What happens if the mechaincal linkages in a non FBW plane fails? or the control column...
It's similar situation, the things that control the hydraulics can get knocked out either way, however, I would agree there is probably a greater chance that something will go wrong with a complicated computer and electronics than a relatively simple mechanical system....

With the reasons for the crash/disappearance I certainly do not know enough to come up with a solid ideas on what happened... I think that the parties involved are holding alot back from the public...

BTW, correct me if I'm wrong, but isn't the whole point in the 406MHz ELTs to allow rescuers to find them easier... Did it not work or something?

http://www.news.com.au/heraldsun/story/0,21985,25576862-5005961,00.html
 

DEBRIS floating on the Atlantic Ocean in the area where a missing Air France passenger jet is suspected of crashing has been sighted by crew on a French freighter, Brazilian media has reported.

The sighting by the crew on the Douce France is said to be in the same area off the coast of Senegal where a Brazil TAM airline pilot spotted what was thought to be a burning piece of wreackage.

a detailed meteorological analysis
 

See Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data

Ladies and Gentlemen, when an Airbus 330 suffers a total electrical failure, flight is still possible through the use of backup. The horizontal stabilizer can be used to sustain flight in the vertical plane until electrics can be restored. The rudder on this particular aircraft would be electrical and therefore control in the horizontal plane can be achieved through the use of asymmetric power. But this is difficult to perform in the best of conditions and if the aircraft entered into a descending roll, a spin could be inevitable and would be unrecoverable unless electrics would be restored.

But let us look at what takes place if a severe lightning strike were to have taken place. There could have been a short circuit of the buses and hence the engine driven generators would drop off line. If the short exist on the buses even the likely hood of restoring power through the APU generator is unlikely.

In this situation, the emergency generator should now come on line and will more than likely be powered by the engine driven pumps and not the RAT. The RAT will only power the emergency generator if there is an unlikely combination of engine failure/failures and short circuiting. This situation is so unlikely that the summary section for the Electrical Emergency configuration does not take into account that the Emergency generator is powered by the RAT and hence that summary can only be used if the emergency generator is being powered by the engine driven pumps.

Now having said all of that is it really likely that the emergency generator could not come online? Did the engine driven pumps fail to get the emergency generator online, and if so, is it likely then that the RAT failied to power the emergency generator after the engine driven pumps could not do its job? Well the answer to this is yes it could happen and this would be indicated by looking up on the overhead panel and seeing a red light next to the SYS for the emergency generator. But highly unlikely I say.

But let us say then that the emergency generator does not come online, there are 2 batteries that can supply minimum power to some of the flight instruments for 25 to probably 30 minutes but the CPC's will not be powered and hence the aircraft will now depressurize.

Did these pilots try and perform some sort of emergency descent with an aircraft which may have had MAN PITCH TRIM ONLY, ie an aircraft that was in backup? If this was the case then the aircraft could have gone into a roll and hence a spin that would have been unrecoverable.

But I believe that one thing is for sure and that is this aircraft had two working engines but with a flight control problem.

This is an interesting analysis, Aviator 38.

Excerpt:

" 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. "

Cheers

Severe icing is possible in CB weather down to -50 C

Byalphaindia.
You and I know that it is the duty of aircraft manufacturers, airline operations staff and pilots to deal with even the most extreme weather conditions. Of course we would never blame the weather itself !

The A330 doesn't have a compass that could depolarize. Only the stby (whiskey-) compass, maybe.

Air France CEO mourns crash of flight AF447 with international passengers onboard

>> Pierre-Henri Gourgeon said Air France flight AF447 had reported “the failure of several onboard computer systems” after flying through an area of “extreme turbulence” prior to air traffic controllers loosing contact with it.

I wonder how many of those were flight control related. Mech backup in "extreme turbulence" with everything that entails is not a situation I'd ever want to be in.

ECAM Actions.

Whilst I will not speculate on what may have happened, I hope that this event will expedite the worldwide coverage of Automatic Dependent Surveillance (ADS) , especially in Oceanic areas where VHF radio and normal radar is non existent. This would greatly assist the search and rescue operations, especially if there are survivors involved.

Whilst it is unbelievable in this day and age that a modern aircraft like the A330 would disappear whilst airborne, it is more unbelievable that the last exact position of the aircraft is not known. All of us aviators should push for the worldwide coverage of remote areas with ADS and other satellite based monitoring.

I strongly disagree. Straight away the FDR will tell you what G-loads were experienced and at what frequency. This will indicate to investigators the likelihood of turbulence as a major factor.

Exactly. They might start without preconceptions, but not without hypotheses - just like the hypotheses presented here. They will then test these hypotheses using the scientific method, until they find one (or maybe more than one) consistent with the facts.

