AF447 accident - icing, pitot tubes and radar in the frame

Isn't it time to ground the 330s (and any 340s) which are equiped with these information systems until the problems can be identified and corrections made? To me, the 330's recent problems (the prior icing incidents, the recent event with one of Qantas' 330s, and now F447)are eerilly like those experienced by the first deHavilland Comets - sudden, unexplained, catastrophic failures resulting in sudden, complete loses. Eventually, the Comet's crashes were traced to metal fatigue, I believe around the window areas, arising from numerous cycles of pressurization/depressurization, a phenomenom of jet flight unknown at the time. The 330/340 are highly electronically optimized, something Boeing seems to hve resisted. Perhaps these systems are failing for reasons we do not know, just as the Comet's fuselages failed. It is time to find out for sure. The Qantas incident could well have resulted in a complete loss.

Stop with this grounding nonsense! The A330 is an exeptionaly safe aircraft; and the Qantas A330 was nowhere near a 'complete loss', in fact, it only deviated a couple hundred feet.
As I've said before, I love Boeing, I always find things that are wrong with Airbus's aircraft. But, in the last 9 years, there have been no less than 32 737 crashes, with over 1000 fatalities - but the 737 isn't grounded, and it would be stupid to do so. (Also, sometime during the 80/90s, there was a 737 crash - in fact, several - that were attributed to the same cause but the final reason for the accidents was never found. Under your advice, the 737s would not be flying.)
The Comets began crashing after a relativley short numer of cycles. In fact, I belive it was only about a year before the comet 1's began to break up mind flight.
A330s have been in the air a lot longer. And their almost spotless safety record shows that it is a very safe aircraft.

yes i agree we should all resist jumping on the ground all airbus 330/340 aircraft. it should be noted that even the current boeing 777/737NG series are equally electronically sophisticated in terms of flight controls and systems. people should note that a few years back a malaysian airlines boeing 777 had a similiar uncontrolled deviation from flight path while flying out of perth australia and it was investigated and attributed to flight control software which has suitably modified by boeing after the incident. this proves that such events are not exclusive to a330/340 series aircraft. the basic difference between airbus and boeing is that airbus aircraft are protected to a great extent by flight control software which do not allow abnormal pilot control inputs to endanger the aircraft whereas with boeing the pilots are allowed to have final authority on the aircrafts flight performance to the extent that boeing flight control software can be overriden by its pilots but this is not the case for airbus aircraft.

what happened to af447 is at this stage still unknown to the extent that neither aircraft debris nor fldr or cvr beacon signals have still been picked up. all analysis being done at the moments is based on acars transmissions sent by af447 till its disappearance.

what we know is there was extremely turbulent weather conditions prevailing on the flight path of af447 these conditions seem to have overwhelmed flight af 447 to the extent that its external flight data sensors failed and may have fed erroneous information to the aircraft flight computers and led to its crash.

we also cannot rule out an act of terrorism until otherwise proven. there is every possibility the plane exploded in mid air too.

the only puzzling thing in case of an mid air explosion is the fact that almost 5 days after the crash we still are yet to find any trace of debris, bodies within the projected crash impact radius.

in 1986 air india flight 182 a 747-200 crashed of the coast of ireland after exploding in mid air due to a bomb on board killing 329 passengers. in that incident debris and bodies were found within hours of the plane coming down.the fldr and cvr were recovered within 4 weeks by the deep sea submersible scarab.

so lets hope that we can find as soon as possible what went wrong with flight 447.

The comparisan with the Qantas incident can not be made.
Qantas A330 fleet is equiped with Nortrop Gruman ADIRU.
AirFrance fleet is equiped with Honeywell ADIRU.
The Honeywell ADIRU's are not affected by this failure.

The lack of debris found on the ocean so far might indicate that the aircraft did not break up in flight but flew intact into the water. Working backwards this may suggest that after suffering systems failures caused by the suspected weather phenomenon (icing, lightning strike, heavy turbulence), the crew lost attitude information and without any visual references were unable to stabilise the flight. There have been a number of crashes where this loss of information has lead to disaster - Korean Air 747 at Stansted, Flash Airlines 737 in Egypt, for example.

Too much reliance on computers, pilots these days are glorified bus drivers who simply push buttons. There is no feel for how the aircraft is operating. In an abnormal situation as the A330 found itself, it seems it couldn't recognise the problem through its computers.......what system on board a modern airliner asks the pilots to intervene in the case of sensor confusion?

