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AF447

Old 8th Jun 2009, 12:30
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As I said back in the original thread, icing in my experience is the most dangerous result of flying in bad wx. Ironic if it turns out the pitot system iced up.

RIP
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Old 8th Jun 2009, 12:39
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Coffin Corner & Temp effects

Sooo. My first post here! This is based on some somewhat crude calculations but should at least give us newbies an idea of 1. what the coffin corner is and 2. what happens if there is a sudden temperature increase.

Note that this graph is NOT made for a specific aircraft, the calculations are based on dummy figures for illustrative purposes. Also, the graph is not valid below FL250 (this is based on a/c being in cruise configuration). There are two flight envelopes in this picture, one at ISA (solid) and one at ISA+30 (dashed). MDD is the drag divergence Mach.



So, if you are at 37 000 ft and have a sudden temperature increase you can find yourself dangerously close to a low speed stall, however adjusting your speed will means you get Mach effects and flutter as soon as you leave the high temp area. You are essentially in a coffin corner situation even though the individual flight envelopes gives you a decent speed margin.
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Old 8th Jun 2009, 12:44
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The Air India is as F14 says, a carbon copy: the squawk disapeared from radar, as did the AF447
No, the AF447 'squawk' did not "disappear" from radar; AF447 was well outside radar range when it transmitted it's final messages.

Am I the only person to think that the BS content of this thread is beginning to creep up again?
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Old 8th Jun 2009, 12:49
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Air France+Airbus knew about PITOT

Milka, exactly what I mentioned here :
#599.
See original ACARS link here.
Eurocockpit - Accueil

""
A 0210, le premier des deux "FAULT REPORTS" concerne donc l'ATA 34 (message "FLR [...] 34111506EFCS2 [...]") et signifie :
  • ATA 34 (navigation)
  • 11 (Sensors, power supply and switching)
  • 15 (Pitot probes)
  • 06 (cruise)
Le sous-ATA 11/15 concerne donc... les tubes Pitot. Avec comme conséquence la panne FLR 27933406 (Flight control primary computer en croisière), puis toute la longue liste des messages WRN (WARNING) qui découlent de la perte totale de références anémométriques."
(...)
"En clair, quelques minutes après l'accident, le BEA, Airbus et Air France avaient bien entendu le contenu des messages, et leur signification. Ils savaient qu'il s'agissait - de nouveau - d'un problème sur les tubes Pitot."

Translation :
"One of the first two fault reports is relative to ATA34, meaning "PITOT sensors". Hence the consequence, FLR 27933406 failure plus the whole series of WRN messages, etc."
(...)
"Clearly, AF and BEA knew right after the accident the content of these messages and understood they had — again — a PITOT problem."

EuroCockpit

One of the 3 pilot unions refuses any A330/A 340 flight if 2 over 3 PITOT are not replaced NOW.

See this DGAC (french FAA) directive dating back 2001 about "severe incidents related to PITOT".

Image 2001 354.JPG


PS : Sorry, guys, but I don't have the ability to post the PDF,
I apparently don't have access to that functionality here.

Last edited by Quantz; 8th Jun 2009 at 13:13.
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Old 8th Jun 2009, 13:05
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Refuse any flight on A330 if PITOT are not replaced

Dysag :

Read that internal note from one of the 3 french pilot unions :

"REFUSEZ TOUT VOL SUR A330 / A340
N’AYANT PAS AU MOINS
DEUX SONDES PITOT MODIFIÉES"

Translation : "Refuse any flight on A330/A340 unless they have at least two sensors over three replaced."

They relate also a prior incident with ACA flight occurring last september, exactly similar to AF447 problems.

EuroCockpit
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Old 8th Jun 2009, 13:13
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US Air and Aer Lingus following suit

This just reported on Bloomberg:

June 8 (Bloomberg) -- US Airways Group Inc., the smallest U.S. full-fare carrier, and Aer Lingus Group Plc are replacing air-speed sensors on Airbus SAS A330s similar to equipment on an Air France jet that crashed off the coast of Brazil.

