On August 2, Lockheed Martin handed over the 52nd C-5 Galaxy to undergo the U.S. Air Force’s RERP (reliability enhancement and re-engining program) upgrade, after which the aircraft are known as the C-5M Super Galaxy. With the RERP program complete, the Air Force’s fleet of C-5Ms is expected to serve into the 2040s.

The final C-5M conversion was ferried from Lockheed Martin’s Marietta, Georgia, facility to Stewart AFB, New York, where it will receive an interior paint overhaul. It will then be delivered to Air Force Reserve Command base at Westover ARB (air reserve base), Massachusetts, where it will be operated by the 439th Airlift Wing.

An overhaul of the Galaxy fleet began in the 1990s, when Air Mobility Command found that the majority of aircraft still had around 80 percent of their service life remaining. In 1998, the C-5 AMP (avionics modernization program) began. This upgraded the avionics to comply with GATM (global air traffic management) requirements and installed new navigation, communications, and autopilot systems. The flight deck was outfitted with flat-panel displays. The first C-5 AMP flew on December 21, 2002.

In the meantime, Lockheed Martin began studying the RERP upgrade in 2001, resulting in the first flight of a development C-5M on June 19, 2006. The main feature of the RERP was the substitution of the original General Electric TF39 engines with the same company’s F138 (CF6-80C2L1F). De-rated to 50,000 lb thrust in the C-5M installation, the F138 provides 22 percent more thrust than the TF39, resulting in improvements in takeoff performance and climb rate, increased payload, and more economical cruise. The engines are also compliant with FAA Stage 4 noise requirements. RERP also covered a host of other enhancements—over 70 in total—with changes to the airframe structure, landing gear and flight controls, as well as environmental, pneumatic, fuel, hydraulic, and electrical systems.

Between 1968 and 1973, Lockheed built 81 of the original C-5As, re-opening the line to build 50 slightly improved C-5Bs between 1985 and 1989. Two C-5As were modified to C-5C configuration, also referred to as C-5A (Space Cargo Modified). These aircraft had the rear passenger accommodation deck deleted and the rear cargo door split into two. They were operated from Travis AFB, California, in support of Department of Defense and NASA space programs.

All surviving C-5s received the AMP upgrade, but only one C-5A—plus the two C-5Cs— went through the RERP process. Following considerable debate, it was not decided to proceed with RERP until 2008, with the upgrade being primarily aimed at 49 C-5B airframes. The last of the original C-5As was withdrawn from service in September 2017.

Deliveries of operational C-5Ms got underway to Dover AFB, Delaware, on February 9, 2009. Other bases operating the Super Galaxy are Westover and Travis, while training is undertaken at San Antonio-Lackland, Texas. They are operated by both active-duty and reservist units.

Underlining the capability of the C-5M are 89 FAI-certified records, the most held by any aircraft type. In operational terms, the C-5M is one of a tiny handful of aircraft that can carry main battle tanks, being able to haul two M1A1 Abrams tanks over intercontinental distances. With this capability, the Super Galaxy remains vital to the U.S. Air Force’s mission to rapidly deploy large equipment that would otherwise rely on sea transportation.