Tech Log The very best in practical technical discussion on the web


Old 2nd Sep 2009, 23:59
  #4321 (permalink)  
Join Date: Jan 2002
Location: USA
Posts: 286
The US FAA is now flexing some might.

September 2, 2009
US airlines must replace speed sensors on some of their Airbus planes, parts that have come under scrutiny since the crash of an Air France jet three months ago.

The Federal Aviation Administration (FAA) on Wednesday ordered carriers operating A330 and A340s -- Delta Air Lines and US Airways -- to swap probes manufactured by Thales with components made by Goodrich.

The FAA order, which takes effect from September 8, affects about 40 planes, and follows similar action by European authorities in response to the crash of Flight 447 that killed 228 people. The A330 crashed into the Atlantic Ocean on a flight from Rio de Janeiro to Paris on June 1.

Investigators said they do not yet know what caused the crash but are interested in what role, if any, unreliable speed readings from the plane may have played in events leading up to the disaster.

The investigation is expected to take another year.

European safety officials have reported speed indicator discrepancies on some A330 and A340 planes at high altitudes in bad weather. Investigators indicate that planes equipped with Thales probes appear more susceptible in rough conditions.

Regulators are especially concerned about ice crystals forming on sensors and throwing off readings. Inaccurate readings can disengage the autopilot or other automatic functions and cause the pilots to lose control of the aircraft.

There have been several reports of problems with Thales sensors.

Airbus in July urged airlines to switch to Goodrich, which already supplies sensors on most of the world's A330/A340 fleet. About 200 planes are equipped with sensors made by Thales, Airbus has said.

Separately, US transportation investigators are looking into possible anomalies with speed and altitude indicators on two A330 planes in May and June.

Privately held Thales is Europe's largest defense electronics company, which has so far declined to comment on the sensor matter.

wes_wall is offline  
Old 3rd Sep 2009, 00:00
  #4322 (permalink)  
Join Date: Jun 2009
Location: I am where I am and that's all where I am.
Posts: 660
Will, unless somebody has proof the pilots were playing canasta on the flight desk as the plane flew into the storm there is no way the pilots can be blamed for the AF447 mess without leading to a conclusion that their training had astounding gaps.

One does not convict on "slightly more likely". One convicts on "beyond reasonable doubt" in polite societies.

Too little evidence exists for a conviction of anybody.

Plenty of evidence exists that various elements of pilot training, the instrumentation, and the flight data computers could be improved.

With all that evidence of "not quite good enough and MIGHT cause problems" there is cause to work for improvement. There is not sufficient evidence to prove the disaster was not caused by a mouse that got on board and chewed through some critical control cables. So apportioning blame and crying for revenge is stupid. It also, if you cannot tell, offends my sense of justice.

JD-EE is offline  
Old 3rd Sep 2009, 03:45
  #4323 (permalink)  
Join Date: Aug 2005
Location: fairly close to the colonial capitol
Age: 52
Posts: 1,686
What I would like to know is when the pitots are replaced, do the ADIRU/FBW software boxes get 'updated code' ?
vapilot2004 is offline  
Old 3rd Sep 2009, 14:21
  #4324 (permalink)  
Join Date: Nov 2006
Location: SoCalif
Posts: 898
The Air Data Modules are the interface with the pitot probes. They convert dynamic pressure to a data bus. I don't know, but there would be the logical location for correction calculations. It's done in the Air Data Computer in planes without ADMs.

Thinking about the amount of fright testing needed, it's kind of surprising there would be more than one maker of pitot probe certified. Is there more than one on Boeings? The 737 doesn't even have a choice of engines..

Graybeard is offline  
Old 4th Sep 2009, 00:34
  #4325 (permalink)  
Join Date: Feb 2000
Location: Sao Paulo
Age: 75
Posts: 792
JD, are you not shooting the messenger? Unless Noelbaba has removed one or more posts stating his own opinions, all I've seen is his posting of something from eTurbonews.
broadreach is offline  
Old 4th Sep 2009, 08:29
  #4326 (permalink)  
Join Date: May 2009
Location: China (CGO)
Age: 72
Posts: 164
Won't Change Much for AF447 But...

