Ground crews perform pre-flight checks on a J-10A fighter jet prior to a training exercise at an airfield in southwest China on Feb. 27, 2019. The J-10A fighter jet is attached to an aviation brigade of the air force under the PLA Southern Theater Command which has sent several airplanes to southwest China to conduct training on regional air defense combat and covering assault operations, in a bid to hone the troops' all-weather combat capability. (eng.Chinmil.com.cn /Photo by Wei Jinxin)