The MV-22 Osprey is a tilt-rotor assault aircraft intended to replace the CH-46 Sea Knight fleet. Its engine nacelles rotate 90-degrees to make the vehicle capable of vertical flight, short takeoff, or act as a turboprop aircraft. The Osprey is able to cruise at a speed of 240kts. It has a ferry range of up to 2,100 nm. With 24 combat troops or 6,000lbs (2727kg), the MV-22 has a range of 430 nm and with 8,300lbs (3772kg) has a range of 220 nm. Unfortunately, safety and mechanical issues and the subsequent design alterations have substantially slowed down the introduction of the Osprey. Currently, it is hoped to be operationally capable by 2006. The USMC has plans for a total of 360 MV-22's.