AF 447 Likely Crashed Because of Pilot Error

The first thing I did Friday morning was to go to BEA's website and read the most recent note about AF 447. For the first time the investigators published excerpts from the voice recorder of the downed A330-200. After reading the note it was pretty clear to me that major errors by the pilots caused this tragic accident in June 2009.

As already known, the pitot probes failed during the Airbus's flight through the Intertropical Convergence Zone (ITCZ). Experts believe that super cold water hit the tubes and froze on contact. The tubes failed and the Airbus suddenly did not have any reliable speed data. Consequently, the auto pilot and auto thrust disengaged. The A330 switched into alternate mode, giving the pilots full control of the plane. According to the transcript, the two first officers in the cockpit tried to call the captain, who was resting at the time, but he did not respond. Even though at least one of the first officers was pretty experienced on the A330, they failed to correctly interpret the computer's error messages. They were too consumed by figuring out what all the error messages meant to just focus on flying the plane.

Finally, the captain was back in the cockpit, but the situation worsened. The first officer pulled the plane up and it climbed from 35,000 feet to 38,000 feet, which was too high for the current situation in the ITCZ. Climbing also slowed down the plane and signals went off indicating that the Airbus was about to stall. At an altitude of 35,000 feet, the speed of a plane has to be within a very narrow limit, otherwise it will stall if the angle of attack is not adjusted. A difference of only 20 knots can cause a plane to stall. However, the first officers did not react correctly. The plane was still too slow and turbulence was rocking the plane to the sides.

With the fly-by-wire's envelope system down the first officers pushed the sidesticks too hard and the plane began to roll. Normally, the A330's fly-by-wire system would prevent that, but since it was down, there was no automatic protection anymore. However, and contrary to earlier reports, the Airbus was completely controllable. No primary flight systems failed. The envelope system was down, but the fly-by-wire system was still intact. The pilots had 100% control over the plane.

The first officers were not able to stop the stall. With very high vertical speed, the A330 shot toward the Atlantic. Ironically, one first officer increased thrust to 100%, increasing the plane's speed even more as it was heading toward the water. Pretty soon, the first officer realized he was not able to regain control of the plane. At 10,000 feet, he handed the controls over to the second first officer in the cockpit, who only had a few months flying experience on the A330. They must have realized they were doomed. Ironically, the pitot tubes worked again after less than one minute. The last words in the cockpit were "go ahead, you have the controls," when the first officer handed the controls over to the second first officer. A few seconds later they hit the water and were dead. And with them all 225 people on board flight AF 447.

So what happened? First, the Airbus's systems did not fail. The only thing that did fail were the pitot tubes. This is not really cause for a crash if pilots are well trained in these situations. Pitot tubes have frozen over before and never did a plane crash because of it. In this case, a chain of unfortunate events caused the accident. The following is a list of all the errors and issues that led to this terrible accident:

1) Instead of focusing on flying the plane, the two first officers were too focused on the computer's error messages. Flying the plane at an angle of 5 degrees with thrust at 85% would have been enough to fly without working pitot probes.
2) The first officers made the plane climb to 38,000 feet instead of descending. This decreased speed and caused the stall.
3) They were not well trained to regain control of the stalling plane. This had not been part of their pilot training.
4) They were not trained to realize that the frozen pitot tubes caused these problems.
5) The most experienced captain was not at the controls when the problems started.
6) At 10,000 feet - the most crucial phase of the accident - the least experienced first officer was in control of the plane.

In my opinion, well-trained pilots should have been able to handle this situation. In a BBC documentary from 2010, pilots encountered the exact situation in a simulator and managed the situation very well. Of course a simulator is not a real plane and the pilots in the simulator knew what was happening, but I strongly believe that all pilots should have the training to handle such a situation and a stall.

I am convinced that the crash of AF 447 will result in lots of troubles for Air France and Thales, the manufacturer of the pitot tubes, as they will be charged with manslaughter. Air France will be blamed for not training its pilots well enough and Thales will be blamed for building faulty pitot probes, even though the company claimed that they are able to handle all real-world challenges.

For Airbus, this is a result they can live with. The A330's fly-by-wire system was working and the plane is not to blame for the crash. But that's the only good news...

