Could a Computer Glitch Have Brought Down Air France 447?

[RamboLiberal]

As the French team leading the investigation into the Air France Flight 447 crash works through the multitude of likely and less likely disaster scenarios — from the repercussions of stormy conditions to an act of terrorism — perhaps among the most difficult to assess will be possible flight computer malfunctions. Air France CEO Pierre-Henry Gourgeon noted on Monday that immediately preceding AF447's disappearance, automatic messages sent by the plane indicated "multiple technical failures." As details emerge regarding these messages, experts will struggle to understand whether they were the inevitable result of the plane's breaking up or indicators of the failures that led to the accident.

Gourgeon said the "succession of a dozen technical messages" sent by AF447 showed that "several electrical systems had broken down" immediately prior to the crash. A chronology of these messages acquired by the São Paolo daily Jornal da Tarde show that moments before the plane is believed to have plunged into the ocean, its autopilot became disengaged and the plane sustained damage to its stabilizing controls and flight systems, as well as a failure of the systems that were monitoring the aircraft's speed, altitude and direction: the ADIRU (Air Data Inertial Reference Units) and the ISIS (Integrated Standby Instruments System). These are key components in fly-by-wire systems, which use computers and wires instead of mechanics and hydraulics to control a plane's flight.

On Wednesday, TIME revisited an October 2008 incident in which a Qantas Airbus 330 — the same model as AF447 — unexpectedly went into a brief yet harrowing 20-second nosedive, causing multiple injuries and requiring an emergency landing. The investigation that followed blamed an ADIRU failure for the 330's uncommanded dive: one of the plane's three ADIRUs, which are designed to help the plane's flight-control computer fly the plane safely, began sending erroneous data spikes to the flight-control computer. Instead of deferring to the information of the two functioning ADIRUs as it normally should, the computer acted on the false data and sharply altered the plane's course, with near disastrous results. It was later learned that the same plane had experienced a similar occurrence in September 2006, as had three other flights. All those planes carried the same brand and model of ADIRU, as do more than one-third of the 330s and 340s in the Airbus fleet. So if this model of ADIRU has a history of failure, why does Airbus continue to fit them in its 330s and 340s?

According to Airbus spokesman Justin Dubon, any comparisons between the Qantas and Air France flights are fundamentally misleading. "One thing that has got to be clear is that there are more than one manufacturer of ADIRUs, and the ADIRU manufacturer for the Qantas case is not the same for the Air France case," he tells TIME. As reported in the aviation trade magazine Air Transport News, manufacturer Northrop Grumman makes the ADIRUs for Qantas, and Honeywell for Air France. "There are no similarities in ADIRUs between the two cases," says Dubon.

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For now, Gourguechon(International Secretary General of the French Pilots Union (SNPL) and an Air France pilot of 10 years) finds the endless speculating exhausting. "Initially we were talking about electrical failure, yesterday we were talking about icing conditions, tomorrow we will talk about something else," he says. "ADIRU failure is as credible as very bad weather, hail, an electrical failure. I would not give priority to one scenario."

http://www.time.com/time/world/article/0,8599,1902907,00.html?imw=Y

[anigbrowl]

1. Insufficient data

I knew newspapers and magazines need to fill copy holes and people want to know what's going on with this story...but given the remoteness of the incident and its ocean location, right now it's all so speculative that I'm turning away from it until they can assemble more information. We might never get an answer of this one.