The T-6 Texan II is a single-engine turboprop aircraft built by the Raytheon Aircraft Company (which became Hawker Beechcraft and later Beechcraft Defense Company, and was bought by Textron Aviation in 2014). A trainer aircraft based on the Pilatus PC-9, the T-6 has replaced the Air Force's Cessna T-37B Tweet and the Navy's T-34C Turbo Mentor. The T-6A is used by the United States Air Force for basic pilot training and Combat Systems Officer (CSO) training, the United States Navy and United States Marine Corps for primary and intermediate Naval Flight Officer (NFO) training, and by the Royal Canadian Air Force (CT-156 Harvard II designation), Greek Air Force, Israeli Air Force (with the "Efroni" nickname), and Iraqi Air Force for basic flight training. The T-6B is the primary trainer for U.S. student naval aviators (SNAs). The T-6C is used for training by the Mexican Air Force, Royal Air Force, Royal Moroccan Air Force, and the Royal New Zealand Air Force.