First Clues in AF 447 Crash

About a month and a half ago I wrote on this blog that I was hoping the search teams would find the black boxes of downed Air France flight 447. To my own surprise, they recovered both boxes last week. Yesterday, investigators were able to have a first look at the data stored in one of the black boxes, but the voice recorder still needs to be analyzed. The families of the people who died in the crash as well as the public will finally know what happened to the A330-200 on June 1, 2009. French investigators confirmed they will be able to fully understand the causes of the crash.

In my opinion, the most surprising development was a telex Airbus issued to all A330 customers today, which stated that there are no recommendations for Airbus's highly successful widebody aircraft. Many of us asked ourselves today: What does that actually mean? And this is the sensational part of today's news - it means that AF 447 did not crash because of any technical difficulties or errors with the fly-by-wire system. This is shocking news. In a good way though for Airbus and everybody who believes in and trusts Airbus's fly-by-wire technology.

After AF 447 crashed almost two years ago, many people - and even experts - believed the jet crashed because of a "stroke inside the plane's computers," as Germany's Der Spiegel wrote in 2009. They assumed the plane's fly-by-wire system shut down, following the icing of the Airbus's pitot tubes, rendering the pilots unable to fly the plane manually. I never believed in this theory as my earlier blog posts about the topic pointed out. Many aircraft have had issues with iced pitot tubes and none of them crashed. It was just not a good reason for a modern, state-of-the art airliner to crash.

But this brings us to the next question: Now what caused AF 447 to go down in early June 2009? Well, it is still too early to know that. We now know more about what didn't cause the crash, but we still do not yet know what caused it. The investigators mentioned today it would take until this summer to come to a final conclusion. There is still a list of numerous reasons for the crash, among them pilot error. Indeed, errors by the crew now seem to be the likeliest possibility. Listening to the voice recorder will answer a lot, if not all, of these questions. While today is a good day for Airbus and the A330, there are still no good answers for the families of those who died on June 1, 2009.

AF 447 Found in Atlantic

To be honest, I was not very hopeful that we would ever hear anything again about AF 447. So you can imagine how surprised and excited I was when I read the news two days ago about a submarine finding parts of the downed A330-200.

AF 447 was en route from Rio to Charles de Gaulle when it crashed into the Atlantic after passing a bad weather front in the ITCZ in June 2009. The emphasis here is on AFTER, not during - contrary to many media reports. Almost two years after the accident, even experts are still unsure about what happened to F-GZCP.

A popular theory is that the Airbus's fly-by-wire system, including all flight computers, broke down, rendering the pilots unable to fly the plane. Based on the automated messages AF 447 sent to the Airbus headquarters in Toulouse, this is not very likely. Another theory is that the pilots did not know the aircraft's exact speed, because the pitot tubes were jammed with ice (the plane was flying through a very moist bad weather front) and the Airbus did not receive any consistent airspeed data anymore. The automated messages confirm that this happened. However, this alone cannot be the cause of the crash. Yes, the pilots may not have had exact airspeed data, but they still had over-ground speed information based on GPS. This is not exact, but enough to fly the plane safely in a situation like this.

As in most cases, I strongly believe that many causes led to this fatal accident: Pilots who probably were not very familiar with the aircraft's computers and technology; a stressful and highly demanding situation they were not well trained for and never experienced before; multi-system failure; and it was in the middle of the night, so the crew probably couldn't see anything (contrary to earlier reports, the A330 has a manual horizon, so the crew always knew where up, down, right and left were).

Two years later, important questions remain, which make this accident so mysterious: Why didn't the crew radio to other planes traveling the same route that they were experiencing difficulties? They still had electricity and another Air France jet was directly behind them. A Lufthansa plane directly in front of them. Why did the Airbus hit the water belly first if the crew couldn't control it? Why was the captain not in the cockpit if it was a tricky situation?

Hopefully, in a few weeks from now, we will have answers to these questions. Fingers crossed that the search teams will find the black boxes!

AF A380 Missed Approach JFK

And another nice video of a missed approach at JFK. I wonder why? The A380 almost touched down on the runway already. Oh, and I just love the sound of the A380's flaps being retracted. So futuristic...

Air France 447 - One Year Later

June 1 marked the first anniversary of the crash of Air France flight 447. One year later we still don't have any answers whatsoever on why the Airbus A330 crashed into the Atlantic. Still, pretty much all scenarios are possible. Most journalists, and some experts, blame the crash on faulty pitot tubes or a bug in the A330's fly-by-wire system/avionics. None of this is confirmed. All is speculation. Even if the pitot tubes were not working correctly - that is not a good reason for a plane to crash. As mentioned several times before, all airplanes are equipped with GPS and still receive above-ground speed information even if the pitot tubes fail. A bug in the fbw system could potentially be the cause, but this has never happened before and would still not explain why no "mayday" signals were sent.

