Air France 447 - NTSB Investigates Speed Data On Airbus A330s

US aviation safety investigators are looking into possible anomalies with air speed and altitude indicators on two Airbus A330 jets, officials said Thursday.

The National Transportation Safety Board, which is helping French authorities determine if speed sensors were a factor in the crash of an Air France A330 this month, said it is also investigating incidents involving a TAM Airlines flight from Miami to Sao Paulo in May and a Northwest Airlines flight between Hong Kong and Tokyo Tuesday.

Both flights experienced cockpit readings showing a loss of primary speed and altitude information, the safety board said in a statement. Both planes landed without incident.

Investigators are looking at flight data recorder information as well as crew statements and weather information.

Airbus spokesman Clay McConnell said the manufacturer would "provide all support to the NTSB" as it reviews the two incidents. Further, the company said procedures are in place that would allow pilots to maintain safe operations in the event of unreliable air-speed data.

All 228 people on board Air France Flight AF447 were killed when the plane plunged into the Atlantic Ocean on a flight from Rio de Janeiro to Paris on June 1.

Crews have yet to recover the aircraft's flight data and voice recorders. But French investigators leading the probe said data transmitted from the doomed jet before it crashed indicated unreliable speed readings.

Investigators say it is too early to know if that data would prove central to the crash. Possible ice accumulation on pressure-based speed sensors has emerged as an issue in the investigation.

Due to questions about icing, Airbus recommended prior to the accident that airlines consider replacing speed sensors on long-haul planes, like the A330, which some airlines have done.

Airbus said the recommendation was related to aircraft performance, not safety.