The fact that no remains or wreckage has been found, despite the extensive search operation deepens this mystery still further. I wonder if it just possible that following an explosive decompression, the flight crew were incapacitated, but the plane flew on uncommanded, with the Autopilot disarmed, it might have settled into a totally different heading, but too high for anyone to regain consciousness, to fly on for several hours, before running out of fuel, only to crash thousands of miles from the presumed crash site!

As many of you all know, this would not be entirely without precedent. Consider the Learjet crash over the Midwest USA, and the Helios crash, for previous examples of this sort of thing.
With no one on the lookout for the missing plane, an unusual radar track might have been missed.

I am not a pilot, and there may be many good technical reasons to suggest this idea is wrong, ie lack of further ACARs transmissions etc, but the complete absence of any wreckage near the presumed crash site might suggest that maybe it just did not crash into the sea where it was “supposed” to have done. I am not in anyway trying to raise hopes that any one would have survived this strange disappearance, but some lateral thinking might be necessary in order to consider an outcome other than a crash into the sea between Brazil and West Africa.

The point is, it is almost unthinkable that a plane of that size would crash into the ocean without leaving some trace on the surface of the water, unless it somehow managed to land intact, (unlikely!) and just sank! Nevertheless, with no one conscious to open the exits, deploy the life rafts and escape, it might have sunk without trace.

No one grounds their cars just because another similar car on the road has crashed. Planes can be just as deadly as cars in an accident.

It makes sense to ground that specific 'troubled' aircraft only, not its entire aircraft family worldwide, and issue recommendations whiile waiting for an investigation and it's final safety recommendations.

It seems like PPRuNe has locked it's AF447 forum topic.

Pilots at Northwest Airlines (Delta) have experienced 2 known cases where "ALL" flight instruments were lost and the aircraft was flown with just the ISIS backup and manual thrust. Both cases where at night at cruise altitude over tropical regions while flying in cirrus clouds while navigating around thunderstorms. One crew lost all instruments twice in a matter of 15 minutes.

Hi I have a question , On 17 August 2006, F-GZCP was involved in a ground collision , was this wing ever inspected , and or replaced on the D-Check ?

I was wondering if the Turbulence may have caused any hairline cracks to break if any ?

Unfortunately, AF447 was tracked down by a military laser system which was ignited from sea level.

Pravda.ru describes new laser technologies that the Russian army is capable to put in action. They claim they can instantaneously destroy any sort of enemy aircraft caped into their beam system.

Russian satellites supply the tracking system with target information.
Then the beams creates a plasma lens just ahead of the target. It looks like a very bright clouds of lights and thunder. In that case during 4 mns the tracking system disconnects the power from equipment inside the target so that the target cannot maneuver out of the clouds.

When the aircraft hurt the plasma, the speed fall immediately to zero. Then it falls into the hot 2500 oC depression. that causes A330 to be seen during 6 sec as a falling burning flash. During that time 75 tons of material are volatilized into gas.

It is impossible to find any debris. The people are all buried in the heat.

France has recently deployed a new maritime military hub with nuclear capabilities that challenges Iran naval force and air force. Russian and Iran share the same economic area and the monetary system.

Typically Iran is thought to have bought from Russia most of the advanced arms. It is a terrorist act.

Yours faithfully

I have personally experienced the motor vehicle damage from large billiard ball size hailstones in an afternoon thunderstorm. Such large stones apparently form by being held aloft high in cumulus updrafts. The density of ice is much greater than a billiard ball. Fire lots of them at 800 kph into the front of an airliner - what happens ?

The AP is reporting this morning that Air France had not replaced the Pitot tube on AF 447 as previously advised by Airbus. Www.ap.org., "Probe: Airline Did Not Replaced Instruments on 447." This coupled with the strong evidence that 447's speed readings varied, should be enough at least to ground 330s with the old Pitot tubes.

I note you did not publish my last comments about pilots being glorified bus drivers. Maybe you should read the comments in the Times Online dated June 7 entitled The Computer Crash. 747 pilots are less reliant on technology and are more likely to fly by "feel" than Airbus pilots. No blame here except to say I'd rather fly Boeing which has not moved completely over to "fly-by-wire".