The search for the black boxes is still ongoing and the area where those boxes can be have been narrowed down to twenty-five square kilometers. Still, that is like finding two shoe boxes in an area half the size of Manhattan. However, I am still positive that the black boxes will be found and the mystery will be solved. I still don't really believe any of the current scenarios. Fingers crossed we will know more a year from now.

If you want to read more about the search and a documentary that is currently being produces, please click here.

Reuters: Breakthrough in Air France Crash Black Box Search

Today is a good day - for those who lost relatives and friend in the crash of Air France flight 447 on June 1, 2009, as well as for everybody else interested in aviation. I am very sick of hearing that AF 447 crashed because of turbulence, bad weather or pitot tube malfunctions. I want to know what really happened to the Air France A330 almost one year ago.

The French defense ministry today announced the search teams have found what could be the first concrete clues to the location of black boxes missing from last year's Atlantic jet disaster, but warned on Thursday there was no guarantee the breakthrough would lead to their recovery. This allows experts to narrow the search to a few square kilometers from several thousand ahead of the anniversary of the airline's worst crash.

To read the full Reuters story, please click here.

Air France Flight 447 - The Last Minutes

It's been nine months since Air France flight 447 crashed into the Atlantic, killing all 228 people on board. Still, the black boxes have not been found and we don't really know what happened. The following is what I believe happened. I will try to reconstruct what was going on on board the A330 over the Atlantic on June 1, 2009. I have no idea if what I'm posting here is correct and I am not able to explain everything. But knowing a bit about planes and aviation in general, I think I have a pretty good understanding of what contributed to this horrible crash.

It was a rather calm afternoon in Rio de Janeiro on May 31, 2009. Captain Marc Dubois and his two First Officers David Robert and Pierre-Cedric Bonin started to prepare the A330-200 with the tail number F-GZCP for the 11 hours and 30 minutes flight to Paris Charles de Gaulle at around 6 pm local time. The plane was fairly new, only four and a half years old, and had gone through a major overhaul just two months before. Captain Dubois was a very experienced pilot, with more than 11,000 flight hours, more than 1,500 on the A330. He knew this plane and he knew it well. His two First Officers were in their 30s and fairly new to the A330.

Flight 447 was pretty heavy that afternoon. Dubois allowed for ten tons of cargo to be loaded into the plane plus 70 tons of kerosene. In the end, the A330 was only 240 kilograms lighter than its maximum weight. But it didn't matter. The fuel he had pumped into the Airbus was more than enough to get them to Charles de Gaulle. At 10.03 the A330 lifted into the air and headed north, north-east along the Atlantic coast of Brazil. An hour after takeoff they reached their cruising altitude of 35,000 feet. The air was a bit rough, but nothing serious so that Dubois engaged the Airbus's autopilot pretty early into the flight.

At around 1.15 am on June 1, 2009, the Airbus left the mainland of Brazil and headed towards Fernando de Noronha, an island 350 kilometers to the east of the coast of Brazil. The "fasten seat belt" signs were illuminated. Dubois knew this area well - it is feared for its strong winds, heavy turbulence and unpredictable weather conditions. They were about to enter the "Intertropical Convergence Zone" (ITCZ), an area which encircles the area around the equator. Strong thunderstorms develop in the ITCZ and clouds filled with hail and lightning pile all the way up to 15 kilometers above the sea. There is no "flying above the weather" inside the ITCZ. In the spring and early summer thunderstorms are particularly strong and common. But Dubois checked the latest weather details before take-off and kept a constant eye on the A330's weather radar.

At 1.33 am the last contact with Brazil's air control took place: AF 447 was flying through moderate turbulence, but the cockpit crew stated that the Airbus was flying at normal level (35,000 feet) at a speed of 865 km/h and that they were using airway UN873 to get to Senegal within 50 minutes. Dubois and Robert were in the cockpit, the plane still flying mostly on autopilot. They started to see supercells with thunderstorms in the distance. Those thunderstorms caused winds of up to 165 km/h that were starting to hit the Airbus. Still, the cockpit crew was not worried. The ITCZ is a nasty area to fly through, but planes do that all the time and Dubois had done it dozens of times before. If the supercells started to become too nasty, he would have to leave his assigned corridor and manually fly around them. But the weather didn't look too bad that night. Only a few bad cells were directly in the way.

