An MV-22B Osprey crashed in shallow water off Okinawa, Japan, on Tuesday, the latest in a series of Marine aviation mishaps.

All five crew members aboard the Osprey were rescued by the Air Force's 33rd Rescue Squadron at Kadena Air Base, Okinawa, III Marine Expeditionary Force announced.

The crew members were being treated at the United States Naval Hospital at Camp Foster, according to a III MEF news release, which did not specify the severity of their injuries. They are with Marine Aircraft Group 36, 1st Marine Aircraft Wing.

"A formal investigation into the mishap has been launched," the news release says. "There will be no further information on the cause of the mishap until the investigation is complete."

Tuesday’s crash is the latest serious incident for Marine aviation so far this fiscal year, which began in October. Five other incidents have been classified as Class-A mishaps, which involve loss of life or damage of more than $2 million.

Most recently, Marine Capt. Jake Frederick was killed on Dec. 7 when his F/A-18C crashed about 120 miles southeast of Iwakuni, Japan. Frederick was also assigned to 1st Marine Aircraft Wing.

October saw three Class A mishaps, according to the Marine Corps. On Oct. 20, a CH-53E Super Stallion from Marine Heavy Helicopter Squadron 465 clipped a building with its main rotor while flying a training mission as part of the Weapons and Tactics Instructor Course near Yuma, Arizona. No injuries were reported.

On Oct. 25, an F/A-18C with Marine Fighter Attack Squadron 251 crashed while landing at the Twentynine Palms Expeditionary Landing Field in California, according to the Marine Corps. The pilot ejected safely.

Two days later, a fire broke out in the weapons bay of an F-35B with Marine Fighter Attack Squadron 501 during a training flight, but the pilot managed to safely land the plane at Marine Corps Air Station Beaufort in South Carolina. The incident was the first Class A mishap for the F-35B.

And on Nov. 9, two F/A-18Cs collided during a training mission over the Pacific. Both pilots escaped injury. One pilot ejected and the other safely landed at Naval Air Station North Island in California.

Marine aviation is facing a perfect storm of aging aircraft worn out from more than a decade of constant combat operations, budget cuts that have delayed badly needed repairs, and delays in the F-35 program, which will eventually replace all of the Marines’ F/A-18 Hornets, EA-6B Prowlers and AV-8B Harrier II jets.

The Corps is working furiously to keep its planes and helicopters flying longer than expected while buying new aircraft.

Marine Commandant Gen. Robert Neller has said the service has a plan to increase the number of flyable aircraft and flight hours that pilots get, but the process is moving slower than the Corps would like.

"We are in a pretty tough place and we had to develop a plan and our plan is happening. But it’s not happening fast enough," Neller told reporters on Dec. 7. "The bottom line is we’ve got to recapitalize aviation. We need to replace our airplanes. We’ve got to get better parts support. We’ve got to get more hours so if there is a human factor involved in this, we make sure that the air crew have been flying so we drive that down."