L3Harris has proposed a new avionics modernization package for the Boeing KC-135 Stratotanker, an aerial refueling aircraft that the US Air Force expects to keep in service beyond 2050.
The company disclosed the proposal on September 15. It would replace obsolete cockpit instruments with digital equipment and introduce an open architecture designed to simplify future upgrades.
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L3Harris says commercially available components and industry-standard interfaces could reduce dependence on individual suppliers and address the declining availability of replacement parts for existing avionics.
The proposal has not been announced as a US Air Force contract. It is one possible solution for sustaining KC-135 operations as the service faces a much longer transition away from the tanker than originally envisioned.
KC-135s could approach 100 years of age
Boeing built the KC-135 between 1956 and 1965, which means some surviving aircraft could approach a century since manufacture if they remain operational into the 2050s.
The US Air Force has already completed the Block 45 cockpit modernization across the KC-135 fleet. That upgrade introduced digital engine instruments, a radar altimeter, a modern flight director and an improved autopilot.
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Other changes are underway or planned, including new communications and networking capabilities. L3Harris is proposing a further modernization based on a government-owned architecture and technology already used on other C-135 variants.
The company says its package could reduce maintenance risk and aircrew workload while allowing new capabilities to be incorporated without a major redesign of the cockpit.
KC-46 cannot replace KC-135s quickly enough
The longevity of the KC-135 is closely linked to the pace at which the US Air Force can introduce replacement tankers.
Boeing's KC-46A Pegasus is replacing part of the KC-135 inventory, but the Air Force plans to retire aircraft largely on a one-for-one basis with incoming KC-46s through the late 2030s. The service intends to maintain a minimum tanker inventory of 466 aircraft.
Beyond the KC-46, the Air Force has been studying its future aerial refueling requirements and the Next-Generation Air-refueling System, or NGAS. The schedule for a future tanker leaves the KC-135 with a role for decades.
Air Mobility Command has previously acknowledged that additional service-life work could become necessary as the Air Force determines how to bridge the period between current tankers and their eventual successor.
L3Harris already has experience modifying aircraft from the C-135 family. The company says it has completed mission-system upgrades for C-135 variants operated by the US Air Force and the UK's Royal Air Force.
