A medical helicopter crashed early Friday in northern Arizona as it was landing to pick up a patient, hurting three crew members aboard, one critically, officials said.

The pilot, flight paramedic and flight nurse were hurt in the crash near Ash Fork, according to Jonathan Collier, a spokesman with Air Evac Inc.

They were taken about 50 miles east to Flagstaff hospital, where one was in critical condition Friday afternoon. Another crewman was in serious condition, and the third, the pilot, was in good condition.

Collier said their families had asked that they not be immediately identified.

The crew of the Eurocopter AS350 were on their way to pick up a motorcycle accident victim and were landing about 2 miles west of Ash Fork when the accident happened, Federal Aviation Administration spokesman Ian Gregor said. The FAA will investigate.

An ambulance crew and members of the Juniper Hills Fire Department were waiting for the chopper when it tried to land in a field about 3:30 a.m.

"When he came in there was lots of dust and dirt, and we believe he was browned out," said Denny Davenport, chief administrator of the fire department. A "brownout" refers to circumstances in which a helicopter pilot loses bearings in poor visibility.

The flight originated from Air Evac's base at the Prescott airport, one of several it runs in Arizona.

Air Evac is a subsidiary of Louisiana-based PHI Inc., which provides helicopter services for the energy industry and has a medical evacuation division.