Airmen tested the performance of the Boeing [BA] Tactical Data Link (TDL) for the company’s KC-46A Pegasus tanker during Mobility Guardian 2021 (MG21) on May 15-27.

Air Mobility Command (AMC) began the large, flagship readiness exercise in 2017 and holds it every two years.

The TDL system “has performed well” during MG21, Air Force 1st Lt. Emma Quirk, an AMC spokeswoman, wrote in an email.

“During MG21, the crews were able to get hands-on experience and familiarity with Tactical Data Link and— for the first time— AMC maximally connected the mobility forces present at the exercise from ground mobile command and control centers to airlifters to tankers,” she wrote. “AMC aircraft also used Tactical Data Link to connect outside the Mobility Air Force with A-10s and F-16s partners who participated. Crews were given the opportunity to familiarize and practice on the tactical data link with trainers available on-board for feedback and troubleshooting.”

During the exercise, 16 of 16 AMC planes connected over TDL in-flight, including the KC-46A, the Boeing C-17, KC-135 and KC-10, and the Lockheed Martin [LMT] C-5 and C-130, AMC said.

AMC wants to make its aircraft, including the KC-46A, KC-135 tanker and the C-17 transport, nodes in the Air Force’s Advanced Battle Management System (ABMS) and the larger DoD Joint All Domain Command and Control, called JADC2, network.

“The KC-46 and other mobility aircraft will continue to evolve into a critical role for linking the joint force, to include next generation aircraft and systems,” AMC said. “Beyond Line-of-Sight and TDL are going to be a second language to mobility aircrews as they serve as integral nodes in the global mesh network, enabling interoperability through connectivity at scale.”

AMC said that MG21 featured the return of Air Force tankers to the former Wurtsmith AFB in Oscoda, Mich. and the first participation of the KC-46A in the Mobility Guardian exercise.

“Since we are able to be airborne for long periods of time and we start to bring these systems online, the data link capability on our legacy tankers and the KC-46 is going to be a game changer,” Air Force Maj. Thomas Gorry, 22nd Operations Group chief of training and KC-46 lead planner, said in a statement.

AMC also said that “tankers are integral to enabling a nuclear response capability, extending the reach of not only strategic bombers, but also airborne national command centers.”

Under ABMS Capability Release 1, the Air Force Rapid Capabilities Office is to design, buy, and install communications pods for ABMS on a limited number of KC-46s to allow Lockheed Martin F-22 Raptor and F-35 Lightning II fighters to receive and transmit information rapidly.

Such communications pods will act as translators between the F-22 and F-35, as both aircraft have had problems with incompatible data links–the Multifunction Advanced Data Link for the F-35 and the Intra-Flight Data Link for the F-22.

Last year, the Air Force identified six Category I–critical–deficiencies with the KC-46A: two Category I performance deficiencies with the Remote Vision System (RVS); a performance deficiency with the boom telescope actuator for connecting the refueling boom with slower aircraft, such as the A-10; a product quality deficiency report (PQDR) related to fuel manifold leaks; a PQDR related to the APU drain mast; and a PQDR related to Auxiliary Power Unit (APU) duct clamp cracks (Defense Daily, Oct. 27, 2020). The Air Force has said that it has worked with Boeing to plan out fixes, including a new RVS 2.0 and a more pliant standard for the boom.

In January, the Air Force and Boeing resolved the two Category I deficiences with the APU, per Air Force Gen. Jacqueline Van Ovost, the AMC commander (Defense Daily, Feb. 1).

A new DoD Inspector General report finds fault with the Air Force for adhering to a reduced KC-46 flight testing regime prior to the 2016 Milestone C production decision despite recognized problems with extending and retracting the refueling boom–a stiffness of the boom–during refueling operations with the C-17.

That “high axial load” problem resurfaced in 2018 in KC-46 refueling of A-10, C-17, and F-16 aircraft. Such problems resulted in a $100 million Boeing boom redesign funded through contract modification awards in August, 2019 and in March, 2020.

“Despite encountering flight test failures in January 2016 that required Boeing engineers to redesign the refueling boom, the KC-46 Program Office officials did not change their decision to perform reduced flight testing prior to the Milestone C decision,” the report said. “This reduced flight testing did not include the stressing conditions under which the refueling boom problem could potentially occur. As a result, in 2018, when Boeing attempted to test full
functionality of the KC-46A tanker refueling boom after Milestone C, flight test reports documented that refueling
boom performance remained a problem during in-flight refueling of the A-10, C-17, and F-16 receiver aircraft.
Specifically, the 38 KC-46A tankers that Boeing delivered could not refuel the A-10 or several variants of the C-130 receiver aircraft, and Air Force officials imposed operational limitations allowing the B-52, C-17, F-15, F-16, F-35A, HC/MC-130J, KC-10, KC-46A, and KC-135 receiver aircraft to aerially refuel only under limited flight conditions.”

The DoD IG said that “retrofit of the refueling boom for the delivered KC-46A tankers is not estimated to begin until
January, 2024, and will result in additional undetermined costs, as well as approximately a 5-year delayed delivery
of the first KC-46A tankers with fully mission-capable refueling booms.”