有内胎的机轮轮毂和轮胎内侧面画红色标线，其目的是为了便于检查

A （ ） is the horizontal direction to or from any point, which is measured clockwise through 360°from magnetic north by an ADF indicator.

An ADF （ ） reflects the horizontal direction, or angle, between the A/C and the station.

Unlike DME, both VOR and ADF do not include an airborne （ ） ．

DME and VOR have similar airborne equipment except that DME includes （ ） while VOR does not.

DME measures （ ） ．

DME provides a distance reading in （ ） ．

DME adds to a basic VOR system another feature, namely （ ） ．

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.