[转载]

大概就是把油门把手往后推的意思（和楼上说的一样拉到空挡）
It means reduce the throttle settings. Retard as a verb means to pull back or reduce or delay. The antonym is advance, i.e., advance = increase, retard = decrease.

仅仅是收油门到慢车位的意思而已

根据《GLOSSARY OF AVIATION TERMS. Flightpath.AVIATION ENGLISH FOR PILOTS AND ATCOs》，retard的解释如下：
retard (v) to pull back the throttle / thrust lever(s) on the centre pedestal to reduce the engine speed and the resulting thrust; to throttle back; just prior to touchdown the automatic system in the flight deck says ‘retard, retard’.

电脑建议手慢车的点。 可以提前也可以晚点。 看实际的下降率和速度。 速度快下降率大可以早点收慢车。 就会在电脑说之前收。 反之也可以晚点。 之后电脑还会喊 5 就是比较小的下降率的时候