The C-21A is a military designation for the Learjet 35A, a twin-engine transport jet. Learjet designed and manufactured the aircraft in the 1970s. The U.S. Air Force began acquiring the C-21A, a modified Learjet 35, in 1984, utilizing the fleet for passenger and cargo missions for decades. The aircraft is known for its speed, achieving a maximum of 542 mph, and its capacity for eight passengers or cargo in its 42 cubic foot area.
Learjet, the manufacturer, has a history rooted in high-performance civilian and military aircraft. Founded by Bill Lear in the early 1960s, the company established a reputation for producing fast, reliable business jets, beginning with the Learjet 23. This legacy led to the development of the Model 35/36 series, which served as the foundation for the C-21A.
Access solutions aid meticulous maintenance across the C-21A. For the nose section (radome, avionics, cockpit), solutions like the A-Frame Aviation Platform or Platform Ladder Warthog provide the necessary height. Forward fuselage maintenance (entry door, cargo, environmental control system) benefits from the Cantilever Platform and Modular Stepover Platforms. For the landing gear, Aviation Chock and Cone Trolleys are indispensable, along with access platforms for detailed work on the Nose and Main Landing Gear.
Middle fuselage access, including the wing box and fuel tanks, can be served by the Bridge Deck or Super Trestle Scaffold. For the Wing & Engine Pylon, stands and platforms like the Super Service Stand or Ultraraise are used for anti-ice systems, engine maintenance (fan, compressor, turbine, hydraulics), and fuel systems. AFT fuselage and tail section maintenance (bulkhead, cargo, rear avionics, APU, and empennage surfaces) are efficiently reached using platforms such as the Easyraise or Super Maintenance Platform. A range of elevated access options support general aircraft access from AF to BF.
