When a sleepy Marc Dubois walked into the cockpit of his own aeroplane, he was confronted with a scene of confusion. The plane was shaking so violently that it was hard to read the instruments. An alarm was alternating between a chirruping trill and an automated voice: “STALL STALL STALL.” His junior co-pilots were at the controls. In a calm tone, Captain Dubois asked: “What’s happening?”
Co-pilot David Robert’s answer was less calm. “We completely lost control of the aeroplane, and we don’t understand anything! We tried everything!”
The crew were, in fact, in control of the aeroplane. One simple course of action could have ended the crisis they were facing, and they had not tried it. But David Robert was right on one count: he didn’t understand what was happening.
As William Langewiesche, a writer and professional pilot, described in an article for Vanity Fair in October 2014, Air France Flight 447 had begun straightforwardly enough – an on-time take-off from Rio de Janeiro at 7.29pm on 31 May 2009, bound for Paris. With hindsight, the three pilots had their vulnerabilities. Pierre-Cédric Bonin, 32, was young and inexperienced. David Robert, 37, had more experience but he had recently become an Air France manager and no longer flew full-time. Captain Marc Dubois, 58, had experience aplenty but he had been touring Rio with an off-duty flight attendant. It was later reported that he had only had an hour’s sleep.
Fortunately, given these potential fragilities, the crew were in charge of one of the most advanced planes in the world, an Airbus 330, legendarily smooth and easy to fly. Like any other modern aircraft, the A330 has an autopilot to keep the plane flying on a programmed route, but it also has a much more sophisticated automation system called fly-by-wire. A traditional aeroplane gives the pilot direct control of the flaps on the plane – its rudder, elevators and ailerons. This means the pilot has plenty of latitude to make mistakes. Fly-by-wire is smoother and safer. It inserts itself between the pilot, with all his or her faults, and the plane’s mechanics. A tactful translator between human and machine, it observes the pilot tugging on the controls, figures out how the pilot wanted the plane to move and executes that manoeuvre perfectly. It will turn a clumsy movement into a graceful one.
This makes it very hard to crash an A330, and the plane had a superb safety record: there had been no crashes in commercial service in the first 15 years after it was introduced in 1994. But, paradoxically, there is a risk to building a plane that protects pilots so assiduously from even the tiniest error. It means that when something challenging does occur, the pilots will have very little experience to draw on as they try to meet that challenge.
The complication facing Flight 447 did not seem especially daunting: thunderstorms over the Atlantic Ocean, just north of the equator. These were not a major problem, although perhaps Captain Dubois was too relaxed when at 11.02pm, Rio time, he departed the cockpit for a nap, leaving the inexperienced Bonin in charge of the controls.
https://www.theguardian.com/technology/2016/oct/11/crash-how-computers-are-setting-us-up-disaster
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