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Higher And Higher
November 21, 2009: Now that the U.S. Marine Corps has a squadron of ten MV-22 tilt rotor transports in Afghanistan, these aircraft are being put to work by taking advantage of some unique capabilities. For example, MV-22s operate more effectively in the thin air of the mountains than the helicopters currently used. However, above 20,000 feet (6,500 meters), the MV-22s can only carry cargo, as there is no oxygen for passengers (although this can be arranged for special situations.)

The MV-22s, which fly higher and faster than the helicopters they replace, are less vulnerable to ground fire. MV-22s were only fired on a few times in Iraq, and none of the aircraft were hit. The high speed and altitude (at least 9,000 feet, or 3,000 meters), kept the aircraft out range of most enemy weapons. Helicopters fly lower and slower. To do otherwise would further reduce the range of a helicopter. A big advantage in Afghanistan is the higher speed (about twice that of helicopters), enabling reinforcements to reach their objective in a more timely fashion. MV-22s also have longer range than helicopters, meaning more of Afghanistan is within range of fast moving reinforcements (of troops and supplies.)

The MV-22s proved easier to maintain than the CH-46 aircraft they are replacing. The MV-22s needed 9.5 man hours of maintenance for each hour in the air, versus 24 hours of maintenance for each hour the CH-46s fly. These helicopters are all over twenty years old, which adds a few hours to their maintenance requirements. While the MV-22 required less maintenance than expected, the dust and sand in Iraq led to some engines being replaced earlier than expected. That problem has been tended to, so the MV-22s in Afghanistan will have less of a problem.

Some of the MV-22s sent to Afghanistan are 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.
From http://www.strategypage.com/htmw/htairmo/articles/20091121.aspx