the Mekong Delta, attacking ground forces and gunboats and defending against French bombing raids, until a ceasefire was arranged in January 1941. Later that year, on 7 December, Thailand was invaded by Japan. The RTAF, as the most openly anti-Japanese branch of the military, took an active role in the resistance. Combat Wings 1 and 5 engaged superior Japanese units at Thailand's eastern border, but suffered heavy losses (almost 30% in the case of Wing 5) before the cease-fire the following day. Structure The Air Force is commanded by the Commander of the Royal Thai Air Force (ผู้บัญชาการทหารอากาศไทย). The Royal Thai Air Force Headquarters is located in Don Muang Airbase, Bangkok, Thailand. The RTAF consists of headquarters and five groups: command, combat, support, education and training, and special services. Headquarters Group Royal Flight Aircraft Administrative Center Royal Flight Helicopter Administrative Center Air Warfare Center Office of Public Sector Development, RTAF Office of Intellectual Development, RTAF Command Group RTAF Secretariat Directorate of Administrative Service Directorate of Personnel Directorate of Intelligence Directorate of Operations Directorate of Logistics Directorate of Civil Affairs Directorate of Information and Communications Technology Office of the RTAF Comptroller Directorate of Finance Directorate of Inspector General Office of RTAF Internal Audit Office of RTAF Safety Office of RTAF Judge Advocate Combat Group The Royal Thai Air Force Combat Group is divided into 11 wings plus a training school, plus a few direct-reporting units. Squadrons The following squadrons are currently active with the Royal Thai Air Force. Support Group Directorate of Aeronautical Engineering Directorate of Communications and Electronics Directorate of Armament Directorate of Quartermaster Directorate of Civil Engineering Directorate of Transportation Directorate of Medical Services First set up in 1913 in the same year as the Air Force, providing nursing services only, and over the years has gradually expanded. It operates Bhumibol Adulyadej Hospital and Royal Thai Air Force Hospital in Bangkok, as well as smaller hospitals at each wing. The directorate has made a teaching agreement with the Faculty of Medicine, Chulalongkorn University to train students at Bhumibol Adulyadej Hospital, accepting about 30 students per academic year. Education and Training Group Directorate of Education and Training Air War College Air Command and Staff College Senior Air Officer School Squadron Officer School Officer Training School Academy Instructor School Non-Commissioned Officer School Air Technical Training School RTAF Language Center Personal Testing Center Technical Service Division Chaplain Division Navaminda Kasatriyadhiraj Royal Thai