Super cooled water freezing in the pitot ports would have been pre-curssor to all the other faults reported by ACARS. The autopilot flew the aircraft nuts trying to cope with erroneous readings before alternate law kicked in. Once at an unusual attitude with no reliable speed data in darkness and with electrical failures, the aircraft was likely to have stalled and tumbled, over stressed the structure and then explosively decompressed.

02:10Z:
Autothrust off
Autopilot off
FBW alternate law
Rudder Travel Limiter Fault
TCAS fault due to antenna fault
Flight Envelope Computation warning
All pitot static ports lost

02:11Z:
Failure of all three ADIRUs
Failure of gyros of ISIS (attitude information lost)

02:12Z:
ADIRUs Air Data disagree

02:13Z:
Flight Management,
Guidance and Envelope Computer fault
PRIM 1 fault
SEC 1 fault

02:14Z:
Cabin Pressure Controller fault (cabin vertical speed)

The sad question is did pilots have anti-icing switched on and should they have even penetrated the CB cell ?

As an interested observer, though essentally 'man in the economy cabin' as I'm not a pilot, and not involved in the aviation industry, perhaps someone better informed than I can clear up a couple of things which are puzzling me about this crash:

Firstly do commercial airliners use GPS as a secondary speed indicator? If they do, how could the autopilot and/or the crew become so confused about the true ground speed? Several contributors to debates in the non-specialist media have reported using hand-held GPS in the cabins of airliners to obtain what appear to be reliable ground speed measurements.

And of course conversely if commerical aircraft don't use GPS and/or it's not available to the autopilot as a speed input, why on earth not?

Secondly, can anyone guess at why there appear to have been not one single voice transmission received from the flight crew during the incident? - this strikes me as very unusual, particularly since the automated error messages sent by the aircraft's control systems were sent over the space of 4 minutes. In every other accident I've been aware of, even if the crew have had only a few seconds they've been able to issue a Mayday call.

Would be very interested to hear any info/educated guesses on this.

If pitot tube(s) were reporting wrong info and if pitot tubes had heaters to prevent icing,
then lightning could be the culprit. Lightning strikes on aircraft noses are common .. the arc could attach to the pitot "point", melting it, thereby blocking air flow/pressure in the tube(s).

PS My "Lightning Book" was published by MIT Press .. a remained in print for decades.

Quick response to Graeme. I think the idea of using GPS for groundspeed is not realistic in the circumstances, despite being a theoretical possibility. It is quite possible that these guys had seconds, not even minutes, to control the aircraft. Trying to calculate a reasonable airspeed from a groundspeed with the aircraft in severe turbulence, and maybe worse, is not really plausible I'd suggest.

The Mayday issue is somewhat similar. I think the only purpose of a Mayday in these circumstances is to alert the SAR people to where you are going down. But with no realtime voice communication, I'm not surprised that the radio call never made it to the top of the crew's priorities in what may well have been the few minutes, or less, that they had.

And to Chris Jordan, apologies if your earlier comment was not published. It is now. If it wasn't published earlier than I assure you it was a tech or human error and not deliberate. I scarcely ever decline to publish comments - abusive language being pretty much the only grounds, and that's fortunately rare.

Get the Airline to fix the pitot tubes on all planes that have not done it so far. Also add a back-up system wherein the pilot can fully fly the plane when the computers and sensors are not working properly. Don't wait until the investigation is completed. The pilots and the flying public should demand it!

If they won't, then the government (the French) should intervene and force them to do it.

If the money is not spent, the flying pulic will do it for them!

Albeit only a recreational pilot, I think an independent GPS might help in alerting pilots to undetected (slow) changes in speed and altitude.

I use a GPS to show altitude when I cannot get the QNH to set the altimeter; New Zealand has (mountainous) areas of no radio coverage at low altitude.

Also, I would notice if the groundspeed differed substantially from what I expected; knowing roughly the velocity of wind and adding or subtracting it to the airspeed derived via the pitot/static.

In turbulence the airspeed can be all over the place, and if a pilot is trying to keep the airspeed down to protect the airframe (s)he is busy, especially if the aircraft is close to the ground. A GPS is probably not much help to make the second-by-second decisions necessary to keep the aircraft flying, but it might show unwanted trends in the flight.

With a piston engine you know the power setting and with an horizon, real/virtual or artificial, a pilot should be able to keep an aircraft flying with a blocked pitot. I know nothing about turbines but I imagine a pilot knows what to expect from any given setting.

