- May 24, 2021, 11:27 AM Precision Aviation Group (PAG) has gained a new specialization in Rolls-Royce M250 turbine engines through the acquisition of Keystone Turbine Services (KTS) in Coatesville, Pennsylvania, PAG announced today. In addition to being an OEM-approved aftermarket MRO of the M250 series of gas turbine engines, KTS is a Honeywell authorized warranty and repair station for Pratt & Whitney PT6A and PT6T fuel controls, power turbine governors, and related accessories. M250-series engines were originally developed by the former Allison Engine. To date, 31,000 have been produced, and 16,000 are in service, according to Rolls-Royce, which acquired Allison in 1995. The global fleet has logged more than 250 million flight hours among 170 aircraft types, primarily rotorcraft but also fixed-wing. Helicopter types utilizing the engine include the Bell 206 series and MD Helicopters MD500 series.