The legendary longevity of the Lockheed Martin C-130 Hercules is not just the result of excellent design and manufacture. It’s also due to careful planning and management, including well-timed replacement of critical structural components.
Some of these components, including the centre wing box, require extensive experience and specialist equipment to replace, which is why only a few organisations around the world are trusted to undertake this work.
Marshall is one of those trusted few—and here’s why.
The C-130 is a remarkably long-lived asset that provides immense value to any cost-conscious operator; in fact, some aircraft built during the 1950s are still in operation nearly 70 years later.
Over the decades, the C-130 has served as the logistical backbone of military and civilian operations, flying long hours in some of the world’s most forbidding environments. These missions will inevitably put extreme wear and tear on even the sturdiest airframe.
This is why the major components or systems on all aircraft, including the C-130, are subject to operational limits. These limits are established through extensive analysis and testing, and reflect how structural integrity and mechanical reliability will degrade over time given the conditions an aircraft encounters.
Once these operational limits have nearly been reached or an inspection has identified signs of fatigue, an aircraft may fail to meet safety standards as safety or performance may be compromised. At this point, the affected components or systems will require overhaul and/or replacement to ensure the aircraft remains airworthy.
Certain critical component or systems are designated “lifed articles,” meaning their operational limits are specified in terms of total flight hours or age. One such lifed article is the C-130’s centre wing box—a major primary structure that connects the aircraft’s outer wings to the fuselage. The centre wing box bears a significant operational load and experiences exceptional stress during flight, especially in demanding environments or during extended flying hours.
The lifespan of the original centre wing box for a C-130 Hercules is roughly 20 years, depending on how the aircraft is operated. Once a centre wing box has reached its end of life, it will need to be replaced in order for the aircraft to remain airworthy.
Lockheed Martin has developed a highly cost-effective solution for any fleet operator operating a C-130 with an ageing centre wing box.
Designed and produced by Lockheed Martin, the new enhanced service life centre wing box can effectively re-life an aircraft once installed, potentially extending its useful lifespan by more than 20 years.
However, replacing a centre wing box is not a simple process involving removing a premade component and swapping in a new one: it is the aerospace equivalent of invasive spinal surgery, and can only be attempted by a team with extensive engineering capability and specialist equipment. From start to finish, it is a combination of highly complex tasks that demand deep knowledge of the airframe and avionic components to ensure it is carried out correctly and safely.
C-130 centre wing replacement
To accommodate the unique risks and requirements of centre wing box replacements, Marshall has developed a range of bespoke tooling and equipment, alongside a set of detailed operational instructions. The Marshall team works with certified Lockheed Martin kits containing all necessary parts and components, om addition to service bulletins outlining the step-by-step stages for performing the replacement.
The first step in the process is to remove the components that surround the centre wing box on the aircraft, including the outer wings, fuel systems, internal wiring and plumbing. At this stage, the aircraft will be jacked, levelled and tied down to the hangar floor to support the airframe; this is a vital step in the process to avoid structural damage such as twisting to the fuselage.
Once this is all in place and the airframe is secure, the old centre wing box can be detached and removed vertically using an overhead crane. Precision is particularly important during the removal, as any incorrect or sudden movements can cause significant damage to the aircraft.
All of the interfacing structures and main frames are then thoroughly inspected for damage while the centre wing box is no longer in place. Any issues can be addressed and rectified before moving onto the next stage in the process.
At the same time, existing 20-year-old plumbing (including auxiliary fuel tank cells) and wiring within the centre wing box will be replaced, with removed hardware/components available for servicing and retention as spare stock. Likewise, the team replaces the centre-wing-to-fuselage fairings with removable fairings to reduce the time taken by future maintenance and inspections.
The new enhanced service life centre wing box is now ready to be positioned and installed, and the internal wiring, plumbing and surrounding components are reconnected.
Once the new centre wing box is installed, Marshall will perform pressurisation tests, engine ground runs and flight tests to ensure the new centre wing box and rebuilt systems are performing as expected. This process will be repeated until all fault codes have been satisfied, and the aircraft can be signed off, repainted and released back to the customer.
Since the 1970s, Marshall has completed nearly 80 centre wing box replacements on both legacy C-130 models and the current production model C-130J Super Hercules, extending the collective lifespans of these aircraft by at least 1,600 years.
To date, we remain the only organisation outside the United States to have successfully completed a C-130J centre wing box replacement.
These achievements have earned us formal recognition as the world's first authorised Centre of Excellence for C-130 centre wing box replacements—a testament both to our engineering capabilities and to the strength of our relationship with Lockheed Martin.
“Recognizing Marshall as the first Lockheed Martin-approved Centre of Excellence for its work leading the C-130 centre wing box replacement program is a natural choice.
“Marshall is a vital part of the C-130 Hercules community because it embodies a commitment to excellence in C-130 maintenance and support, ensuring these versatile aircraft continue to serve operators reliably and efficiently in meeting global mission demands.”
Rod McLean
Vice President and General Manager, Air Mobility & Maritime Missions, Lockheed Martin Aeronautics
Lockheed Martin C-130 taking off at Cambridge Airport
