The CH-53 is used by the USMC as a heavy lifter, capable of carrying up to 32,000 lbs (14,500 kg) up to 57.5 miles (92 km), dropping it off, and returning. It's normally used for transporting supplies, artillery equipment, light armored vehicles, or retrieving downed aircraft (including another CH-53). The USMC is planning on upgrading its existing 172 CH-53E's to a new CH-53X model to extend its service life to 2025. Upgrades would include new engines, improved rotor technology, a new cockpit, and increased payload capacity. However, in March 2004, a USMC analysis determined that a new airframes would be more cost effective than upgrading existing 53E's. Service entry for the 53X is planned for 2015.