Thus has science and engineering been carried out since the days of the enlightenment.

thapr2,

I strongly suspect the TAM pilot will be interviewed by the investigators. So that will come out.

If the aircraft had been flipped onto its back, Alternate Law, ADIRU and ISIS failures would make some sense. Then the crew find themselves in a monster CB, at night with no flight instruments, so they loose control, aircraft breaks up, hence loss of pressurisation?

That is correct. However the angle I am coming from is whythe a/c was in this precarious situation in the first place. (And this is why I don't want to speculate).

But, you do not magically find yourself in the middle of a storm. And if you do, you would have worked out that your a/c would still be within limits. So I am looking at one of the the possibility that there may have been a prior weakness in the structure - whether this be an inherent weakness or something like a crack that has occurred during operations.

So yes, the FDR will tells us the conditions at the time, but if an important piece of fuselage/wing is not found, then we may never know what failed.

This is just one of the many things going through my mind. And I didn't really want to say this much as any speculation causes discussions and it may not even be right.

Informative posts only - AF A330 loss
 

I read somewhere that Air France 447's wing touched an A320 rudder in a taxi incident prior to departure. The A320's rudder was severely damaged, but AF447's A330 wingtip was not. AF447 departed, and is now missing.

First things first: Did the taxi incident occur?

Answers to big problems or issues are often simple. Here is one possibility: AF447's wing was weakened if not visibly damaged; the airplane suffered stresses during flight via flight in turbulence; the damaged, stressed wing broke off; the airplane plummeted into the sea.

What supports this?

1. Alleged taxi incident involving A320 and AF447.
2. Alleged time delay of four minutes from altitude to impact.
3. No calls from the pilots.
4. Sudden spurt of messages sent to base: multiple system failures.
5. Item 3. and 4. indicate an inflight breakup.
6. Airplanes don't fall out of the sky for no reason.

I don't want to hijack a thread by creating a new one. However, it is my hope the above can be expanded on by professional aircraft engineers and even, God forbid, pilots.

The 117 pages of uninformed drivel on "the other thead" has turned it into a complete farce. Nothing good can come of continuing with it.

Oh they will find the position of the boxes I am sure, as they give off a sonar signal for up to 30 days, IIRC.

Whether they can get to them or not is another matter.

Debris Sighted
 

RIO DE JANEIRO - BRAZILIAN media outlets are reporting that debris from the missing Air France passenger jet has been sighted floating on the Atlantic Ocean by the crew of a French freighter.
The Douce France is reported to be in the same area off the coast of Senegal where a Brazil TAM airline pilot was also reported to have seen a burning piece of wreckage

Poison, re flight controls on the A330
 

Having flown the A340 for several years - the 340 has exactly the same flight controls as the A330 - I have to tell you that your statement:

The rudder on this particular aircraft would be electrical and therefore control in the horizontal plane can be achieved through the use of asymmetric power.

is incorrect.
Normally the rudder is electrically controlled, but may - in case of all flight control computers fail for whatever reason - be mechanically controlled (via cables from rudder pedals to hydraulic actuators).

In other words, it is possible to control the aircraft in the horisontal plane by rudder, so no reason for using asymmetrical thrust!

Is there a possibility that a 'Blue jet' (atmospheric lightning) could have struck the aircraft causing associated damage to airframe/electronics? Has there been any incidents of this kind of phenomenon affecting aircraft before or ineed any research?

Translations
 

I am a humble PPL, 200 hours, but I am English and have lived in Brazil for 20 years
I am a newbie here, but have read this site for years and never commented. I joined because I feel I may be able to contribute with translations from Portuguese, as I work as a professional translator. Feel free to contact me if you wish, no charge of course..
I am not going to comment on possible causes of this terrible accident.

Tarman
Well said.


Ivanbogus
Bollocks!

Poison
Thanks for that, so the aircraft is pretty much in 'MECH BACK UP' from the start of 'ELEC EMERG CONFIG.?'

Could a reversion to 'ELEC EMERG CONFIG' with a subsequent inability for the reinstatement of electrical services via the various available emergency back up generators be possible if there was also an 'ELECTRICAL SMOKE' problem that the crew were already dealing with?

I'm not trying to play Devil's Advocate here, Poison, but as a pilot with 20 years service under my belt & over 11,000 hours experience with 9,000 hours on B757/767 & A330/340 aircraft, I can't help but notice similarities with the SwissAir MD-11 crash i.e. Kapton wiring (common to both types)- 'Short Circuit' (reported by ACARS type system)- Loss of all electrics (would lead to our agreed 'Control Problem)'- ELEC EMERG CONFIG (specific to Airbus aircraft)- all for the crew to deal with at FL410, over the Atlantic at night in a violent storm.

