The four-engined Y-20 airlifter, thought to be the largest aircraft in service with the People’s Liberation Army, will be further re-engineered to perform aerial refueling duties.

Developed by the state-owned Aviation Industry Corporation of China (AVIC) and nicknamed “Chubby Girl” because of its plump, 47-meter-long fuselage, the Y-20 entered service in 2016 as the Chinese copy of the US Air Force’s C-17 Globemaster III strategic transport aircraft.

Citing sources within the military, Chinese newspapers including the Global Times have revealed that a tanker variant of the Y-20 is now under development.

Some observers claim they have identified a prototype of the Y-20 tanker series in a high-resolution satellite photo of Yanliang Airport managed by AVIC in the western city of Xian, the birthplace of the Y-20.

The Y-20 is powered by four 12-ton-thrust Russian-made Soloviev D-30KP-2 engines. However the PLA reportedly intends to replace these with the Chinese-made 14-ton-thrust WS-20 turbofan engine. The new engines will be necessary for the Y-20 to handle a maximum cargo capacity of 66 metric tons, and a maximum takeoff weight of 220 tons.

The PLA is in urgent need of tankers larger than the HU-6 – a variant of its outmoded H-6 bomber – to refuel fighters and bombers during longer missions targeting Taiwan as well as patrols and aerial training flights above and beyond Chinese waters in the South and East China Seas.

The PLA also operates a small number of the Russian-made Ilyushin Il-78 tanker that is modeled after the Il-76 airlifter. However, reports say the PLA has been unable to negotiate an acceptable price for further purchases of the Ilyushin.

The J-20, the PLA’s fifth-generation stealth fighter jet, is capable of being refueled while airborne, as is the H-20, China’s next-generation strategic bomber currently under development and trial.

The PLA may also develop new early warning aircraft based on the Y-20 platform to make full use of its 4,500-kilometer range and maximum payload of 66 metric tons.

Read more: ‘Chubby Girl’s’ sister to boost China’s military capability