The countdown measures the difference between the aircraft's expected time and the scheduled time. This is based on the current route, runway, and instructions. A higher time means the aircraft will be earlier. A negative time means the aircraft wil be late. ; i- ]: q3 m" ~8 ?; Z倒计时测量飞机预计时间与预定时间之间的差值。这是以当前航线、跑道和指示为基础的。时间越长,表示飞机越早起飞。时间为负数表示飞机将晚点。