Air France A330-200 missing [Archive] - Page 3

Dutch Bru

2nd Jun 2009, 14:16

NOTE TO PRESS 02/06/09 (09:20 Brasialia time)
REPORT OF THE SEARCHES OF AIR FRANCE FLIGHT 447

The Air Force Command says the aircraft that are in the mission's search flight AF 447 localized and small traces of aircraft wreckage in the ocean, however it is not possible to state that belong to the missing aircraft.

At the dawn of Tuesday (02/06), the R-99 6751 aircraft that took off from Fernando de Noronha-PE at 22h35 (Brasília time) to perform scans using the synthetic aperture radar, identified around 01:00 (Brasília time) some "return" in the radar indicated that non-metallic and metallic materials floating in the ocean. The positions of these "returns" were marked by geographical coordinates and led to the search rescheduled, focusing now, approximately 650 kilometers north of Fernando de Noronha-PE.

Aircraft C-130 saw, around 06h49 (Brasília time), material at two points about 60 km distant. Among them, a plane seat, small white pieces, an orange ball, a drum, and traces of oil and kerosene.

Finally, the Air Command reports that it maintains 10 aircraft available on the actions of search and rescue aircraft.

See the location of sightings:

Veja o local dos avistamentos:
http://www.fab.mil.br/sis/enoticias/imagens/pub/3585/i09629235651087.jpg (http://www.fab.mil.br/portal/imagens/avista_voo447.php)

RiSq

2nd Jun 2009, 14:20

Like others have said, it seems odd that AF came out straight away with there opinions on the cause unless they have more information then they are letting on.

For fellow non-professional pilots commenting on this thread, pleas be careful what you post, news stations and reporters monitor this site and it just helps fuel there overactive imaginations and need to get "The scoop" so they will newsflash all sorts of madness.

These professionals commenting on the likes of Sky news are bad enough. I can only assume they've given up the profession some time ago and taken up the mindset of armchair pilots on MS FS.

Those informed, please keep posting.

XB70_Valkyrie

2nd Jun 2009, 14:22

It is simply kind of external, autonomous satellite mobile phone with included GPS attached to whatever part of the plane is most easily adapted for that purpose.

Yes, that is what ELT/EPIRBs do (but not sat phone). The newer 406 MHz units include a GPS and can transmit lat-long and have higher accuracy than the 121/406 beacons but in this case a beacon would be "good enough" to find the a/c I'd imagine. If the ELT had been activated and received we would have heard about it early on.

The issue is building something that can survive an impact and not be dragged to the bottom.

PS the postings about A319 electrical issues and A300 rudder breaking off aren't really as relevant as the ADIRU/pitch-up, WX and terrorism discussions.

Someone asked this and I didn't see an answer, does the AF A330-200 have the same make/version ADIRU as the QF A330-300?

deSitter

2nd Jun 2009, 14:31

Here is an example patent:

Lightning strike protection method and apparatus - Patent # 7525785 - PatentGenius (http://www.patentgenius.com/patent/7525785.html)

One thing immediately evident here is the mistaken notion that simply conducting the current through the composite is sufficient to protect it. Again, the main thing that protects an aluminum airframe is the fact that conduction currents MUST occur on the OUTER SURFACE of a metal conductor - the electric field cannot penetrate more than a few thousandths of an inch into metal because the internal free electrons rearrange themselves to cancel out the applied field - thus a conduction current can only exist very near the surface of any metal. However, if this metal is itself encased in some other material - for example, an insulated wire - that material can still become extremely hot from the kinetic action of the conduction electrons. No matter what ground testing has been performed, I very much doubt that an embedded metal mesh could deal with the megaJoules of current coming from a large lightning strike without blasting away the surrounding matrix in which it is embedded. Such a mesh would necessarily have to exist on the outer surface of the composite to be really effective. The only realistic test of such things is to fly around in a thunderstorm with a drone, and try to have it take a strike, and look at the results. Has anything like this been done?

-drl

md-100

2nd Jun 2009, 14:34

I guess this A330 have a 406Mhz ELT..

The ELT activates with G-force.
No ELT signal had been tracked (SAR doesnt have the exact location)

so no impact (G-force) or an explosion/fire of the ELT.

deSitter

2nd Jun 2009, 14:36

I'm absolutely in favor of INTELLIGENT speculation - that is often how the causes of airplane accidents are uncovered. But just throwing up every possible scenario is less than pointless.

-drl

grimmrad

2nd Jun 2009, 14:36

Nobody so far (even now it occurs with wreckage spotted) has brought up the possibility that the aircraft may have actually tried to return due to WX + malfunctions and made a turn. Someone in the forum mentioned that that would be his first option in a situation with heavy WX and trouble on board - to get down in a controlled fashion at the closest runway asap. And this would have been behind them. That would mean that everybody seems to be concentrating at the wrong area and the actual plane might be many many miles away...?
Just a thought.

Diclosure: not working in the airline industry (but a scientist/physician)

donnlass

2nd Jun 2009, 14:37

Whats a RAT please?

Is it that little generator that drops through the fuselage as in the Air Transat glide incident?:confused:

Cheers

Donnlass

BoeingGTi

2nd Jun 2009, 14:39

Ram Air Turbine

abc987

2nd Jun 2009, 14:40

Lots of amazing speculations including more and more contorted reasoning.

All I know is that the Safety folks will not have ruled out terrorism as quickly as the folks on this discussion group. We live in very turbulent times, so surely a bomb is a more credible cause than many of the arcane theories put forward here.I respect your opinion, and will provide my reasons for not agreeing with you;
If this was terrorism, isn't the point of terrorism to cause fear of you for your cause... In the past when there has been a bombing there has (generally) been multiple terrorist groups claiming that they did it, this is because they want to be associated with the death of many people... No terrorist group has claimed responsibility for this as of yet, and the responsible one surely would want to be associated with their dirtywork. However, on the other side, it might not have been terrorism as such, there is a innumerable amount of possible people and causes for someone to put a bomb on that plane, or any plane. As simple as someone (somehow) doing it as a lone agent, as complex as anything (logical) you can imagine really...
However it is less likely that one of those happened in the opinion of many people here (including me) than the likelihood of a failure in the aircraft, human error, or weather...
The arcane concepts are just concepts that in some cases (not always though) make sense with the information that is available now, in all likelihood many (almost certainly including mine! :)) will be proven wrong when more facts are found/revealed over time...
I thought my idea wasn't stupid, now I realise that I am a complete idiot for not realising that fuel and other bits might float without surface tension, and completely forgetting that it could have broken up in midair... But, what are you supposed to do about ideas you want to share, you shouldn't be scared that you will be ridiculed... The media if they are following this thread should know after what has been said over these pages on this topic that what is here is speculation, and it can be very well-informed speculation, or not, but no speculation *should* be reported by the media, if they still do it, it is them that is at fault, not the people who shared an idea, as nothing more than an idea....
I do not own this forum, and if whoever does own it disagrees with my views, then they can do whatever they want with what I have written.

And to something on the topic, does anyone know what is with the ELT?

DingerX

2nd Jun 2009, 14:47

The 24-hour news cycle is more demanding than the available news. So they go casting about.

Here there really isn't any information, so they read off what they find elsewhere. Then those sites start citing the media, and we get a feedback effect that amplifies the non-information. So, this nonsense about people sending cellphone messages. BS.

When members of the news media starts reading off posts on a website, whatever claim to authority that website has disappears very quickly, as the site becomes the focus of attention and of people with all kinds of weird motivations. It's far easier for someone to make a post that sounds authoritative and factual than for someone to make one from authority or containing facts. So, after every recent accident of note, the PPRuNe thread gets inundated with noise for the first 72 hours or so, as verisimilar jockeys try to put up every unimaginable combination to sound important. And I'm sure the moderators are deleting thousands of posts, including some pertinent ones that only seem superfluous.

So, I must clarify something. When in answering a post asking what Richard Quest's PPRuNe username might be, I speculated "Speedbird Yoke Peter". My rationale was that such a username would be homage to the hand-in-hand work that the European press and the safety organizations did to improve safety in the aftermath of the tragic loss of the BOAC Comet (YP) off of Elba at the dawn of the Jet Age. I did not mean in any way to refer to the tabloid reports of the lurid circumstances surrounding the alleged arrest of Mr. Quest in Central Park, and I apologise if my speculation was taken in that way.

cockney steve

2nd Jun 2009, 14:49

Today on BBC Radio 2, Jeremy Vine interviewed Philip Stott, Emeritus Professor of Biogeography, London University. the broadcast was at approx. 12.20 BST,2nd. June.

A non-sensationalist, accurate explanation of the area's weather conditions, Cu-Nims' Etc. and the potential for destructive energy therein. A very rational and balanced piece....the BBC website has a "listen again" feature,for those interested. BBC news still reporting sighting of some debris , as before.

mm_flynn

2nd Jun 2009, 14:56

I guess this A330 have a 406Mhz ELT..

The ELT activates with G-force.
No ELT signal had been tracked (SAR doesnt have the exact location)

so no impact (G-force) or an explosion/fire of the ELT.

to my knowledge all civil ELTs need to a) maintain connectivity to their antenna (which may be built in), b) not be destroyed by impact or fire, c) most importantly - remain on the surface of the water.

No ELT signal means very low likelihood of rafts being deployed - which by now means no survivors. It says nothing else about this accident.

Flavia Lima

2nd Jun 2009, 15:02

I used online translator and not correct! Sorry ...

Here the fix:

I spoke with passengers who were on the flight prior to the AF 447, the AF 444, which came from Paris and landed in Rio airport at five o'clock in the afternoon of Sunday. Two hours later, the same aircraft took off with the flight AF 447.

They told me that the plane suffered a strange turbulence in the region where missing. That the plane 'trepidou'e the pilot made a sudden maneuver.

There was also a breakdown in the electric system of those screens that show a map of Orta flight for each passenger - and for watching movies where too. They surprise because the sky was clear, without clouds, even with sunlight.

Can I see you know much about airplanes. Someone can explain what would have happened with the Airbus A330?

Blind Squirrel

2nd Jun 2009, 15:10

He said: "The only thing we know for certain is that no distress call was sent by the aircraft, but the normal automatic alerts, for a three-minute period, indicated the shutdown of all the systems."

Admittedly, politicians are not technicians, but I don't know how he can know either of these things. Certainly, no distress call was received, but does that mean none was sent? And I'm not sure he knows what he's saying when he speaks of a complete "systems shutdown."

HeathrowAirport

2nd Jun 2009, 15:11

Well if we put this into context, AirFrance the AIRLINE itself has a message reported of a Short circuit via ACARS from the plane Itself, In Systems (Electronics) Its an abnormal low-resistance connection between two nodes of an electrical circuit that are meant to be at different voltages. This results in an excessive overcurrent limited only by the Thevenin equivalent resistance of the rest of the network and potentially causes circuit damage, overheating, fire or explosion. Now if I read further on in my book, It says Common usage of the term implies a condition arising from failure of electrical insulation, from natural causes (lightning, wind, and so forth)

So the likelyhood could be a Lightning strike, in a storm (Possible, not defineable) and lightning strikes at, this is what can happen; YouTube - An electric pole on fire (http://www.youtube.com/watch?v=Zru1V_OC88o)

Lamyna Flo

2nd Jun 2009, 15:13

They told me that the plane suffered a strange turbulence in the region where missing.

What passengers describe as "strange" is often just normal, moderate turbulence or aircraft movement. I would pay attention if the flight crew were making the above statement. Not pax.

There was also a breakdown in the electric system of those screens that show a map of Orta flight for each passenger - and for watching movies where too. They surprise because the sky was clear, without clouds, even with sunlight.

AVOD/IFE systems often have problems. It usually doesn't indicate anything sinister.

Someone can explain what would have happened with the Airbus A330?

If you read back over the last 26 or thereabouts pages of postings, you will see a number of intelligent speculative posts (and a large number of truly idiotic ones) about what might have happened. Nobody, however, can explain what actually did happen until all the facts are in, and even then maybe not with 100% certainty. We just have to wait.

abc987

2nd Jun 2009, 15:19

Can I see you know much about airplanes. Someone can explain what would have happened with the Airbus A330?

At the moment, I personally, and hopefully everyone else here, can tell you that, with the current information that has been provided to the public, no member of the public can truly explain to you what has would have happened with the a/c. All that members of the public are able to do is speculate on what has happened, and a large amount of this speculation could very easily, and I dare say with the current information we have likely will, be proven wrong once the official investigations are finished and far more information is revealed. I would also strongly caution you as a member of media, against publishing anything that has not been supported by very credible sources. This is because once something comes from the media, most people will believe it is fact, and that could include people personally affected by this. The effects of informing people based on information that is not independently verified and checked against many sources unless coming from a highly credible one (the government being an example in some but certainly not all countries) can be far further reaching and worse than expected.

Evanelpus

2nd Jun 2009, 15:19

I used online translator and not correct! Sorry ...

What does trepidou'e mean?

Can I see you know much about airplanes. Someone can explain what would have happened with the Airbus A330?

If we could do this, anxious relatives wouldn't have to wait months, if not years to find out how their loved ones died.

I'm sure that as a eager journalist you want to have all the answers yesterday. Sadly, no-one knows yet what happened to flight 447, there have been some educated guesses already here, some downright stupid ones too. I'm not going to add to the speculation on this tragic accident, I have attended the aftermath of aircraft accidents and I can tell you that the images will be with me until the day I die. Let's hope the authorities find out quickly what happened.

Mephistopheles

2nd Jun 2009, 15:21

On another note, surely in this day & age we should not be relying on seriously out dated HF in some of the most remote parts of the world.
Or at the very least get better equipment-perhaps like the HF in Austrailia since that always has been very clear & easily contactable.
Again, the penny pinchers may be indirectly one of the links in a crash but they as usual will never be held to account.
So how much is safety really worth?

hellsbrink

2nd Jun 2009, 15:22

Its an abnormal low-resistance connection between two nodes of an electrical circuit that are meant to be at different voltages.

Not necessarily. A "short" is when, for some reason, you have an abnormally low resistance in a circuit which results in an extremely high current flow almost instantly. Now, a common cause of that is the failure of electrical insulation in a circuit and the increase in current is so much it will cause excess heat which could cause the insulation on adjacent cabling to fail, leading to an overvoltage in a lower voltage circuit as you describe as bare cables decide to touch each other.

The cause of the original degradation could be many, of which an overvoltage from a lightning strike is one, but not the only, cause.

Let's just wait on the reports, shall we.

jimpy1979uk

2nd Jun 2009, 15:28

With regards to ELTs on Airbus aircraft. There would have been likely three ELTs on the aircraft. One is fixed, its located in the rear ceiling area of the cabin with an external antenna, its the small antenna in front of the fin. Its controls are located in the overhead panel in the flightdeck. As the aircraft is likely to of broke up the chances are the ELT and antenna still being in serviceable state are very small.

There are also two portable ELTs located in the cabin but these would have to be activated by anyone that could have got to them.

Some information about the ELTs that may have been to this MSN are found here: ELTA : Elt, power supply, satellite transmission, physico-chemical analysis (http://www.elta.fr/uk/emergency-locator-transmitters-elt/1/emergency-locator-transmitters/9)

As for the ELBs on the DFDR and CVR these activate on contact with water. If you want some specs here's a website for the manufacurer of one type of ELB its: Dukane Seacom Aviation Products (http://www.dukcorp.com/seacom/products/aviationProd.htm)

wes_wall

2nd Jun 2009, 15:29

New information provided by sources within Air France suggests, that the ACARS messages of system failures started to arrive at 02:10Z indicating, that the autopilot had disengaged and the fly by wire system had changed to alternate law. Between 02:11Z and 02:13Z a flurry of messages regarding ADIRU and ISIS faults arrived, at 02:13Z PRIM 1 and SEC 1 faults were indicated, at 02:14Z the last message received was an advisory regarding cabin vertical speed. That sequence of messages could not be independently verified."

I have seen this posted several times, but have not seen a reply to it. Would someone explain / comment on ADIRU, ISIS, PRIM 1 and SEC 1 faults.

clearedtocross

2nd Jun 2009, 15:34

There are different variants of ELT's, broadcasting on at least three different frequencies (121.5, 243 and 406 Mhz), the 406 MHz now being fashionable since it is traceable by satellites and can modulate a registered ID and an optional GPS calculated position onto the carrier frequency.

However, there is a big difference regarding crash sustainability to blackboxes like CVR and FDR. The latter do not have to work after a crash, it's good enough if they keep recorded information.

An ELT however must work after a crash only. This means that it must be powered and wired to an antenna which in itself must not be obstructed by large metallic structures (faraday cage) or what's even worse - water.

Even the technically less burdened will understand that it is not so easy to construct and place an ELT that will be working after its holding structure crashed into the water (or into a rock) at a few hundred knots. An ELT is therefore totally useless for the purpose of tracking an aircraft that slammed into the sea. Black Box beacons that will work submerged are transmitting their pings in a way not detectable by satellites or flying aircraft.

However, it is possible and systems are commercially available to track an object (persons, cars, ships, containers, etc.) via satellite (and GPS position) as long as it it travelling. Then, in an emergency, the end of a track would indicate the position of the stricken object.

MU3001A

2nd Jun 2009, 15:35

Mephisopheles: Again, the penny pinchers may be indirectly one of the links in a crash but they as usual will never be held to account.
So how much is safety really worth?

Are you of the opinion that better communications equipment could have prevented this accident?

aa73

2nd Jun 2009, 15:36

IIRC, back around the 1996 time frame, an Air France 744 was scheduled to fly the Jo'burg-CDG route. Upon accepting the aircraft, the flight crew noted that the wx radar was inop. After much discussion, the decision was reached to launch, but with a massive wx deviation around the ITCZ. Approaching the line of wx over central Africa, intense lightning was observed. Crew even called up a local control tower which was reporting heavy rain and lightning. Despite large wx deviations, crew ended up flying through a CB. After extreme turbulence and in flight upset, aircraft was diverted to Nice. Structural damage as well as one fatality were the results.

As detailed in book "Catastrophes Aeriens".

Mark in CA

2nd Jun 2009, 15:39

Two earlier posts provide some data that I haven't yet seen put together. The timining is interesting.

