in the sequence (under torsional loads) breached in other locations.

Last edited by The Chaser; 13th Jun 2009 at 12:54. Reason: syntax
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