Safety Of 737s In Question

(CBS)  There are troubling new questions about the world's most widely used airliner, the Boeing 737. Federal investigators are looking into an incident involving Metrojet, the low-cost arm of US Airways.

Metrojet flight 2710, bound from Orlando to Hartford, was at 33,000 feet over the Maryland coast Tuesday when the jetliner unexpectedly jerked to the right, CBS News Correspondent Bob Orr reports.

Sources tell CBS News that preliminary information from the flight data recorder shows that the plane's nose abruptly moved to the right, and the right wing dipped slightly.

Inside the cockpit, the autopilot compensated for the right roll by turning the control wheel to the left, but the crew reported the rudder pedals had moved on their own.

The pilots disengaged the autopilot, regained control, and made an emergency landing at Baltimore-Washington Airport. No one on board was hurt.

Investigators now want to know if the mysterious in-flight movement was caused by what's called an "uncommanded movement" of the plane's rudder.

It's a critical question.

Air-crash investigators have long believed, but have not yet proven, that uncommanded rudder movements played a key role in two unsolved plane crashes, in Colorado Springs and Pittsburgh.

In 1997 the FAA ordered a fix, requiring airlines to replace parts of the suspect rudder system on all 737s. The jet involved in yesterday's incident had already been retrofitted.

That's the most troubling part. If a rudder problem played any role in the Metrojet incident, it's possible that the FAA fix is incomplete or even incorrect, and possible that a hidden flaw on the 737 remains.