a series of interesting observations (to a layman anyway) on Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data

appear to indicate that the storm was not `unusual` in iteself , but might have had unusual properties , being `dry` air turbulence , which wouldn`t be spotted on the radar.

the A330-200 t.h.s does have a mechanical control chain and cable loop which runs from the pedestal wheels to the input on the t.h.s.actuator. .If the E.F.C.S. has failed then this allows a physical mechanical input but will still need blue and/ or yellow hyd sys .Similarly, the rudder also has a cable system with direct control from the rudder pedals.

"And perhaps already covered, the pingers on the recorders are distance related from the sonar. So when you consider the possibilities as a three dimensional box including the depth along the debris field in miles, it truly is a needle in a haystack."

Even more daunting when you consider the bottom of the box (i.e. the sea floor) is very unlikely to be flat ... far from it if its anywhere near mid-Atlantic. I imagine this means pinger signals may well be masked by topography and could require a very close pass to pick up. My opinion is that location, not recovery, will be the bigger challenge regarding CVR and FDR ... especially if the tail section experienced significant breakup.

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So far the latest info in FMC's thread re AF's release of the 'AIRMAN' ACARS fault info is the most pertinant info avail and this is what we should be looking at.

What sequence of events could cause a Prim Computer to fail causing the AP in cmd to disconnect followed by the other faults 1 minute later is what we need to be looking at. Especially the loss of the Primary flt info provided by the ADRIRU's? And how could this effect the pressn when the packs would still be operating in pneumatic mode if there were a multi elect bus loss with control of the outflow valves still avail in 28 vdc mode....

Lets stick with what we know..

Belgique, why would
?

Not sure that this has any relevance but it is more than likely that all three crew members were equally proficient at operating the aircraft. It is to me irrelevant who was in what seat given the levels of experience in this cockpit.

Joe90 wrote:
Excellent point, but the cells move, or collapse in one place and reform somewhere else along the squall line throughout the duration of the storm so what was good, may not be when you try to divert in that direction. Not nice, especially if it is dark.

I just happen to browsed the Yahoo website and they have released the identity of the flight crews on the downed AF...

List of passengers aboard lost Air France flight - Yahoo! News

I know that Air France has been spewing too much stuff (lightning, pressurisation ,electrical failure, etc.) that they shouldn't in these early stages of the investigation but a retired Air France pilot (Jean Serrat) on France 2's main news broadcast last night stated that internally at Air France people are talking about extreme icing conditions in the time period preceding the crash...

As I said, I think AF should be a lot quieter than it is about this incident but thought people might like to know

Re no lightning strikes above FL300. I experienced a lightning strike at FL320 while circumnavigating some isolated summer thunderstorms at night over central Texas two years ago in an Airbus 319.

BlindinG

FDR/CVR locator beacon which is known as the "pinger" transmits an acoustic signal at 37.5 Khz and can be detected by a special receiver. The FDR/CVR can be retrieved as long as this "pinger" is still intact on the FDR/CVR. But there is always a chance that the "pinger" can separate from the FDR/CVR in case of high impact.

@Lost in Saigon:
If the indication was accurate, it would have almost certainly been a climb. Even if the aircraft was descending at a rapid rate and there was a hull breach, the cabin altitude would have not descended appreciably during that time until they were below 8000 feet.

A question ...

Can Sonar buoys hear the pinger?

Could a maritime patrol aircraft drop a pattern of sonar buoys to start localising the black boxes?

(and I can understand if no-one wants to answer)

I would think that it would certainly be an option and the reports indicate a US P-3 Orion was out helping in the search. It would make sense that they might be using their anti-drug / anti-sub technology to help in the search.

Rhino

FDR and CVR requirements.

TSO C123a (CVR) and C124a (DFDR)
Fire (High Intensity) 1100°C flame covering 100% of recorder for 30 minutes. (60 minutes if ED56 test protocol is used)
Fire (Low Intensity) 260°C Oven test for 10 hours
Impact Shock 3,400 Gs for 6.5 ms
Static Crush 5,000 pounds for 5 minutes on each axis
Fluid Immersion Immersion in aircraft fluids (fuel, oil etc.) for 24 hours
Water Immersion Immersion in sea water for 30 days
Penetration Resistance 500 lb. Dropped from 10 ft. with a ¼-inch-diameter contact point
Hydrostatic Pressure Pressure equivalent to depth of 20,000 ft.

