The mysterious end of Air France flight 447 (AF447) June 3, 2009
Posted by David Cenciotti in Aviation, aviation safety, civilian aviation.Tags: Aviation, Qantas, CAT, Air France, aviation safety, A330, Airbus, in flight emergency, QF72, jetstream, Clear Air Turbulence, turbulence, ADIRU, Air Data Inertial Reference Unit, airspeed, altitute, aircraft, plane, civil aviation, AF447, Air France crash, FDR, Flight Data Recorder, ELT, Emergency Locator Transmitter
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As everybody knows, on Jun 1, 2009, an Airbus 330 of the Air France, flying as AF447 from Rio de Janeiro (SBGL) to Paris (LFPG) was reported missing while overflying the equatorial Atlantic Ocean. Although the pilot did not radio any kind of alert message, since the news was reported by the mass media, the first speculations suggested that the plane may have flown into a thunderstorm and break up as a consequence of the severe turbulence it may have encountered or because it was hit by a lightning. Even if in-flight break up is not unprecedented, as I’ve explained many times in this blog (make a quick search using the word “turbulence” in the search box located on the upper right hand coloumn of the site), if not impossible, a catastrophic impact of turbulence on a civilian plane is at least extremely rare. Explosions caused by a lightning strike (search for “lightning”) are rare as well. So which was the root cause of the loss of the Air France 447 that cost the lives of 228 people on board? It is extremely hard to say for many reasons. Unlike the previous crashes I’ve analysed on this site, the AF447 is much more mysterious. There are just a few details available, there are no witnesses, there are no radar logs, there are no communications by the pilots reporting an emergency or a failure. And, most important, it will be very hard to find the FDR (Flight Data Recorder), as the few aircraft’s remains surfaced on the Atlantic Ocean, 650 chilometers from the Brasil’s coastline, in an area where the sea is some 9.000 feet deep. 
For sure, what can be said is that the pilots, most probably, did not have time to radio a “Mayday”. This can be caused by a quick event (an explosion, an airframe collapse, a sudden illness) or by a concurrent radio failure. In my opinion, the radio failure is unlikely, as the A330 has plenty of communication equipments (VHF and HF radios, INMARSAT, ACARS, etc.) and also because this would imply that there were two failures more or less at the same time: a catastrophic failure and a radio or electric failure (of both the 3 generators and the Ram Air Turbine?). A sudden loss of pressurization could have been a cause, if the pilots did not react quickly and did not wear the masks before loss of consciousness occurred. But, if this is what happened on AF447 the aircraft would have not exploded, but fly under autopilot until it had fuel in its tanks.
What could have caused a catastrophic collapse (bomb explosion aside) could have been something similar to what other two Airbus 330 of Qantas experienced in the last months. As I wrote on this site on Oct. 7, 2008:
“On Oct. 7, an A330-330 “VH-QPA”, flying from Singapore to Perth as Qantas 72 with 303 passengers and 10 crew members on board, made an emergency landing in Learmonth Western Australia after it suffered a sudden change in altitude that caused 33 (still unconfirmed figure) injuries”. Then, on Oct. 20, 2008, I explained: “Even if it is too early to have a full explaination of the causes of the Qantas flight QF72 plunge that caused many injuries (see also: “Qantas flight forced to land: is turbulence dangerous?”) the preliminary review of the data recorded by the Digital Flight Data Recorder (DFDR) made by the ATSB indicated that the event developed in three steps:
the aircraft was levelled at FL370 when initiated an uncommanded climb of about 200 ft, before returning back (autonomously to 37.000 feet). About 1 minute later, the aircraft pitched nose-down, to a maximum pitch angle of about 8.4 degrees, and plunged about 650 feet in about 20 seconds, before returning again to FL370. Finally, about 70 seconds after returning to the cruising level, it pitched again nose-down, to a maximum angle of about 3.5 degrees, and descended about 400 feet in about 16 seconds, before returning once again to FL370. Such a “behaviour” seems to rule out the hypothesis of a CAT (Clear Air Turbulence) and the ATSB is in fact focusing on the faulty data in Air Data Intertial Reference Unit (ADIRU) 1 that “deceived” the aircraft’s flight control system. The ADIRU is an aircraft’s vital system. It feeds other on board key systems (autopilot, engine control system, flight control system, etc) with information about speed, altitude, position and attitude of the plane. On board the Qantas 72 flight, the ADIRU generated false warnings (stall, over-speed, etc) that the flight control’s computer faced with incorrect aircraft movements. The reason for the faulty data is still unclear. Someone pointed to the possible corruption caused by an electronic interference from an onboard portable device (laptop, PDA, tablet pc, etc.). Following the event, the ATSB initial report, Airbus issued recommendations to A330 and A340 operators that are equipped with the same ADIRU, including guidance and checklists for crew response in case of a similar inertial reference system failure“.
