n.飞行器的起落架；底架；下架

The undercarriage was fully retracted. 起落架被完全收起。

Undercarriage appeared to be down and in place. 起落架已放下在正常位置。

The pilot found that the undercarriage could not be retracted. 飞行员发现飞机的起落架不能缩回。

The undercarriage on light aircraft does not always retract in flight. 轻型飞机飞行时起落架不一定缩回。