Anecdotally, Airbus CEO Thomas Enders told the Paris tabloid "Le Parisien" that "We are studying other ways of collecting flight data... For example, the most important data could be sent out over a satellite link in real time, as is already the case with maintenance data. We're working on this with our partners and suppliers."

Le Parisien also quotes blackbox inventor Pierre Jeanniot as saying the recorders were "obsolete" and "new technologies are available."

Airbus envisage la fin des boîtes noires - Yahoo! Actualités (in French)
ArthurBorges is offline  
Old 4th Sep 2009, 08:33
  #4327 (permalink)  
Join Date: Feb 2007
Location: i don't know
Posts: 320
eTurboNews | Travel and Tourism Industry News


BEA director Paul-Louis Arslanian, The director of the French agency investigating the crash of Air France Flight 447 said Monday that investigators could take at least a year-and-a-half to reach a conclusion.

The captain should be present in the cockpit while cruising thru this very strong thunderstorm passage.

Reading this article I could not clearly determine who of the two (Basusta or Arseline) did the last statement. Either way, it is sustaining one of my main concerns about inflight rest facilities and policies of many airlines.
If the captain, and this is meaning the most experienced or sometimes the only experienced on certain routes or the only aera-qualified, is to be on deck in certain difficult situations, then I agree 100%. But if they are confined into rest facilities in the back or the cargo cptmt of the aircraft, then they clearly cannot cope with such common sense requirement. The same applies to certain procedures that basically only allow the skipper to rest in the middle of a flight (t/o and ldg presence) and on most such routes the critical phase is mainly at this time (Himalaya, Ocean etc.).

The authors of such claims should really help us by building up pressure on airlines to review some rest policies and locations. Simply because most of such decisions are made for the profit or like EK having rest facilities adjacent to the cockpit REMOVED and replaced in the very rear of a long aircraft for passenger comfort reasons. I'd rather be safe than a little more confy!
GMDS is offline  
Old 4th Sep 2009, 10:11
  #4328 (permalink)  
Join Date: Jan 2008
Location: Pretty far away
Posts: 316
The authors of such claims should really help us by building up pressure on airlines to review some rest policies and locations. Simply because most of such decisions are made for the profit or like EK having rest facilities adjacent to the cockpit REMOVED and replaced in the very rear of a long aircraft for passenger comfort reasons. I'd rather be safe than a little more confy!
There isn t any rest policy and as a captain, I really do not need one. I ve got my own swiss pocket knife called common sense and experience to help me DECIDE what and when I am going to do it. Period.
Experience is to have ploughed those tropical routes years in and years out as a F/O watching how " the old man " does it..............or screws the pooch. That s also experience.
As to common sense, I don t think I need to give a specific definition but let s say that along with experience, it is what brings you home alive.

I too, have made errors of judgement, and trust me when I say I am a sorry, prudent, scared wooss when it comes to CB s. Luckily, I came out ok without sending any pax through the roof. But still, this memory humbles me when I am wicked enough to think about it.

The answer to that isn t in writing the 10 000 s rule in the rule book which will go forgotten in less than a week, but putting emphasis on training.

One thing that has always rocked me off my saddle at AF is that when you upgrade to command, your training captain is likely to be a guy who was upgraded just a year before you. What kind of experience can a guy like that bring you ???? Just about zilch. Sure thing, he ll stuff your head with " ze book of rrrrrrrules " like a turkey on Thanksgiving, but as far as experience is concerned he is just as virgin as you are.
Safety culture comes from Flight Safety department but is relayed, or should be , down the ranks by old hands and it should be something one should be enthousiastic about and not have 4000 different pig headed minds about.
This culture, just like geraniums on spring time, has to be " nourrished " on a regular basis otherwise it goes into oblivion within months.
The Jo burg incident in 1998 could have had the same ending had Mr Boeing not built his 744 like a tank. For a few weeks / months, all of what people could talk of were " hu dangerrrrrrrrrrrous cee bee werrrrrrrrre " veer this 40 deg, veer that 50, AF planes all over the bloody place. Superb ( and I m not jesting here because when AF puts its mind to it, they really come up with some fantastic material ) publications, rehash on line check, you name it. What happens then ???................zzzzzzzzzzzzzzzzzzzz !! The matter is considered as " solved " as Inspector Clouzeaux would put it, forgetting that people leave and new one join. This is a never ending task and no zzzzzzzz is allowed.
Nor can it be left solely to the goodwill of some fantastic fleet heads of training, who too, won t be around forever.