First, this from The Aviation Herald:

New information provided by sources within Air France suggests, that the ACARS messages of system failures started to arrive at 02:10Z indicating, that the autopilot had disengaged and the fly by wire system had changed to alternate law. Between 02:11Z and 02:13Z a flurry of messages regarding ADIRU and ISIS faults arrived, at 02:13Z PRIM 1 and SEC 1 faults were indicated, at 02:14Z the last message received was an advisory regarding cabin vertical speed. That sequence of messages could not be independently verified.

And then this from a weather analysis:

It appears AF447 crossed through three key thunderstorm clusters: a small one around 0151Z, a new rapidly growing one at about 0159Z, and finally a large multicell convective system (MCS) around 0205-0216Z. Temperature trends suggested that the entire system was at peak intensity, developing rapidly around 2300-0100Z and finally dissipating around dawn. From a turbulence perspective, these cold spots would be the areas of highest concern as they signal the location of an active updraft producing new cloud material in the upper troposphere.

If these are correct, it puts the ACARS messages occurring during the most severe convective system.

starliner

2nd Jun 2009, 15:41

During design and certification it is incumbent upon the manufacturers and agencies to consider an "infinite" number of failure modes and satisfy themselves that systems and software will react to failure modes in a manner that does not compromise the safety or integrity of the aircraft.

Human fallibility will surely miss something along the way, as any software designer will attest. The design response to this is to provide redundancy.

The few data that seems to be emerging here does suggest that here could be a situation where the system responses may not have been appropriate. It is a moot point as to whether human control responses may have been more suitable.

For this reason it is critically important to recover as much evidence as possible.

peter we

2nd Jun 2009, 15:43

At the million volt level of lightning, insulators can become conductors.

Air, for instance, is an superb insulator, but put a few tens of million volts across it and it will conduct.

The heating effect is caused by multiplying Volts by Amps to get Watts.

The behaviour of lightning when it strikes is sometimes bizarre.

Which is why all sorts of equipment ( e.g aircraft) are tested in a lightning test chamber.

jimpy1979uk

2nd Jun 2009, 15:43

The ADIRUs(Air Data Inertial Reference Unit) provide information such as Altitude, Airspeed and other air data information as well as inertial position which is an independant navigation position for the aircraft, search for inertial navigation on the net and you'll get an idea about what its all about. There are three ADIRUs on this type of aircraft.

The ISIS(Integrated Standby Instrument System) is electronic version of the back up instruments. It contains all the required sensing elements in a single unit to provide similar information to the ADIRUs

Prim 1 is one of the primary flight control computers of which there are three.
Sec 1 is one of the secondary flight control computers of which there are two. These are brains behind the flight control system. There are three laws for the FBW system and these are Normal Law, Alternate Law and Direct Law.

Geotrash

2nd Jun 2009, 15:45

Besides that, inside an airplane is a perfect Faraday Cage which is also immune to external interferences.

Not quite correct. A Faraday cage depends on being effectively grounded, which an aircraft in flight is not.

Cheers,
Dave

Akhenaton

2nd Jun 2009, 15:51

[Quote Aviation Herald]
New information provided by sources within Air France suggests, that the ACARS messages of system failures started to arrive at 02:10Z indicating, that the autopilot had disengaged and the fly by wire system had changed to alternate law. Between 02:11Z and 02:13Z a flurry of messages regarding ADIRU and ISIS faults arrived, at 02:13Z PRIM 1 and SEC 1 faults were indicated, at 02:14Z the last message received was an advisory regarding cabin vertical speed.
.../...
The sequence of messages reportedly received via ACARS raises memories of the Accident: Qantas A333 near Learmonth on Oct 7th 2008, sudden inflight upset injures 74 people on board and Incident: Qantas A333 near Perth on Dec 27th 2008, navigation system problem, and turns attention towards the emergency airworthiness directive released by both FAA and EASA, see also EASA issues updated emergency directive regarding Airbus A330 and A340 ADIRU issues.
[End of quote]

Seems to me the most accurate and troubling facts... (But i'm not a pro)

Loose rivets

2nd Jun 2009, 15:56

BBC News

"In this area, they saw an orange buoy, an airplane seat, small white pieces, an airplane turbine as well as oil and kerosene.

Shallow water, or light turbine?

Folk should get some idea of the scale of potential power when talking about lightning. The worst scenario could see an aircraft vaporized. The total energy in a mature cell is up there with an atomic bomb. It's just that the the discharge is seldom focused in line with an airborn hull.

Faraday cages, and fiber-optic's immunity, is nothing but wishful thinking.

I know from personal experience, that a 'bolt' can enter an aircraft. The light intensity, once the sheath has been irradiated away, would saturate then destroy the fiber data-lines.

A discharge goes much where it wants. My biggest went in what became a 4" hole in the top of the wing, round the rubber fuel bags, and out a similar hole - in line with the top hole. I'm under no illusion that if the 'bolt' had been more vigorous, we'd have lost the wing in moments.

H_Pipeline

2nd Jun 2009, 15:57

I found this very interesting and factual analysis of the weather condition prevailing near the INTOL and TASIL location at the time AF447 would have been flying in the area, I though some would find it interesting. I assume that the author of this analysis is okay to share it on a forum since he made it available on the internet.

Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data (http://www.weathergraphics.com/tim/af447/)

If the link isn't working, try a bit later, it is because the server is too busy, or down...

Tail Chase

2nd Jun 2009, 16:08

The Brazilian AF press release makes a few points quite clear...
1,) They are not identifying the objects as belonging to AF447...
2.) It wasn't a turbine that was seen floating, but rather a drum-like object....

Cheers
Tail Chase

PJ2

2nd Jun 2009, 16:12

Loose_rivets;
Faraday cages, and fiber-optic's immunity, is nothing but wishful thinking.
Yes, concur, but perhaps you misperceive the intent of the metaphor of a "faraday cage" as used in this discussion. It is useful in conveying an understanding as to why 99.9% of aircraft struck by lightning are not affected. That's all that was intended I think - in lightning strikes, the aircraft is simply part of the path "on the way to electrical ground". That lightning can do the damage described may be true in terms of the energy levels contemplated but the hull losses simply aren't there.

Of far greater concern here, I think you'd agree, is the power of convective columns within the thunderstorm cell(s) and the possibility of low to poor radar returns from same. Like most who do/did this work, I've seen it once or twice and been surprised at the violence of "what wasn't supposed to be there according to the radar"...

poison;
I think looking for cause(s) in the area of electrics/lightning/emergency elect configs etc is looking in the wrong areas; the reasons for saying this have been resident in this thread for about a dozen pages when BOAC first asked the question about the #3 VHF. The ACARS and #3 VHF systems are powered by the AC1 and DC1 buses respectively; the AOM does not list the bus(es) which power the SATCOM but most assuredly SATCOM would not be powered in any abnormal electrical configuration. Only the #1 VHF is powered by the DC ESS bus in either the Emergency Electrical Config or Flight on Batteries Only.

FYI, the ACARS switches automatically from #3VHF to SATCOM when out of VHF range.

If the ACARS sent "maintenance" messages etc then obviously it was working and therefore so was the #3 VHF, ergo the electrical system was working up to the point where, it is rumoured only, flight control/autopilot system maintenance messages, (see previous posts re the possible nature of the messages) were being sent. There is some mention here of "alternate law". Of course, it is impossible to know this at the moment until either the messages are verified and made available publicly, or the DFDR is found.

We don't know what the aircraft was doing or how it was performing after these messages were sent therefore, with present knowledge, even "intelligent" speculation is not possible from that point on and we will have to wait for other sources of facts. The DFDR/CVR will be of immense assistance. Though AF runs a FOQA program, I doubt that the QAR would have survived but we can hope.

Brakes on

2nd Jun 2009, 16:17

4 PW's
You talk about "uninformed drivel" having said in the same post "I read somewhere that Air France 447's wing touched an A320 rudder". Apart from the fact that it was an A321 and happened in Paris this happened in 2006!!!!
I would call this uninformed or not bothering to check your inputs as so many others do or rather do not do.

cockpitvisit

2nd Jun 2009, 16:20

Why can't we all just wait until something/somebody is found?
...
Every post is feeding the journo's and in turn they are getting facts wrong.

Curiosity is a part of human nature. There is nothing wrong in speculation. Yes, some posts are repeated over and over again and get boring, but most of readers can filter through it. If you don't like this thread, simply don't read it instead of telling other people what to do. Every regular visitor here knows that crash-related threads contain lots of useless posts.

There is no harm done in speculating here. It does not endanger any hypothetical survivors, it does not hinder the search and recovery efforts, it does not hinder the investigation in any way. If crash-related info and speculation starts getting censored and restricted to the members of the profession, aviation will appear scarier to the general public because they are hiding something. Less people will fly, airlines will make more losses and lots of professional members of this forum will lose jobs. We passengers are paying your wages - and despite often having no clue, we like to be informed.

I do not contribute to PPRuNe (the reason is I have nothing to contribute, being an SLF), but I enjoy reading it, including speculations - I am sure many others do either.

misd-agin

2nd Jun 2009, 16:20

lexxity (http://www.pprune.org/members/93123-lexxity)

Lady Lexxington

Join Date: Jul 2004
Location: The Manor House
Age: 29
Posts: 964

Replying to post #487. Ditching has already been discussed and dismissed due to several factors amongst them the weather, the dark and the sea conditions found on the open sea as opposed to somewhere like the Hudson.

I've never sailed across the South Atlantic, only the North and the swells can be awesome, enough to toss a 70,000grt vessel, designed for those conditions, about so I don't see an airframe standing a chance. I do stand to be corrected though.
http://static.pprune.org/images/statusicon/user_online.gif http://static.pprune.org/images/buttons/report.gif (http://www.pprune.org/report.php?p=4968676)
********************************************************

Guess we'll have to rewrite past history and advise people that actually survived ditching in open water in the past that they in fact didn't make it. I've flown with a pilot that survived one. He talked about his ditching being easy, as opposed to the other crew that he knew about that ditched in the North Pacific or Atlantic under adverse conditions and survived.

Swells in the ocean can be awesome. And sometimes the seas are amazingly smooth. U.S. television show covers fishing in the Bering Sea in winter. Sometimes it's amazingly calm, and other times there are terrible sea states. Airframes can, and have, survived water landings(ditchings) so they are survivable.

Unfortunately a debris field has been found so it appears, from the limited information available, that a ditching was not attempted.

Rodent1982

2nd Jun 2009, 16:26

4 PW's
You talk about "uninformed drivel" having said in the same post "I read somewhere that Air France 447's wing touched an A320 rudder".
This happened in 2006!!!! I would call this uninformed or not bothering to check your inputs as so many others do or rather do not do.

Metal fatigue does happen, and has brought down planes in the past. So a bad repair or generally something missed could well be a contributor 3 years later, especially in extreme turbulence no? Not just metal fatigue but there was a case where a tail strike was badly repaired which lead to (correct me if I'm wrong) decompression and an in-flight breakup?

I am uninformed, but I wouldn't dismiss anything in this aircrafts history.

Mephistopheles

2nd Jun 2009, 16:41

MU3001A

Are you of the opinion that better communications equipment could have prevented this accident?

Unfortunately I doubt we will ever know but one thing is for sure that if the comms in that area were little more than non existent the crew would have had an additional source to refer to. As is the case things tend to go wrong when you a farthest away for anywhere & with little or no comms.

weido_salt

2nd Jun 2009, 16:43

cockpitvisit

Good post indeed.

Metal, indeed has a very long memory.

As we all know, bend a piece of metal often enough and long enough and it will break. The trick is to discover where the metal intends to break.

ZeBedie

2nd Jun 2009, 16:44

I have seen this posted several times, but have not seen a reply to it. Would someone explain / comment on ADIRU, ISIS, PRIM 1 and SEC 1 faults.

They had degraded flight controls, no autopilot and no flight instruments.

Coyote44

2nd Jun 2009, 16:45

Is it true to say that on Alternate Law, the A/C can be manually controlled thru the stabilizer and the rudder?

overthewing

2nd Jun 2009, 16:48

SLF, non-journo question. If all the controls, autopilot etc., are knocked out, how long does it take for them to reboot under 'normal' conditions?

DC-ATE

2nd Jun 2009, 16:49

PJ2 -
Of far greater concern here, I think you'd agree, is the power of convective columns within the thunderstorm cell(s) and the possibility of low to poor radar returns from same. Like most who do/did this work, I've seen it once or twice and been surprised at the violence of "what wasn't supposed to be there according to the radar"

I submit that if the radar in use today isn't capable of "seeing" this kind of convective activity, that you avoid these areas completely. Using the C-Band radar we had, I don't recall an active cell failing to show up on the scope.....providing the operator knew how to use it.

jurassicjockey

2nd Jun 2009, 16:50

I find it very frustrating that with the availability of sat. internet access in the back, with the resultant access to excellent real-time wx data including radar, the SLF have better weather information than we do up front at times. How long will it take to incorporate a useful, current data stream to the cockpit. I guess only the bean counters know the answer to that one.

SLFinAZ

2nd Jun 2009, 16:54

My understanding is that the "AP Disconnect/alternate law" message preceded the later string of system failures. If correct then the indication is some sort of "upset" or turbulence induced unusual attitude prior to other issues...or am I misreading the information available. Based on the early comments by AF it seems in line with the picture of an upset followed by various system failures indicating some type of catastrophic failure.

If a sudden unexpected extreme turbulence event caught the pilots by surprise and forced the plane into a position of unusual attitude severe enough to disconnect the AP would the switch to alternate law create problems in recovering the aircraft?

Benbecula

2nd Jun 2009, 17:01

I didn't really want to comment on this, so I won't speculate on the reasons why AF447 crashed.
However, what worries me is that it seems some professionals are really dismissive of the potential of lighning damage on modern aircraft.

I've read through all of the posts and it seems strange that no one has mentioned positive lightning, which account for less than 5% of all strikes.
Positve strikes are at least 6, and often up to 10 times more powerful than standard strikes. Modern passenger aircraft are not built to withstand positive strikes as the technology is not available: the discovery of positive lightning is pretty recent.
Positive lighning occurs when a positively charged leader forms at the cloud, and a negatively charged streamer issues from the ground.

Positive strikes can occur far away from CB (of course, originating in CB), due to their immense energy which can reach up to 300KA and would therefore far exceed the 20nm cordon recommended for CB avoidance for shear/turblence/strikes etc. Compare this to standard negative strikes of up to 30 KA and it is easy to see why these strikes are very dangerous.
For pilots who dismiss lightning strikes as almost harmless, well, you'd be right. Up to 95% of the time. It is unlikely to happen, but it can and has bought down aircraft, Pan Am 214 is an example.

snaproll3480

2nd Jun 2009, 17:04

Regarding the flight control law questions:

No entirely true. In normal law the flight contol computers provide various protections which keep the aircraft within operating and structural limitation. The first level of degradation is alternate law in which some of those protections are lost, but the aircraft still flies normally. The next level of degradation is direct law, at this point, the aircraft does not have any protections but still flies like any normal aircraft with full control authority. The last level of degradation is manual back-up where the pilot has only rudder and manual pitch trim to control the aircraft while computers are reset. Manual reversion is not designed to be used to control the aircraft in other than straight and level flight as a temporary siutation. I have landed the 332 in the sim in manual reversion and it can be done, but the chances of being in that situation are exceedingly slim.

Regarding the PRIM and SEC question, the loss of PRIM 1 and SEC 1 would probably leave the aircraft in alternate law which is not an emergency situation in itself but would be another distraction if more failures were occuring. With any 1 of the 3 prims, and 1 of the 2 secs the aircraft is in normal law. The degredation logic is somewhat complex, but with any 1 of either type of the flight computers you could at least have direct law.

The flight computers are all independently designed and built by different companies to ensure that a design or manufacturing flaws could not affect all of the computers.

sika hulmuta

2nd Jun 2009, 17:04

Is it true to say that on Alternate Law, the A/C can be manually controlled thru the stabilizer and the rudder? Today 17:44

Hi Coyote44, Alternate Law is no big issue - some of the magic protections will be lost depending on the failure (bank angle, g, overspeed, alpha etc). The aircraft effectively becomes a traditional airplane. Then comes Direct Law, which is still fully functional control of flight, before it eventually degrades to rudder, trim and thrust control only.

KanzaKS

2nd Jun 2009, 17:08

PRIM 1 and SEC 1 refer to the FLIGHT CONTROL PRIMARY COMPUTER (FCPC)

ISIS Integrated Standby Instrument System

ADIRU Air Data Inertial Reference Unit

I suggest an excellent article on A330/340 Flight Controls

http://www.davi.ws/avionics/TheAvionicsHandbook_Cap_12.pdf

Coyote44

2nd Jun 2009, 17:19

Thanks for the input. I was merely trying to enquire if their systems could've degraded to backup mode, which in severe turbulance would've been impossible to control, IMHO.

FrequentSLF

2nd Jun 2009, 17:23

I am a SLF and I have been bashed many times for my comments but there are two posts on this thread that I must criticize.

Metal fatigue occurs over the time, a strike (i.e. with another object) will not have any significant impact on the metal fatigue failure. CI611 went down 20 over years after being poorly repaired...

Faraday cage...it is an ideal conductor therefore does not need to be grounded (actually is otherwise)...one of its function is to protect from lightening strikes... Wikipedia has a quite good description of it...

edit: deSitter gave a accurate description of a Faraday cage

FSLF

snaproll3480

2nd Jun 2009, 17:24

Coyote, the short answer is yes. If all the computers were lost and they were in manual reversion and they were in severe turbulence, then the plane would be almost impossible to control.

Danny

2nd Jun 2009, 17:45

Some of you are not very bright are you? This thread is about the missing AF A330.

We allow some educated theorising about what may have happened and we also allow explanations of associated systems (hardware and natural) that could explain some of the possibilities. However, those of you who haven't figured out yet why your technical discussions on Faraday cages or the differences between X band and C band radar keep disappearing are prime examples of why this thread has to be moderated all the time.

Take your technical debates to the Tech Log forum. You are wasting all your time and effort trying to wave your willies at each other on this thread.

Also, all those outraged types who think that somehow airline pilots who post on anonymous forums have to somehow live up to their imaginations had better get a real life soon. Airline pilots come from all backgrounds and have their own opinions on everything. Whether we agree or not is of no concern to the idiots who come on here and blather on about how badly behaved pilots are when they have no idea whether they are indeed pilots or just spotty faced anoraks whose closest association to a/c flight controls are the keys on their computer and some flight sim software.

I'll reopen this thread but any of those time wasters who haven't figured out yet that this is not a private chat room for them to try and convince the other about how knowledgeable they are about one system or another, had better realise that there are specific forums for their debates and this thread is not it.

