Boeing T-43
The Boeing T-43 is a modified Boeing 737-200 that was used by the United States Air Force for training navigators, now known as USAF combat systems officers. Informally referred to as the Gator (an abbreviation of "navigator") and "Flying Classroom", nineteen of these aircraft were delivered to the Air Training Command at Mather Air Force Base, California during 1973 and 1974. Two additional aircraft were delivered to the Colorado Air National Guard at Buckley Air National Guard Base (later Buckley Space Force Base) and Peterson Air Force Base, Colorado, in direct support of cadet air navigation training  at the nearby U.S. Air Force Academy. Two T-43s were later converted to CT-43As in the early 1990s and transferred to Air Mobility Command and United States Air Forces in Europe, respectively, as executive transports. A third aircraft was also transferred to Air Force Materiel Command for use as the "Rat 55" radar test bed aircraft and was redesignated as an "NT-43A". The T-43 was retired by the Air Education and Training Command in 2010 after 37 years of service. Design and development. On 27 May 1971, the United States Air Force (USAF) placed an order for 19 T-43s, modified  versions of the Boeing 737-200 as a replacement for the USAF's aging fleet of Convair T-29 navigation trainers, as part of the Undergraduate Navigator Training System. The Boeing aircraft was selected in preference to a trainer based on the Douglas DC-9. From its entry into service in 1974 until the mid-1990s, the T-43As were used for all USAF Undergraduate Navigator Training. Starting in the mid-1990s, the T-43As were used for USAF Undergraduate Navigator/Combat Systems Officer training with the exception of those USAF navigators/CSOs slated for the F-15E and B-1B). In 1976, with the U.S. Navy's  retirement of its T-29 aircraft and deactivation of its associated Training Squadron Twenty-nine (VT-29) at NAS Corpus Christi, Texas, those student naval flight officers destined for land-based naval aircraft began training in USAF T-43s at Mather AFB under a program known by USAF as "Interservice Undergraduate Navigator Training" (IUNT) and by the U.S. Navy as the NAV pipeline for training student naval flight officers slated for eventual assignments to land-based naval aircraft. Externally, the T-43 differs from the civilian aircraft by having more antennas and fewer windows. The T-43A has stations on board for twelve navigator students , six navigator instructors, as well as a pilot and co-pilot. The student training compartment is equipped with avionics gear as used in contemporary operational aircraft. This includes search and weather radar; VHF omnidirectional range (VOR) and tactical air navigation system (TACAN) avionics systems; long range navigation system (LORAN-C); inertial navigation system; radar altimeter; and all required VHF, UHF and HF communications equipment. Five periscopic sextant stations spaced along the length of the training compartment were used for celestial navigation training. However, with the advent of GPS, student navigators were no longer taught celestial navigation or LORAN. The aircraft  has considerably more training capability than the aircraft it replaced, the T-29. VT-29 had been training student naval flight officers for various land-based naval aircraft such as the P-3 Orion, EP-3 Aries, and variants of the Lockheed C-130 Hercules. Inside each T-43A training compartment were two minimum proficiency, two maximum proficiency and 12 student navigator stations. Two stations form a console, and instructors could move their seats to the consoles and sit beside students for individual instruction. The large cabin allows easy access to seating and storage, and reduced the distance between student stations and instructor positions. The aircraft  were initially assigned to the 323rd Flying Training Wing (323 FTW) of the Air Training Command (ATC) at Mather AFB, California, plus two additional aircraft assigned to the Colorado Air National Guard at Peterson AFB, Colorado, to support introductory air navigation training for cadets at the United States Air Force Academy. When the 323 FTW was inactivated and Mather AFB closed by Base Realignment and Closure (BRAC) action in 1993, most of the T-43s were transferred to the 12th Flying Training Wing (12 FTW) of the Air Education and Training Command (AETC) at Randolph AFB, Texas, with the 12 FTW  assuming the specialized undergraduate navigator training (SUNT) role while the U.S. Navy's Training Air Wing SIX (Trawing 6), a Naval Air Training Command organization at NAS Pensacola, Florida, assumed a role for training those USAF student navigators slated for eventual assignment to the F-111, EF-111, F-15E and B-1B. Operational history. The T-43 was last based at Randolph Air Force Base, Texas, and operated originally by the 558th Flying Training Squadron (558 FTS) and since 1996 by the 562d Flying Training Squadron and by the 563d Flying Training Squadron since 1999. The two additional aircraft used for introductory air navigation  training of USAF Academy cadets continue to be operated by the Colorado Air National Guard at Buckley Space Force Base and Peterson Air Force Base, Colorado. In addition, several T-43A were later modified to a transport aircraft configuration designated "CT-43A", such as one previously operated by the 6th Air Mobility Wing (6 AMW) at MacDill AFB, Florida, in support of United States Southern Command (USSOUTHCOM) for transport of the USSOUTHCOM commander in Central and South America. The 6 AMW's CT-43A aircraft was replaced by a Gulfstream C-37A aircraft in early 2001. Throughout its service in the ATC and the  successor ATEC, no T-43 was ever lost in a mishap. Among the T-43s removed from navigator training and converted to CT-43A executive transports, one aircraft assigned to the 86th Airlift Wing (86 AW) at Ramstein Air Base, Germany, to support United States European Command (USEUCOM) crashed in Croatia in 1996 while carrying U.S. secretary of commerce, Ron Brown, and 34 other passengers. There were no survivors and subsequent investigation determined that this was a controlled flight into terrain (CFIT) mishap as a result of pilot error. On 17 September 2010, the last T-43 flight was flown at Randolph Air Force  Base, and it was subsequently retired from the active Air Force service after 37 years of service.