Published: May 12, 2011 6:09 PM EDT
Updated: May 12, 2011 3:09 PM EDT

WASHINGTON (AP) - A government watchdog says he doesn't know why errors by air traffic controllers increased 53 percent last year, but that an inexperienced work force could be one reason.

Department of Transportation Inspector General Calvin Scovel says the Federal Aviation Administration is placing too many inexperienced controllers at some of the nation's busiest and most complex air traffic facilities.

Scovel told a Senate Appropriations subcommittee Thursday that his office is investigating the rise in errors.

FAA Administrator Randy Babbitt attributed the increase to new practices that encourage controllers to report more errors without fear of punishment for the mistakes. He also said new equipment at some radar facilities is able to spot more instances of planes coming too close together - errors that probably went unnoticed before.

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