Did the aircraft stall, or breakup due to overspeeding, or ... Let´s hope the CVR and FDR are found.

And, cannot a second buoyant pair be fitted to the tail, designed to break off?

Looking to buy a used tricycle, NOT made in France, after the Airbus event I'm afraid it'll come break into bits as I ride it. I live in the mid west so we get a lot of Thunderstorms, not as bad as over the Equator but pretty rough none the less. Hey, just wondering if anyone has a pain free solution to pop nasal pimples, I have a monster that kills me every time I breathe!

Thanks chaps,

Fugly

I've failed to find where I read that the pitot replacement was not regarded as a safety issue, and that the new part just offers better reliability. If "better reliability" means better servicability of the part, and not better performance in severe conditions, then I can understand why it would not have been considered an urgent issue, but that suggests that replacing the pitots isn't addressing the problem.

I have to suppose that "better reliability" was trying to convey "reliable data in a broader range of conditions". Why else are these items being changed in such a hurry? But if that is the case, what, other than safety concerns, prompted the decision to fit the more reliable part?

Can anyone better informed shed any light on the differences between the old and new pitots?

Does anyone know where Korean Airlines source their pitot tubes from?

I have been a pilot on large commercial jetliners including most recently, B777 and B747-400. I have never flown or been qualified on Airbus products, although I am familiar with much of their flight procedures, automation and systems. Even among different subsystem manufacturers, many product designs are very similar, if not identical. I have no idea who the pitot-static system manufacturer is for the B777 nor how that system and its integration compares to that of Airbus. Further, I have no idea if a faulty pitot-static system was contributory to the loss of AF 447. I do know that a failed wing anti-icing sensor caused erroneous inputs to my systems on a 777 that resulted in serial stall and performance misinformation as well as auto-throttle disconnect while passing FL350 during climb. The problem was quickly corrected by selecting manual-on for wing anti-ice. The assumption was the aircraft had encountered structural ice during climb while passing through moisture at lower altitude. Ice cannot be effectively visually recognized by aircrew on large jetliners, especially at night. Crews are told to rely on sensors. The failed sensor disabled the Auto Wing Anti-ice system. The ice reduced the flight efficiency of the wing, as well as adding some actual weight. The flight computers (and pilots) were unaware of the aircraft's resultant reduced climb performance. In many instances, a failed sensor and ice would never be recognized because the effect of the ice would not be sufficient to impare aircraft performance before it sublimated. In this instance, the aircraft reached an actual performance ceiling well before expected. When the auto-throttles and auto-pilot cannot maintain required climb-rate and speed, they disconnect. Once the ice was eliminated, the wing performed as expected as did all other systems. The point is, all these automated systems are individual computers controlling mechanical devices integrated into "master" management computers attempting to make optimal decisions among those devices. The layering of these computers, their software and algorithms is science unto its own. The human factors interface is yet another complicating issue. "Garbage in, garbage out" is a well known computer proverb. The requirement for a pilot to ferret out the "garbage" of extremely complex systems while in a real time emergency is a major problem under continual study. AF 447's loss may never be definitively determined. It is far too soon for judgments to be made about this particular incident. It is ridiculous to make negative general statements about Airbus or Air France. It is absolutely outrageous stupidity to make negative general comments about the quality and value of any workforce, including pilots, unless you've done the work yourself (and yes, there is a significant difference between a Cessna and a jetliner).

Certainly there are significant differences between light aircraft and airliners, just as there are between boats and ocean liners, but it is their similarities that ultimately cause the crashes. In is in this context, as a recreational pilot, I attempted to answer Graeme, June 7.

In my opinion, as a passenger, being confused by computers is not an excuse for crashing, although it appears to be a reason. Examples: Some airliners have taken off essentially stalled (tailstrike), some flown too slow (stalled).

I believe speculation and theorising is valid and necessary. We are trying to understand; soon my wife will fly to Paris and me to London, halfway on an Airbus.

I am concerned a B777 wing could ice-up owing to the anti-icing being switched off by a faulty sensor, with no warning until the auto-thrust disconnected.

People will always make mistakes, and aviation is particularly unforgiving, but do pilots actually know they can fly their aircraft if they need to, in the way I know I can fly mine? Some clearly do, and many probably don´t.

Non-pilot here.