Another similar event, involving the Airbus 330 ADIRU, occurred a few weeks later when, on Dec. 27, 2008 a Qantas Airbus A330-300 cruising at FL360 (36,000 ft) enroute from Perth to Singapore, at about 1729 Local Time, experienced an autopilot disconnection followed by an ECAM (Electronic Centralized Aircraft Monitor) message (NAV IR 1 Fault) indicating a problem with ADIRU Number 1. The crew actioned the Airbus Operations Engineering Bulletin (OEB) procedure by selecting the IR 1 push-button to OFF and the ADR 1 push-button to OFF. Both OFF lights illuminated. The crew elected to return to Perth and an uneventful overweight landing was conducted. At the time that the autopilot disconnected, the aircraft was approximately 260 nautical miles (NM) North-West of Perth airport and approximately 350 NM South of Learmonth airport.
Even if someone speculated the area around Perth was a sort of “Perth Triangle” interested by strong radio signals (by some sort of secret naval station), the above two Qantas safety events show that there were some problems with the ADIRU of the Airbus 330 in the recent past. What if the AF447 experienced an uncommanded flight controls input at high speed, high altitude (in severe turbulence/thunderstorm conditions) like Qantas 72?
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I'm the author of "F-104 Storia di un mito", the only official book published by the Italian Air Force to celebrate the retirement of the Starfighter in 2004. I'm also a photographer and my pictures have been used in books, magazines, websites and calendars.
This is a place to talk about military aviation, flying, photography and much more.
The above image was created by Andy Spagna, as a gift for my first trap landing on the USS Nimitz, by modifying a real "Centurion" patch celebrating the 100 arrested landing on the aircraft carrier.
Hi David
this will be a mistery for a long while.
I would like to highlight 2 facts:
1. Air France bomb threat on 27th of May
http://www.foxnews.com/story/0,2933,524835,00.html
2. Real local weather conditions:
this link is only in Italian but basically is one passanger of flight AF456 Paris/San Paolo, flying over the area about 5 hours after the accident, reporting perfect weather conditions and uncommon temporary descent from 40FTL to 30FTL in the same area (looking for evidencies?).
http://www.lastampa.it/_web/cmstp/tmplrubriche/giornalisti/grubrica.asp?ID_blog=91&ID_articolo=872&ID_sezione=&sezione=
Air France AF447 ADIRU manufacturer : Honeywell
Qantas QF72 ADIRU manufacturer : Litton (Northrop Grumman)
Source: I work for Air France…
Thank you Benoit.
Since you work for AF, can you tell me what’s your opinion about the accident?
David
Benoit
Can you tell us if both manufacturers uses similar software?
You know, Dell Computers manufacture computers and uses MS Windows as others computers manufacturers.
Do they buy components from the same manufacturers?
Navy ships are speeding toward a patch of ocean in the Atlantic that is littered with debris from an Air France plane that crashed with 228 people on board, seeking to recover clues to the jet’s mysterious tragedy.
The naval operation, a day after the debris was spotted off Brazil’s coast, included two mini-submarines to recover the plane’s black box flight recorders if they can be found in the depths of the Atlantic.
Both Brazil’s defense minister and a French military official have said there is no doubt the debris came from the mysterious crash.
The first ships to arrive will be Brazilian, joining three cargo ships from France and the Netherlands that were rerouted to the area after debris from Air France flight AF447 was spotted.
Brazil has announced three days of national mourning. Catholic and Muslim services are to be held in Paris, including one in Notre-Dame cathedral to be attended by French President Nicolas Sarkozy.
Hello,
As a physicist in turbulence related studies and as a person with some rough knowledge on the embarqued software business, I would like to expose my personnal point of view on this terrible accident.
1/ It seems to be clear now that this accident is connected with turbulence. Then this calls for some possible responsibility of Air France and the pilot : the plane should not have been there (in retrospect it is easy to say) and some risk has been taken. Because maybe half of the passengers have to take a connecting flight in Paris, is there some, maybe unsaid but risky, commercial policy to avoid as much as possible delay, and so avoid as much as possible a longer route that would possibly bypass the turbulent spots ?
2/ Then, one possible interpretation of the accident, can be in my view do to a failure in the control equipment of the plane. In case of strong turbulence, there is commonly a strong intermittency in the external parameters captured by the probes in the air plane’s environment. This leads to data very difficult to interpret for the embarqued softwares, and in my view in the extreme case impossible at all to manage. Possibly, there is also some problem with the internal correctness of these softwares that could result in an uncontrollable airplane…
I hope that there will be sufficient material to achieve a conclusive impartial enquiry.
Regards, Marie.
