The Shenyang J-31(or "FC-31 fifth Generation Multi-Purpose Medium Fighter")also known as the "Gyrfalcon" (鹘鹰), or "Falcon Hawk" by some military enthusiasts,is a twin-engine, mid-size fifth-generation jet fighter currently under development by Shenyang Aircraft Corporation. The fighter has also been referred to as the "F-60" or "J-21 Snowy Owl" (雪鸮) in some media reports.Its official name is Shenyang FC-31; J-xx nomenclatures in the Chinese military are reserved to programs launched and financed by the army, while this plane was developed by a private company.