If you don't want what you write on here deleted then think before you post it. Is it directly relevant to the topic? Are you guessing or using ill sourced info such as what you have heard from the media? are just trying to let us all know how grieved you are about the tragedy? Think carefully and you won't waste yours and our time!

Flapsnegative

2nd Jun 2009, 18:11

BOAC Flapsnegative - you appear to have been in the area at the time? Was there any chat on 123 about the ride there? Do you know if the (reported) ?TAM? a/c report of 'fire sighted' was reported on 121, HF or 123?

We were at UN866 at FL370 around the time, the AF was at the UN873, one airway to the east. Neither on 123 or 121 there was talk about the missing airbus, not surprising since the A330 went officially missing only several hours later. We didn't hear a TAM report on floating fire either, but there was some low level ELT-like noise on the 121, but it was so faint and brief that it came over the squelch treshold for just one or two seconds, so it is quite improbable to have originated from an aircraft below.

Also there was a post on blue jets lightning, we didn't notice any discharges from above or below, but the moon was actually quite clear when above the clouds (helpful for reference in manual flight without prim or stby instruments, but not within CB) so that could have prevented sighting of a blue jet.
The top of the clouds we experienced at that time I would estimate at FL400, but in the ITCZ it's nowhere the same, it could easily be much higher nearby.

AMF

2nd Jun 2009, 18:15

PJ2 Loose_rivets;

Of far greater concern here, I think you'd agree, is the power of convective columns within the thunderstorm cell(s) and the possibility of low to poor radar returns from same. Like most who do/did this work, I've seen it once or twice and been surprised at the violence of "what wasn't supposed to be there according to the radar".

That is indeed the greatest concern. I'm not sure why anyone is even talking about a lightning strike being a cause of this horrible accident in the face of growing evidence via ACARS messages and transposed weather analysis that the aircraft was being subjected to a sustained measure of severe to extreme turbulence just prior to being lost.

The aircraft doesn't have a lightning strike detector and the pilot didn't report a strike! The whole "lightning" theory was put forth as an off-the-cuff extrapolation from a "short" message when it hadn't come to light there was also a susequent 4-minute stream of other messages showing the autopilot disconnect, reversion to abnormal law, other electical failures, and cabin press problems.

IF the aircraft encountered severe-to-extreme turbulence at high altitude (that accounted for the autopilot off and abnormal law), heavy with fuel, and quickly ended up in a jet upset (which would explain the AP/abnormal law) where the only path brought you into more developing weather, the chances for engine flame-out (cabine press problems) would also be high during the whole event and the aerodynamic forces even more extreme including torsional forces no aircraft is designed to withstand.

I think many are on a "Can't see the forest for the trees" snipe hunt there because their interest or hobby lies with electrics. If anyone steps away from the keyboard, however, and pushes their computer from the desk to the floor and proceeds to kicks it around, you'll get those same kind of messages if it could report it. Those electrical faults did not happen outside the much larger problem of that entire aircraft being subjected to severe outside conditions.

I believe (yes, speculate) this tragic event was a result of a severe/extreme turbulence enounter at altitude still heavy with fuel, and subsequent jet upset..ACARS electrical report of failures a result of equipment being hammered ....with a subsequent loss of aerodynamic and engine control.

The "Forest" here is the aerodynamic/aircraft control issue due to severe-to-extreme turbulence because the aircraft was operating at high altitude. It's just not about the Airbus being able to handle the stress of such turbulence directly if it's flying right-side up below is Turbulent Air penetration speed with plenty of margin between stall and overspeed, the hull probably can. But if the aircraft was heavy for FL 350, slowing to a turbulent air penetration speed also brings any aircraft at high altitude closer to the AOA where control can be lost if it's hit with other, sudden outside forces and the flight controls can't respond quickly enough.

The training for recovering from a loss of an aerodynamic loss-of-control event at high altitude in jet, transport aircraft is minimal to none and given the pilots may have to attempt it during continuous, CB-produced turbulence is perhaps impossible. That's why flying into forecast areas of even moderate turbulence at heavy at high altitude where buffet margins are close is to be avoided, and anything severe escaped with haste, the problem being initiating a higher-than-half bank (such as when you're hand-flying which it seem these AF pilots may have had to) turn after you're in it possibly making the difference between staying inside your buffet boundary and going outside it.

Anyway, the electric faults would more likely be a result of something going aerodynamically amiss with this flight related to the weather, not a cause for it going amiss. I don't buy the "lightning strike made bad things happen" scenario a bit. Lightning is a small worry yes, but it's the LAST thing that's worrisome about operating in close/too-close proximity to severe thunderstorms. Some have latched onto it because it happened to be included in the "possibility" first statement given by a PR man at AF, and are experiencing a Primacy of Learning tunnel-vision, IMO.

Aerodynamics, not Electrics, would seem to be the right tree to be barking up. Given moder aircraft design, explaining the loss of an aircraft due to electrical fault-as-beginning-the-failure-cascade scenarios is exceedingly difficult at best.

Explaining electrical faults (as well as other system faults and the pilots inability to communicate) due to severe buffeting and aerodynamic loss of control and engines seems far more likely, and not a "first time in history, one in a million chance" occurance. These things have happened too many times, and it's why aviators learned long before anyone here began their careers avoiding those weather conditions takes priority over all else, and loss of control at high altitude is a can of stress and engine control worms nobody want to ever open.

This aircraft was 3 hrs into a flight fueled for an 11hr trip, and at FL350, over 200 pax. Can any of you experienced Airbus 330-200 guys tell us what the likely weight and the low-end buffet boundaries for for that weight would be? And what max turb air penetration speed is? What was the ISA deviation at FL350 in that area that night?

hajk

2nd Jun 2009, 18:20

Jurassicjockey wrote:
I find it very frustrating that with the availability of sat. internet access in the back, with the resultant access to excellent real-time wx data including radar, the SLF have better weather information than we do up front at times.

Once the cockpit depends on something, it has to be fairly bullet-proof and the kinds of drop outs that you can get from satellite based internet let alone servers operated by third-parties. Having once worked on avionics, I can say that getting anything new built into a commercial cockpit is a long and painful process.

Tail Chase

2nd Jun 2009, 18:22

To Heli Sticktime et al
Re-capping the official info released so far regarding the ongoing SAR effort on the Recife ACC and SOLANT ACC area covered by CINDACTA III, what we have is as follows:

a) At 0230LT/01062009 a C-130H staging through SBRF and an Embraer P-95 maritime patrol acft based at SBSV were enlisted to perform the initial SAR effort;

b) On 1908LT/01062009, the following additional SAR assets were called-up:
- 01 x Sikorsky UH-60L Black Hawk to SBNT;
- 01 x SC-95C (SAR version of the EMB-110P2) to SBNT;
- 01 x CASA C-295M SAR-configured acft to SBNT;
- 01 x Eurocopter AS332M SAR-configured helicopter to SBNT;
- 01 x C-130E to SBNT with SAR rescue teams;
- 01 x C-130H to SBFN, backtracking along AF447s flight path from GCLP to SBFN;
- 01 x Brazilian Navy Frigate (with SAR-configured Sea Lynx helicopter);
- 01 x Brazilian Navy Patrol ship;
- 01 x Brazilian Navy Corvette

c) At 1930LT/01062009 an Embraer R-99B SIGINT/ELINT acft was enlisted to aid in the AF447 SAR effort;

d) At 0029LT/02062009 The Brazilian AF stated that the crew of TAM flight inbound to Brazil spotted "luminous points" on the ocean's surface within the boundaries of the Dakar ACC

e) At 0100LT/02062009 Brazilian AF R-99B 6751's synthetic aperture radar plotted metallic and non-metallic debris floating on the ocean surface roughly 650km NW of SBFN;

f) At 0649LT/02062009 Brazilian AF C-130H 2466 and C-130H 2474 made visual contact with debris plotted by R-99B 6751's SAR. The debris fields were approximately 59km apart and roughly south of AF447's filght path. The debris fields contained an aircraft passenger seat, an orange float ou buoy, a drum or cylinder, several small unidentified white-colored items and oil/jet fuel slicks.

Cheers

jimpy1979uk

2nd Jun 2009, 18:23

There's a lot of speculation to what the messages that were transmitted by the aircraft back to France. A lot of information could be obtained from them as they would be in order of occurance. The ground based software to analyse this is called AIRMAN for Airbus aircraft.

It will give all the cockpit effects(ECAM warnings etc), class 1 and class 2 maintenance messages. Basically if you've ever seen the PFR after a flight thats exactly whats on the AIRMAN system, but in near real time.

matblack

2nd Jun 2009, 18:30

What would be the effect on a modern airliner such as the A330 if it experienced a high speed stall at high altitude? I seem to recall a 737-800 coming close to experiencing such an event which required flying at slightly reduced altitudes by the airline for a period afterwards whilst it was investigated. Unfounded speculation of course but if the A330 was operating at 41,000 ft with significant load and optimum cruising speed and then encountered unexpected severe turbulence could this cause such a stall and could the damage to the aeroplane be severe enough to cause a break up?

dead_pan

2nd Jun 2009, 18:30

Of far greater concern here, I think you'd agree, is the power of convective columns within the thunderstorm cell(s) and the possibility of low to poor radar returns from same. Like most who do/did this work, I've seen it once or twice and been surprised at the violence of "what wasn't supposed to be there according to the radar"

Given the considerable advances in ground-based weather radar over the past decade, one wonders whether this technology has been somewhat neglected by a/c manufacturers/operators? Also, there must be other technologies out there which could significantly enhance the detection of CBs (LIDAR, optical systems etc). Lightning can be detected at considerable ranges using very straightforward RF detection equipment.

Aascanius

2nd Jun 2009, 18:36

My question is whether pilots have access in the cockpit to IR radar images of the type that are available from NOAA or other govt/commercial providers. From the analysis of the weather at the time of the incident (available within this thread) it seems that the AF pilots could easily have diverted around the cells that they entered, but maybe their weather avoidance radar malfunctioned or did not show them the "big picture". Seems like having the most recent satellite radar onboard would be very helpful for choosing the path of least weather resistance.

Tail Chase

2nd Jun 2009, 18:47

Hi CDG1
The latest info indicated that two merchant vessels were already in the general area where the debris fields were spotted, with a third MV on its way to the site. I understand that two MVs are French, while the third is a Dutch ship.

According to Brazilian Navy spokesperson, the three MVs are tasked solely with retrieving survivors or bodies. Should any of the vessels sight aircraft parts or components, they are instructed to identify and plot their position - but not retrieve. A Brazilian Navy vesselis enroute to the site and is expected to arrive on the morning of June 3rd.

The Brazilian Navy spokesperson relayed information regarding local weather conditions and sea state (1.5 to 2m waves, 30ºC water temp and 15 kt wind).Barring other factors, that would seem to indicate that retrieving debris will be somewhat easier than expected.

Cheers

Has anyone heard if any ships have reached the area where debris were spotted?

There was talk of two Dutch vessels and a French freighter rerouting themselves as they were said not to be too far away.

Dutch ship was said to be "Jo Cedar" and French freighter was said to be "Douce France". Are there any more news on this?

YHZChick

2nd Jun 2009, 18:56

I don't know if I'd say it's taken "so long" to pin point the crash site. The debris has been located. There are other factors such as current and whether the aircraft may have broken up in air or upon hitting the surface to consider.

All things considered, I'd say the remnants of the air craft have been located rather quickly.
:D to the men and women involved in the recovery.

snaproll3480

2nd Jun 2009, 19:03

AMF,

According to the QRH and based on a weight around 210t:

(speeds are approximate)

Green Dot (minimum clean speed): 245 kts

Turbulence penetration speed: 260 kts

Vls w/ 0.3g buffett margin: 235 kts

Speeds are all indicated so no ISA deviation necessary.

Tail Chase

2nd Jun 2009, 19:15

Hi YHZ Chick
I think that it'd be premature to state that AF447's wreckage has been found inasmuch as what was sighted earlier today was from a C-130H flying, at best, 500ft to 1000ft ASL.

The idea is to retrieve whatever components are found in the two debris fields, find mfg serial numbers and determine whether these match or not what was installed in AF447's airframe. And that will only be possible after such items are collected - which will not happen before tomorrow. If you factor in the time to correctly identify whatever is found and see whether the serial numbers match, and chances are that a positive or negative ID will only be available some time between Thursday or Friday.

Unless, of course, they find a chunk of sheet metal with the register "F-GZCP" painted on it...

Cheers

MrFixer!!!

2nd Jun 2009, 19:19

First of all I really am impressed with the effort of some (only some) of the "professional" guys here who actually went to the length of plotting the exact (or very near) location of that a/c, and provided all sorts of data for that flight .:D

However, with my experience of nearly 10 years of working on A330s (and lots more) I really am surprised with the amount of half baked knowledge some guys have about the actual a/c and its systems. I am not slagging anyone but it sounds ridiculous to try and sound like aviation experts whilst quoting the media news here.:ugh:

I will better clarify some things about A330 systems ( from a Techies perspective) in the Tech Log....in the meantime I will let guys here make assumptions and shoot in the dark as to what happened.....mind you we are all speculating and doing the same...but blaming Lightening strikes, or Composites or some kind of 'Short Circuit' tells us who knows what about how it works...carry on guys....you are doing fine :ok:.....as mentioned earlier....wasting yours and others time!!!

Dysag

2nd Jun 2009, 19:31

Storm threat to modern aircraft

BBC NEWS | Americas | Storm threat to modern aircraft (http://news.bbc.co.uk/2/hi/americas/8079591.stm)

AMF

2nd Jun 2009, 19:34

snaproll3480 Speeds For Am
-
AMF,

According to the QRH and based on a weight around 210t:
(speeds are approximate)

Green Dot (minimum clean speed): 245 kts

Turbulence penetration speed: 260 kts

Vls w/ 0.3g buffett margin: 235 kts

Speeds are all indicated so no ISA deviation necessary.

Thank you Snaproll.

So only 15kts IAS between Min Clean speed and Max Turb Air Penetration speed for that weight at appx 210tn, and 25kts between the same and Low Speed Buffet margin.

As we know exceeding the Max Turb speed during severe/extreme will wreak havoc on components at the least, and any aircraft is in danger of structural damage under those conditions. And we all know what can happen if the low-speed buffet margin is suddenly exceeded.

My ISA question is related to the performance/ability of the engines to accelerate an aircraft of that weight out of a turbulence-induced low-speed condition at that altitude.

Another Airbus 330-200 question related to the ACARS messages that the A/P had disengaged and reverted to Abnormal Law. I assume the Airbus has an automatic low-bank (or 1/2 bank) function or it's equivalent when the aircraft is at high altitude under even normal, smooth conditions that protects the aircraft from a wing-loading stall condition where the buffet margin is small.

My question is, on this type of Airbus does this bank protection still exist at high altitude during non-AP operation in Abornmal Law?

suninmyeyes

2nd Jun 2009, 19:34

Benbecula

You wrote:

"For pilots who dismiss lightning strikes as almost harmless, well, you'd be right. Up to 95% of the time. It is unlikely to happen, but it can and has bought down aircraft, Pan Am 214 is an example."

Pan Am 214 was brought down by a lightning strike in 1963 only 4 years after the Boeing 707 was introduced. Boeing redesigned the fuel vent outlets so it could not happen again. It is not really appropriate to use that accident which happened 46 years ago to substantiate your argument of how dangerous lightning strikes can be.

wilyflier

2nd Jun 2009, 19:39

Sad logical conjecture
59 km seperation of debris fields possibly suggests aerial breakup into 2 components. , the second component remaining airborne for longer and flying further.but a dense weight fell earlier to the water.at a shorter distance*(engine?)
Or, a lighter draggier component fluttered down at a later time but travelled a shorter distance (part of tail,or blown out airframe part?)
Even if the first part came off and fell vertically the second part travelled at 32 miles or more (controlled descent?)

Lost in Saigon

2nd Jun 2009, 19:42

What would be the effect on a modern airliner such as the A330 if it experienced a high speed stall at high altitude? ....

.....Unfounded speculation of course but if the A330 was operating at 41,000 ft with significant load and optimum cruising speed and then encountered unexpected severe turbulence could this cause such a stall and could the damage to the aeroplane be severe enough to cause a break up?

Short answer.... No

Heavy aircraft can experience a stall or "Mach Buffet" (stalling of the wing due to supersonic flow) at much lower altitudes than 41,000.

AF447 could have experienced some form low speed stall, Mach Buffet stall, or "Jet Upset" due to turbulence, but a proper recovery would not put the aircraft in an over-stress situation.

It is generally a poor recovery technique that causes the loss of an aircraft in these situations.

theamrad

2nd Jun 2009, 19:46

Investigators will want to discover if the Air France Airbus suffered such severe turbulence that it caused catastrophic structural damage - the loss of a rudder, engine mounting, or even a broken wing.

SOURCE : BBC
Not sure if that will go down well with the mods here at the moment - since any reference to structural overloading of components seems to warrant deletion. No matter what the source or how qualified one might be.Specifically, in my case - the entire transcript of public hearings held by the NTSB concerning AA587.

snaproll3480

2nd Jun 2009, 19:50

The various protections available in each flight law may be explained on this site:

SmartCockpit - Airbus 330 (http://www.smartcockpit.com/plane/airbus/A330)

Thats a good source of generic Airbus information. It's not specific to each company but most conform to the airbus procedures.

The short answer is that there are still protections available in Alternate Law, not Abnormal Law, although I guess thats gramtically correct, but that's just semantics.

I'm out for tonight, catch up again from Oz.

jauh

2nd Jun 2009, 19:54

vovachan

2nd Jun 2009, 19:58

I am thinking Pulkovo 612, the other recent instance when a plane crashed during cruise in a severe thunderstorm. Except no sophisticated electronics or composites were involved. That case was thoroughly investigated, and it was concluded that flight at near ceiling + severe turbulence = stall +double flameout = loss of control.

