绕机检查的要求：What is the requirement for walkaround check?

A、可由副驾驶执行。It can be done by copilot.
B、由地面机务人员或跟机机务人员执行。It is done by ground maintenance personnel or onboard maintenance personnel
C、机长手持绕机检查单，按照规定路线执行绕机检查。The captain carries the walkaround checklist and does the walkaround check according to regulated route

D、当飞机有故障时，机长按照MEL执行保留程序。When aircraft has fault, the captain implement the defferred procedure according to MEL