Dear Marie,
I do agree with you that a “possible” explaination can be found is a failure connected with the control equipment of the plane. However, it is hard to believe that a single cause can bring an aircraft down. I strongly believe in a series of contributing factors as in each aviation accident.
David
Interesting analysis, as to the alleged bomb, the source if Fox “News” and thus is quite suspect. As a former Boeing employee, I have no real knowledge to offer other than armchair analysis. It strikes me that extreme turbulence could bring a plane down, especially turbulence that is outside of the design parameters. *IF* this is the case, then the question of what the pilot was doing there comes to mind.
This is almost as tinfoil hat as the bomb theory, but a small meteorite could be at fault? I don’t recall why we were discussing this in Boeing, but there is, although admittedly insanely small, a chance of an aircraft being it by a meteorite. I recall someone saying it had happened, but we could never verify it and thus sort of chalked it up to urban folklore.
As I think about it, no accident is caused by a single event. My suspicion is that there was a flaw in the aircraft that was exploited by a chance natural happening. For example, a few poorly installed rivets and turbulence over design specifications? A gap could create an opening in the fuselage for a lightning strike entry?
This is PURE speculation. As a frequent traveler and someone who has worked for an airplane manufacturer, my heart goes out to the families of those who perished.
Interesting comment Christopher, I have never thought to a meteorite but, although “insanely small”, there’s also such a chance. Anyway, I would focus, as you said in the series of contributing factors that most of times are the main reasons for aviation crashes….
Thank you,
David
Hi
I really feel sad about the families involved.
Le Monde has reported the 4 messages received between 23.00 and 23.14
Still, I haven´t seen anywhere a clear report of the real wheater conditions at the time of the accident.
http://www.lemonde.fr/societe/article/2009/06/04/l-airbus-d-air-france-volait-a-une-vitesse-erronee_1202293_3224.html#ens_id=1200707
A 23 heures, soit vingt minutes avant l’entrée prévue de l’Airbus dans l’espace aérien du Sénégal, le pilote envoie un message signalant qu’il traverse une zone de fortes turbulences, dans des cumulo-nimbus chargés d’électricité et des vents violents. Les satellites météo attestent que les vents soufflaient à 160 km/h.
Les problèmes commencent à 23 h 10 lorsqu’un message signale la déconnexion du pilote automatique. On ignore si cette opération a été effectuée par l’équipage ou si elle a été provoquée par les systèmes de sécurité. Cette déconnexion intervient, en effet, automatiquement lorsque les ordinateurs détectent une panne grave.
L’équipage a-t-il voulu dévier de sa trajectoire pour éviter les zones les plus dangereuses ? Si oui, l’opération s’annonçait délicate. Selon un pilote cité par l’Estado, le contrôle manuel d’un avion à haute altitude est “extrêmement difficile”. Une chose est sûre : à partir de cet instant, l’Airbus est piloté manuellement.
A la même minute, un autre message informe que le “fly-by-wire”, autrement dit les commandes électriques de vol qui activent les volets et les ailerons, passe sur le régime “alternative law”. Cette alimentation de secours est actionnée automatiquement en cas de pannes électriques multiples. L’avion conserve alors suffisamment d’électricité pour voler, mais plusieurs systèmes de contrôle de la stabilité de l’appareil sont détériorés. Dans une telle situation, une alarme sonne pour alerter le personnel de cabine.
A 23 h 12, deux autres messages auraient signalé des pannes dans deux équipements fondamentaux, Adiru (Air Data Inertial Reference Unit) et ISIS (Integrated Standby Instruments System). Ces ordinateurs fournissent des informations capitales sur l’altitude, la vitesse et la direction du vol.
A 23 h 13, de nouveaux messages indiquent des pannes électriques dans l’ordinateur principal (Prim1) et l’auxiliaire (Sec1) de vol. L’ultime message est envoyé à 23 h 14. Il signale : “cabine en vitesse verticale”. C’est l’indice d’une dépressurisation, cause ou conséquence d’une désintégration en vol
It could be many things. It could be some sort of secreted thing by the govt.
Sarkozy wanted to speak to Obama this night but he did not accepted the encounter at dinner and he preferred to pass the night with his family. Who knows if things are connected?
It could have been also something connected to some military base secreted naval base like in the other article was said a Perth Triangle a Bermuda Triangle a Brasilian Triangle…but in any case, I believe that if the information till know retrieved and deduced are correct and real and true the paths that are showing in the last hours of the incredible storm the plane was passing tru’, the loss of pressure and the messages sent during the fall of the plane investigation must follow this path.
It’s incredible that in 2009 still we are going on the Moon and trying to plant asparagus on March, and shamefully we cannot reach the deepest areas of our sea and at least do what had to be done.
It’s not rethorical, as a traveler and as a sensible person I feel too close to the pain and I just find a little relief in thinking these people have not suffered a lot “thanks” to the loss of pressure…
A mistery is a mistery so since nothing has been found I’d be considering too that passengers are still alive or there are survivors…who knows?!
