This Massive Hangar Bay Is Where The USAF Gives Its Biggest Jet A Tune-Up

The USAF’s biggest aircraft, the giant C-5 Galaxy, is not known for its reliability or ease of maintenance, although some of these concerns are being addressed with the new C-5M upgrade configuration. Still, these behemoths need a lot of TLC, and much of that work is done periodically at Dover Air Force Base’s Maintenance Squadron Isochronal (ISO) Maintenance Dock.


This huge hangar bay is equipped with all the scaffolding and tools needed to partially disassemble a C-5 and put it back together in far better condition than when it arrived. According to the USAF:

“In an effort to maximize the lifespan of the C-5 fleet, the aircraft goes through a series of inspections that vary in recurrence and depth; pre-flight, home-station check, Maintenance Steering Group-3 Minor, MSG-3 Major and Programmed Depot Maintenance.

All C-5 aircraft in the inventory undergo an eight-year scheduled maintenance timeline through the MSG-3 process. The cycle for these inspections goes as such: Programmed Depot Maintenance, Minor ISO, Major ISO, Minor ISO then starting back at PDM. Each inspection is two years apart and continues for the lifecycle of the weapon system. Dover AFB has the only facility in the Air Force that is able to conduct Major ISO inspections.

The MSG-3 Major inspection takes approximately 55 days, depending on what services and repairs the aircraft needs. Maj. James Wall, 436th MXS commander, said at the 55-day rate, the ISO dock is able to turn out nine aircraft a year, which keeps the entire C-5 fleet on its eight year maintenance cycle.

During an ISO inspection, aircraft maintainers strip down the C-5 looking for any deficiencies, faults, cracks or any other problem in every system and of the aircraft.”

Programmed Depot Maintenance occurs over at Warner Robins Air Logistics Center in Georgia, which is the most invasive of the C-5’s maintenance routines. Yet by keeping the C-5 in good condition between its visits to the depot, work there will take less time and the USAF will be able to get more out of the aircraft that have in the meantime.

Nothing in the USAF’s inventory can move what a C-5 can, and the type will continue to soldier on for decades to come (2040 and possibly beyond). This means that Dover AFB’s ISO dock’s work will be absolutely essential to keep the smaller, but more capable C-5 fleet flying far into the future.


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Photos via USAF

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