LYKA

2nd Jun 2009, 19:58

http://www.airbus.com/store/mm_repository/safety_library_items/att00003117/media_object_file_FLT_OPS-ADV_WX-SEQ07.pdf

Of particular interest from this note is (emphasis mine):

"It is important to note that reflectivity of particles is not directly proportional to the hazard that may be encountered in a cell. Air can be very humid, when close to the sea for instance. In this case, thermal convection will produce clouds that are full of water. These clouds will have a high reflectivity, but will not necessarily be a high threat. On the other hand, there are equatorial overland regions where converging winds produce large scale uplifts of dry air. The resulting weather cells have much less reflectivity than mid-latitude convective cells, making them much harder to detect. However turbulence in or above such clouds may have a higher intensity than indicated by the image on the weather radar display."

elpilotofrances

2nd Jun 2009, 19:58

And CMC ( central maintenance system ) is powered by AC1 normal and AC ESS on gnd ......

etesting2000

2nd Jun 2009, 20:14

One of the commercial MV diverted to search looks like it is in a search pattern now. Link to position plot.

JO CEDAR tracking map (http://www.sailwx.info/shiptrack/shipposition.phtml?call=PFDI)

ttcse

2nd Jun 2009, 20:22

While debris reports give locations to the southeast of route, various maps of ocean currents in that area shows the flow to be toward northwest. That would rule out currents.

Flyinheavy

2nd Jun 2009, 20:30

Brazilian secretary of defence Jobim just stated that the FAB has spotted a 5 km wide (long?) area of debries and that there would be no more doubts that they are of AF447...

cavok73

2nd Jun 2009, 20:33

Watching to a FAB spokesman on TV today I heard the word barrel/drum.
Makes me wonder about the cargo manifest and if there was any DAC, Dangerous Air Cargo.

Mercenary Pilot

2nd Jun 2009, 20:35

Wreckage is from Air France flight: minister

RIO DE JANEIRO, June 2 (Reuters) - Wreckage spotted in the Atlantic Ocean is "without a doubt" from the Air France jet that disappeared en route to Paris from Rio de Janeiro with 228 people on board, Brazil's defense minister said on Tuesday.
A Brazilian Hercules plane on a search mission for the missing passenger jet saw a band of wreckage along a 5-km (3-mile) strip, Nelson Jobim told a news conference.
"It confirms that the plane fell in this area," he said.

(Reporting by Maria Pia Palermo; writing by Brian Ellsworth; editing by Stuart Grudgings and John O'Callaghan)

Reuters, Tuesday June 2 2009

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egbt

2nd Jun 2009, 20:38

"59 km seperation of debris fields possibly suggests aerial breakup into 2 components."

If it were on solid ground, maybe... but you have to take ocean currents into the consideration here. On top of that, there's no confirmation yet that the two debris fields are related

Not likely to be the case, currents are likely to be uniform over several 10's of miles so if debris went in over an area of a few miles they would stay that way for some time. Even if they happened to fall at a boundary between 2 oceanic currents the drift would only be a Knt or two, insignificant over a few hours. A few exceptions of course but I don’t think there would be any in this area.

Graybeard

2nd Jun 2009, 20:47

We can deduce:

The Satcom was powered at least until after the last ACARS message, so other systems to keep the plane controllable should have been powered also.

There was not so much flight upset that it took the Satcom antenna out of line of sight of the geostationary satellite, which would have been almost directly overhead. What kind of antenna did it have?

The Satcom antenna was receiving valid steering signals from an IRU to keep it pointed, since it was surely a steered antenna.

GB

Tail Chase

2nd Jun 2009, 20:55

Hi Guardian 11
I'm not a pilot. But I have a question to the FAB (Brazilian Air Force); The last tower contact with cindacta 3 was 22:33 right? At 2:20 FAB started to search for the lost aircraft. My question is; why did it take 4 hours for them to realize that?

Perhaps to better understand the problem, it would be best to review the timeline leading up to the mishap...

At 2233LT, AF447 performed a VHF contact with CINDACTA III (SOLANT ACC), reporting INTOL, indicating that it expected to report TASIL at 2320LT;

At 2248LT, AF447 exited CINDACTA III radar coverage. At the time the flight was cruising at FL350 and 453kts - as per the flight plan;

At 2314LT, AF447 issued a number of ACARS messages to AF maintenance center;

At 2320LT, AF447 failed to report its passage by TASIL and entry into Dakar ACC.

Failure to report waypoint passage at the expected time does not entail the immediate launching of a SAR operation. Unless, of course, a distress call is made or an ELT transmission is detected - and neither occurred. Under those circumstances, there is a standard waiting period before placing SAR resources on alert status. At the moment I cannot recall the duration of that waiting period, but I very faintly recall a 90min period - but I might be in error.

Hence, should memory be serving me correctly, the Brazilian SAR system would only be placed on alert footing at around at 00:50LT. Once placed on alert status - and in the absence of solid information as to where the event took place - you can add an hour for mission planning and preparation.

As for resorting to Mirage 2000s, bear in mind that these are based at SBAN - which entails a 1.880 km flight to SBNT - easily a 2:30hr flight. They would have to land at SBNT, refuel and then take-off to fly some 1.200 km to the general area where the mishap might have taken place. Although I do not have the Mirage 2000C performance charts at hand, I think it would be safe to say that a pair of Mirage 2000Cs would be unable to execute a meaningful search pattern, in the dark of night, for more than 10min before reaching "bingo fuel"...

Cheers

PUG128

2nd Jun 2009, 21:01

For what it's worth (not much):

Today, a TP pilot that was flying a paralell route (in his words about 80nm west from the AF's route) at basically the same time and in a similar acft (not said in the interview, but it would be a TP's A330 or A340) was interviewed in a portuguese TV channel (TVI).
For those who understand portuguese, the vid of the interview can be watched here (http://www.videos.iol.pt/consola.php?projecto=27&pagina_actual=1&mul_id=13140239&tipo_conteudo=1&tipo=2&referer=1).

Basically he said that:
- He doesn't believe a plane can be brought down only by turbulence. Although not impossible but highly unprobable.
- He doesn't believe in a single factor for the accident
- He stated that aircrafts are prepared for lightening strikes.
- He found turbulence on his flight path but nothing "unusual" for that particular route. He did had to re-route to avoid, but nothing unusual (10/15nm).
- He didn't hear any distress call from the AF's crew
- He acknowledge that sometimes they experience difficulties with radio (HF) transmissions and "use" other aircrafts to relay the information
- He DID hear some requests from the ATC to other acft in the 'area' to try to reach AF447 on different frequencies, including another TP flight that departed from Natal

He spent a good part of the interview "evading" the (usual at that TV station) sensacionalism-inducing questions, and stick to the (IMHO correct) posture of "noone knows nothing for sure at the moment and I'm not going to speculate, but it was a strange and fast happening".

./J
(an idiotic anorak)

OleOle

2nd Jun 2009, 21:02

While debris reports give locations to the southeast of route, various maps of ocean currents in that area shows the flow to be toward northwest. That would rule out currentsIf the debris is in the north equatorial counter current it could drift eastward at up to 3 knots which is like 70nm in 24hours:

Eastward flowing surface speeds in the western section of the current have been estimated by Fratantoni (2001) to be up to 147 cm s-1 and by Richardson and Reverdin (1987) to be up to 143 cm s-1 extending down to 350 m at 28°W
from: The North Equatorial Counter Current (http://oceancurrents.rsmas.miami.edu/atlantic/north-equatorial-cc.html)

protectthehornet

2nd Jun 2009, 21:40

saw you on CNN and you spoke of mild turbulence

that isn't in my AIM!
light

moderate

severe

extreme

egbt

2nd Jun 2009, 21:52

Well as someone has seen fit to delete my link to and quote from the BBC lets try again. An official statment says that the wreckage 400 miles off the Brazilian coast is from the aircraft.

France is sending a reasearch ship with two mini subs.

protectthehornet

2nd Jun 2009, 22:01

Does anyone know the exact level of turbulence reported by the flight some 14 minutes prior to the last transmission of data?

I've heard the Air France head use the term "heavy" turbulence. Would this correspond to ''severe'' or extreme. Was the turbulence report made by the crew?

AMF

2nd Jun 2009, 22:02

Lost in Saigon Quote:

Short answer.... No

Heavy aircraft can experience a stall or "Mach Buffet" (stalling of the wing due to supersonic flow) at much lower altitudes than 41,000.

AF447 could have experienced some form low speed stall, Mach Buffet stall, or "Jet Upset" due to turbulence, but a proper recovery would not put the aircraft in an over-stress situation.

It is generally a poor recovery technique that causes the loss of an aircraft in these situations.

Applying proper recovery technique might not be possible if the aircraft was descending in conditions as severe as what caused the jet upset in the first place, say, down through the CBs they were flying above and around. On top of that, there's the issue of engine flameout due to aerodynamic blanketing, hail, fuel pump unporting, or component failure of auto-relight features, etc.

The fact is, most pilots train for unusual attitude recovery where the recovery is accomplished in benign conditions with all flight controls working normally, a full panel, not to mention the engines running and outside visual reference. Many places don't even give "jet upset" training...i.e. loss of aerodynamic control at high altitude.

And a real-world jet upset, let alone sever or extreme turbulence involving all the forces, cannot be rendered or trained well in a simulator because the test pilots during certification don't even put the aircraft through those paces.

ttcse

2nd Jun 2009, 22:03

Ole, of course ocean currents aren't constant. Go here (http://www.oceanweather.com/data/), click the map section for recent charted flow depictions. You can even play a java-loop. No eastward flow is depicted in the debris area
http://i.cdn.turner.com/cnn/2009/images/06/01/brazil.plane.jpg

Lost in Saigon

2nd Jun 2009, 22:06

Does anyone know the exact level of turbulence reported by the flight some 14 minutes prior to the last transmission of data?

How did the crew report turbulence? Was there an ACARS message to company or a report to other aircraft?

EchoIndiaFoxtrot

2nd Jun 2009, 22:19

I think the assumption would have to be that contact was made with AF via ACARS regarding severe turbulence at 0200 GMT as -

a) last contact by AF 447 with Brazilian ATC was at 0133 GMT,

b) no other a/c reported getting any comms from AF 447 that night, and

c) it is AF themselves who stated the captain reported the turbulence

etesting2000

2nd Jun 2009, 22:44

Prime Minister Francois Fillon told the French parliament that the cause of the plane's loss had still to be established.
"Our only certainty is that the plane did not send out any distress call but regular automatic alerts for three minutes indicating the Failure of all systems ," he said.

This is the first I have seen saying all systems. Previous reports listed several faults, not all systems. Granted, he is not an engineer but he must have been briefed by such.

blueloo

2nd Jun 2009, 22:45

The speculation now turns to the QF incident:

This is from the Sydney Morning Herald:

Meanwhile, Qantas dampened speculation that the aircraft's loss could have been caused by the same fault that caused a Qantas Airbus A330-300 destined for Perth to experience a sudden drop in altitude last year, injuring 74 passengers.

A Qantas spokesman said the company's engineers were monitoring developments in France and would act on any directive issued by Airbus or air safety authorities.

Full article hereSMH Air France Debris (http://www.smh.com.au/world/floating-wreckage-found-in-plane-crash-zone-20090602-buf2.html)

paddygranger

2nd Jun 2009, 23:03

A few thoughts:

1) Could the poor weather conditions in the area be related to the lack of communication from the aircraft? How sensitive are aircraft communication systems to severe weather related interference, taking the location specific communication characteristics into consideration as well.

2) In the case of an aircraft entering severe and sudden / unexpected weather conditions, requiring full on and dedicated "lets keep this plane in the air" action, where does this place the action to report back to AF, both in terms of operating hierarchy as well as human nature?

3) Do we have any more information about the most recent maintenance / repairs carried out on the aircraft? Under this point, I am considering how repair work may have failed when exposed to severe turbulence.

Thanks.

Patrick (non pilot / aviation industry)

wes_wall

2nd Jun 2009, 23:20

It would appear that there is more information regarding the last 4 minutes of flight than has been discussed. I am not familiar with the systems of the Air Bus airplane, thus cannot comment with any authority on the alerts transmitted to AF maintenance. But I do have questions relative to them.

Taking each transmission on its own merit, what would likely have had to occur to trigger the first automatic ACARS alert.

Then, would each subsequent alert be a result, or a contributing factor, of a failure reported by the preceeding transmission.

Following the transmission trail and analysing the fault(s) should provide somewhat of a picture of the work load being placed on the crew, and the potential conditions which existed in the cockpit at the time.

Offchocks

2nd Jun 2009, 23:25

If you are in severe turbulance, you would be dealing with the situation not typing out an Acars report to inform your airline that you are in turbulance.
Note in severe turbulance you probably will not be able to read the flight displays.

SASless

2nd Jun 2009, 23:30

While you are considering sea currents...also add in winds that would scatter debris as well. As the break up (if that is what happened) occurred at a fairly high altitude then the lighter bits would drift much farther downwind than the more dense pieces. If there were thunderstorms about and strong vertical movement was involved it gets even far more complex to plot the dispersal pattern(s).

Add into this equation....the same effect as the wreckage settles to the sea bottom....and the debris field(s) that will generate. As the water is pushing 20,000 feet deep in that area....this is going to be a very difficult recovery operation and probably will not amount to much in percentage of wreckage being recovered.

Google a bit and read up on the research it took to discover the missing H-bombs from the B-52/KC-135 collision off the Spanish Coast many years ago.

wileydog3

2nd Jun 2009, 23:45

protectthehornet.

It was in my notes and in my brain but there was a disconnect. Failure in Primary Brain/Talk computer. Chalk it up to pilot error. (truth is I remembered light, moderate and severe but had forgotten about extreme and also wanted to check on the actual definitions. What we often call moderate in the States does not fit the definition)

So yes, I read the boards. And I may get toasted for using this and other boards as a resource but the paradox is that this board and a few others are where the real EXPERTS are. The second paradox is the constant railing against know-nothings in the media and that they would read the boards.

I have been very fortunate to have been in almost 100 different cockpits and flown with some really great aviators. I flew with Nick Warner at Toulouse on the 330 and 321 prior to the accident. My first focus is on Man Machine Environment and what we know. I try to stay away from spectacular speculation and stick with what we know as it develops.

But this thread, as others on accidents, is where the real knowledge lies. It can be like mining in that a lot of stuff has to be tossed out but I know that and that is why I read and participate this site.

And thanks for the critique. I can't get better if I am not shown where I failed.

AR1

2nd Jun 2009, 23:45

Quick comment regarding CF on aircraft. On delivery of Harrier GR5 some 20 years ago, 2 flying in close formation for a photo shoot. One was struck by lightening, which conducted, exited and struck the other aircraft. Wings suffered de-lamination of CF, though both recovered successfully.
That's from memory - but its evidence of CF not being the worlds most lightening resilient material.

agusaleale

2nd Jun 2009, 23:53

In some way this accident remembers me the one with Austral Flight 2553, which encountered bad weather en route with Cumulonimbus clouds (reportedly topping at 15,000m) an outside air temperature of -59deg.
FYI:
ASN Aircraft accident McDonnell Douglas DC-9-32 LV-WEG Nuevo Berlin (http://aviation-safety.net/database/record.php?id=19971010-0)

Extracted from Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data (http://www.weathergraphics.com/tim/af447/):
Tim Fantastic analisys you performed here. Let me just feed you a couple of thoughts. I'm a A310 pilot, and flown UN873 at night dozens of times, and deviations up to 80 nautical miles off track have been frequent. With tha A310 I don´t fly through any well shaped GREEN radar return at that altitude and in that area. Cb's are too tall in that area, and FL350 is well within the unacceptably active altitude, and will produce EXTREME turbulence (not severe), something aircraft structure can't cope with. The images you posted show an isolated cell right on UN873, between INTOL and the MCS, one that would probably favour a deviation of at least 25nm left of track. This deviation would put the aircraft facing the worse MCS zone, and would require further deviation. The thing that puzzles me is that such deviations would require ATC coordination, and even if unable to contact the control, pilots will broadcast their deviation on interpilot 123.45 frequency. How come in a fairly busy area as that one at that hour, no one heard about AF447 deviating, nor ATC, nor other pilots? This is very strange, you don't fly trough such a storm...

PUG128

3rd Jun 2009, 00:28

According to portuguese site "diario.iol.pt", that is quoting "Folha Online" (a brasilien newspaper), brasilien Defense Minister Nelson Jobim has officially announced that the debris found is indeed of AF's A332.

According to the cited source:

«Não há dúvida» de que os destroços localizados pela Força Aérea Brasileira a flutuarem no oceano Atlântico pertencem ao avião da Air France, que desapareceu na madrugada de domingo para segunda-feira, com 228 pessoas a bordo.
Jobim fez o anúncio numa conferência de imprensa, após visitar os familiares das vítimas num hotel do Rio de Janeiro, indicando que o Airbus A330 caiu em águas brasileiras.
Quick and dirty translation:
"There is no doubt" that the debris found floating in the Atlantic Ocean by the Brasilien Air Force belong to the AF's Aircraft gone missing during Sunday to Monday night with 228 souls on board.
The announcement was made in a press conference by Jobim, after paying a visit to the families of the victims at a Rio de Janeiro's hotel, and stating that the aircraft crashed on brasilien waters".
Here's the link (http://diario.iol.pt/internacional/airbus-air-france-rio-de-janeiro-aviao-queda-aviao-tvi24/1067674-4073.html)to the portuguese site.
./J

protectthehornet

3rd Jun 2009, 00:31

no charge for the professional courtesy...we've spoken before...we even know that runway 23 at clt slopes downhill

you might want to google cumberland maryland B52 for the inflight breakup of a B52 back in 64.

you did mention that if all electrics were lost the plane would still be controllable...I hope you will expand on that here...and I mean all electrics....even the standby gyro not powered etc.

rwremote

3rd Jun 2009, 00:58

Graybeard - Final Four Minutes of Reports

Active tracking Antenna's have been replaced by phase scanned microstrip patch arrays or similar for communication via the Inmarsat Satellite Network, and stub helical for LEO's such as Iridium and low speed Inmarsat.
So there is no need for any "tracking" or "pointing" of the antenna.
There are a multitude of data speeds offered, from 600bps up to 64kbps.

Air France may well have their own proprietary system for ACARS, but if using the Inmarsat System, then as you say, they will have been pretty much right below the AOR-E Satellite at 15 West (I believe the Aero service at this time is on the I-3 satellites not the newer I-4), so will have had a good "view" of the Satellite.

With the Satellite pretty much overhead, the signals would only be obscured if the antenna were to move out of its (pretty much) 150 degree (+/- 75) view of the sky. For those "Four Minutes" the aircraft (I'm presuming), could have been at any attitude just so long as the antenna's were within their field of view for the satellite.

jauh

3rd Jun 2009, 01:23

Taking each transmission on its own merit, what would likely have had to occur to trigger the first automatic ACARS alert. ...