David grazie and thanks for the comments, and keep in touch.
Take care
M.
“A mistery is a mistery so since nothing has been found I’d be considering too that passengers are still alive or there are survivors…who knows?!”
The LOST scenario…..just kidding.
Possible can be also that the pilot was able to “land” on water, and that because radars are not present in that area and because human make errors lifeguard and all the slow and inefficient machine of rescuing moved only 9 hours later at 10 am.
So if a storm was going on there, on water, the plane has sinked…
This story about the substitution and update of failing pieces of the plane is a COVER to cover some bigger person, interest and truth.
We cannot believe in what anybody says , what is needed is evidence. As on 11 2001 september has been prooved it has been all organized attacks, nobody can say no to this.
Can a land on water be made by such a plane?
Is it possible to know more on different cases and situation that the people and prilot have been through in such a situation?
Reports say that storm motivation are totally a false path, since there was no storm going on in the air…
Please let us know. even if it dangerous to know…
Even if everything is possible, I’m not a “conspiracies fan”.
BTW, the Hudson river ditching is the proof that some maneuvers can be succesfull not only in movies but also in real life (although, as we discussed a lot here, know-how, experience and luck are paramount). And there’s also the possibility that the aircraft attempted a ditching but broke apart but this is just another speculation. Unfortunately I think that in the case of AF447 we can only discuss (a little) about “what could not have been the cause”…..
35 years as an aircraft development engineer on Airbus, Boeing, Bombardier and many military programs have taught me that we wait for impirical data, facts…ignore the news media circus, in a week it will not be news, and the engineers will then diligently investigate and resolve the cause, then rectify the design if required, or change operating procedures, if human factors were to blame.
Hi Wight,
you’r right. The main reason for discussing aviation accidents on this blog is just to explain or correct the information provided by the “media circus”. For sure we have to wait the actual data.
Even though it is somehow sad, every aviation accident is an inescapable step to prevent a future one…..
David
On 08.06.09 Radio Band News FM transmitted the following report on the AF447 during which (as you can hear…in Portuguese) I was interviewed to provide my opinion about the various theories concerning the A330 accident.
The spot is available at the following address (you can hear me at the beginning):
http://www.archive.org/download/RdioBandnewsFm/Sheila0806Airbus.mp3
Dangerous goods perhaps ???
have you said “insanely small”?. See this page:
http://www.flickr.com/photos/bootbearwdc/55039857/
A meteorite can hit and bring down an aircraft of course. It is just a probability issue.
Intriguingly, in the aftermath of TWA flight 800’s crash in 1996, the New York Times published a letter by Columbia professors Charles Hailey (physics) and David Helfand (astronomy), in which they stated the odds of a meteor-airplane collision for aviation history up to that point: one in ten.”
For what its worth I was on Flight QF72 Singapore to Perth again an A330 in late 2006, when I experienced the worse ‘drop’ ever in my flying experience, most on board were somewhat alarmed! Probably nothing but thought I’d mention it!
Looks like that route is particularly turbulent: QF68, an A330 from Hong Kong to Perth was hit by turbulence 4 hours out of HK as it was flying over Borneo. Seven passengers were injured….
http://online.wsj.com/article/SB124607165106964441.html an A330 had the same series of weird computer events going from hong kong to tokyo, but didn’t crash.
Good morning guys,
I`m a ground maintenance engineer and I`ve joined right now your forum so i`m not up-to date about at which point we are with all the hipotesis of what had appened at FL 350 outbound INTOL the last rep point of the recife FIR.
I belive in Airbus about several customers report dealing with ” PITOT problems”; there was one of the first Service Information Letter 34-0** dated 10 Oct 1994 about “…airspeed differences under marginal weather…” issued for A 330/340…..
Then a SB for all airbus fleets was issued several years later.
Assuming the existance of technical problems regarding pitot/static disagree and the fact that the AF447 was flying into a cloud situated in the ITCZ: all these factors leads to a mismatch of the air speed data into the FCC; the consequence was the A/P disconnection and a sort of alternate mode of navigation of the Flight control computer……..
Immagine the scenario: inside clouds, turbulence, night and without a/p…….
Remember what happened to the A300 of American Airlines flight 587 departing from JFK that went into a preceeding B 747 wake turbulence; the co-pilot were flying by hands the a/c……the vertical fin collapsed and the a/c finally stall and crashed tragically……without any pilot possibility to send a radio mayday!!!
That`s my possible hypotesis of what could happened to AF447. Obviously the A 330 didn`t stall but for sure went into a downworth vertical spin impossible to counteract without a rudder!!!
Tks to Airbus and to Airfrance….
Bye bye to all.