Only four of every 10 V-22 Osprey tilt rotor aircraft can fly in combat operations, according to a Seapower magazine article that cited Marine Corps statistics. As the Osprey’s primary user, the Marine Corps told Seapower that while the service’s entire MV-22 fleet is operating at around 60 percent availability, the Block C variation is flying at a mission-capable rate of 80 percent – right at the readiness parameter set by former Defense Secretary James Mattis. Both the Marine Corps and Boeing are working to improve the Osprey’s readiness numbers. Capt. Christopher Harrison, a Marine Corps spokesman, pointed out that the Osprey remains the service’s “most in-demand and deployed aircraft.”