The U.S. Air Force’s KC-135 Stratotanker fleet has received the Automatic Dependent Surveillance-Broadcast Out, or ADS-B Out, upgrade, thanks to the efforts of a team led by the Air Force Life Cycle Management Center’s Tanker Directorate. The system broadcasts the precise position and location of aircraft in real time, giving air traffic control better visibility to track and manage, while enhancing safety by providing aircrew more situational awareness of nearby aircraft. The ADS-B Out program was established to upgrade the KC-135 fleet with the next-generation transponder system that is critical for air traffic control’s visibility into their respective airspace.
Installation of this capability was mandated by the U.S. Federal Aviation Administration to allow the fleet of 396 KC-135s to operate in controlled airspace. Aircraft without this modification would be subject to sub-optimal routing around high-traffic airspace adding wear and tear to the engines and increasing fuel costs. From the beginning, while the modification is critical to KC-135 worldwide operations, the challenge was to modify the fleet without “grounding” large numbers of aircraft at any given time to perform the upgrade.To tackle this challenge, the ADS-B Out team divided the modification into “bite-size” field-level maintenance actions to simplify the final modification to only a routine flight software update and a single field-level box swap.
The team also negotiated and took possession of 40 transponder line-replaceable units, or LRUs, to create a rotable pool of assets for upgrade. From there, to avoid the long factory upgrade lead time, they stood up a central Contractor Field Team, or CFT, at Tinker AFB where the transponders were delivered, upgraded and sent back out to the bases. There are 35 KC-135 bases or operating locations worldwide, so the central node was critical to quickly turn transponders. The team leveraged commercial shipping allowing the transponders to be delivered to the field within two days of the upgrade. Additionally, the team deployed three additional CFTs to the largest KC-135 bases; Fairchild AFB, Washington, McConnell AFB, Kansas and MacDill AFB, Florida to upgrade transponders on-site to supplement the efforts from the central CFT at Tinker AFB. The team finished OCONUS upgrades within two months of the fielding effort, allowing them to set their sights strictly on CONUS bases.
During the modification window, the team had to quickly react to real-world operational needs to address critical Air Mobility Command requirements. With very short notice, the team delivered three transponders to CONUS bases and two transponders to bases in the U.S. Central Command area of responsibility. They utilized their network of fellow professionals working at McConnell AFB and Fairchild AFB to analyze the schedule for aircraft rotating overseas in order to transport the LRUs as cargo on those aircraft. These time windows were small and required a vast amount of coordination, but due to expert stakeholder management, the team was able to fill the MICAPs and return grounded aircraft back to continue their refueling mission.
The effort began Oct. 7, 2019, and as of June 1, even with the slow-down from COVID-19, the team finished more than 99% of the 396 aircraft and are only waiting for the last couple of jets to return from deployment. This initiative has been a tremendous example of the synergy that exists between the Program Office, AMC, Air National Guard, and Air Force Reserve Center Weapon System Managers, and the maintenance experts at each base. ADS-B Out is one of many efforts underway to keep the KC-135 mission-ready today as well as posture to support the future fight. When the time comes, the KC-135 Program Office will be prepared to do what it takes to support the warfighters’ needs and enhance the United States Air Force’s ability to fuel the fight.