of vertical separation between each other to avoid each other's rotor wake, which causes turbulence and potentially control loss. Avionics The V-22 is equipped with a glass cockpit, which incorporates four multi-function displays (MFDs, compatible with night-vision goggles) and one shared central display unit, to display various images including: digimaps, imagery from the Turreted forward-looking infrared system primary flight instruments, navigation (TACAN, VOR, ILS, GPS, INS), and system status. The flight director panel of the cockpit management system allows for fully coupled (autopilot) functions that take the aircraft from forward flight into a hover with no pilot interaction other than programming the system. The fuselage is not pressurized, and personnel must wear on-board oxygen masks above 10,000 feet. The V-22 has triple-redundant fly-by-wire flight control systems; these have computerized damage control to automatically isolate damaged areas. With the nacelles pointing straight up in conversion mode at 90° the flight computers command it to fly like a helicopter, cyclic forces being applied to a conventional swashplate at the rotor hub. With the nacelles in airplane mode (0°) the flaperons, rudder, and elevator fly similar to an airplane. This is a gradual transition, occurring over the nacelles' rotation range; the lower the nacelles, the greater effect of the airplane-mode control surfaces. The nacelles can rotate past vertical to 97.5° for rearward flight. The V-22 can use the "80 Jump" orientation with the nacelles at 80° for takeoff to quickly achieve high altitude and speed. The controls automate to the extent that it can hover in low wind without hands on the controls. New USMC V-22 pilots learn to fly helicopter and multiengine fixed-wing aircraft before the tiltrotor. Some V-22 pilots believe that former fixed-wing pilots may be preferable over helicopter users, as they are not trained to constantly adjust the controls in hover. Others say that experience with helicopters' hovering and precision is most important. the US military does not track whether fixed-wing or helicopter pilots transition more easily to the V-22, according to USMC Colonel Matthew Kelly, V-22 project manager. He said that fixed-wing pilots are more experienced at instrument flying, while helicopter pilots are more experienced at scanning outside when the aircraft is moving slowly. Armament The V-22 can be armed with one 7.62×51mm NATO (.308 in caliber) M240 machine gun or .50 in caliber (12.7 mm) M2 machine gun on the rear loading ramp. A 12.7 mm (.50 in)