On June 1, 2009, Air France flight 447 from Rio de Janeiro (Brazil) to Paris (France) suddenly entered an aerodynamic stall and crashed into the Atlantic Ocean, killing all 228 passengers and crew onboard. Although the initial reports on the possible causes of the disaster evolved around the malfunction of the plane’s pitot tubes, the investigation concluded that the main reason for the tragedy was pilot mistake.

Tom Dieusaert, a Belgian journalist and writer, does not believe it was quite so. In his new book “Computer crashes: When airplane systems fail” he argues that pilots are commonly blamed for tragedies like the Air France F447, but something more subtle – the plane’s computer software – is often overlooked.

AeroTime had a chance to talk with Tom about his book, plane crashes and the computer systems that control modern airplanes. 

Your book is titled “Computer crashes”, but the accidents you cover, most notably the Air France Flight 447, are officially blamed on the pilot. Why did you choose to focus on the technology rather than human factor?

Air France 447 which was actually the case that caught my attention and inspired me to write the book. There were a lot of on-going problems with the airplane – and the pilots just were the last ones to solve those problems. In my opinion, the pilots should have never been put in the position to solve those problems at the very end. There is a lot of emphasis on what the pilot should have done. But there is not enough emphasis, which I tried to put, on all the troubles the machine already had.

The concept of “human error” is still used a lot in the press but the human operator is only one of the many defenses the system should have.

The pilot is not flying the plane anymore. The pilot is just there to solve the problem, when everything else fails, so he is the last resort. I think it's a bad analysis to pinpoint the pilot and just forget all the other trouble that machine had. But of course, the industry doesn’t want a critical eye on the problems their planes have, and they find it easy to target the pilot, the one who is flying the plane.

I’ve spoken to quite a lot of pilots about this accident, including the pilots that fly the same plane – the A330 or the A340, which is almost the same thing), and they said if you put 10 people in the same situation, 9 out of 10 would have done the same mistake. That’s what is called retrospective bias. We look backwards and we say that the pilot should have done this or should have done that. It’s not very easy to put ourselves in the place of those people when they had a lot of contradictive information on their instruments.

Tom Dieusaert is the author of “Computer crashes: When airplane systems fail”

In your book you say that computers behaving erratically or malfunctioning are quite common, but the reason the public doesn’t know about it is that it is not advertised (or even acknowledged) by the manufacturers and more importantly, the safety boards. What is the motivation for authority bodies to ‘keep a blind eye’ on the technical issues found on planes?

Let’s take the example of the Air France accident, where, I believe, personally, there was a pilot error, but I do not want to say it was the cause of the accident, it was just one of the whole chain of things that went wrong. And the biggest part that went wrong were all the previous events, also the design of the airplane. For instance, those pitot tubes were not functioning well and had not been functioning well for a few months before, two years before the crash. Airbus had a lot of issues with those new pitot tubes on their A330s. There had been events, 20 or 30 events in 2 years. One of these events went wrong, which was the Air France one. Air France took 6 months to change these pitot tubes on their plane, and the plane that went down was going to have them changed the day it was supposed to arrive to Paris. So it is actually a mistake of the company. That plane should not have been flying at all. But afterwards the blame was put on the pilots.