BAD HARDWARE WEEK

Could a Computer Glitch Have Brought Down Air France 447?

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 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.
The Air France plane that crashed into the Atlantic this week was awaiting replacement of a speed sensor that investigators identified as a likely contributor to the accident.

The sensor, made by Thales SA, gave inconsistent readings on the speed of the Airbus A330 jet en route to Paris from Rio de Janeiro June 1. Airbus SAS had advised airlines more than a year ago to replace the sensors on A330 jets with models that are less vulnerable to ice, two people with knowledge of the matter said yesterday.
France’s chief crash investigator today told journalists at a briefing near Paris that the failure of the air sensor to convey reliable speed data may have kicked off the chain of events that led to the deaths of all 228 people aboard.