I totally agree - reverse engineering a fault tree would be one of the few reasonable approaches to speculating about what has actually happened as opposed to seeing whether circumstances fit a particular external event...

So, if I recall correctly a/p disengage and alternate law are claimed to be the first messages, so using occam's razor, what could have triggered that?

On a parallel note, PRIM/SEC 1 are on the same DC bus, right?

barit1

3rd Jun 2009, 01:41

I can find only one accident (PAA 707, 1963) (http://www.airdisaster.com/cgi-bin/view_details.cgi?date=12081963&reg=N709PA&airline=Pan+American+World+Airways) in which a jet transport aircraft was brought down by lightning. Better tank vent design seems to have overcome this problem since that time.

Tail Chase

3rd Jun 2009, 01:58

Gentlemen,
Although the Brazil's Minister of Defence is claiming that the debris field found this afternoon contains the wreckage of AF447 (although I'll grant that it probably is), personally I feel his statement is rather premature. I would rather wait until Friday, by which time the first Brazilian Navy vessel will have reached the area, collected the first items and relayed to Airbus and AF the pertinent data. However, since politicians are politicians, I suppose that this is to be expected

Cheers

GlueBall

3rd Jun 2009, 02:14

In May 1976 Iranian Air Force B747-100 was hit by lightning with fatal consequences.

ASN Aircraft accident Boeing 747-131F 5-8104 Madrid (http://aviation-safety.net/database/record.php?id=19760509-0)

vapilot2004

3rd Jun 2009, 02:17

pressure system controllers on this type get information from the ADIRU , could a malfunction on one of the ADIRU's lead to a decompression?

@Eagle21
Remotely possible, but the outflow valves even if driven fully
open would not depressurize the cabin very rapidly as long as there
was bleed air and at least one pack operating.

stebern

3rd Jun 2009, 02:22

I accept that speculation can be dangerous, but there is a great pool of knowledge on this forum, especially from experienced crew.
An overall look at the posts tends towards:
* A catastrophic lightning strike is beyond reality.
* Given the stress testing on A330 (and other) airframes, turbulence would have had to have been unprecedented to bring about a mid-air break up.
* The lack of pilot comms suggest sudden and total loss.
* The apparent size of the debris field tends to indicate a catastrophic break up at considerable altitude.
So do we not have an explosion here? Either by some bizarre confluence of events (aka the TWA Atlantic explosion some years ago), or by malice?
The fact no terror group has claimed responsibility does not rule out mental instability of an individual - either against themselves or against others.
I am very interested - and crew who fly there regularly would be able to tell us - in the level of pre-flight security, including baggage checking, in Rio.

lomapaseo

3rd Jun 2009, 02:49

I can find only one accident (PAA 707, 1963) in which a jet transport aircraft was brought down by lightning. Better tank vent design seems to have overcome this problem since that time.

IIAF B747 Spain comes to mind and I'm sure that IGH will have a page full of details on others :)

however you comment about better tank design and add in grounding of joints, flash arrestors etc. has made this cause even scarcer since these very old reports.

Iceman49

3rd Jun 2009, 02:51

Good info on violent thunderstorms and where they form:

NASA Satellite Finds The World's Most Intense Thunderstorms (http://www.sciencedaily.com/releases/2006/10/061026095353.htm)

SLFinAZ

3rd Jun 2009, 04:10

I'm curious if we have any type of confirmation that the 1st automatic report was in fact the AP disconnect and the shift to alternate logic? If so based on my limited understanding that would indicate that an upset of some type preceded the following cascade of electrical and system failure warnings. If the initial domino in the chain had been a lightening strike (positive or standard) wouldn't the electrical warnings be either 1st or in close sequence?

It appears that the initial upset was 1-3 minutes prior to the burst of follow up system failure warnings. Has AF clarified or released the order, "time stamp" and content of the warnings as of yet?

protectthehornet

3rd Jun 2009, 04:20

capn bloggs

it would have been so simple to just answer the question. I had read the previous posts and am confused.

It would seem SOME airbus 330/200 series planes have mechanical links via hydraulics to the rudder

and that latter models have electrical controls of the rudder without mechanical links.

But electrical controls are different than electronic controls...at least in my world and understanding of the words.

So, someone other than capn bloggs, would you please clue me in?

Electrical implies no computer, but electrical control.

It may also interest some to know that the Airbus 330/300 has a smaller rudder and vertical stabilizer than the A330/200

BlenderPilot

3rd Jun 2009, 04:30

PaleBlueDot wrote . . . . This is completely unacceptable! Whole two days has passed and they still do not know for sure even where the plane actually is. The year is 2009. I have seen refrigerators with non-stop Internet connection. And here we have 216 people sent in the middle of nowhere without even reliable and constant positioning reports. I really think that, after this, all us had to put some public pressure to make continuous satellite flight tracking mandatory. When I suggested simple and autonomous external GPS device that would not require extensive aircraft design changes, I was not aware that cheap devices exactly like that already exist. For example:

This is what has really surprised me the most out of all this tragedy. I flew helicopters for a bottom feeder company in the Gulf of Mexico, 5 seat, 400K USD crappy helicopters, BUT these helicopters had a Blue Sky Network tracking via Iridium satelites, and the company knew my position almost every minute! They had a girls sitting in a room looking at a computer screen looking at all the aircraft moving around all the time, and if I had a problem, all I had to do was to push a yellow button and her screen would turn red and my position be updated every few seconds.

I find it incredible that AirFrance didint know exactly where they lost contact with the plane, I heard several times that there were searching this huge 1000 mile radius area!! That is absurd from my point of view, how can a company operating a 20 year old 5 person helicopter know where there helicopter is at all times, and AF not know EXACTLY where they lost contact with their 200+ person plane!!!???

Boomerang_Butt

3rd Jun 2009, 04:45

Sorry if this is a repeat, but to answer Valkyrie

Someone asked this and I didn't see an answer, does the AF A330-200 have the same make/version ADIRU as the QF A330-300?According to Steve Creedy in this morning's Australian, the make on AF is different to that used by QF. I believe he said this was from a 'reputable source', but did not name them/it.

EDIT: Link to Steeve Creedy's article... the text is slightly altered to the hard copy I read. Disaster focus on Qantas A330 incident over WA | The Australian (http://www.theaustralian.news.com.au/story/0,25197,25579625-23349,00.html)

Boomerang_Butt

3rd Jun 2009, 04:52

Also, sorry if I missed it (but a lot of posts are getting moved/deleted) in regard to my earlier question about ELTs...

The fixed ones in the a/c, do they activate on contact with water or only due to a high impact force? E.g., if an aircraft broke up mid-air does that mean the ELT would not activate?

Someone mentioned EK aircraft having a manual switch in the flight deck. Is this in addition to any mechanism which activates the ELT (that is, an extra option)? Does anyone know if AF also have this feature? If so, no mention of ELT signals so far would suggest that whatever happened, there was not time to hit that switch, or that the crew were focused on something else.

Finally, as CC, I am somewhat familiar with the portable 406 beacons carried onboard, but do not profess to know HOW they work. All we are told is in a ditching if you throw them in the water they will activate on their own. Surely these 2 beacons (as usually carried) would have activated whether they were separated at some point form the a/c, or attached to bulkheads, when coming in contact with water (as they would have at some point). Or is this subject to surving impact/fall/fire/high G's?

From comments earlier about fixed ELT, I'm assuming portables won't work once fully submmerged? Not trying to start anything, just looking to expand my knowledge in the hope I'll never have to use it first hand...

AMF

3rd Jun 2009, 05:05

A turbulence/load factor-induced jet upset and loss of aerodynamic control with possible engine-flameout is a far, far more likely scenario given conditions at the time and place. Data showing autopilot disengagement and reversion to Alternate Law would also lend credence to that scenario, and possibly exacerbate the situation given the altitude, weight, and q-corner buffet boundaries. No crew would be thinking about (or possibly capable of) radio communication during attempts at recovering from such an event while still experiencing those outside, severe conditions.

Your theory would be the very last thing I'd suspect and there is absolutely no evidence to suggest it, and promoting it smacks of speculative sensationalism. The aircraft wasn't cuising in a benign environement when it was lost. In fact, the enviroment just prior and during the time frame was extremely dynamic in a potentially dangerous (convective) way. Check the met summary and you'll find actual evidence of that.

ekw

3rd Jun 2009, 05:16

Time to look also at what was in the cargo hold. Severe turbulence could have upset something that wasn't supposed to be there. A hull breach caused by even a small chemical explosion at FL350 would cause an explosive decompression, which is what I think the ACARS information adds up to.

Whether the crew could recover would depend on what had been damaged during the initial event, but assuming they lost control there and then, the aircraft would break up on the way down due to g forces. Anything in contact with sparks and aviation fuel would catch fire, hence reports of spot fires on the ocean surface.

Benbecula

3rd Jun 2009, 05:24

To SunInMyEyes,

"Pan Am 214 was brought down by a lightning strike in 1963 only 4 years after the Boeing 707 was introduced. Boeing redesigned the fuel vent outlets so it could not happen again. It is not really appropriate to use that accident which happened 46 years ago to substantiate your argument of how dangerous lightning strikes can be."

Yes, but if you read my post, I'm talking about positive lightning. The re-designing of fuel vent outlets will have made absolutely no difference to the outcome of a positive lightning strike to any aircraft as positive lightning was only discovered in the 70's.
Data from the National Transportation Safety Board on lightning-related incidents in the US from 1967-93 recorded 40 lightning-related aircraft accidents. There were 10 commercial airplane accidents reported, 4 of which were associated with 260 fatalities and 28 serious injuries.
I don't believe lightning applies to Air France here, but it is not as benign as folks make out.

LEVEL600

3rd Jun 2009, 05:26

@jauh (http://www.pprune.org/members/216713-jauh) -both hot bus 1 and dc ess. bus probably, I agree with your idea...

Final 3 Greens

3rd Jun 2009, 05:28

Severe turbulence could have upset something that wasn't supposed to be there. A hull breach caused by even a small chemical explosion at FL350 would cause an explosive decompression, which is what I think the ACARS information adds up to.

SLF/PPL here, so forgive the question, but if there was a hull breach in sev turb and bearing in mind the Qantas 747 where the hull was breached by the crew 02 tank, could a similar event have happened to this aircraft. i.e. bottle detached and provoked to explode.

In sev turb, could an otherwise survivable breach cuase a break up.

Apologies if the A330 system/02 bottle design renders this a non starter.

I fly as a pax on the A330 a lot and am therefore concerned about this incident.

Phalanger

3rd Jun 2009, 06:14

While many people keep going on about how this was explosive, the initial messages sent by the aircraft were not about de-pressurisation. They were about electrical/systems failures. Unless there is other evidence, the de-pressurisation should be viewed as a result, not a cause of the failures (eg. bombs, cargo, holes formed in the hull by lightening etc). Even now the initial quotes of depresserisation has now moved to more important vertical speed warnings as the last messages. This would suggest that the aircraft was in trouble then out of control. 5kms length wise spread of pieces found over a day later would easy be done by currents, and the fact it's in length wise, not area would help add to this. From an separation at 35,000 feet you would expect a much larger area with larger pieces in different areas that had air resistance on them.

As for the lack of radio contact, if all the systems were going dead around you at once in the middle of the Atlantic, I would be a lot more worried about the aircraft and lives then sending out a dooms day message for arm chair experts.

One thing that does that does interest me is if the statement of the aircraft experiencing turbulence by Air France was from the aircraft, or by their own guesses (as they have not stated any contact made to them after the ATC messages). Maps here also suggest that at that time they were not in the main storm and AF gave a very round figure for the time. This would not be the first time AF blamed lightening and turbulence straight away. Doing so in the past moved the blame away from them in the media, and right now they have very little blame on them from the media again (seems like a very effective method, but at the cost of the whole industry).

BEagle

3rd Jun 2009, 06:38

They also said that the A330 series computer system is susceptible to electro magnetic interference

I very much doubt that it is any more susceptible than other comparable aeroplane.

When the A330 was under consideration for the UK's Future Strategic Tanker Aircraft programme, one of my first queries was whether the susceptibility of the FBW system to EMI, for example caused by a receiver aircraft in close formation leaving its intercept radar on by mistake, had been considered. "Yes", I was told, "there is no issue".

Personally, I consider the EMI accident theory to be a roseate herring.

slings

3rd Jun 2009, 06:58

Back in 1981 in the netherlands a fokker F28 fellowship (later developped through to F100) crashed due heavy turbulence caused by flight through a CB.

The right hand wing separated.

So people stating turbulence can not cause a crash are wrong.

LINK (http://www.airdisaster.com/cgi-bin/view_details.cgi?date=10061981&reg=PH-CHI&airline=NLM)

Akhenaton

3rd Jun 2009, 07:13

.../...Taking each transmission on its own merit, what would likely have had to occur to trigger the first automatic ACARS alert.
Then, would each subsequent alert be a result, or a contributing factor, of a failure reported by the preceeding transmission.
Following the transmission trail and analysing the fault(s) should provide somewhat of a picture of the work load being placed on the crew, and the potential conditions which existed in the cockpit at the time.

1°) Electric failure to heat external sensors =>
2°) Iced external sensors =>
3°) Without sensors informations, autopilot disengaged, fly by wire system changed to alternate law =>
4°) flurry of messages regarding ADIRU and ISIS faults
5°) PRIM 1 and SEC 1 faults (again electric failures)
6°) Stall (last message received was an advisory regarding cabin vertical
speed.)

RWA

3rd Jun 2009, 07:16

This would suggest something the aircraft was in trouble then out of control. 5kms length wise spread of pieces found over a day later would easy be done by currents, and the fact it's in length wise, not area would help add to this. From an separation at 35,000 feet you would expect a much larger area with larger pieces in different areas that had air resistance on them.

Excellent point, Phalanger, I've been thinking along the same lines. It's 'promising' (if you can use such a word in the current context) in that they'll be able to fix the likely point of impact with a little more accuracy than the earlier reports suggested; which in turn gives them a ghost of a chance of recovering the FDR/CVR. Not good odds on that though, it will probably only make the difference of the radius of search being in tens of miles rather than hundreds.

As for the lack of radio contact, if all the systems were going dead around you at once in the middle of the Atlantic, I would be a lot more worried about the aircraft and lives then sending out a dooms day message for arm chair experts.

I have to second that -whatever happened, the available evidence suggests that it happened very quickly. On a related note, suggestions that some sort of worldwide tracking system should be set up to cover all the world's oceans, this would cost literally billions to set up and run (whether it was satellite-based or ship-based); and, again on what little evidence is available, knowing where the aeroplane was would have contributed nothing to prevent the accident, and (now that the wreckage has been located) very little to the task of searching for the FDR/CVR.

According to Steve Creedy in this morning's Australian, the make on AF is different to that used by QF. I believe he said this was from a 'reputable source', but did not name them/it.

Booomerang-Butt, I checked this out and it appears simply to be a difference in standard equipment between the two models (A332/A333) rather than any difference between airline preferences. And, as I'm sure you'll know, the idea that electronic interference may have contributed to the Qantas incident came up mainly because there is a big naval signalling station near Learmonth, where it occurred.

Flying Mech

3rd Jun 2009, 07:29

I have read the 32 pages or so of this thread with interest. Some good info,some drivel & a few good theories expressed. I am an A/C Engineer so I am not going to speculate on the exact ins & outs of how to / or not fly an A330, but consider this as a possibility of what happened.

The 3 pilots study there WX briefing in RIO prior to Departure and decide that the WX enroute for the proposed flight plan is not expected to be outside Normal operating limits for the A/C ( It is another conversation to ask how accurate the WX forecast actually was but time will tell when the FDR is downloaded)
The A/C departs & flies on the sheduled route for approx 3 hours uneventfully at night.

I have heard of a case where severe Lightening Bolt punctured the Radome & Disabled the WX Radar antannae thus disabling both radar systems on the A/C - maybe this happened in this case also.

So the crew are now flying with no WX Radar at nite using a WX forecast at least 4 hours old. During that time the storm intensitys & Locations may have increased & changed location. Maybe the crew decided to turn back & hit one of these large storms head on & the extreme wind Forces inside the storm tore the A/C apart.

Does this sound like a realistic possibility to any of you guys who actually fly in that part of the world?

eagle21

3rd Jun 2009, 07:31

I would like to remark that the latest news reports say: saw a band of wreckage in a 5km (3 mile) strip, Brazil's Defence Minister Nelson Jobim said.
BBC NEWS

Considering it took 24 hours to locate the area, and taking into account the drift from wind and currents , I don't see why we could discard that the aircraft was in one piece until it hit the water.

NARVAL

3rd Jun 2009, 07:32

Although the initial failure report in the automatic message seems to have been about electrical problems (I do not know which) and the "tree" of possibilities of systems degrading from there is a vast one, I have kept in mind since the sad news ot the accident the following facts:
the A330 is a beautiful aircraft but it has shown, again and again , very susceptible to probes icing, with the deicing system on auto (numerous reports). This leads to very rapidly presenting the crew with a very lame aircraft to say the least (I give you a factual example below, recent, on an A330, without comments). This has happened at high cruise altitudes, with no ICE alarm, with the heating on AUTO, and out of clouds in some cases...
"Light tutbulence. The speed indication on the right PFD falls suddenly from 280 to 100 knots in red tape for a few seconds Almost immediately the speed on the left PFD falls to green dot minus 15 knots with a speed trend of minus 50 knots. Red alarm A/P OFF ADR
DISAGREE, IAS DISCREPENCY, ALTN LAW PROT LOST, REAC W/S DET FAULT.
Then amber alarm RUD TRV LIM FAULT.
Then STALL STALL STALL with Toga Lock indication.""
The crew changes flight level, the captain pilots with the stand by instruments,
The speeds become normal again.
The status after that:
amber crosses on PFDs
W/S DET FAULT, ALT LAW PROT LOST, ADR DISAGREE et F/CTL RUD TRV LIM FAULT (2
NOGO).Plane in Alternate law
This shows how an unconfortable event (loss of airspeed indication) that would have been minor in, say , an A300, becomes a major headache in those very sophisticated cockpits. Just for information and not saying that is
a possible explanation...but lose electrics, and apart from dealing with retrieving the generators, you may have that kind of thing loaded on top...
My thoughts go to them all...

blueloo

3rd Jun 2009, 07:34

My only comment would be that the forecast is to be taken as a rough guide of only what to expect. It is far from accurate, and really only an indication of where there may be a few bumps and a bit of weather dodging. The scale of it, and the fact that it is only a forecast makes it of only little to moderate use.

