On February 14, a USAF-operated Boeing TC-135W (serial 62-4133) departed Offutt Air Force Base (AFB), Nebraska, for Greenville-Majors Airport, Texas, where it will be reassigned to the air arm’s Big Safari Program and redesignated as an NC-135 platform.
The aircraft was flown to Texas by members of the 238th Combat Training Squadron under the callsign ‘Windsor 01’ and will ultimately become responsible for the testing of surveillance equipment modifications which, if successful, will be added to the USAF’s core fleet of RC-135S/U/V/W reconnaissance aircraft. This is not the first time that 62-4133 has been operated in the test role since it completed its maiden flight in July 1962. In 1967, the aircraft was redesignated as an EC-135B when it received a 10ft nose extension and was fitted with equipment from the EC-135N Apollo Range Instrument Aircraft (ARIA).
It was then converted into a TC-135S in 1985 and served as a training aircraft for the RC-135S Cobra Ball fleet. At the time, these aircraft did not have the ‘chipmunk cheeks’ fitted to the forward fuselage that is a synonymous feature of the RC-135 fleet today. Until now, the aircraft had served as part of the 45th Reconnaissance Squadron in this same role.
Having been delivered for its new assignment, 62-4133 will now take over the Big Safari test role from NC-135W (serial 61-2666), which has been responsible for testing equipment for the core RC-135 fleet since the mid-1990s. This aircraft – which is the sole remaining C-135 in the USAF inventory that is equipped with Pratt & Whitney TF-33 turbofan engines – will be retired from use once 62-4133 becomes fully available.
Its retirement follows a series of divestments of a similar nature, including the two OC-135B Open Skies aircraft and the WC-135C/W Constant Phoenix fleet, which was used for atmospheric testing and collection purposes. As these aircraft have aged, parts have become less available and the airframes have grown more difficult to maintain. The introduction of 62-4133 as the new NC-135 test aircraft will bring the Big Safari Program in line with the remainder of the fleet.
Two training-configured TC-135Ws (serials 62-4127 and 62-4129) still remain assigned to the 55th Wing at Offutt. In 2019, 62-4127 became the first aircraft to have ‘Baseline Charlie’ installed, which was the fleet-wide glass cockpit modification. This was the first real sign of alternatives to 61-2666 being used to test RC-135 fleet modifications