I'm imagining the flight deck of AF447 with auto-pilot engaged. As I understand it from reading various posts, it is recommended (required?) that this aircraft's (others, as well, no doubt) flight into turbulence be navigated by the autopilot.

It's night. Black Dark. Probably no visibility out of the cockpit, unless maybe some strobe flash. Bumpy, maybe really bouncy, but, nevertheless, a regular, routine flight. Let the technology do it.

Suddenly, and then continuously for a few terrifying minutes, everything is confusion on the computerized instruments. Alert but relaxed pilots go into high gear trying to figure out what's real. Too confusing. Can't respond fast enough, or accurately.

What the Hell's going on?

Down car.

All's that I am saying is that the plane has been designed around a ratio that is supersonic and is quite common for smaller freighters. With this in mind the integer base for the plane was reversed to obtain the horizontal stabilizers which means that at 100.3120 it is not worthy enough to leave a storm cluster of significant magnitude because simply the way the numbers descend. It seems that it would be requiring an additional horizontal slat possibly on the left side to maintain it's stability within the air at the aft of the plane. The fact is that upon leaving a storm the order of air would change, and almost reach supersonic speed, if trying to accelerate. If the tail was dipping, and the pilot accelerated thinking nothing was wrong that could cause potential stresses upon the horizontal stabilizers because they probably haven't been treated with the proper neutral laminants, as well as the regular wings probably haven't either. Note that 100.3123 has been utilized for regular efficient wingsets before with no problem. However when you move to the left to 100.3120 additional averages of air are placed against the plane which may react differently under certain barometric pressures. This could lead to additional weighting of the regular wings which are 1.01 cu feet under really what they should be which averages the weight request amidst and combined with the fuselage. Therefore would not be able to raise the tail as it itself was being averaged single with probably close to a speed approaching sound therefore an inconsistancy of the stress of the wings combining with the fuselage and the pilot adjusting speed to bring the tail up ripped the plane apart because they were running at two different stresses and could not maintain because they became inconsistant. This is probably caused because the tail is almost exactly averaged with the planeset information and is correct. Unless just requiring a straight out storm horizontal stabilizer 33.0061410999803763999999991042675
58.06400541999999999999999999979 feet and proven that this plane would not malfunction at this rate which normally it would and would have to be set back further lighter aircraft could tolorate this setting for all around use. However since it is a freighter plane I would have to recommend a setting such as 105.93665637521396588948698421145 57.9224395324999999999999999984625 feet for the horizontal stabilizer distance if wishing the 57 feet 1 inch vertical stabilizer. Unless wishing closer to the regular set of 106.8740947707218309523786864953 required distance of 57.931596121249999999999999999125 feet.

One more comment if you would please. At 100.3120 it is possible that coherent X-radiation was being collected by the plane and as it reached the magnetic field densities at the edge of the storm front was discharged in a powerful emmision of light. If this occured it is possible that this could have caused the air taking the essence of the lift and removed the plane of it's ability to lift. I say this now. It does not mean that the plane is not airworthy at present only that there could be too much weight demand under the normal wingset of 1.01 cu. feet under what it would probably do better at, and not that it isn't doing well now. I believe that the plastic of the vertical stabilizer would act as an attractant of this behaviour, and should be somehow magnetically shielded against this type of collective discharge to limit the possibility of it occuring again, if the horizontal stabilizers are not adjusted. The reason I say this is because there really wouid be too much loss.

I believe Ian's comment of 6/6/09 is plausible and would explain the anomalies known at this time. If AF447 encountered a hail shaft, the removal of pitot tubes explains the loss of air data. Destruction of the radome and radar antenna would mean trying to avoid the thunderstorms by only visual means. Ruptured windscreens (yes, they are very thick)would explain the rapid decompression and possibly incapacitate the pilots, making manual recovery impossible.
Airliners manuever near "multi-cell tropical convective" (BEA's description)storms routinely. We always fly upwind of the strongest storms, but with jetstream winds in excess of 100 knots, hail can be encountered many miles from the storms as depicted on radar. With a near-solid line, finding the safe corridors can be difficult. These severe storms are also capable of vertical growth in 1000s of feet per minute, and could have grown to "meet" the aircraft.
Please continue to keep the families in your prayers. The discovery of the recorders will only remind them of the terrifying last moments of their loved ones. Comedians using this thread please consider how you would feel if one of your family was involved.