JANUARY 8, 2026 – The 379th Expeditionary Logistics Readiness Squadron recently implemented an innovative method using nitrogen gas to test the integrity of vehicle air conditioning systems within the U.S. Central Command area of responsibility.
U.S. Air Force Staff Sgt. Charles Penov, 379th ELRS vehicle maintenance section noncommissioned officer in charge, introduced the method to reduce the time required to diagnose leaks, start maintenance tasks and return vehicles back into service.
The new method involves removing all refrigerant from the air conditioning system and refilling the system with nitrogen gas. Technicians identify leaks in the system, now pressurized with nitrogen gas, by spraying soapy water on air conditioning lines and connections. They observe where a bubbly effect occurs in the water which indicates a nitrogen leak, also indicating refrigerant leaks in the same location during normal operations.
U.S. service members and joint coalition partners throughout the region rely on vehicles for transportation to and from work areas, living quarters and dining facilities, as well as transporting distinguished visitors. Faulty air conditioning systems on buses in particular create hazardous conditions during the summer season for passengers, prompting the vehicles to be removed from service for repair. Penov’s new nitrogen gas testing setup addressed the faulty bus systems but can be repurposed for inspecting general use vehicles too.
Penov said he repurposed existing parts from around the shop to make the method work using a storage cylinder to contain the nitrogen gas, a dolly to transport it and regulators to distribute it. He used specialized equipment to safely remove refrigerant from the vehicle and store it to be reused after repairs have been made. Everything he needed was already in the shop, he just needed to assemble it and implement the process.
“The impact has been huge,” said Chief Master Sgt. Shaun Welsh, 379th ELRS vehicle management flight chief. “Part of our charge from the 379th Air Expeditionary Wing commander was for us to think proactively on how to prepare our replacements here. Penov’s set-up is easy to use, cost efficient and provides a diagnostic capability that conventional A/C diagnostic tools simply don’t.”
Penov identified several problems with the previous process used to test the integrity of air conditioning systems. The old method created negative pressure in the lines and leaks were harder to identify if rubber lines sealed shut under a vacuum. Technicians also sometimes had to repeat the lengthy empty-and-refill procedure to pinpoint leaks with the traditional method.
Penov said the process was inefficient, time consuming, and expensive by comparison, taking several hours. The new method cuts down the time needed to diagnose a leak by more than half, substantially increasing technicians’ diagnostic and maintenance through efficiency.
The new process is also safer, said Penov. The refrigerant used in conventional testing methods is hazardous to both the technician and the environment and technicians risk the substance leaking during testing. By contrast, nitrogen gas is already abundantly present in the atmosphere so leaking nitrogen gasses from air conditioning systems during testing is safe.
Penov, an Air Force Reservist, implemented the technique from his civilian job as a freightliner technician in his hometown of Colorado Springs, Colorado. He said the procedure was routine during his civilian work and knew the deployed vehicle maintenance shop could benefit from including the process as part of their toolkit of diagnostic methods.
“We provided him the time and space he needed to refine the idea and fabricate the setup,” said Welsh. “Vehicle management is inherently industrial and not pretty, but innovation doesn’t have to be pretty either. After learning of his civilian experience and seeing the tester in practice, we communicated the idea to Air Forces Central to share with the rest of the U.S. Central Command area of responsibility.”
Penov said his goal is to ensure every single bus is operational and ready for service by the time the team’s replacements arrive. His innovative testing method helps ensure the incoming rotation can seamlessly transition into operations by having more vehicles available for drivers and fewer maintenance demands to address.
Story by Tech. Sgt. Justin Norton
United States Air Forces Central