RAD_ALT_ALIVE

3rd Jun 2009, 07:37

RWA,

QANTAS group A330s (both -200 and -300) are equipped with Litton ADIRUs.

The other option available to customers is Honeywell.

So, can an Air France pilot/engineer tell us which ADIRU manufacturer they use?

NSEU

3rd Jun 2009, 07:39

The fixed ones in the a/c, do they activate on contact with water or only due to a high impact force? E.g., if an aircraft broke up mid-air does that mean the ELT would not activate?

I believe they only operate with high impact force (the manufacturer's notes don't mention water activation... only "crash situation"). I don't have any values for the g forces required, but I'd imagine they would need a respectable jolt to operate them (certainly higher than bumps sustained during aircraft ground handling). The sensor may be oriented in a particular plane/axis, so a mid-air breakup may not trigger it.

The ELT transmitter unit is mounted to the stringers on the upper fuselage and a short coaxial cable runs to the external antenna. The ELT has an internal battery pack.

Someone mentioned EK aircraft having a manual switch in the flight deck.

Yes, there is a guarded switch on the cockpit overhead panel for both activating the ELT and cancelling a triggered ELT. You can't disable the unit with this switch, only reset it if it has been triggered. You may see this switch in cockpit photographs. The switch can either have a black plastic guard or a red/orange flap to keep it (the switch) in the armed position.

Rgds.
NSEU

Homebrew1

3rd Jun 2009, 07:47

Does a generator off line interuption cause the AP to disengage or change it's "law mode" in an Airbus? In the boeing it does and at an unopportune time ie flying into servere turbulance at night while on limited or load shedded power could increase the chances of inadvetant loss of control then A/C overload. A 737 was lost recently due to an unrecovered upset.

Akhenaton

3rd Jun 2009, 07:51

.../...the A330 is a beautiful aircraft but it has shown, again and again , very susceptible to probes icing, with the deicing system on auto (numerous reports). This leads to very rapidly presenting the crew with a very lame aircraft to say the least.../...

External sensors iced. => AP disengaged, alternate law with reduced securities, and so on.... (in a very disturbed environment, at night, over the sea, no visual references). Stall !

Boomerang_Butt

3rd Jun 2009, 08:10

Thanks NSEU, it helps explain the lack of signal, I guess I expected even with an in-flight breakup that *some* sort of signal would have been receieved. (Not saying this is the case with AF, just generally speaking)

There's so many theories/hypothesis going around at the moment, but I did question one pilot stating in a blog that turbulence on its own could cause an accident... I thought that while one factor may contribute more than another, that it takes two or more factors (the holes in the cheese if you will) to result in something such as we have seen here...? So that would mean while turbulence may contribute to difficulty or damage there would have to be something else (system failure, human factor/control issues or stress) for it to result in a crash. Correct?

BBB3

3rd Jun 2009, 08:16

Where are prim1 and sec 1 located? Close to each other?

eagle21

3rd Jun 2009, 08:20

Unlikely but not to be ruled out:

http://www.dartmouth.edu/~chance/teaching_aids/books_articles/Cassidy.pdf

A close shave, plane almost hit by "meteor" - Ajarn Forum - Living and Teaching In Thailand (http://www.ajarnforum.net/vb/the-virtual-pub/19366-a-close-shave-plane-almost-hit-by-meteor.html)

Oisiaa

3rd Jun 2009, 08:28

I believe they only operate with high impact force (the manufacturer's notes don't mention water activation... only "crash situation"). I don't have any values for the g forces required, but I'd imagine they would need a respectable jolt to operate them (certainly higher than bumps sustained during aircraft ground handling). The sensor may be oriented in a particular plane/axis, so a mid-air breakup may not trigger it.

The ELT used in our aircraft must sense a 5g force in any direction (spherical sensitivity) for a sustained duration of 11 milliseconds.

BRISTOLRE

3rd Jun 2009, 08:41

There are numerous flights leaving Brasil for Europe at this time of the evening. AF have a B744 flying GIG-GRU-CDG, not sure if this would take the same routing as an ETOPS twinjet though.

Other reports have mentioned a Lufthansa aircraft flying a similar northerly track from GRU-FRA that evening and not experiencing any sig wx problems.

I flew back on Saturday evening GIG-LHR on a BA B772, we experienced the usual light-moderate chop for a good few hours from the north east of Brasil, up over FLZ continuring 2hrs north of the Equator on a similar northbound routing. We took significant wx deviation just north of 0 deg before returning back to track.

Red Paddy

3rd Jun 2009, 08:48

Just a point. I'm a Boeing pilot and I'm not familiar with Airbus systems.

In the case of an electrical failure, there should be a systematic shut down of systems-ie non essential items first. Would ACARS fall into the bracket of a non essential item? Would the fact that it kept transmitting faults until a final catastrophic conclusion to the events(as indicated by the cabin v/s message) indicate a random shutdown of systems in a progressively deteriorating situation? Also there has been a suggestion that the on board mobile phone system continued to operate.

To me there is only one thing that could cause a shutdown that would leave non essential items operating while essential items such as the ADIRU's and ISIS shut down and that would be a fire in the avionics bay knocking out essential systems in an erratic manner and not shutting down non essientials first.

Whether the fire was caused by a lightning strike is another matter.

For the record I spent the evening yesterday with the family of a beautiful girl lost in this tragedy and am merely trying to better understand events.

Blind Squirrel

3rd Jun 2009, 08:49

"An Awacs radar aircraft is going to carry out a 'mapping' [cartographie] of the débris to try and determine the scene of the accident and thereby make possible the recovery of the black boxes. This mapping will be completed by a Falcon 50 which will take off from Natal, in Brazil, and by a fresh Atlantique 2 flight....

"The Pourquoi pas is en route to the area. Equipped with two robot submarines--a Nautilus mini-submarine and a research robot capable of operating in depths up to 6,000 metres--this Ifremer [French maritime research institute] vessel is eight days' sailing distance from the area. Its mission is to try to find and recover the Airbus' black boxes, whose signals will be transmitted for no more than thirty days. They can be recovered from depths of up to 4,000 metres in the Atlantic. 'A needle in a haystack,' as one expert summed it up on Tuesday. In the race against the clock to find these black boxes, the French military too has committed additional resources to the operation. Two Breguet Atlantic 2 'submarine-hunter' aircraft equipped with radar and long-range infrared scanners, as well as a Falcon 50 designed to detect pirates and drug-runners and an Awac radar aircraft will provide aerial coverage."

BOAC

3rd Jun 2009, 08:57

Is the A320 series so unrelated from the A330 that this is irrelevant?- I am reliably informed by a 330 man that the electrical system is different, so apparently yes. Personally I do not consider it 'irrelevant' however, as it shows what CAN be lost in an electric aeroplane and the problems that can ensue.

JamesT73J

3rd Jun 2009, 08:59

Where are prim1 and sec 1 located? Close to each other?

I don't think they are; I recall reading that they are in totally seperate bays.

bubbers44

3rd Jun 2009, 09:12

It was an Air France PR guy that said it was a probable lightning strike. He just pulled it out of his A--. Nobody knows what happened. Hopefully they will recover the black boxes and get some real information.

woodja51

3rd Jun 2009, 09:16

In severe turbulence the AOA probes on the bus can be triggered into a disagree position which will trigger alternate law - removing many protections including the ability to stall the aircraft.

THe auto pilot will also disconnect at this point.

A reset of prims/secs etc may reengage normal law ( I think??? but not sure if it can only be done on the ground) .. then the AP becomes available again.

In big bumps it could always be possible to over control and overload the airframe if not careful.

Not saying any of this happened but if the ACARS was sending this type of report then might have occurred.

Will wait for the FDR but the airbus is certainly NOT uncrashable as AB would like us to believe..

W

O_K_

3rd Jun 2009, 09:43

Written by Red Paddy in post:

In the case of an electrical failure, there should be a systematic shut down of systems-ie non essential items first. Would ACARS fall into the bracket of a non essential item? Would the fact that it kept transmitting faults until a final catastrophic conclusion to the events(as indicated by the cabin v/s message) indicate a random shutdown of systems in a progressively deteriorating situation? Also there has been a suggestion that the on board mobile phone system continued to operate.

To me there is only one thing that could cause a shutdown that would leave non essential items operating while essential items such as the ADIRU's and ISIS shut down and that would be a fire in the avionics bay knocking out essential systems in an erratic manner and not shutting down non essientials first.

------------------------------

Exactly along the lines of what I have been thinking. On page 7 in this thread it is mentioned that ACARS is powered from AC1, and that it would be unpowered in an EMER ELEC CONFIG. That would indicate that the elctrics were working as long as the ACARS was transmitting, all the way until the vertical speed waring.

The flight controller computers are located away from eachother, so a single fire should not take out all of them.

So, if there is power, and at least some of the FCC's are working, what about the inputs (and outputs)? If all the sensors started to report conflicting information, how would that affect the computers? If there was not enouh consistant data to know what data to ignore.

HundredPercentPlease

3rd Jun 2009, 09:46

Back in 1981 in the netherlands a fokker F28 fellowship (later developped through to F100) crashed due heavy turbulence caused by flight through a CB.

The right hand wing separated.

So people stating turbulence can not cause a crash are wrong.

LINK

No sir, that flight travelled though a tornado and experienced g loadings of +6.8g to -3.2g.

The most severe turbulence should not see more than 2g.

There is no suggestion that the AF 330 went into a tornado, at least not at the moment.

green granite

3rd Jun 2009, 09:57

I read that the French are now saying that the data recorders may never be found.

With the availability of modern satellite and data transmittion technology, the possibility of continual tx of FDR information should be possible. Given how essential that data is in understanding the causes of an accident perhaps this should be considered by the powers that be for A/C crossing deep oceans.

I know it would be costly, but then again so is the recovery of sunken black boxes.

HarryMann

3rd Jun 2009, 09:59

From an separation at 35,000 feet you would expect a much larger area with larger pieces in different areas that had air resistance on them.

The heavier pieces travelling further would though, be more likely to sink, no?

Thuis reducing the apparent surface debris field?

deltayankee

3rd Jun 2009, 10:12

With the availability of modern satellite and data transmittion technology, the possibility of continual tx of FDR information should be possible.

This looks like a good solution but there are issues in the details. One of these is that the satellite connection is easy to manage when the aircraft is flying in a normal attitude and with normal electrical power; it is not so easy in an emergency situation. You could end up with the remote recorder missing all the most interesting data because the connection was lost. Designing a system that will work in extreme conditions is much more demanding.

IO540

3rd Jun 2009, 10:18

With the availability of modern satellite and data transmittion technology, the possibility of continual tx of FDR information should be possibleThe problem is cost, of developing the system, and of transmitting that much data.

I've done some work on airborne satellite data and yes it is definitely very possible using existing services but it's not cheap. Take a big airline, and take how many planes they have airborne at any one time, and multiply this by the cost of (effectively) a DSL connection, and it will be well up in the millions a year.

Some satellite networks are struggling with reliability already. If you loaded up somebody like Immarsat with every jet sending a few hundred kbits/sec the whole lot would just collapse.

Then the data has to be collected from around the aircraft systems. Implementing a certified solution, across the many aircraft types, would be a huge task whose cost would make the satellite data cost pale into insignificance.

Phalanger

3rd Jun 2009, 10:23

The heavier pieces travelling further would though, be more likely to sink, no?

Thuis reducing the apparent surface debris field?
As the piece separated fall from a higher height, they are more affected by the air on their shape. This means they will land further away from each other, you would expect wings, back fuselage, forward to all end up in different areas and some to stay off to the side. Pieces would also come down with high air resistance on them to their weight, which would hold together more than a piece being aimed with low resistance and high kinetic force.

tubby linton

3rd Jun 2009, 10:25

I would suggest that those looking for the crashed aircraft have a look at the Palomares B52 crash of 1966 when a nuclear weapon was lost in the Mediterranean for over two and a half months despite the full resources of the United States Navy looking for it.The bomb was located but was lost again when it was being recovered and it took a further two weeks to relocate it.
Recovering the recorders from the bottom of the ocean is going to be a very slow and difficult job,assuming that they are ever found.
1966 Palomares B-52 crash - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Palomares_hydrogen_bombs_incident)

SkyBat

3rd Jun 2009, 10:34

daisy120

3rd Jun 2009, 10:39

Tim Vasquez's report, whilst being fairly technical, concludes well. We don't at the moment know the ADD status of AF447 and what if any MEL's the a/c dispatched under. So called ETOP's dispatch with single radar, IRS fault or a prim/sec problem is not unfeasable. Comment was made that many crews frequently attempt to fly over weather; in an almost max weighted 330 or even 340, this would be folly. Pilots who have little experience of other types may attempt this manoeuvre but for those with L1011/747 classic/DC10 time, that would be a rare judgement call. The digi radar on the Bus requires more analysis and very carefull gain and tilt management than earlier analogue types. The buffet thresholds at close to or even at, max recommended or above optimum altitude levels are also narrower than non FBW types. For these reasons, lateral wx deviation, even by track displacements of over 100nm are not uncommon within the ICZ that I operate through. It appears through Tim's track analysis of 447, that no significant wx avoidance was applied. As an after thought, wrt CRM and crew rest issues, were the senior crew resting at the time of the 'event'? What was the crew pilot compliment/experience? was this a training sector for either the capt or F/O?
As a senior check and trainer on the 330 and 340, I always, without exception employ two cardinal rules.
. Rough air speed protocols versus altitude limitations must be applied early on in the piece. If the air is rough,(med/light, med turb and above), select M.78 without delay. "Chunking down" of mach to finally achieve target .78 is not recommended.
. Early wx deviation and crew lockdown is key to successfull wx damage avoidance. Never attempt to outclimb weather. Cherry picking the weaker cells and risking penetration of invisible gust regions, again is folly. Keep the big picture in mind, take the additional fuel at flight planning and large track mile deviations.
The above is intended to compliment Tim's fine piece and in no way wishes to undermine the severity of the event and its tragic outcome. RIP pax and fellow crew.

.

BarbiesBoyfriend

3rd Jun 2009, 11:03

I suspect this a/c was broken up by a powerful Cb.

There are many precedents for this and the 'facts', such as they are, don't contradict this.

Is there anyone on here with intimate knowledge of the A330 structure that could refute this? Is it a particularly 'strong' a/c, like the Bae 146 for example? I suspect not.

I've had the misfortune to fly in a fully developed Cb- entirely my own fault I may as well add.

If I learned one thing about flying that day it's this:

Don't.

jauh

3rd Jun 2009, 11:04

@LEVEL600
both hot bus 1 and dc ess. bus probably, I agree with your idea...

Ok, so the only "simple" explanation I could think of for a/p disengage + alt. law + 3 mins of ARIDU + ISIS fail messages would be a fault with pitot-static system (Aero Peru anyone? Not saying they were blocked on take off, but could've iced up).

PRIM/SEC 1 must've been still running off DC ESS and not HOT BAT as ACARS was TXing, correct? If it was a short on DC ESS that probably would take out more than just PRIM/SEC. I also presume that a lightning strike to a wing would've knocked some core censors out like fuel flow, etc, which would've been reported via ACARS?..

Just trying to fit theory to facts, not the other way around...

ManaAdaSystem

3rd Jun 2009, 11:05

I do hope technology has evolved a little bit since 1966.

As for planning, unless my ETOPS alternates are below minima or there is a cyclone sitting on my flight track, the flight will depart. Any enroute WX affecting the flight will be briefed before departure and dealt with enroute. I think this is a pretty universal practice.

There seems to be some sort of consensus that this accident was in part caused by WX. AF 447 would not have left RIO without a working WX radar, given the enroute forecast. So if the WX was a factor (I'm not saying it was), why would they even go near it?

I have never flown through a CB in my entire career. I've been pretty close, in between, touched the edge, above, but never IN one. I've been 100 miles off track to avoid the monsters, in areas where only HF was available. There are contingency procedures for this scenario.

A failed Wx radar enroute would give the pilots some challenges. Continue, divert, return? They could have gone through WX already, so a turn back may have not be a good option. WX enroute to alternates could also be bad. So they would have found themselves between a rock and a hard place, trying to pick their way through CB's visually.

I don't have any statistics, but WX radars seem to have more failures than other systems. I had one fail on me just yesterday.

Pure speculations on my part, I really, really hope they find the cause of this one.

BTW, would a WX radar failure be an Acars event transmitted to maintenance?

mrdeux

3rd Jun 2009, 11:07

Like all accidents, this it pretty hideous, and we can only hope to learn something before we move on.

I'm not an Airbus pilot, but I had a very major event in Boeing a while back, which involved multiple, and seemingly random and unrelated electrical failures. From the cockpit they made no sense, but a larger view showed that the wiring all ran through the same area.

FE Hoppy

3rd Jun 2009, 11:08

HundredPercentPlease

Join Date: Jun 2003
Location: UK
Posts: 177
Quote:
Originally Posted by slings
Back in 1981 in the netherlands a fokker F28 fellowship (later developped through to F100) crashed due heavy turbulence caused by flight through a CB.

The right hand wing separated.

So people stating turbulence can not cause a crash are wrong.

LINK
No sir, that flight travelled though a tornado and experienced g loadings of +6.8g to -3.2g.

The most severe turbulence should not see more than 2g.

There is no suggestion that the AF 330 went into a tornado, at least not at the moment.

BIG FAIL.

Go find the definition of severe and extreme turbulence then come back and retract this BS.

Self Loading Scot

3rd Jun 2009, 11:35

SLFinAZ:
I'm curious if we have any type of confirmation that the 1st automatic report was in fact the AP disconnect and the shift to alternate logic? If so based on my limited understanding that would indicate that an upset of some type preceded the following cascade of electrical and system failure warnings.I've been reading a lot and saying nothing, but this is pretty much where I've gotten to as well. My pure conjecture based on the alleged ACARS reports and timings, together with Tim Vasquez's excellent weather analysis: something very sudden and very violent (most likely although not necessarily: extraordinary turbulence) got the a/c badly out of shape, leading to deselection of autopilot and selection of "Alternate Law", and from then on who knows what caused the cascade of errors. Here's hoping they can get the FDR back at least.