Here are the parameters required to be recorded:
http://www.ntsb.gov/Events/symp_rec/...s/Grossi-2.gif
I'd rather wait for the professionals to determine the cause.

By the way, the results of the investigation are all based on probabilities. This is the most likely event etc. It is not necessarily definitive. In cases especially like this the actual cause may never be known.

Yes, our Orion anti-sub aircraft are equipped with air-dropped sonobuoys with both passive and active sonar. The active equipment can map the ocean floor while passive buoys can detect underwater sounds including the ultrasonic pingers on DFDR's and CVR's.

Despite being on drug-interdiction duties, they would almost certainly had these buoys at the ready for deployment from their base of operations.

mickyman

Specifications
Flight Data Recorder
Time recorded = 25 hour continuous
Number of parameters = 18 - 1000+
Impact tolerance = 3400Gs / 6.5 ms
Fire resistance = 1100 degC / 30 min
Water pressure resistance submerged = 20,000 ft
Underwater locator beacon = 37.5 KHz; battery has shelf life of 6 years or more, with 30-day operation capability upon activation

Cockpit Voice Recorder
Time recorded = 30 min continuous, 2 hours for solid state digital units
Number of channels = 4
Impact tolerance = 3400Gs / 6.5 ms
Fire resistance = 1100 degC / 30 min
Water pressure resistance submerged = 20,000 ft
Underwater locator beacon = 37.5 KHz; battery has shelf life of 6 years or more, with 30-day operation capability upon activation
Source: www.ntsb.gov

The ULB, also known as the "pinger" usually have the following specifications to satisfy TSO-C121

Underwater Locator Beacon (ULB)

Operating Frequency:37.5 kHz ± 1 kHz
Operating Depth:Surface to 20,000 feet
Pulse Length:Not less than 9 milliseconds
Pulse Repetition Rate:Not less than 0.9 pulse per second
Useful Life:Six years
Operating Life:30 days (minimum)
Acoustic Output, Initial:1060 dynes/cm2 rms pressure at 1 meter (160.5 dB)Acoustic Output, After 30 days:700 dynes/cm2 rms pressure at 1 meter (157.0 dB)
Operating Temperature:28º F to 100º F
Actuation:Fresh or salt water, surface to 20,000 feet
Radiation Pattern:Rated output over 80 percent of sphere

Hope this helps :ok:

Uh, I think you may be thinking of something other than a 'pinger' sonobuoy.

From: Sonobuoys

Bubbs:
Orion's carry both active and passive buoys. The passive array equipped buoys are fully capable of picking up the DFDR/CVR pingers.

Sorry Bubbers, but for clarification I should have mentioned these are two different sonobuoys.

ADIRU faults
 

Is it not entirely possible that the same ADIRU fault that caused the airbus on route to Perth to plummet towards the ground ( it took a reading from the fauty unit rather than a reading from the other 2) could have happened here? couple that with flying through severe turbulance/ thunderstorms , and if the plane did dive towards the ground for a number of seconds , would it be recoverable?

And the active equipment can't map the ocean floor as you suggested. Perhaps you were were thinking of side scan sonar which undoubtedly will be used in the search. No problem.

Buoys might have limited value in this search.

The pingers can nominally be heard for about 2 miles (10,000 ft) The depth of the ocean in this area appears to be about 10,000 feet, but varies between about 8,000 feet and 12,000 feet. It would be pure luck to drop a monitoring buoy in a position where it heard a pinger, given the depth in the area, and the fact that at the surface, the radius of success is substantially smaller than 2 miles..

The distance the pinger can be heard will also be affected by any thermal layers in the ocean, and the terrain where the wreckage came to rest, both reducing the range..

The search won't begin to be effective until towed sensors that work below the surface are deployed. I suspect they are being flown in as we discuss this.

Taken from RTE News website...
"French air safety investigators have said they are not optimistic that the black boxes from the missing Air France jet will be found.
And the director of the Office of Inquiries and Analysis, Paul Louis Arslanian, said that even if the flight data recorders were recovered, they might not explain the cause of the crash."

Why is this attitude being taken by the investigators? It almost sounds as if they are not willing to try too hard. Surely, they should be resolved to get to those boxes to try to determine the cause of this accident. I'm sure ( as said previously) modern technology is up to the job if the money is made available.

I'm sure one or the other nation has subs in the area with passive array towed sonar.

