（1）飞机蓄电池是飞机上的应急电源，当飞机发电机发生故障时，它可给重要用电设备供电，以保证飞机安全着陆，（2）飞机蓄电池是飞机发动机起动、点火的唯一电源,对于上述描述正确的选择是（ ） 。

Flying from one radial to another is normally referred to as （ ） the radial.

The CDI needle of the VOR indicator shows the pilot that his aircraft is not on course when it （ ） ．

（ ） is not a necessary step to use a VOR effectively for navigation.

（ ） guided approach is non-precision approach.

The VOR signals travel on a line-of-sight basis. This means （ ） ．

Radio beams transmitted by a VOR station are called （ ） ．

（ ） is not a feature of a basic VOR system.

Which of the following is not a part of the VOR indicator?

The fuel used on piston engine aircraft is （ ）.

ATC is a service used for the purpose of anti-collisions between aircraft; anti-collisions between aircraft and （ ） on maneuvering area, and expediting and maintaining an orderly flow of air traffic.