WASHINGTON — A Marine Corps aviation squadron known as the Thunder Chickens will head to Iraq in September to introduce the Bell-Boeing V-22 tilt-rotor aircraft to combat, ferrying troops and cargo across a turbulent province considered the heart of the country's Sunni insurgency.

Ten V-22 Ospreys will be based at the al Assad Marine Corps air station in Anbar province after the 171-member Marine Medium Tiltrotor Squadron 263, or VMM 263, lands in Iraq next fall. The unit has been training for more than a year out of its home base at New River Marine Corps Air Station, N.C.

Gen. James T. Conway, commandant of the Marine Corps, announced the time and date of the first V-22 deployment at a Pentagon briefing Friday, joining other Marine Corps officials and V-22 boosters in expressing confidence that the aircraft has fully resolved the problems of a troubled past and is ready for war.

After the announcement, members of the news media were taken to a Marine base in Quantico, Va., for a ride aboard an Osprey.

The aircraft, co-produced by Bell Helicopter Textron and Boeing Rotorcraft Systems, takes off and lands like a helicopter and flies like an airplane, reaching speeds and distances well beyond those of traditional helicopters.

The Osprey program has struggled to survive at times and was grounded for 18 months after two fatal crashes in 2000. Critics continue to question the Osprey's suitability for combat, but the Pentagon announcement Friday constituted an unqualified endorsement of its airworthiness after an extensive redesign and more than 19,000 hours of flight tests.

"We think we can add a lot to the fight," said Lt. Col. Paul Rock Jr., commander of the Thunder Chickens, a nickname passed down from a predecessor squadron.

The squadron, which will represent the first wave of V-22 combat deployments, will be based in a hard-to-control province with more than 1 million Iraqis, a defiant Sunni Arab insurgency and one-time hot spots such as Fallujah and Ramadi.

Seven helicopters have been destroyed and others damaged during the war, Marine officials said Friday. But Lt. Gen. John Castellaw, deputy commander of Marine Corps aviation, said the Osprey is far more agile than the CH-46 helicopter, which it is replacing, and can fly high enough to escape missiles or small-arms fire.

The V-22 — known as an MV-22 in the Marine Corps — is designed to ferry 24 Marines at a time or haul up to 20,000 pounds of cargo at more than 250 mph, twice as fast as the Vietnam-era CH-46.

"It's harder to shoot a rabbit that's running than one that's sitting still," Castellaw said.

The Marines plan to buy 360 V-22s, the Navy is slated for 48 and the Air Force Special Operations Command will buy 50.

"This is one of the most important events in the history of the program," Bell spokesman Bob Leder said. "We're very enthusiastic."

Flying an Osprey is considered an elite assignment. The Thunder Chickens' 28 pilots, including two women, all volunteered and were chosen by a Marine selection board. Rock, 40, who goes by the call sign Rocket, has been flying V-22s since the late 1990s.

The VMM 263 descends from the original Thunder Chickens helicopter squadron, the HMM 263, which dates to the Korean War era. The earlier squadron and its fleet of CH-46 Sea Knight helicopters were phased out last year to make way for the new tilt-rotor unit, which was commissioned March 3. Eventually all six CH-46 squadrons at New River will become tilt-rotor units.

According to unit lore, the squadron initially was called the Thunder Eagles, but the name got mistranslated in Vietnam and the new moniker stuck.