Su-27UB Flanker-C

The Su-27UB, NATO reporting name Flanker-C, was developed as the two-seat operational trainer for the Su-27 family. It preserved much of the single-seat Flanker's performance and combat capability while adding a second cockpit for instruction, conversion training, and complex mission work. The first two-seat prototype activity occurred in the mid-1980s, and the type became central to training pilots for the wider Flanker family. Its airframe also influenced later two-seat multirole developments, especially the Su-30 line.

Unlike a purely stripped trainer, the Su-27UB retains the Flanker family's large twin-engine airframe, high fuel capacity, powerful radar lineage, and air-to-air weapons compatibility. The second cockpit slightly changes weight and internal volume, but the aircraft remains suitable for air-defense training, weapons instruction, and operational missions where two crew improve workload management. Its combination of range, maneuverability, and twin-seat instruction value made it a durable platform across Russia and export operators.

The Su-27UB supports pilot conversion to the Flanker series while also giving air forces a combat-capable two-seat aircraft for command, interception, and advanced tactics. Its significance extends beyond training because the layout helped establish the basis for two-seat multirole derivatives such as the Su-30. In Russian and export service, the type improves force readiness by allowing instruction on the same aerodynamic and systems family that pilots use operationally.