In order to prepare flying around a few cells and because of worsening turbulence, Dubois disengaged the autopilot and firmly took over command of the A330 soon after they left the coast of Brazil. "Flight attendants, please take your seats!" At 1.48 am, Air France 447 left Brazilian radar surveillance. The next ten to 15 minutes were fairly bumpy, but soon after, the A330 had passed through the most severe portion of the thunderstorm area and flew into calmer skies. Dubois re-engaged the autopilot and left the cockpit to take his break (all pilots on long-haul flights take a rest at some point). First officer Bonin took over the pilot's seat. The flight attendants were allowed to move around the cabin again. Soon after, the nightmare started...

While flying through a thunderstorm and without the cockpit crew noticing, ice crystals started to form on the Airbus's pitot tubes. The pitot tubes provide planes with much-needed airspeed data, in addition to the GPS system that also offers details on the plane's speed over ground. The Airbus A330 is equipped with three pitot tubes, which are mounted at the front of the plane. At around 2.08 am, the pitot tubes started to measure different speeds. The autopilot needs consistent, exact speed data to control the plane. In this case, the computers were provided with three different speeds. Consequently, the autopilot shut down and the auto-thrust system too. The A330 was now back in the hands of the two First Officers in the cockpit. At 2.10 am the plane sent automated messages to Airbus's headquarters in Toulouse, France, that the autopilot and auto-thrust had disengaged.

The cockpit crew was now confronted with a situation they had probably never experienced before. The autopilot was dysfunctional and the plane's speed was not clear anymore. However, they could still see the speed over ground via the plane's GPS system. At that moment they had to make sure they were fast enough but not too fast either. And they needed to manually fly the plane while figuring out what was going on. Only seconds later the plane's TCAS turned into fault mode and the crew could no longer see where other planes around them were. This was the point when the cockpit crew realized that there's more going on than just inconsistent speed data. Computer after computer, monitor after monitor and system after system started to die. Soon after, the fly-by-wire computers resigned and the A330 turned from normal law into alternate law. The pilots could now fly the Airbus outside of its usual fly-by-wire limits. At that time, Air France 447 was halfway between Brazil and Senegal.

Whatever happened that night, the entire systems of the Airbus crashed. Within five minutes, AF 447 lost all systems necessary to fly the plane. The cockpit crew tried in vain to re-start the systems. They didn't work. The pilots started to realize they wouldn't make it, but kept trying. It was their only chance. The Airbus was not responding to any stick inputs. The movements of flight controls in modern airplanes are converted to electronic signals transmitted by wires (hence the term fly-by-wire), and flight control computers determine how to move the actuators at each control surface to provide the expected response. When those computers die, it renders a plane uncontrollable and that is what probably happened that night. Bonin's and Robert's only chance was restarting the systems. They tried it three times, but they wouldn't re-start (two error messages relative to restarting the systems were sent between 2.11 and 2.14 am). The plane was now flying downwards at a high speed. The pilots tried it again and YES the system restarted, the monitors started to turn on again. The computers realized they would hit the sea momentarily and lifted the nose of the Airbus up. They were only 600 meters away from the water at that point.

But it was already too late. With forces of 35 times the earth's gravity, the A330 hit the water, fuselage first. The forces were so strong that the rudder of the plane broke off, parts of the wings broke off and seat belts cut people into two parts. F-GZCP was gone. And with it 228 people. Everything happened within less than five minutes. Not even enough time for the First Officers to call the Captain back into the cockpit.

Even today it is not clear if and how the faulty pitot tubes caused the fly-by-wire system to die. Neither is it clear why the crew did not try to radio "mayday" to planes around them. Until the black boxes are found, we will not know what really caused all the systems to fail. Was this a problem that can only happen on Airbuses? Probably not, because apparently all electronics failed. A Boeing 777 cannot be steered without electronics either. However, on pretty much all older planes an accident like this one could not happen; they are still flown manually, not through electronic interfaces.

I am absolutely convinced that this problem was not caused by Airbus's fly-by-wire system itself. Something must have caused all backups to fail. However, I have no idea what this could have been...