Plane speed systems failures discovered

Washington: On at least a dozen recent flights by US jetliners, malfunctioning equipment made it impossible for pilots to know how fast they were flying, federal investigators have discovered. A similar breakdown is believed to have played a role in the Air France crash into the Atlantic that killed all 228 people aboard in June.

The discovery suggests the equipment problems are more widespread than previously believed. And it gives new urgency to airlines already scrambling to replace air sensors and figure out how the errors went undetected despite safety systems.

The equipment failures, all involving Northwest Airlines Airbus A330s, were brief and were noticed only after safety officials began investigating the Air France crash and two other recent in-flight malfunctions.

The failures were described by people familiar with the investigation who spoke only on condition of anonymity because they were not authorised to comment publicly.

Like the fatal Air France flight, the newly discovered Northwest incidents and the two other malfunctions under investigation all involved planes with sensors made by the European electronics giant Thales Corp. Thales officials declined to comment. The company has previously said its sensors were made to Airbus specifications.

The Federal Aviation Administration hasn't issued a safety directive, but spokeswoman Laura Brown said the agency hopes to have one soon.