VOR共有（）个频道。

The separations of aircraft include vertical, lateral and （ ） separations.

Moderate icing means the depth of icing is （ ） mm per minute.

The typical ATIS may include （ ） .

The ATIS information is normally updated every （ ） .

The ATIS informs （ ） pilots of weather condition and other pertinent information at the airport.

“Active runway” means “Runway currently in （ ）”.

The pilot-in-command shall （ ） a flight plan to the relevant ATC unit at least one hour before the estimated time of departure.

Among “Distress”, “Urgency “and “Danger”, which one needs immediate assistance?

In weather report, “CB” means .

The primary principle to follow when dealing with hijacking event is （ ）.