Officials have released some details of these messages, but a more complete chronology was published Wednesday by Brazil's O Estado de S. Paulo newspaper, citing an unidentified Air France source.
Air France and Brazilian military officials refused to confirm the report. But if accurate, it suggests that Flight 447 may have broken up thousands of feet in the air as it passed through a violent storm, experts told The Associated Press.
The report said the pilot sent a manual signal at 11 p.m. local time saying he was flying through an area of "CBs" — black, electrically charged cumulo-nimbus clouds that come with violent winds and lightning. Satellite data has shown that towering thunderheads were sending 100 mph (160 kph) winds straight into the jet's flight path at that time.
Ten minutes later, the plane sent a burst of automatic messages, indicating the autopilot had disengaged, the "fly-by-wire" computer system had been switched to alternative power, and controls needed to keep the plane stable had been damaged. An alarm also sounded, indicating the deterioration of flight systems, according to the report.
Three minutes after that, more automatic messages indicated the failure of two other fundamental systems pilots use to monitor air speed, altitude and direction. Then, a cascade of other electrical failures in systems that control the main flight computer and wing spoilers.
The report repeats a detail previously released by Brazil's Air Force: that the last message came at 11:14 pm, indicating loss of air pressure and electrical failure. The newspaper said this could mean sudden de-pressurization, or that the plane was already plunging into the ocean.

CB, supercooled water droplets and airframe icing
 

I am one of those who assumes for obvious reasons that (Air (bus)) France will not let any stone unturned to find the DFDR and CVR. So they'll manage and we'll know. Until then I would not want to speculate, but at the same time wouldn't to leave some speculation without comment.

Concerning those posts questioning whether icing could not have played a role (in the disabling of a series of flight related functionalities on board of the A332), I wanted to point to supercooled water droplets. A remarkable phenomen, which, in the absence of a seed crystal or nucleus around which a crystal structure can formate, makes that a liquid (in this case water) can remain fluid well below its freezing point.

Droplets of supercooled water often exist in stratiform and cumulus clouds. They form into ice when they are struck by the wings of passing airplanes and abruptly crystallize.

Why?
 

"Why is this attitude being taken by the investigators? It almost sounds as if they are not willing to try too hard. Surely, they should be resolved to get to those boxes to try to determine the cause of this accident. I'm sure ( as said previously) modern technology is up to the job if the money is made available."AOB9

Sorry once again I can't find the damned quote function.......however:

I am not a conspiracy theorist but we should bear in mind that the French investigators will be under Judicial or Government Ministerial control - they are not independent as was proven over the Concorde investigation.

Airbus is an important element in the French economy and so, if those who have wondered about flight controls in such a situation - poss total elec failure for example - are right to be concerned, then you can bet Airbus & Air France will know already if it was a factor.

If AF447 did break up at high altitude, as investigators are now speculating, it is essential that an early explanation is found for the apparent rapid and fatal depresssurisation – Lightning strike or the massive forces within a tropical storm, whatever the cause, until there is a reasonable and plausible explanation it will inevitably put the A330-200 fleet and potentially the whole Airbus family, in a negative light .

If they cannot locate the FDR/CVR or pinpoint the reason for the accident it would be the worst result.

Assuming the aircraft weight, the weather in the area, and the flight level they were flying, together with the limited communication possibilities they had over the ocean, AF447 was not in a comfort zone to start with.

I suspect that they are trying to keep expectations low, as there is a fairly good chance he may be right. If they are actually found, they will look like heroes.

Based on the history of these types of incidents, searchers have been able to find the recorders in circumstances that seem equally difficult more often than not. They also want to find the recorders, since if another similar unexplained incident happens, it would wipe out orders not only for the A330, but also for the A350 and any chance at keeping the tanker program. (Think deHaviland Comet)

probe icing
 

This French publication (in French) is reporting that AF knows of ACARS messages from AF447 indicating icing of the probes. There's an AD for the A330 about this starting from 2001 I believe. Can anyone else confirm the existence of these messages?

AVION D'AIR FRANCE DISPARU : Du givre localisé sur les sondes de l'Airbus A330, actualité Société : Le Point

This is what I was trying to get to in my earlier post. It would seem that the ACARS transmitted painted a grim picture of what was going on with the airplane. Since all my flying was in Boeing equipment, and that sometime back, thanks to the info provided thus far, I am beginning to understand the potentially poor conditions during this time frame, and the integrity of the airplane is certainly in question. No doubt, cabin pressure was showing an acceleration in altitude, not a loss.

I also think there is a good chance the airplane may have gone down more intact. An in-flight breakup at altitude would have made for a very large footprint of debris, not what has been found and reported.