I agree with you, a control problem leading to total loss of control with 2 serviceable engines seems the most likely but it's how you get to the 'Control Problem' I'm concerned about.

Even if it was what 'Capt Moody' seems to keep coming back to, the on board (electrical) fire with an attempted controlled ditching scenario, you can't dismiss that this A330 could have been fitted with Kapton wiring (the ones I flew certainly were) as was the Swiss' MD-11. And I think we (pilots as opposed to 'armchair flyers') have all seen on our CRM courses what the flight deck on that doomed MD-11 was like.

I hope to God the investigators get something out of this.

PM me if you don't want to continue this discussion in public.

Cheers.

Considering the scenario of an upset caused either by a faulty ADIRU or bad weather the crew could have easily found themshelves operating under the ABNORMAL LAW.

ABNORMAL ATTITUDE FLIGHT LAW
A completely different law emerges automatically when the aircraft is in an extreme upset as follows:
* pitch attitude > 50 deg nose up or > 30 deg nose down
* bank angle > 125 deg
* AOA > 30 deg or >-10 deg
* speed > 440 kts or < 60 kts
* mach > M0.96 or < M0.1
The abnormal attitude law is:
- PITCH ALTERNATE with no protection except LOAD FACTOR protection. No automatic pitch trim.
- ROLL DIRECT with full authority
- YAW ALTERNATE
After recovery the flight law reverts to:
- PITCH ALTERNATE law
- ROLL DIRECT law
- YAW ALTERNATE
The aircraft returns to a degraded mode (not normal law as usual) because there is a certain level of suspicion about its ability to control the aircraft (that is how could it have got to the extreme flight state in the first place? The protections should have intervened well before the pitch, bank, AOA, speed and mach limits above).


I wonder what indications the crew have to realise they have entered this abnormal law? It could be very difficult in a bussy and turbulent enviroment to give an adecuate response to this type of scenario.

What are your toughts??

A german aviation mag has a recent map of the suspected crash site (source: Brasilian Air Force) with distances and ATC-regions.
Suche nach Airbus A330 von Air France im Südatlantik - FLUG REVUE

Why you so "serious professional Pilots" with so many concerns about all "non pilot idiots" start your own privet silent pilot network and only let in members with 10000+ hours and scanned pilot license.

speculation exist and will always exist whatever u feel, or is it just to get your own seriousness and ego confirmed?

This morality posts over and over are more pathetic then the others

Dedicated Search and Rescue Dedicated Search and Rescue aircraft have homing receivers that can be used to home on VHF or UHF beacons.

They don't, but dedicated anti-submarine aircraft and other dedicated platforms my drop hydrohpones that can detect sonic transmissions.

No, it would cost money, lots of money, to install such homers in many aircraft. The use of such homers would then require crew training which would increase training time, working hours, require more aircrew etc etc.

However all aircraft are capable of localising a VHF or UHF beacon but they need lots of spare fuel to do so. The technique is simple but I shall not post it here.

PS

FE Hoppy said some mil ac have ULF Homers and no training is needed. I would suggest that some training would be needed but concede it might not be very much. Equipment costs however would remain a significant hit on the bottom line.

At night, probably in cloud, without ADIRU's and ISIS, they were in serious trouble.

A lightning strike may cause an surge which in turn may cause transient electrical faults to be generated. Anybody who has had an APU/Gen trip on him will know that. These faults mostly clear out but some remain on the STATUS page (on EICAS) till the landing gear does a full extension and retraction cycle (i.e. next landing). This status message(s) may have been transmitted by ACARS to maintenance as the ACARS reporting logic does not factor in lightning strikes. It is plausible that the airplane may have had several lightning strikes and that caused several (maybe) erroneous messages to be generated. Also explains the 4 minutes of ACARS transmission (because a regular position report also takes a couple of seconds of transmission (VHF in progress, SATCOM in progress) etc whereas maintenance reports only go by a error code.Time in transmission, only a couple of seconds. 4 minutes of ACARS transmission would almost need a lot of status/failure messages to have been generated simultaneously---signature electrical surge behavior...Saying all this, still not good enough reason to bring an airplane down...

The Aviation Herald
 

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.

@ grebllaw123d: not correct. Newer A330s/340s have 'electrical rudder' as correctly stated by poison.

Grebllaw123d,

Yes I do understand that you think that I have made a mistake in my statement but I can assure you that I have not. You see having flown all of the A340 variations, which you may well have only flown the A340-300, I can tell you emphatically that the A340-500 and A340-600 no longer has mechanical backup but rather backup. And yes there is a difference. You see with mechanical backup you have mechanical control over the horizontal stabilizer and the rudder, but with backup you only have mechanical control over the horizontal stabilizer.

