_______ is a route assigned to pilot when any part of an airway or route is unusable because of NAVAID status.
A.New route
B.Substitute route
C.Old route
D.Planned route
正确答案是B
_______ is a route assigned to pilot when any part of an airway or route is unusable because of NAVAID status.
A.New route
B.Substitute route
C.Old route
D.Planned route
正确答案是B