Not sure where the SAS comes from.
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Old 8th Jun 2009, 13:19
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FE Hoppy,

This page will provide the speed/temperature calculations you need:

Aerospaceweb.org | Atmospheric Properties Calculator
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Old 8th Jun 2009, 13:30
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SAS signifies the type of company. Like INC in the US or PLC in the UK.
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Old 8th Jun 2009, 13:40
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Sources of purported pilot report of strong turbulence

Le Monde Article
Un journal de Sao Paulo, le Jornal da Tarde, a eu connaissance de la chronologie et de la teneur de ces messages, selon lui grâce à une source proche de la compagnie française. Ces informations ont été publiées, mercredi 3 juin, par le très sérieux Estado de Sao Paulo (les deux quotidiens appartiennent au même groupe de presse).
Two respected Sao Paulo papers (owned by the same press group) the Jornal da Tarde and Estado de Sao Paulo published the messages June 3. Perhaps a Portuguese speaking member can check out those articles for more details.

AF Press Release:
The aircraft hit a zone of stormy weather with strong turbulence at 2am this morning (universal time), i.e. 4am in Paris. An automatic message was received from the aircraft at 2:14am (4 :14am in Paris) indicating a failure in the electric circuit a long way from the coast.
The language leads me to suspect that somebody in AF checked the satellite images and provided this information to the person(s) writing the PR. Note that the next sentence goes on to discuss ACARS reports. Now all it would take for a rumoured report of pilot or ACARS reported turbulence to be produced from this PR is a bit of journalistic legerdemain
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Old 8th Jun 2009, 14:12
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From the AF Press Reports site, the only reference to strong turbulence was their second press release, and this seems to be a generic statement.

The aircraft hit a zone of stormy weather with strong turbulence at 2am this morning (universal time), i.e. 4am in Paris. An automatic message was received from the aircraft at 2:14am (4 :14am in Paris) indicating a failure in the electric circuit a long way from the coast.
They make no reference to how this information (turbulence) was obtained, but I note On the other hand that they are very specific when it comes to the ACARS. Seems like one is documented, and the other ??? Did the BEA briefing on Saturday reveal any info on the validation of turbulence area?
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Old 8th Jun 2009, 14:14
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shandar
Nice try with the graph - but the max altitude (peak of the graph) should be several thousand feet lower as well.
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Old 8th Jun 2009, 14:16
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The Air India is as F14 says, a carbon copy: the squawk disapeared from radar, as did the AF447, no 7700 was picked up and ZERO mayday calls were made..
If the crew where battling severe turbulence at the time i would say that Sq 7700 was the last thing on there minds.

Ironic if it turns out the pitot system iced up.
Or completely removed from the airframe.

It is more than blausable that the crew where doing everything right regards working there way through a line of CB's only to fly under a anvil, and i am sure most of us have seen the results of what heavy hail can do to a airframe. and it would more than account for the signals sent to AF, as well as leaving little time for the crew to react as systems failed before the aircraft become unflyable.
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Old 8th Jun 2009, 14:29
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Yaw String, from a meteorologist in the United States commenting on Appendix 1 in the Australian investigation:

"What's stated in Appendix 1 also happens in the CONUS. A nighttime MCS can produce considerable downward motion on the flanks of the MCS (what flank depends on the environmental winds). This creates a warm pocket of air due to the rapid subsidence from the stratosphere and sometimes can be seen on infrared as a "warmer" area of cloud tops immediately to the north or west of tstms, embedded in colder cloud tops. The MCS also reeks havoc on flight level winds and can increase them by 50kts or more on the north side of the complex,when compared to modeled flight level winds. I see this all the time in the spring."

MCS is Mesoscale Convective System
He was speaking for the Northern Hemisphere; it may be in the Southern Hemisphere, the winds might appear on the south side of a MCS, but I don't know that.
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Old 8th Jun 2009, 14:31
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Pitot Design

All I've read implies the airspeed goes to zero when the pitot tube ices over. Do these Thales pitot have a small drain hole that allows the impact air to bleed off to zero? Otherwise, the airspeed indicator should show the speed at which total freezing occured.

