July 18, 2008: The jet engines (that drive the propellers) in the U.S. Marine Corps new tilt rotor V-22 aircraft, are wearing out ahead of schedule. Overall, V-22 engines last nearly 500 hours (and some have gone over 600 hours), but in Iraq, the average is not quite 400 hours.

The MV-22s used by the marines can carry 24 troops 700 kilometers (vertical take-off on a ship, level flight, landing, and return) at 390 kilometers an hour. The V-22 is replacing the CH-46E helicopter, which can carry 12 troops 350 kilometers at a speed of 135 kilometers an hour. The V-22 can carry a 10,000-pound external sling load 135 kilometers, while the CH-46E can carry 3,000 pounds only 90 kilometers.

The marines began using the MV-22 in Iraq late last year, and have been satisfied with the results. However, it was expected that there might be problems with engine durability. Every other vehicle that uses a gas turbine engine in Iraq (from M-1 tanks to C-17 jet transports) have reported increased wear on their engines because of the copious and continuous dust and sand in Iraq.

For the V-22, another problem is that even frequent inspections won't always catch an engine that's about to die from too much dust and sand. Several MV-22s in western Iraq (Anbar province, where marine MV-22s have been operating) have experienced engine failures. There have been no crashes, but there have been emergency landings (followed by quick engine changes so the $70 million, 20 ton aircraft could get home under its own power). The Rolls Royce T-406 engines weigh about a ton each, and put out 6,000 horsepower. Marine maintenance crews are trained to put a spare engine inside a V-22, along with needed tools, fly out to where another V-22 has made an emergency landing, do the engine change quickly, and get back to base in one piece.