相关题目
A controller should pass ATC clearance to a pilot at the time （ ）.
In which case a controller is not supposed to say NEGATIVE（ ）.
After receiving takeoff clearance, pilot must takeoff within （ ） minutes or he will ask for a new clearance/.
The abbreviated call sign of N357826 is （ ）.
In RTF communication, the A/C call sign 9099Y is spoken as （ ）.
Prior to starting transmission, a pilot or controller should （ ）.
When flying in the mountainous area, and there is strong wind or strong updraught/downdraught, the aircraft should maintain at least （ ） meters minimum safety altitude from the obstacles.
Helicopters can operate at a height between 1 and 10 meters with 10 meters distance from obstacles, but its flying speed should not exceed （ ） km/h.
The flight time refers to （ ） .
Landing time refers to （ ） .