The Colin report adressed all this and strongly advised to go back to basic which was done in part but not the whole way. In order to judge this report, one should have implemented it in full. Instead, some people started winging about " Whot ??? you want me to go and get a command on short haul when I had .......PLANNED on a forever Daiquiri splash on the beach. Nope !!! " and the implementation of this rule was postponed ...........yes !!!............10 years. Do I need to translate into NEVER or NEVER NEVER land, cuz sometimes I feel this is where we live ??? .

I see nothing shocking in the fact it is going to take that much time to come up with conclusions. If memory serves, Swissair 111 took just as long as that, and they had a lot more evidence to work with.
I can already hear the rant about " The BEA, the french state, AF, not to mention Airbus" will see to it that the books are cooked " well done ".
Hoy !!!! smell the coffee !!! So many states are involved that this will never be possible even if the french wanted it that way and for all their flaws, I don t think they do.
Something will come out of this and I am confident the ventilator will have enough dung for everyone to stay occupied cleaning himself for the next 10 years.

Last edited by Me Myself; 4th Sep 2009 at 13:52.
Me Myself is offline  
Old 4th Sep 2009, 12:31
  #4329 (permalink)  
Join Date: Mar 2001
Location: us
Posts: 694
GMDS, noelbaba's quotation of the eTurbo news article by Unal Basusta is laced with what appears to be noelbaba's opinions. Basusta's reporting, while itself containing some conjecture and opinion, has no sentence about the captain needing to be present in the cockpit during severe thunderstorms.

The French press (Figaro, Le Monde, France Soir) in reporting on Arslanian's conversation with aviation reporters on August 31 makes no mention of Arslanian saying anything at all about where the captain was during the final minutes of AF 447.
SaturnV is offline  
Old 4th Sep 2009, 13:48
  #4330 (permalink)  
Join Date: Jan 2008
Location: Pretty far away
Posts: 316
The French press (Figaro, Le Monde, France Soir) in reporting on Arslanian's conversation with aviation reporters on August 31 makes no mention of Arslanian saying anything at all about where the captain was during the final minutes of AF 447.
...................and for one very good reason.............nobody has a clue. The fact his body was the only recovered of the 3 techies doesn t prove a thing as to where he was seating. One can only speculate.
All the BEA will ever be able to conclude, be it tommorrow morning or in 18 months, will only be the most likely scenario..........unless the flight recorders are retrieved. I ve stopped holding my breath on that one.

Look folks, the french press has got to sell paper. Last week it was real estate in Paris supposidly .........affordable ( tons of laugh ), this week it s 447. In summer they come up with the usual " The wisdom of greek philosophers " when everyone is trying to get laid on a sunny beach. I think they call that " Les maronniers " in journalistic terms. Topics they pop out of the hat when they have nothing else to say. Next week it will be the famously dreaded french " La rentree " where doomsday and social Armagedon are the journo s prediction and politicians run for cover. We then quietly move on to Xmas where family turns to be a jolly good thing ( highest rate of divorce claims comes boxing day ) and so on.........
Do yourself a favour, stop reading the french press.
Me Myself is offline  
Old 4th Sep 2009, 13:54
  #4331 (permalink)  
Join Date: Feb 2000
Location: Sao Paulo
Age: 75
Posts: 792
JD, my apologies; noelbaba's post is a mixture of the original article and what appear to be his own opinions. You had obviously done a better job of checking than I.
broadreach is offline  
Old 4th Sep 2009, 16:00
  #4332 (permalink)  
Join Date: Jun 2009
Location: I am where I am and that's all where I am.
Posts: 660
No problem, broadreach, I have done that very thing before. So I had to go back and double check.
JD-EE is offline  
Old 4th Sep 2009, 20:14
  #4333 (permalink)  
Join Date: Jul 2009
Location: IAH
Posts: 58
I recall that the F/O had more experience flying the A330 and more rotations on the South American sector than the captain, although the captain had more flying hours overall. So I just wonder if the captain's presence, if it was missing, on the FD would have made a difference. Unless the CVR is recovered, we can only guess what transpired after TO up to the end. My humble opinion is that in the case of F-GZCP, what could go wrong, did go wrong.....throughout the short flight. The finger of blame points in many directions.
promani is offline  
Old 5th Sep 2009, 02:16
  #4334 (permalink)  
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 77
Posts: 1,330
Crash Location - A revisit using OSCAR & Quikscat data