This is also the same for the MSN 660 which is now missing. It's flight controls are electrically controlled and are hydraulically operated but the stabilizer can be mechanically controlled. However like I said you would not know this if you only fly the A343 and yes it is the same as some of the older generation A330's but is not the same as MSN 660.

Now an apology is not required from you but please do your homework before you respond next time.

Wader 2

ULF homing beacons are fitted to some mil aircraft that carry equipment that may need to be recovered. No crew action or training required to operate them.

RealQuax
 

OK, I did not know that!

Does it then mean that there is no mechanical backup for the rudder in case all flight control computers fail?

brgds

KTM 11, there is only one legal requirement for a functional WX radar on aircraft and this is tailored by every manufacturer for the specific type. Companies publish this requirement in the MEL or DDM (as applicable).
This "law" is only valid before commencing any flight.
When airborne it is the crew which has to decide the best course of action, and yes, there is the possibility that a return may be the best action.

I doubt that the AF crew had a chance to consider this option at all. With all details available here it appears that the wx radar was a "minor" problem they were dealing with.

Being sure that the crew followed law no. 1 precisely, "Fly The Aircraft", they faced a situation not covered in any QRH or manual.

It does not appear that any action they went for helped at all. Even well trained crew, unfortunately, can and will face unrecoverable situations.

I am NOT a bus driver but... reading all posts..

what if :
1) an electrical failure thus ...
2) a restricted (cable driven) surfaces movement and ..
3) weather radar not abailable ?? and maybe
4) a depressurization because of total electrical failure ? and
5) going around some VB tops at 35000 and
6) have to emergency descent with no radar and went into CB

is that scenario possible ??

Is a conclusion I have after reading almost of comments

thanks
MD-100 (fly-by-cable)

golfyankeesierra -
I don't know what 'bands' are being used these days, but your statement implies "X" Band Radar. Why airliners were ever fitted with 'X' Band, I'll never know. With "C" Band that we had, you could 'see' through cells with no problem.

I think Tim Vasquez' meteorological analysis posted earlier is a very good read. One of the possible scenarios he mentions is that if it encountered a vigorous updraft in a fledgling cell, of which there were quite a few developing at the time, then it wouldn't show on the radar, as the precip wouldn't have had time to develop yet. To me that seems more pausible than lightning, for what it's worth (ie. absolutely nothing)

Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data

To have a better understanding of the A330 systems
SmartCockpit - Airline training guides, Aviation, Operations, Safety

I wonder if the last message received by AF would have been LO DIFF PR, meaning the a/c was descending at a very high rate.

Your toughts??

OK,

Let's make things a little clearer for everyone so I don't tie myself up and lead people down the wrong path as a result of my wording or not putting in all of the information.

On the 330 Airbus has "Normal Electrics" and "Emergency Electrics", when you have neither one of these situations you are then in what would be considered as as total electrical failure. But do remember that you have battery power but it is terribly limiting.

Even in an Electrical Emergency Configuration you have the Prim 1 and Sec 1 powered and hence control, although it may be in alternate law, is still available in pitch, roll and yaw. Not to mention that on the A330 in an Electrical Emergency Configuration the A330 has Autopilot 1 available, unlike the A340, since this is a requirement for the ETOPS certification.

Now what I was referring to was the total electrical failure which means that all flight computers are not powered. This will now lead to backup. But even with backup you can still have control over the rudder as the rudder is powered by the BCM (Backup Control Module) and this provides yaw damping and direct rudder command with the pedals. The BCM computer has it own electrical generator and is supplied by the Blue or Yellow hydraulic system.

But again let us say that even this BCM failed then the horizontal plane could be controlled by asymmetric power. But to get into this situation is so unlikely. The likely hood of the Electrical Emergency Config not taking place is very unlikely as I said. But if this does not take place then there could be a moment when all 5 computers may not be powered and then Backup will become effective. In backup you have mechanical control over the horizontal stabilizer and the control over the rudder, be it electric through the BCM if it is powered. In backup you are not expected to fly the plane accurately. It is a time when you are meant to restore the flight computers. That means you need to cycle the pushbuttons. But this is only achievable if there is power to the relevant buses. If my memory serves me right even the hot battery bus will power the Prim 1.

Airbus is not perfect but they sure have a heck of a redundant system and for an aircraft to suffer a total electrical failure, ie not to even be in Electrical Emergency Config is bizarre. But even with out this Electrical Emergency Config, no battery power is hard to fathom. And the loss of a BCM which is has its own electrical generator? Nothing is impossible but the situation is highly improbable.