The U.S. Air Force and Navy may pursue separate aircraft for nuclear command and control missions for connecting ballistic missile sites and submarines to the president. In the meantime, the Navy is working with the Oklahoma City Air Logistics Complex (ALC), Boeing [BA] and Mississippi-based Vertex Company–a subsidiary of Vertex Aerospace, to replace corroded spar chords on the Navy’s E-6B Mercury Take Charge and Move Out (TACAMO) plane.

The E-6B, which had an original service life of 25,000 flight hours, is now to last 48,000 flight hours, which will likely mean that the plane remains in service until the late 2030s.

“The seal on the spar chord that holds the airframe wing skin to the airframe, we missed that seal when we were doing the E-6 service life extension,” Navy Capt. Adam Scott, the program manager of Naval Air Systems Command’s airborne strategic command, control and communications program office (PMA-271), said in a Feb. 2 telephone interview.

“Moisture is getting through that seal and we’re getting corrosion on the spar chord,” Scott said. “We’re having to replace the spar chords.” Scott praised the work that Oklahoma City ALC, Boeing, and Vertex in sustaining the E-6B, and said that despite the aircraft’s age the repair turnaround time at Oklahoma City ALC has not increased commensurately because of the work of the ALC, Boeing and Vertex.

As the Navy looked to buy new spar chords, material for new ones was not available, because of the plane’s design age, and the service looked to Boeing, which developed a new material so that the Navy had sufficient shelf stock for spar chord replacements. “Boeing answered the bell,” he said.

The Navy said last year that it plans to recapitalize the E-6B with the Lockheed Martin [LMT] C-130J airframe–a move that harks back to the time when EC-130Qs served as Navy TACAMO aircraft between December 1963 and August 1993. The larger E-6B, based on the Boeing 707 airliner designed in the 1950s, replaced the EC-130Qs in the early 1990s.

Asked whether there are risks with using a TACAMO airframe, such as the C-130J, that is smaller than the E-6, Scott replied that risks are always a part of such modernization programs and that the Navy is working to mitigate risk. The C-130J is the “right solution to accomplish the [TACAMO] mission set,” he said. One of the advantages of the C-130J is the ongoing production line, the plane’s “robust industrial base,” Scott said.

The Air Force, for its part, has said that it is undertaking a Survivable Airborne Operations Center (SAOC) program to replace the aging E-4B National Airborne Operations Center (NAOC), possibly with a used, commercial derivative aircraft (Defense Daily, Oct. 18, 2021).

The Air Force said that it intends “to pursue a full and open acquisition strategy for the entire weapon system using a very large platform.” While the Air Force and Navy have been exploring options for a joint replacement of both nuclear command and control planes under SAOC, the services now look as if they will buy different airframes.

The Air Force’s engineering and manufacturing development (EMD) phase for SAOC is to include 2-4 modified EMD aircraft, associated ground support equipment, and a SAOC WS (weapons system) production design.

SAOC is an ACAT 1D program–a category that includes programs with an estimated research and development expense of $525 million or more than $3 billion in procurement in fiscal 2020 dollars.

The E-4B—known as the “doomsday plane”—is a militarized version of the Boeing 747-200 airliner and would serve as the NAOC for the president, defense secretary, and Joint Chiefs of Staff to direct military forces, deliver emergency war orders, and coordinate civil authorities in the case of destruction of ground command and control centers.