相关题目
19KM is equal to （ ） .
20NM is equal to （ ） .
The altimeter setting used in en-route flight should be （ ） hpa.
The vertical separation minimum should be 300m at the altitude of or below （ ） .
Larger separations than the specified minima should be applied whenever in （ ） .
Air navigation services include （ ） .
（ ） is a circle on the surface of the earth, the plane of which passes though the centre of the earth.
（ ） is air traffic control service for controlled flights in control areas.
（ ） is a service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights.
（ ） is a service provided to notify appropriate organizations regarding aircraft in need of search and rescue aid, and assist such organizations as required.
