What caused the Air France crash

The Air France jetliner that skidded off a Toronto runway and burst into flames Tuesday was the first A340 to crash since Airbus introduced the plane in 1992.

Airbus spokeswoman Barbara Kracht confirmed the model as an A340-300, part of the A330/A340 family of six related aircraft that share the same airframe.

Before Tuesday, no A340 in commercial service had ever crashed, Kracht said by phone from Toulouse, France.

The A340 is a popular workhorse among carriers serving Asian and trans-Atlantic routes and has a strong safety record, said Chris Yates, an aviation specialist with Jane's Transport magazine. It can fly 7,400 miles without refueling and is typically configured to carry 295 passengers.

Now, the rest of the article continues glowing about the Airbus. The Captain (from The Andrade Blog) gives a pilot's view on the model.

Airbus airplanes are said to be fly-by-wire. That means that the control inputs to the hydraulically operated control surfaces are sensed by a computer from a control stick not unlike the sticks of game players. The computer then takes the imputes from the stick, runs them through sets of parameters to insure that the jet can properly respond to them, and then sends commands to the actuators to move the control surfaces. (Other large jets send the control inputs from the pilot through control cables that operate the hydraulic actuators directly.) In most cases, the pilot cannot tell the difference between the two types of control inputs. You move your hand and the jet does what you want it to do. Is the difference important in this accident? Maybe. We will know more when we learn how experienced the pilots were in this type of jet.

What the captain also does is give a bit of experienced speculation on what may have happened to cause the crash. More on that in a moment.

Back to the Business Week article. They continue to protect the reputation of the Airbus (which personally I have never enjoyed flights on) by overplaying "nature" and "weather". While my opinion is that these were major factors in the crash, the pilot still had the last say on whether to land or not.

Business Week:

Modern airliners are safer than ever, Yates said, but extreme conditions can still be dangerous, especially during takeoff and landing.

When the Air France jetliner skidded off the runway Tuesday, thunderstorms were in the area.

"You can never account for weather," Yates said. "A thunderstorm can happen anywhere -- it comes down to the judgment of the air traffic controller and the skill of the pilot to determine whether it's appropriate to land or to divert elsewhere."

The Captain's take and likely scenario (is lengthy but very interesting):

The most proximate cause of this accident will be (and I hate to say it) pilot judgment. You do not charge into a thunderstorm and try to land. Delta proved that in the 80's at Dallas. [Tony's side note: That plane was supposed to go from Dallas to El Paso to LAX...I was scheduled for that connection. Had I not received a call a few days earlier that I was selected for that season's baseball All-Star game I would have been...waiting for a plane in El Paso that was not to arrive.] There are wind shifts and downdrafts that are beyond the airplane's ability to overcome, so that if you do everything exactly right you will still crash. That is why you do not go there.

So why would an experienced crew put themselves, their passengers and their airline in such danger? (Crashes have caused airlines to go out of business. Anyone heard of Pan Am lately? People stopped flying on them after the crash in Scotland, and it was not even their fault.)

Scenario. Lets say you are coming from Paris. Despite the fact that this jet has a huge range, no one takes more fuel than you think you will really need, so it is possible that you are running a little short on fuel as you approach your destination of Toronto, Canada. The weather was isolated thunderstorms, and since you do not have to take into consideration transient storms that have a small chance of hitting the airport when you get there, and since carrying extra gas is expensive, you put on a normal fuel load. Going overseas you always have to carry 10% more gas than you expect to burn as well as whatever you add "Just in case." The normal load should be more than enough. Now the thunderstorms hit, and they are right on the airport. Whups. Bad event number one. (There is always a chain of events all of which have to go wrong in order to have an accident. There are always "If only's" at every accident.)

With possible low fuel, you then have holding due to the thunderstorms. Airbuses are very fuel efficient in holding patterns, but you must fly at uncomfortably slow speeds. A lot of pilots like to fly faster, with resultant higher fuel burn. Lets say you fly just a little bit faster than you have too.

The rest of the article is a must read. It is worth the time, also. Click here.