Hurlburt Field, Florida (CNN) -- An Air Force CV-22 Osprey crashed Wednesday during a routine training mission north of Navarre, Florida, injuring five crew members aboard, a military official said.
The crash occurred about 6:45 p.m. at Hurlburt Field's Eglin Range, said Amy Nicholson, chief of public affairs at the airfield.
The five injured crew members were taken to an area hospital, Nicholson said. The extent of their injuries was not immediately known.
The cause of the accident is under investigation, she said.
The Osprey was assigned to the 1st Special Operations Wing, the Air Force said. The tilt-rotor aircraft can fly like an airplane and land like a helicopter.
The Army began developing the Osprey in 1982, though the program was nearly scrapped in 1989 when then-Secretary of Defense Dick Cheney sought to cancel it because of ballooning costs.
Questions were raised about the safety of the Osprey after two crashes, including one in 1992 at a Marine Corps air base in Virginia that killed the crew.
In late 2000, the Marine Corps grounded the Osprey fleet after two crashes -- one in Arizona that killed four crew members and 15 passengers, and another in North Carolina that killed the crew.
A redesign was ordered on the Osprey, and it resumed flights in 2002.
The Air Force began using Ospreys in 2008 after testing the aircraft in 2006. They were first deployed by the Marines in Iraq in 2007 after 18 years and $20 billion in development.
CNN's Mike Mount contributed to this report.