Mindful of the fact that the a/c may have been in an abnormal situation, potentially in violent weather in the dark, I have one question (which hopefully is not too stupid) for those who can answer clearly. On this type, could electrical or computer failures relating to ADIRU and ISIS leave the pilots with no attitude or airspeed indication - or are there old-school hardware backup instruments on this type? As an add-on, if ADIRU and ISIS are completely non-functional, and you have no external horizon reference - is that even recoverable?

Just my stupid SLF question...

Hiflyer1757

3rd Jun 2009, 11:36

"With 2 F/O's onboard what would the norm have been for crew resting, i.e. do AF use cruise Pilots, Commander at rest?"

Asked this very question of a 777 captain yesterday...at his carrier on a flight of this duration with 3 pilots there would be 3 blocks of rest...with the Captain taking the middle block. I asked about how long would that be into the flight and he said around 3-3.5 hours. I do not have any specific knowledge on what AF procedures are and if any of the 3 cockpit crewmembers were out of the cockpit during the incident. However, during our discussion it was felt that after exiting Brazilian Radar and going deep transoceanic that it 'could' be a 'possible' time for that rest.

bsieker

3rd Jun 2009, 11:38

I suggest a look at the TWA 800 (B747 fuel tank explosion) report. Not because I suggest there is any similarity (there is yet no way for us to tell), but because it mentions (for the time) advanced software modeling to simulate the distribution of fragment trajectories based on their aerodynamic properties (size, weight, "lift/drag") to get an idea of the altitude at which parts separated and broke up.

With far more advanced computers and more accurate modeling these days, such an analysis of the debris distribution (taking into account known winds and currents) will be carried out and will, at the end of the day (... week, month, year, ...) give a very good idea of where and in what fashion the aircraft disintegrated.

Initial distribution of the bigger pieces will give a rough idea early on, whether it was an in-flight breakup, of destruction on impact.

Only time and meticulous investigation will tell.

As to the recorders: I can't believe the authorities have given up on recovering them. This is such a grave and rare event that it is essential to find out as accurately as possible what happened. Every effort will be made to recover those recorders, and perhaps even large parts of the airframe, depending on the findings from the recorder.

Bernd

Joshilini

3rd Jun 2009, 11:41

Sorry guys but what does it matter about crew resting? The first and second officer together had more flying experience in the Airbus than the captain.

I wonder what effect positive lightning would have on the aircraft?

jauh

3rd Jun 2009, 11:42

As an add-on, if ADIRU and ISIS are completely non-functional, and you have no external horizon reference - is that even recoverable?

There is a gyroscopic horizon in the cockpit, if that's what you mean...

slings

3rd Jun 2009, 11:56

Okay, maybe my way of writing wasn't correct. I meant severe weather associated with CB's or squall lines may cause turbulence beyond design limits of aircraft.

In general build up here in the netherlands is different from build up in the ITCZ (flew through it over africa, south america and the atlantic).
In my experience it is generally much less active here.
And normally we don't have many tornado's over here.

I am not saying this is what happened to the AF A330 as we just don't know what happened and probably won't know for months or even years if ever.
My point is only that CB's and associated phenomena may cause a break up.

Postman Plod

3rd Jun 2009, 11:59

A couple of questions / observations...

Firstly, the maps used on (for example the BBC) news sites seem to indicate a turn off the NE coast of Brazil, through a "gap" in the storm cells. Is this turn "real", or is it just a bad representation of a great circle route? Therefore did they actually fly through the system being mentioned? Or is the map just wrong?

Secondly, with regards to data transmission, surely we would only be looking at a couple of kb for position information, rather than tens or hundreds? Also, would it really matter about its ability to transmit / receive at every attitude / aircraft state? Surely the fact it can give a "last known position" is still better than what we have here?

As for an EPIRB or something similar, wouldn't you just put something (perhaps in the top of the tail) that would be barostatically activated (I would say on contact with water, but then there is such a thing as rain) and detach from the aircraft, float, and start transmitting?

flapsforty

3rd Jun 2009, 12:05

NB: If you post has disappeared from this thread, it might be found here: http://www.pprune.org/jet-blast/375943-air-france-jet-missing.html

zk-abc

3rd Jun 2009, 12:06

I imagine that he means if it was inflated that would mean that there is a slight possibility the pax and crew or some of them or one of thembmanaged to get out of the plane when in the water. Personally don't think there would be a chance at all but I imagine that they were refering to that.

Very sad event and my heart goes out to those affected by this in anyway.

ABC

Bangkokeasy

3rd Jun 2009, 12:17

My apologies if this is drifting into the technical, but when looking at the debris field, bear in mind that wind and swell are both factors to consider, after the debris has entered the water, even independent of the direction of prevailing currents. Most of the studies on this subject are to do with oil spills, but I guess are relevant here too. The net effect of wind will be between 2.5% and 4.4% of prevailing wind speed, depending on wave interaction, with a mean average of 3.5%, so wind alone will cause floating objects, such as an oil spill or debris field to drift about 1knot per 30 knots of wind. Swell also has an effect, although less pronounced.

SkyBat

3rd Jun 2009, 12:20

Possible Jet Upset?
If bank angle exceeds 45 degrees then Autopilot will disengage.

If bank angle is greater than 125 degrees or
Pitch > 50 Up or 30 down or
AoA > 30 or < 10 or
Speed > 440 kts or < 60Kts or
Mach > 0.91 or < 0.1 ....
then Abnormal Attitude Law is activated which is Alternate Law in Pitch with no protection except load factor protection and no Auto trim and in roll it is full authority direct law with yaw mechanical...
With electrical problems as well....

MartinM

3rd Jun 2009, 12:36

Hi

i would like to clarify some questions i have for my curiosity.

a. is it possible that the cockpit got struck by the lightning first. this would give me an explanation for the cabin decompression?

b. if ACARS reports ADIRU, PRIM1, SEC1, ISIS failure. Is this a reason for divert to alternate or something where the flight will follow the normal path?

c. AFAIK ISIS are the backup instruments. In the older type of A3xx, these instruments are analog. The newer A3xx have the digital. With this failure, do you still have altimeter, speed, attidude indicators?

Thanks

Cheers
Martin

RWA

3rd Jun 2009, 12:52

So, can an Air France pilot/engineer tell us which ADIRU manufacturer they use?

Thanks, RAD ALT ALIVE - so I got it wrong, Litton or Honeywell IS a customer option. So yes, it would be interesting (though not in any sense conclusive) to know which option Air France chose.

About the Qantas Learmonth incident, I discover that there were in fact three similar occurrences in quick succession (the first two being Qantas, the other unknown) and three cumulative Airworthiness Directives have issued, both covering most of the A330/340 range - significantly, those equipped with the Northrop Grumman (now Litton) ADIRUs.

Deciphering ADs is a bit like cracking the WW2 Enigma codes, so if I've got anything wrong someone please set me right.

In the first incident, the ADIRU started feeding erroneous data to the Airbus 'protection' system. So, although the aeroplane was flying level, the flight computers got the idea that it was climbing steeply - and therefore rammed the nose down.

"Investigations highlighted that at time of the event the Air Data Reference 1 (ADR) part of ADIRU1 was providing erroneous and temporary wrong parameters in a random manner. This abnormal behaviour of the ADR1 led to several consequences such as unjustified stall and over speed warnings, loss of attitude information on Captain Primary Flight Display (PFD) and several ECAM warnings. Among the abnormal parameters, the provided Angle of Attack (AoA) value was such that the flight control computers commanded a sudden nose down aircraft movement, which constitutes an unsafe condition. At this stage of the investigation, the analysis of available data indicates that ADIRU 1 abnormal behaviour is likely to be at the origin of the event. Due to similar design, Airbus A340 aircraft are also impacted by this issue."

The pilots eventually regained control, but only by turning off all the automatic stuff and reverting to 'alternate law' and doing an emergency landing at Learmonth. But 40-odd people were injured.

An AD was issued directing that that should be done any time there was a re-occurrence. But then another Qantas bird had the same problem, luckily without any injuries, approaching Perth. They followed the new procedure but it apparently didn't work! So a second AD was issued, and following yet another incident (don't know who or where that was) yet a third one went out:-

"Since that AD was issued, it has been reported that the “OFF” light did not illuminate in the cockpit after setting the IR and ADR pushbuttons to OFF. Investigation has determined that the ADIRU was indeed sometimes affected by another failure condition.

To prevent such a failure, the operational procedure has been updated to instruct the flight crew to de-energize the ADIRU if the “OFF” light is not illuminated after setting the IR and ADR pushbuttons to OFF.

Consequently, AD 2008-0225-E, which superseded AD 2008-0203-E, required accomplishment of the updated AFM operational procedure. Since this second AD was issued, a new in service event has been reported highlighting that, in some failure cases, even though the “OFF” light illuminates in the cockpit after setting the IR and ADR pushbuttons to OFF, the IR could keep providing erroneous data to other systems.

In order to address all identified failure cases, de-energizing the affected ADIRU must be done by setting the IR mode rotary selector to OFF. Consequently, this AD, which supersedes AD 2008-0225-E, requires accomplishment of the updated AFM operational procedure."

You can read the whole latest AD here (click on 'Download' at the bottom):-

EASA Airworthiness Directives Publishing Tool (http://ad.easa.europa.eu/ad/2009-0012-E)

Can't claim to understand it all by a long chalk - in the things I used to fly, a radio (or even an engine!) was an expensive luxury! But I get the feeling that the pilots are being told, "If the inertia gimmicks start talking nonsense to the auto controls, and go ON doing it, turn them ALL off and go back to 'seat of the pants' flying......."

Thing is, I'm struck by the similarity of the earlier cases with what appears to have happened to Air France (on the basis of the 'Aviation Herald,' anyway):-

"New information provided by sources within Air France suggests, that the ACARS messages of system failures started to arrive at 02:10Z indicating, that the autopilot had disengaged and the fly by wire system had changed to alternate law. Between 02:11Z and 02:13Z a flurry of messages regarding ADIRU and ISIS faults arrived, at 02:13Z PRIM 1 and SEC 1 faults were indicated, at 02:14Z the last message received was an advisory regarding cabin vertical speed. That sequence of messages could not be independently verified."

So it reverted to 'alternate law' (whether automatically or by pilot action, we don't know) and then ISIS packed in (which I take to mean that the emergency panel lighting packed in and the instruments went black).........

No way you could fly through a storm at 35,000 feet, presumably in cloud, with no autopilot and no instruments?

Dutch Bru

3rd Jun 2009, 12:55

The Indonesian Adam Air B734 that crashed in the Makassar Strait off Sulawesi on 1 January 2007 had its DFDR and CVR located after 3 weeks at depths of 2000m and 1900m respectively. According to the accident report underwater locator beacon (ULB) signals from the flight recorders were picked up on 21 January 2007 by a US oceanographic vessel Mary Sears and their positions logged.

Just to give an idea of some of the constraints concerning this type of operations, according to the accident report: "Mhe Mary Sears was required to pass within 500 meters of a beacon before it could detect a return. The US Navy Supervisor of Salvage shipped a towed pinger locator (TPL) from Washington, DC, to Makassar. This device is a sonic detector with umbilical cable capable of detecting the underwater locator beacons from the PK-KKW flight data recorder and cockpit voice recorder (if they are still operating), down to a depth of 20,000 feet." The speed with which the TPL was towed through the water was 2-4 kts in the case of the Adam Air B734.

Due to several circumstances (including an initial lack of specialised equipment and disputes about the costs of the salvage operations), the actual salvage started only on 24 August 2007, with the DFDR and CVR being retrieved from the ocean floor by Phoenix International on 27 and 28 August respectively. Functional data were retrieved from both recorders.

Also to give an idea of the specificities of this type of operation, the following text from the accident report: "The underwater survey and recovery used a small ROV, Remora 6000, which was capable of descending to a water depth of 3000 meters. The ROV had three visual cameras and two fixed lights fitted on the front of the vehicle, which were used for visual scanning. The visual range of the camera was about 10 meters. The ROV was also equipped with underwater sonar with good resolution horizontally up to 100 meters. The width of the sonar beam is about 50 meters at a distance 100 meters from an object. The position of the ROV relative to the ship was measured using an underwater positioning system and the ship used differential global positioning system equipment. The coordinates provided by the ship and the ROV were used to mark the location of the aircraft wreckage and these were mapped into a computer. The ROV had a pair of robot arms that were capable of lifting a 25 kg object of a maximum dimension of about 30 cm by 40 cm. The ROV was in the water for about 109 hours and completed five dives."

Although the AF A332 wreckage is arguably at greater depth (between half and double as deep) then that of the Adam Air B734, the above may give an idea of the challenges and constraints of the salvage operations with regard to the AF 332 DFDR and CVR. It would not be impossible though, since the salvage company at the time, Phoenix Intl, states on its website that 6000m is now the max depth of its remotely operated vehicle (ROV), provided of course that the ULB signals are picked up and pinpointed within 30 days.

wiggy

3rd Jun 2009, 13:12

I think the French investigator/spokeman was simply being realistic - no doubt the Press want to know when recorders will be recovered, he's quite rightly emphasising it's an if.

I'm watching some of this in the States at the moment and some of the conjecture is not being helped by the standard of live translating being used by the networks and others...e.g. translating "recorders" as "registers".... and yes, I do know translating is difficult :bored:

Worrals in the wilds

3rd Jun 2009, 13:16

...said the flight data and voice recorders may never be found.

I'm not a commercial salvage operator, but I do dive and read up on deep/technical diving and commercial salvage operations.
According to Reuters, the wreckage lies bewteen 1500 and 2700 metres under the sea: that is incredibly deep for any salvage operation. It is far too deep for divers (the current record is 330m) and while remote operated vehicles or small submarines can reach these depths it is uncharted territory for salvage.

To get two small items from a broken wreckage at that depth will be difficult and expensive. That's not to say it can't be done, but it will be unprecedented, except for the Titanic (in 3900m) which took considerable planning.

misd-agin

3rd Jun 2009, 13:17

Flying Mech - post #638.

You asked if it's a possibility to get a lightning strike and lose the radar. The answer is yes. Did it happend? No one knows.

We'll have to hope that the CVR and FDR are recovered. Hopefully their recovery will solve this accident.

lomapaseo

3rd Jun 2009, 13:28

Arslanian also reportedly said that they would do their best to find the causes without the aid of the recorders.

After catching up reading several new pages here I resisted the urge to hit the reply button to several posts until I read everything. So now only a single reply.

When we talk about large transport aircraft there is no sense in asking or intimating that one design is stronger than the other in turbulence. They are essentially the same. The critical structures are designed to limit loads and less critical stuff is expected to fail first.

So the finding and identification of bits of debris along a path would give a hint of the relative breakup and shedding of parts which in turn may indicated the differences between fire, explosions, upset etc.

Not necessarily a postive conclusion but at least a pointer along with the already commented ACARS.

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.

rubicondsrv

3rd Jun 2009, 13:35

I suspect that if the recorders are not found by the french investigators, a privately funded search for them may ocurr.

the potential financial impact of substantial unanswered questions about this crash on the comercial aircraft industry is suffeciently great to justify spending years searching if necessary.

so I suspect the recorders will be found, but possibly not anytime soon.

Zulu01

3rd Jun 2009, 13:35

Worrals in the wilds Quote:
...said the flight data and voice recorders may never be found.
I'm not a commercial salvage operator, but I do dive and read up on deep/technical diving and commercial salvage operations.
According to Reuters, the wreckage lies bewteen 1500 and 2700 metres under the sea: that is incredibly deep for any salvage operation. It is far too deep for divers (the current record is 330m) and while remote operated vehicles or small submarines can reach these depths it is uncharted territory for salvage.

To get two small items from a broken wreckage at that depth will be difficult and expensive. That's not to say it can't be done, but it will be unprecedented, except for the Titanic (in 3900m) which took considerable planning.

Not true .... as has already been said - SAA Helderberg - they recovered the one of the boxes (I think the CVR) from 3500m deep after 2 months of searching, also brought up about 1% of wreckage for analysis.

Hiflyer1757

3rd Jun 2009, 13:36

http://www.armytimes.com/news/2009/06/navy_p3_airfrance_060208w/"The Navy has sent a P-3 Orion to Brazil to help search for survivors and debris from Air France Flight 447, which went missing Sunday, the Navy said.
The U.S. Southern Command on Tuesday sent the maritime patrol aircraft and 21 crew members from its forward operating base in El Salvador, where it was doing counter-drug missions, according to a statement from the command."

md-100

3rd Jun 2009, 13:36

Does anybody know how far can the signal of the ULB (Underwater locator beacon) of the CVR/FDR be detected?

Worrals in the wilds

3rd Jun 2009, 13:48

Zulu01, fair enough, and thanks for that. I was unfamiliar with that operation. I wanted to assay the conspiracy theorists amongst us that seem to think retrievals at that depth are easy and guaranteed.

"...however the flight data recorder was never found."

from the dreaded Wiki about the SAA, because an operation at that depth is always touch and go. As doubledolphins said, the data may also be degraded.

c130jbloke

3rd Jun 2009, 13:51

It is quite obvious the airplane was destroyed inflight by extreme turbulence.

Bollocks.

It is quite obvious that nobody has any idea what appened to that aircraft until a complete investigation iaw ICAO annexe 13 has taken place, a viable accident cause theroy has been created and then tested to prove it's validity.

Frangible

3rd Jun 2009, 13:59

The US Navy recovered the UAL 811 cargo door about 20 years ago from a depth of over 4300 metres, and seeing that did not have a pinger, recovering the black boxes is not so unlikely.

RWA

3rd Jun 2009, 14:02

"Isn't a computer on an aeroplane supposed to be an aid to good airmanship rather than a substitute for it?

The flying community is rapidly becoming totally dependent upon computers for all aspects of flight based upon the assurance of the manufactureres that "nothing can go wrong - it's all 100% reliable."

Zeque, there's a clear difference between the approaches of the two major manufacturers.

Generally speaking, Boeing leave the final decision to the pilot - they provide him with warnings, like stick shakers and klaxons -but if he 'decides' to try to stand the aeroplane on its head or its ass or its elbow, the 'systems' will let him do it.......

Airbus, on the other hand, build in 'protections' in normal flying trim. Essentially, they won't LET the pilot turn or climb or descend too fast or too hard - they just 'take over' and keep the parameters within set maximums.

"Pilots should be able to isolate computers when the programming has obviously gone wrong."

