There is a bonding system for handling parts and equipment to be used in Presidential dedicated helicopters that assures the very best in quality and assurance. Briefly, parts are removed at half-life and replaced. A part is sent to the OEM and is remanufactured to originally new standards, and it is tracked and kept in bonded rooms until it is reinstalled on the helicopter. In this fashion, the VH-3D Presidential dedicated helicopter does not age. It is constantly being renewed and is now scheduled to continue flying until 2014.
Most helicopters are much more complex than airplanes with many moving parts.
HMX-1 expressed grave concern that some may not understand the length to which the USMC goes to insure the highest of reliability for the Presidents helicopters. Only the VH3D and the VH-60M helicopters have that degree of reliability and other helicopters should not be used to provide executive airlift support for the President. The WHMO expressed this same concern.