RENO, Nev. (AP) - A preliminary report by the National Transportation and Safety Board does not say why a medical helicopter crashed Nov. 14 into a hilly area north of Reno near the Nevada-California state line.

All three crew members - the pilot, flight nurse and paramedic - were killed.

The report says the pilot never contacted air traffic control over the radio or activated his flight plan.

The helicopter had dropped off a patient at a Reno hospital and was returning to its base in Susanville, Calif., when it crashed on a hill slope and disintegrated as it continued down the hill.

It was the second fatal crash of a Mountain Lifeflight helicopter returning to Susanville after dropping off a patient at Renown Medical Center.