I believe that you can do that in either aeroplane, in theory. In a Boeing, you always have that privilege. In an Airbus, you can go to 'Direct Law' (I think!). But, also as far as I know, that means that you won't have elevators or ailerons to fly with, just the rudder and the trim controls.......

Others will correct me if I'm wrong - but as far as I know, that's the situation.

Both sides of the argument have their ardent supporters. All depends, I suppose, on whether you reckon 'situations' cause most accidents - or pilots do........

Dutch Bru

3rd Jun 2009, 14:04

See post # 685

Max detection range would theoretically be in the order of 4000 meters, but in case of the Adam Air B734 actual TPL detection of the ULB's was only within a 500 meter range.

Mapping the ocean floor first with other (faster) detection means (currently ongoing) may locate bigger pieces of the A332 wreckage, assuming that the A332 didn't fully disintegrate in flight as the Adam Air B734 did. Which in the case of the A332 may considerably narrow down the search area for TPL trawls in order to successfully detect the ULBs of the DFDR and CVR and locate them for ROV salvage.

SLFinAZ

3rd Jun 2009, 14:04

LEM,

The 747 in question survived, and so did 3 other 747's that encountered turbulence sever enough to kill one or more passengers. The Russian Tu-154 that entered a flat spin was also intact all the way down. My question here is pretty simple...

Assuming we had an initial upset, does the follow up stream indicate failures during decent (not sure what limits are required for a vertical cabin speed warning) or was the AP fail sensor driven and in effect the plane was unexpectedly handed back to the pilots unexpectedly but in a condition where altitude was maintained for a period of time and a combination of weather and internal issues caused a later loss of control due to system degradation?

Can a FBW avionics system degrade to the point where the plane is still physically flyable but the avionics don't allow it? More and more I get the feeling that the KISS principle is at work here...

khorton

3rd Jun 2009, 14:17

In an Airbus, you can go to 'Direct Law' (I think!). But, also as far as I know, that means that you won't have elevators or ailerons to fly with, just the rudder and the trim controls.......
There is no specific cockpit control to select Direct Law, as Airbus and the civil aviation authorities are convinced that the system would automatically switch to Direct Law in any situation that warranted it. But, I suspect that any Airbus crew would know that you can get to Direct Law, if desired, by switching off enough of the fly by wire computers.
Once in Direct Law, you have conventional control, using elevators, ailerons, roll spoilers, rudder etc. There is a direct relationship between the position of the cockpit controls (i.e. stick and rudder) and the position of the flight control surfaces. In other words it is very much like a "conventional" aircraft.

FMC

3rd Jun 2009, 14:20

Just read that AF have released further information on the ACARS traffic :-

02:10Z A/P disengaged and a fault with one of the FBY computers.
02:11Z - 02:13 Faults in the NAV system was reported in a flurry of messages. Then a fault reported in a system that provides instrument readings (IRU?)
02:14Z Fault reported in vertical cabin speed giving rise to decompression of cabin.

ends

FMC

Diver-BR

3rd Jun 2009, 14:23

The US Navy recovered the UAL 811 cargo door about 20 years ago from a depth of over 4300 metres, and seeing that did not have a pinger, recovering the black boxes is not so unlikely.

One of the additional challenges faced by the investigators is that the ocean floor is very uneven where the AF was lost, it is part of an underwater mountain range. I agree that there's no guarantee of recovery of the recorders.

Dutch Bru

3rd Jun 2009, 14:32

PRESS RELEASE 03/06 (1015 Brasilia time) Brazilian Air Force:

"REPORT OF THE SEARCHES OF AIR FRANCE FLIGHT 447

The Air Command announced that during the searches conducted during the early night and early morning (03/06), an R-99 aircraft of the Brazilian Air Force (FAB) identified at 03h40 (de Brasília time), plus 04 (four) points of wreckage, 90 km south of the region originally covered by aircraft of the FAB. The crews of the R-99 observed the following provision of the items found:

- Various objects scattered in a circular area of 5 km radius;

- 01 (one) object of 7m in diameter;

- 10 (ten) objects, and some metal, and

- Oil stain with extension of 20 km.

During the morning, five other military aircraft take off from Natal-RN into the area of search, and three (03) C-130 Hercules in FAB, 01 P-3 Orion of the U.S. Air Force Falcon 50 French and 01 the opportunity where they go each point identified by the R-99 aircraft in order to obtain more information of the objects detected.

In total, eleven aircraft are deployed from the Natal and Fernando de Noronha Airbases to perform the search.

Five of the Brazilian Navy ships are sailing toward the area of search, with estimates of arrival of the first one (patrol vessel Grajaú) this morning. 03 merchant ships of amongst others Dutch and French nationality have arrived in search of the place of yesterday evening and will assist in the recovery of wreckage found at sea.

The Rescue Coordination Center in Dakar reported the closure of operations for searching the Dakar FIR. However, Dakar continues to contribute to the search operation in Brazil, with the coordination of AWACS aircraft (aircraft radar) of the French Air Force, flying over an area within the limits of that FIR with FIR Atlantic (Brazil), in search of objects on the surface of the ocean."

wileydog3

3rd Jun 2009, 14:33

What is the power source for the ISIS? Does the loss of ISIS along with the ADIRU fault and the reversion to ALT Law indicate a total loss of electrics?
(yes, I know the process is Normal to Alternate to Direct and then with all loss the THS, rudder and FADEC engines. And yes, I understand we are talking loss of both eng generators, no APU, a failure with the RAT and loss of battery power)

Most standby inst packages I have flown were independently powered.

Cause unknown but are we talking about an electrical fire that quickly took out all instruments as well as flight control computers? We saw in Swissair 111 and ValuJet that inflight fires can evolve VERY quickly offering little time for a solution and rapidly diminishing control.

learjet45

3rd Jun 2009, 14:38

I think some on this thread may be over analizing with their speculation and of the technical chatter. IMHO this accident appears to be nothing more than a series of events that led to the structural break up of the A/C due to weather....."exceeded the structural limitations of the airplane" as they say, by possibly flying blind into a very hairy area of that storm system. I have visually put myself in their predicament many times since this happened (although I'm not familiar with the Bus) and each time I've had a serious case of goosebumps. Everything went to hell very, very fast it appears. This flight will def be in future sim rides for many of you I'm sure.
Methinks we'll never know exactly what happened without the FDR and the crew will be blamed, of course. Wrong place at the wrong time.

Lost in Saigon

3rd Jun 2009, 14:59

Much importance has been attached to the following:

at 02:14Z the last message received was an advisory regarding cabin vertical speed.

One very important piece of information is missing though. Was the cabin vertical speed indicating a climb or a descent?

If there was some form of explosive decompression it would of course be a climb. But the cabin cabin vertical speed advisory was the LAST in the sequence of advisories. That could easily be interpreted to be that the cabin was intact and pressurized during the descent to the water. It was only when the cabin descended below the altitude of say 8,000 feet that we would then see a cabin vertical speed indicating a rapid descent rate.

Does anyone know if the "advisory regarding cabin vertical speed" was a positive or negative value? And what was the actual rate of change?

win_faa

3rd Jun 2009, 15:07

learjet45
Methinks we'll never know exactly what happened without the FDR and the crew will be blamed, of course. Wrong place at the wrong time

When an accident of this nature occurs, if you don't pull out all the stops and bend every effort to establish what the cause of this accident, then the airline industry is going to get another accident cause by the same thing.

RatherBeFlying

3rd Jun 2009, 15:09

http://www.nytimes.com/aponline/2009/06/03/world/AP-Brazil-Plane.html

A 23-foot (seven-meter) chunk of plane and a 12-mile-long (20-kilometer-long) oil slick were found early Wednesday, Brazilian air force spokesman Col. Jorge Amaral said. Rescuers have still found no signs of life.

The new debris was discovered about 90 kilometers (55 miles) south where searchers a day earlier found an airplane seat, a fuel slick, an orange lifevest and pieces of white debris.

The location of the new debris is consistent with where experts say currents in that part of the Atlantic would push anything on the surface.That's indicative that whatever broke off in flight contained fuel -- stabiliser or wing. The convective weather would play its part among previously mentioned factors in separating the impact points.

Unlike the 747 breakup off Taiwan, we do not have shore based radar tracks of the various trajectories.

GlidingAerobats

3rd Jun 2009, 15:10

I believe that you can do that in either aeroplane, in theory. In a Boeing, you always have that privilege. In an Airbus, you can go to 'Direct Law' (I think!). But, also as far as I know, that means that you won't have elevators or ailerons to fly with, just the rudder and the trim controls.......I think, there is a confusion here concerning "Direct law" and "mechanical backup". When introducing, the FBW-System, Airbus kept a mechanical backup for the stabilizer trim and the rudder pedals - like on conventional aircraft, these are connected with steel wires (The original fly-by-wire ;-)) from the cockpit control to the aircraft tail. You can hence still control rudder and stabilizer trim even after a complete loss of electrical supply or FBW computers. (Whether that is a nice way to control an aircraft, is another question.)

The "direct law" is a control law that the FBW-computers change into, if there is a certain combination of system losses. Direct law, means, as khorton already said, that the sidestick controls directly the aileron/elevator deflection - without any protections or load-factor/roll-rate law. Primarily this happens, when the computer cannot be certain of the correctness of the input data. (I.e. loss of 2 IRs leads to direct law, if the computer cannot automatically identify the second RU loss. (Source: FCOM A320, I assume, A330 is similar.) The crew can get back into alternate law, by resetting the Flight-Control computers after manually identifying the second defective IR.)

So, the easiest way to get into direct law is probably by switching off 2 ADIRUs. May have the "little" side effect of losing speed, altitude and attitude indication, though...

benmac

3rd Jun 2009, 15:17

All the talk in this thread of ITCZs, hard CBs and turbulence reminded me of a transit I made in a MK2 Vulcan in Dec 65 between Darwin and Singapore. I was flying at 56,000 ft and at the top-of drop for Singapore encountered an ITCZ that stretched from horizon to horizon with giant CBs still pushing upwards well above my altitude. The ride became somewhat hairy with the g meter fluctuating rapidly between + 3g and - 1.5 g and the aircraft shrouded in St Elmos Fires. However, the worst part was trying to descend to Singapore. The uplift from the CBs was so great that even with the throttles closed and full airbrake I could hardly get any kind of rate of descent and stay short of MNE (never exceed Mach ). Of course, at that height,the gap beween MNE and stalling speed doesn't give you much of a leeway. I could imagine an aircraft getting into serious difficulties if the pilot allowed the speed to depart this gap.

Tail Chase

3rd Jun 2009, 15:19

Since the question was posed a few hours ago and a terrorist bomb is still a possibility behind the loss of AF447, there was indeed a bomb scare on May 27 in connection with AF415, which was scheduled to depart from SAEZ that evening.

A late morning telephone call received at AF's offices in downtown Buenos Aires stated that the aircraft - which at the time was parked a few hours after completing AF418 - was carrying a bomb. Local police bomb squads performed a throrough search of the aircraft and found nothing, ascribing the episode as nothing more than a bomb hoax. The aircraft was released and it executed AF415 as scheduled.

In retrospect, one is led to think whether these two episodes bear any connection with each other.

Cheers

Aerochti

3rd Jun 2009, 15:21

According to my AF maintenance source, the ADIRUs manufacturer of F-GZCP (AF447) is Honeywell.

grizzled

3rd Jun 2009, 15:21

As I said waaayy back at the beginning of this thread: The odds are very much in favour of the FDR and CVR being recovered, not the other way around. Those who write that finding them will constitute "a miracle" are not up to date on current technology and methodology.

Yes, this will likely turn out to be an incredibly expensive investigation, but it will be done. Despite those on pprune who speak of conspiracies amongst the investigative agencies, and/or the manufacturer(s), the truth is that the incentives and rewards of a thorough investigation make it far more worthwhile to those agencies than any alternative.

grizz

khorton

3rd Jun 2009, 15:23

I hauled the nose up to beyond the theoretical point of a stall, and managed not only to get over him, but actually to get the nose going down instead of up, theoretically beyond the certainty of stalling in, and land safely..........

......

So I guess I could have done the same thing in an Airbus? Just by remembering which half-dozen buttons to press, in which order? http://static.pprune.org/images/smilies/smile.gifIn Normal Law you can get to the edge of the stall. There is no advantage to going beyond that, as even if you can get to higher angle of attack in Direct Law, there is no additional lift to be found, so no possible way to change the flight path angle. All you would do by manually going to Direct Law is give yourself the possibility to lose control of the aircraft.

I don't agree with every aspect of the Airbus flight control law protections (I would like the option to pull more than 2.5 g in emergency, possibly by pulling through a "soft stop", for example), but the limits on angle of attack seem very well founded in my opinion.

spannerhead

3rd Jun 2009, 15:30

Jo90

3rd Jun 2009, 15:39

Thought for the day.

Q.When is the most likely time to have a lightening strike?
A. When you're picking your way among a mass of Cbs (eg the ITCZ).

Q. Which part of your aircraft is most likely to be struck?
A. The nose.

Q. What lives in the nose (apart from you)?
A. The radar antenna.

Q. If that gets knocked out by a strike have you got a spare?
A. No.

Conclusion: At times like this always maintain a mental or written note of what headings you would fly and for how long if you suddenly lost the Wx radar.

GlidingAerobats

3rd Jun 2009, 15:39

There's too many posts in this thread from people who think that they know the 330 from a technical aspect when quite honestly they haven't got a clue. A few posts back someone mentioned that the stabiliser has a mechanical backup........it doesn't! The 'steel cable' mearly positions a slide valve and hydraulic power moves the stab.

OK, maybe I was not precise enough. On any airliner sized aircraft, nothing goes without hydraulic power, that is clear. My point with the mechanical backup was to point out, that it is possible to control the stabilizer from the cockpit in case of total loss of electrical supply/FBW-computers. The same is of course valid for the rudder pedals. The rudder is of course also actuated hydraulically, but it is possible to actuate it directly without going through the FBW-computers.

I hope, this makes it more clear, what I meant? At no time did I mean to leave the impression that you could actuate the stabilizer in the absence of _hydraulic_ power. Sorry, if I wasn't clear enough in my first post.

ribt4t

3rd Jun 2009, 15:42

Belgique

3rd Jun 2009, 15:42

Air France Flight 447 Crash Cause (http://tinyurl.com/rd9qcl)

Interesting compendium of emails on the AF447 accident.

Seems to suggest that a risk-taking approach to operations in coffin corner was an equally likely culprit. More likely than a lightning strike anyway. If so, it was possibly unwise to do that above a very active ITCZ at night.

Look out below. Tired crews with low awareness levels don't react very well when things suddenly come unstuck.

Cruise captains are likely to be not as well prepared for a sudden coffin corner encounter. The two seats might suddenly end up in disagreement on the appropriate recovery action (roll direction?). Or maybe (the emails suggest) the Airbus will have a third opinion as to which way the pilots "can" roll-out for recovery (rather than "should").

TeachMe

3rd Jun 2009, 15:43

If the weather radar was taken out by lightning (or just failed) facilitating flight in to a storm cell leading to loss of control, would the first maintence text message not have been about the radar failure, not the autopilot disengaging?

TME

HalloweenJack

3rd Jun 2009, 15:46

a series of interesting observations (to a layman anyway) on Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data (http://www.weathergraphics.com/tim/af447/)

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.

xiaoshan

3rd Jun 2009, 15:56

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.

Wakner

3rd Jun 2009, 15:59

"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.

Best

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aeo

3rd Jun 2009, 16:01

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..

The Actuator

3rd Jun 2009, 16:07

Belgique, why would
Cruise captains are likely to be not as well prepared for a sudden coffin corner encounter.?

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.

hajk

3rd Jun 2009, 16:08

Joe90 wrote:
Conclusion: At times like this always maintain a mental or written note of what headings you would fly and for how long if you suddenly lost the Wx radar.
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.

win_faa

3rd Jun 2009, 16:14

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 (http://news.yahoo.com/s/ap/20090603/ap_on_re_la_am_ca/brazil_plane_list)

admiral ackbar

3rd Jun 2009, 16:26

Anyone considered pitot probe contamination or icing?

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

Merlyn

3rd Jun 2009, 16:40

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.

win_faa

3rd Jun 2009, 16:53

BlindinG

MD100 wrote - Does anybody know how far can the signal of the ULB (Underwater locator beacon) of the CVR/FDR be detected?

Excellent question. Has it been answered here already?

Are the CVR and FDR separately enclosed units (i.e. will they be in different locations?).

How far will the beeps, or transmissions reach?

If it 3600m under the water, but can transmit 10km, then it surely shouldn't be too difficult to find with the correct technology??

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.

vapilot2004

3rd Jun 2009, 17:18

One very important piece of information is missing though. Was the cabin vertical speed indicating a climb or a descent?

@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.

Been Accounting

3rd Jun 2009, 17:27

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)

Rhino1

3rd Jun 2009, 17:34

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

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

Jimmy Macintosh

3rd Jun 2009, 17:41

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/proceedings/authors/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.

vapilot2004

3rd Jun 2009, 17:44

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?

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.

win_faa

3rd Jun 2009, 17:45

mickyman

If the airliner went down in one of the deepest parts
of the Atlantic - what effect will pressure have on the
'black boxes' and could the data survive in such conditions?

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 (http://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:

Airbubba

3rd Jun 2009, 18:07

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...

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

Active sonobuoys are used to localize targets quickly and accurately in extreme environmental conditions, against a very quiet submarine, or in an attack mode. The released acoustic energy enables an accurate location from the sonobuoy in both range and bearing to the submarine. When two or more “fixes” are obtained the speed and the course of the target can be established. Active buoys use a transducer to introduce acoustic energy into the water and to manipulate the return echoes which are amplified and for VHF radio transmission. These buoys are designed for deeper depths than passive buoys.

From: Sonobuoys (http://www.globalsecurity.org/military/systems/ship/systems/sonobuoys.htm)

vapilot2004

3rd Jun 2009, 18:19

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.

jr hartley

3rd Jun 2009, 18:30

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?

Airbubba

3rd Jun 2009, 18:38

The passive array equipped buoys are fully capable of picking up the DFDR/CVR pingers.

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.

ST27

3rd Jun 2009, 18:49

The passive array equipped buoys are fully capable of picking up the DFDR/CVR pingers.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.

AOB9

3rd Jun 2009, 18:50

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.

CR2

3rd Jun 2009, 18:55

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

etesting2000

3rd Jun 2009, 18:56

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.