ADELANTO - Authorities say the three men killed in a fiery helicopter crash in San Bernardino County were headed for an air show - one of the few places their vintage aircraft was allowed to fly.

Ian Gregor of the Federal Aviation Administration said Sunday that the 1951 Piasecki PV-18 was classified as "experimental," meaning it could fly only in limited circumstances.

Organizers say the helicopter was headed for display at an annual air and classic car show in Rubidoux.

Authorities say the men's badly burned bodies could take several days to identify.

The helicopter is registered to Joseph William Pike, of Victorville. Phone messages left at Pike's home were not returned.

The helicopter left Adelanto Airport early Saturday, hit power lines, crashed and caught fire, killing all three aboard.