Does the system complexity of the A-3xx cause pitot icing to have more gravity than in a simpler airliner?
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Old 8th Jun 2009, 14:33
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On the topic of sudden temp rise, europe IR today;

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Old 8th Jun 2009, 14:52
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Hello everyone. Please don't bash me if this has already been posted by someone else.

I have just come accoss this picture of the tail section of the aircraft which has just been found. Obviously not the entire tail section but a great deal of it.

Does this show anything interesting from the experts on here?

http://www.fab.mil.br/portal/voo447/...609/foto_3.jpg

http://www.fab.mil.br/portal/voo447/...609/foto_1.JPG
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Old 8th Jun 2009, 15:04
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@XPMorten

Hi

This is a normal satellite picture and you can't see any sudden temperature changes on those. You see the temperature of the closest cloud, water or ground surface which can be seen by the satellite. Warmest over subtropical waters or hot land in the afternoon, coldest on cloud tops. But these varying temperatures vary with altitude, so what you don't see is a horizontal change in temperature. And BTW, the stories in this forum about temperature changes of 20-30 degrees (what degrees?) horizontally and at short notice are not realistic. We are talking about a few degrees centigrade with a difference in cloud or out of cloud.

The temperature differences met vertically in SEV TURB may be much bigger than those horizontally, just by the up and down of the aircraft. In a cloud, the the horizontal temperature is quite uniform.

Last edited by weatherdude; 8th Jun 2009 at 15:24. Reason: Add vertical temperatur difference comparison
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Old 8th Jun 2009, 15:06
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SAR map

In post 552, Flyinheavy posted a recent FAB Google Earth map of the debris area. Unfortunately this is not really a map, but a sketch of the area. The distances shown (79km, 318km, and 824km) cannot even be plotted since they don't meet at a single point. The reporting point TASIL is mislocated about 150 km NE of its actual location.

The 79 km and 318 km distances more or less plot at the location of a previously reported position where the first bodies evidently were recovered (3° 34.08'N, 30° 27.30'W - from the 6-6-09 FAB PowerPoint).

Yesterday FAB posted some photos of the search, among which is a shot of one of the maps used in the search. It is interesting to see a map used by the SAR teams - this shows that water droplets have smeared the ink, and evidently has signatures of the team members:

http://www.fab.mil.br/portal/voo447/...o_assinada.jpg

I have warped the northern portion so it is flat and referenced to latitude/longitude. On this I have plotted in white the aviation waypoints and the location of St. Peter and Paul Rocks. The actual location of TASIL matches that point on the SAR map fairly closely, but other points do not. In yellow I have plotted the 0214Z ACARS location (N3.5777 W30.3744) and the 6 June Recovery location where two bodies evidently were found (3° 34.08'N, 30° 27.30'W). Also plotted in yellow is the "AF447 ultima reporte" location taken from the 6 June FAB PowerPoint presentation.

Interestingly, the SAR map shows yet another location for the last position of AF447 - the red airplane symbol about 27 km WSW of the "AF447 ultima reporte" point. The remainder of the text on the SAR map is difficult to read, but most of the red marks are labeled "Debris." Possibly the red marks inside the northern shaded box are radar targets reported by the R-99 aircraft. The ACARS 0214Z and Recovery locations lie inside a reported Debris area.

-rer47

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Old 8th Jun 2009, 15:07
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Tail section photo

The tail section photo brings odd resemblances with this one:

ASN Aircraft accident Airbus A300B4-605R N14053 Belle Harbor, NY

Last edited by Christodoulidesd; 8th Jun 2009 at 15:10. Reason: added bolt for emphasis, plus title
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Old 8th Jun 2009, 15:08
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Tail section

Thanks for posting the links yorkshireguy, for those having problems accessing the image from the FAB link, I uploaded one of them to imagesack:


Looks like a fairly intact (save from some damage on the rudder's base) vertical stabiliser.
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