This is a revisit of the data I originally presented on page 210, and something between the original and that presented below may be close to the truth.

After analysing OSCAR/NOAA surface current data for the period 01 June - 15 June 2009, and the Quikscat satellite surface (+10m) winds for the same period for the area encompassed by 5°30'N 32°30'W, 5°30'N 29°30'W, 2°30'N 29°30'W and 2°30'N 32°30'W, I have come to the conclusion some of the "observed data" bears no relation to the "actual data" resulting from the location of bodies and other debris from AF447.

The basic problem is that the North Atlantic Equatorial Current had developed a "blip" in the area of the suspected crash location. This area was in fact the location of the Doldrums at the time of the accident and the current was attempting to flow Northeast to become the Equatorial Counter Current. However, at 3°30'N 30°30'W a very strong pull to the West was developing and the surface current velocities over the period from 07 June to 17 June increased to average 9.35NM per day or 20cm/sec along the general line in which the bodies were recovered. This is nearly twice the rate provided by the satellite data. In the meantime part of the current continued from 3°30'N 30°30'W in a Northeast direction at velocities approaching 1.5 times the published figures.

The anomolies associated with the OSCAR data are probably due to a slightly lower than expected Mean Sea Level barometric pressure in the pivotal area to the West of 3°30'N and 30°30'W, resulting in the actual MSL being slightly higher than the one used in the OSCAR/NOAA calculation of the current vectors and velocities.

The Northeasterly branch of the current from 3°30'N 30°30'W carried very little debris with it - the most notable (that we know of) being the Starboard Outer Spoiler which was recovered on 13 June NNE of TASIL. Looking closely at the photos of the recovered spoiler, I sense that the damage which resulted in its separation was caused by the high velocity vertical impact of the underside of the wing with the sea surface as the wing was rotating clockwise (backwards) horizontally. The clockwise vertical rotating force exerted by the Vertical Stabilizer as the tail entered only added to the forces experienced by the spoiler.

The heading of the a/c at the time of impact was probably at some point in the East quadrant, which resulted in the spoiler departing "explosively" in the same general direction. Once the general disturbance caused to the sea by the impact had subsided, the spoiler was likely located some distance east of the remaining debris. Hence it later missed the anti-clockwise turn near 3°30'N 30°30'W and continued with the NE branch of the surface current, and was also unaffected by the surface wind due to its very low surface profile as noted in recovery photos.

In the graphic below, overlay of data is on the 06 - 18 June 2009 composite showing "positions of bodies and debris recovered" produced on page 37 of the BEA's Preliminary Report (French version) into the accident. You should note that this graphic in the body of the report differs from that shown in the Appendix, and when comparing data attributed to specific days, positions do not always match up. The pressure on the BEA to complete their initial analysis and compile the data in a limited time may well be behind these discrepancies.

Knowing the approximate position of the Vertical Stabilizer when it was recovered on 07 June, and that of debris and bodies recovered on 06 and 07 June were fairly well grouped, has helped tighten down the analysis required to back-track to the possible impact point. South of 3°30'N the current vectors and velocities provided by OSCAR seem to be fairly constant, and provided those velocities are reasonably accurate a recalculated position of the impact point is shown.

