A J-11 fighter jet attached to an aviation brigade of the air force under the PLA Western Theater Command takes off for an air combat training exercise at low temperature on April 1st ,2019. (Photo:eng.chinamil.com.cn)

A J-11 fighter jet attached to an aviation brigade of the air force under the PLA Western Theater Command takes off for an air combat training exercise at low temperature on April 1st ,2019. (Photo:eng.chinamil.com.cn)

A J-11 fighter jet attached to an aviation brigade of the air force under the PLA Western Theater Command takes off for an air combat training exercise at low temperature on April 1st ,2019. (Photo:eng.chinamil.com.cn)

A J-11 fighter jet attached to an aviation brigade of the air force under the PLA Western Theater Command takes off for an air combat training exercise at low temperature on April 1st ,2019. (Photo:eng.chinamil.com.cn)

A J-11 fighter jet attached to an aviation brigade of the air force under the PLA Western Theater Command takes off for an air combat training exercise at low temperature on April 1st ,2019. (Photo:eng.chinamil.com.cn)

A J-11 fighter jet attached to an aviation brigade of the air force under the PLA Western Theater Command takes off for an air combat training exercise at low temperature on April 1st ,2019. (Photo:eng.chinamil.com.cn)