飞机为何有时要复飞？

Why do aircraft sometimes execute a go-around?

复飞，是保证飞行安全的措施之一，而复飞的原因是多种的：有的是因机场有障碍，有的是因为飞机本身有故障，更多的原因是天气坏，能见度低等。因为飞机着路，有一个决断高度，当飞机下降到此高度时，驾驶员认为不具备着路条件，就要加打油门，重新把飞机拉起复飞，然后再次进行着陆......多次复飞，驾驶员如觉得不能达到着陆的要求时，为了安全，飞机就要改落备降机场了。

A go-around (or balked landing) is one of the essential safety measures implemented during flight operations. The reasons necessitating a go-around are varied: they can stem from obstacles on the airport surface, inherent aircraft malfunctions, or, most frequently, adverse weather conditions leading to low visibility.For an aircraft to land, there is a critical altitude known as the Decision Altitude (DA) or Decision Height (DH). If, upon reaching this altitude, the flight crew determines that the required landing conditions are not met, the pilot will apply takeoff thrust, pulling the aircraft up to regain altitude, and attempt the landing procedure again... Should multiple go-arounds fail to meet the necessary landing requirements, the aircraft will safely divert to an alternate airport for the protection of the flight.