The back-track involved equating the distance and bearing that the Vertical Stabilizer was from the general track line of bodies (dashed magenta line) with the mean surface current along with wind vectors and velocities from 0300z on 01 June to 1500z on 07 June 2009 (6.5 days). A light blue (cyan) line marks the general line along which debris with a low profile to windage has been recovered. The total leeway vector and distance of the v/s is 255.3°T x 9.38NM from the mean bodies track line, and the daily factor derived from Quikscat data (modified to 2m above sea level [velocity x 0.75]) has been used along with the appropriate current vector and distance in the back-track exercise. The data used is replicated below.

Referring back to the top graphic, the green (lime) line represents the NE'ly branch of the current, and the area between the light blue (cyan) and red lines is the area in which the majority of bodies and debris were located and recovered. Debris to the West of the red line has been subject to significant windage and consequent leeway. One body was located close to the red line, and the assumption is that it was caught up in other debris. Three debris items near 3°15'N 29°45'W do not appear in the Appendix version and possibly are unrelated to AF447. An item marked "07" near the "last known position", has probably broken lose at depth from the wreckage and made its way to the surface, but how long it was there before being recovered on 07 June is another matter. Water spouts are common in the ITCZ, and odd items of debris may have been moved about through being lifted and later dumped some distance away. The current vectors shown are overlaid from the OSCAR data, and it is fairly obvious that the general drift of the bodies and debris hasn't always followed the expected line.

The accuracy of the information presented is of course reliant on data from a number of sources, but is the best that could be obtained.

mm43 is offline  
Old 5th Sep 2009, 08:54
  #4335 (permalink)  
Join Date: Jun 2009
Location: I am where I am and that's all where I am.
Posts: 660
mm43, I really like your analysis. It fits with other known data very nicely. The impact point, for example, is within the annular ring I'd expect for minimum distance from last known position and maximum distance from last known position for a plane that was not spiraling down completely out of control.

No hand of God reached out to stop them cold in their tracks. And they may not have been entirely in control. The distance of your calculated point of impact is near a point I'd expect for a plane that had been going at 4 to 5 nm a minute and was turning to the left and downwards.

Now, as to why it might be turning to the left I can only guess from an ignorant bystanders standpoint. I understand that normal deviations are to the right for traffic control reasons. I have further gained the impression that the planes fly slightly to the right of the nominal track under normal circumstances, although this is not critical to my thinking. The pilot in charge may have deviated to the left planning to go down to an appropriate flight level for a quick return to Brazil for some reason. And then he lost it. Or the entire trip to the ocean may have been in only partial control leading to the deviation to the left.

Maybe he'd executed a partial turn, the engines quit, and he dove to try to restart them. He got too low, tried to pull up into a proper ditching, and didn't made it.

Those are raw almost fantasy reconstructions to fit this additional data consistency. So please don't make a big deal of them.

There are still so many possibilities that it'll be really hard to place solid "blame" on any one thing. But, we may know enough to call for some changed procedures and MAYBE some changed equipment to prevent this happening again. (Personally I'd like to hear that the flight control computer was modified to "very strongly recommend the pilot take over but retain control until the pilot is firmly at the controls" rather than throw up its hands and say "The pilot's got the plane" when the pilot is having trouble due to buffeting getting his arm into position to take control.

JD-EE is offline  
Old 5th Sep 2009, 13:17
  #4336 (permalink)  
Join Date: Mar 2001
Location: us
Posts: 694
mm43, thank you for extensive and excellent analysis.

Two questions, and perhaps you don't have the answer.

1.) Does your calculated point of impact lie to the west of the westernmost vector of the search grid flown by the Brazilian Air Force on June 1? (That search basically overflew the projected enroute track between INTOL and TASIL with a bit of coverage on either side of the track. On June 2, the search boxes were expanded to the east and not to the west of the track. I realize you may not have the coordinates for the area searched by Brazil on the 1st. Although I understand why the grids were expanded to the east, and then south, if the grids had also been expanded to the west in the immediate days after the crash, the wreckage likely would have been found sooner and closer to the actual impact.

2.) Arslanian in his August 31 conversation with reporters said that the wreckage was in waters 3,000 to 3,500 meters deep. Here is a Wiki profile graph of the area. Eyeballing, 30.5 W is roughly near the vertical bar for the Mirante do Vale building. However, the profile is for 3.5N, not 3.1N, and this is basically an east west profile, with no north-south component. Do you have any bathymetric profile for the bottom near 3.12N, 30.54W?