I remembered and dug up the link to the AAIB report in to an A319 that had several electrical failures during the climb out of LHR. I know this isn't the same A/C type or identical errors but it makes you think about the challenges the crew may have had, especially with loss of comms, lighting and having to use visual references to fly.

http://www.aaib.gov.uk/sites/aaib/cm...ection%201.pdf

Bomb Threat called in on May 27 for an Air France flight from Buenos Aires to Paris as reported by CNN. Unconfirmed of coarse but one should suspect this is an initial cause until proven otherwise, even if for another destination.

``Air France had received a bomb threat May 27 for a flight from Buenos Aires, Argentina, to Paris, sources in the Argentine military and police told CNN on Wednesday.``

The A330 has flown successfully for 15 years or so without loss of life. One going down in a severe storm is no way comparable to the Comet.

As usual when airbus and france are discussed there are a number of posts concerning hidden info and conspiracies.

I believe that accident statistics does not provide and statistically significant difference between airbus and boeing aircraft of the same generation (don't know which direction it would point actually).

If this is the case, I assume that all those that suggests that the french/airbus etcetera are hiding info in the interest of the company (nation ...), also suggests that such a behaviour would be able to achieve aircraft with basically equal level safety even if they do not support business practice such as sharing info in the best way to avoid repetition of causes.

Personally, I believe it would be impossible to reach current safety levels if information was not efficiently used to avoid repetion of incidents and accidents.

The source you point to there is saying something perhaps a tad different:

" Ainsi, selon nos informations, sur l'AF 447, des sondes extérieures sont signalées comme ayant givré. Première question : l'excès de glace est-il lié à une défaillance électrique du réchauffage de ces sondes ? C'est très vraisemblable, car, comme nous l'avons écrit lundi, des pannes électriques ont été signalées lors de la dernière transmission automatique de données de l'Airbus, à 04 h 14."

"So, according to our information, on AF 447, the external probes signalled that they were iced-up. First question: was the ice build-up associated with an electrical failure of the heaters for these probes? This seems very probable, for, as we reported on Monday, the electrical system failures were specified in the last automatic data transmission from the Airbus, at 04 h 14."

My reading of this is that they are speculating that the electrical system failures on AF447 caused the failure of the probe heaters, and that the probes then reported that the were iced-up.

AGB

I cannot believe that so many people have bet on the complete left field, long shot, outsider, as the cause of this accident. How many times has weather brought a plane down from the cruise? I would suggest that 1000's of aircraft have encountered CB's at altitude over the years, for one reason or another and survived.

What is more likely, something that has not happened before, or some form of mechanical failure, either latent, or caused by something either not doing what is should do, catching fire or blowing up on board the aircraft. That has happened many times and brought aircraft down.

I thought this thread was about an AF A330 crash, not about sub details and unrelated stories of same, sleeping captains or the continuing unfounded speculation regarding electrical or flight control or pressurization or airframe icing/explosion or airframe failures.

The thread is now repeating itself as new entrants arrive without reading, with their pet "theories" and just plain nonsense. No wonder it's culled regularly.

At this point, nobody, including Air France, even knows the exact lat/long of the accident site let alone the status of the aircraft from entry into the area until disappearance. And if AF or any authority knows, they certainly haven't told anyone here.

We only hear (but have no evidence or confirmation that it is "A330" wreckage) of "pieces" found and a 20km "oil slick".

In the absence of an accident site, the DFDR and the CVR, the only evidence that is certain but which has yet to be released and described here is,

a) the dispatch status of the aircraft under the MEL, (was the radar working, were there any other MEL items?),

b) the exact nature/content of the ACARS messages we are told were received by the airline (and not just by ACARS amateur hackers).

Specifically, what data needs to be confirmed on the ACARS messages are the time stamp of the message, the ATA Chapter reference of the fault, and the exact wording of the fault.

The ACMS and/or AIMS collates and transmits such faults including ECAM messages.

These messages are very specific and targeted for maintenance which then have fault-handling procedures. The messages will, if the aircraft and its systems were capable of sustaining such transmissions, be accurate and sufficient evidence upon which to proceed, again in the absence of an accident site.

Even the path through the satellite-weather images put together and referenced/linked four or five times here is speculative in terms of the aircraft track and timings. We just do not know this information. It is all we have.

Litebulbs
 

I'll try to keep it simple. Engineers cannot design a plane to withstand the highest loads that nature could ever impose on a structure. Those loads will break the plane.

Dysag
 

They have done a pretty good job up till now.