Here's some info about the C-5 AMP program from the GlobalSecurity.org website.
C-5 modernization encompasses both the Avionics Modernization Program (AMP) and the separate Reliability Enhancement and Re-engining Program (RERP) denoted C-5 AMP/RERP. The full modernization effort incorporates a "glass cockpit" with digital avionics, a new aircraft propulsion system, and reliability improvements. Modified commercial engines, nacelles, thrust reversers, and pylons will be integrated into the legacy C-5 airframe. The anticipated performance improvements are intended to optimize cargo carrying capabilities, to include fully loaded take-offs and landings on relatively short runways, and to meet the performance requirements of the Global Air Traffic Management initiative. Additionally, the re-engining is intended to provide significant reliability, maintainability, and availability improvements. A commercial engine support concept (including two levels of maintenance and warranties) will be integrated into the C-5 logistics support system infrastructure. Candidate subsystems for reliability enhancement include the flight control, hydraulics, environmental control, electrical, and fuel systems. Specific upgrades and the extent of the expected reliability improvement will be identified from a series of trade studies.