Notes on the profile here:
File:AF447Cross-Section.jpg - Wikimedia Commons

Also, the vertical scale of the bathymetric profile is greatly distorted, so the slope between peak and valley may not be so much off-the-cliff as depicted.

Last edited by SaturnV; 5th Sep 2009 at 18:42. Reason: Edit to clarify the scale
SaturnV is offline  
Old 5th Sep 2009, 22:08
  #4337 (permalink)  
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 77
Posts: 1,330
JD-EE, Thanks for your comments.

SaturnV, I have managed to dig out a video monitor shot taken in the FAB SAR control center at Recife. It shows that a grid search was undertaken in 2NM lanes 10NM either side of the track and for 55NM past the Last Known Position. With lanes 2NM apart, I expect the altitude flown was 1500 feet. However, it seems from other data in the pic that they finished up concentrating on unrelated debris found well to the SE of the track

The screen shot below has had some Lat / Long points marked, along with TASIL and the possible crash location.

Arslanian in his August 31 conversation with reporters said that the wreckage was in waters 3,000 to 3,500 meters deep.
I thought "they" hadn't been able to find any wreckage, so I think he is just making something up for the media - or maybe the media padded out the story.

The Wikipedia bathymetric profile gives a reasonable idea of the topography in this area, and your reference to the distorted height is good. Put it another way,
the deepest valley is about 1.6km and the horizontal distance from top to bottom is 14km, giving a 6.57° average gradient. Bit much for most railways/railroads (1.5°), but not mountainous by any stretch of the imagination.

I will try and dig out a bathymetric profile for 3.2°N 30.9°W, I think something is available.


Last edited by mm43; 5th Sep 2009 at 22:11. Reason: typos
mm43 is offline  
Old 6th Sep 2009, 00:00
  #4338 (permalink)  
Join Date: Aug 2008
Location: Belgium
Age: 59
Posts: 72
interesting analysis mm43.....

.....however the SAR grid you posted doesn't say much without a date and legenda.

Here is for instance a map with grid west-northwest of the last known poisition, flown by one of FABs C130 on 6 June, which does seem to cover the area you're pinpointing in your highly interesting earlier post on the possible crash site:

But perhaps that is the point you and others try to make: it was six days after.

Having said that, interestingly enough your presumed impact point is within the northen part of the grid of 10000 sqkm of search area along the flight path on the same map, flown by FAB's EMB RJ 99's and fully completed by them on 2 June (re FAB note nr 6 of that date)
Dutch Bru is offline  
Old 6th Sep 2009, 03:50
  #4339 (permalink)  
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 77
Posts: 1,330
Dutch Bru,
Your point about no date on the grid I posted is of course valid. It was obviously before 6 June on account of where the FAB seemed to be concentrating its search. The difference is that on 6 June the FAB were finding debris in the area SW of TASIL, whereas on 2 June I believe the visibility was variable in rain/showers, and even though they may have flown near to, or over the 3
°18'N 30°48'W position the v/s is assumed to have been at 1500z on that day, they obviously sighted nothing.

One and a half days after the impact the floating debris pattern would still have been relatively compact - say a radius of 0.5NM, as I construe the BEA's description of the impact as having little or no horizontal momentum - more a tail heavy "flat spin".

In the cruise, I assume the trim tank was in use - not helpful later on.

Still, it puzzles me as to why the FAB had no radar contacts, e.g. a number of metalic objects were in the debris. The spoiler unfortunately would have been a rather poor target - floating flush with the surface and effectively sea clutter.

mm43 is offline  
Old 6th Sep 2009, 12:17
  #4340 (permalink)  
Join Date: Jan 2008
Location: Herts, UK
Posts: 743
In the cruise, I assume the trim tank was in use - not helpful later on.
Indeed, I also highlighted this point a couple of times back in the thread... unfortunately there doesn't seem to be much acceptance that it could have played a significant role as the systems degraded and heavy turb might have had to be flown manually - something I would have thought would be extremely significant when speed stability was paramount.
HarryMann is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.