The U.S. Marine Corps have found their new MV-22 tilt-rotor transport very useful, and much more expensive to maintain. While the ground crews have managed to keep the MV-22s available 65 percent of the time, it hasn't been easy, or cheap. Operating costs have been $11,000 an hour, twice what was expected. The main reason has been some parts wearing out much faster (in one case, ten times faster) than expected. This led to a shortage of parts, and lots more work (replacing worn parts) for the maintainers. Still, troops and commanders are enthusiastic about the MV-22 because, in combat, "speed is life." The MV-22, which lands and takes off like a helicopter, flies twice as fast as a helicopter.
When marines are told that they could have twice as many cheaper helicopters, instead of the more expensive MV-22, the response is negative. The higher speed and cruising altitude is seen as a lifesaver, something that twice as many slower helicopters won't provide.
As a result of the additional speed, marines have found the MV-22 useful in combat operations, in addition to just transportation. For example, the MV-22s high speed enables them to be more effective in getting quick reaction forces into position to cut off and capture fleeing Taliban. The high speed, and higher flying altitudes, make them safer from enemy ground fire. Some MV-22 have come under fire, but none have been hit, yet.
MV-22s first went to a combat zone in late 2007, when they were sent to Iraq. That's where it was first noted how the high speed and altitude (about 3,000 meters/9,300 feet), kept the aircraft out range of enemy weapons. Helicopters fly lower and slower. To do otherwise would further reduce the range of a helicopter.
The MV-22 can also defend itself. MV-22s sent to Afghanistan can be equipped with a GAU-2B machine-gun fitted to the bottom of the aircraft. The GAU-2B is a remote control turret using a six-barrel 7.62mm machine-gun. This system has a rate of fire of 3,000 rounds per minute (50 per second), and max range of 1,500 meters. The system weighs a few hundred pounds and includes 4,000 rounds of ammo. A member of the crew uses a video game like interface to operate the gun.
The marine MV-22s can carry 24 troops 700 kilometers (vertical take-off, level flight, landing, and return) at 400 kilometers an hour. The MV-22 is replacing the CH-46E helicopter, which can carry 12 troops 350 kilometers at a speed of 200 kilometers an hour. The MV-22 can carry a 10,000-pound external sling load 135 kilometers, while the CH-46E can carry 3,000 pounds only 90 kilometers.