Responding to a spate of fatal emergency medical helicopter accidents, a federal safety panel said Tuesday aviation officials are not acting quickly enough on proposals to prevent crashes.

The five-member National Transportation Safety Board in January 2006 urged the Federal Aviation Administration to take a series of steps to improve the safety of EMS helicopter flights.

At a meeting Tuesday, the safety board acknowledged that the FAA is working on the proposals, but not quickly enough. Over the past 11 months, nine emergency medical helicopters have crashed, killing 35 people.