所需目视参考(required visual reference): 飞行员应该看到 目视助航设施的一部分或进近区的一部分，并有充分时间让飞行员评 估航空器相对于预定飞行航径的位置和位置变化率。在盘旋进近中， 所需的目视参考是跑道周围的物体。Required visual reference: The pilot should see part of the visual navigation aids or part of the approach area, and have sufficient time for the pilot to evaluate the position and position change rate of the aircraft relative to the predetermined flight path. In circling approach, the required visual references are the objects around the runway.

A. 2

B. 3

C. 4

D. 5

A. 300海里/小时；

B. 280海里/小时；

C. 250海里/小时；

D. 230海里/小时

A. 12；

B. 8；

C. 10

A. 雨水从气温高于 0℃处落向气温为 0℃或小于 0℃处

B. 雨水从气温等于或小于 32°Ｆ处落向气温高于 32°Ｆ处

C. 温度为 0℃或 0℃以下的过冷却雨水掉向气温高于 0℃的空气处

A. 积雨云和飞机颠簸

B. 高空急流和飞机积冰

C. 雷暴，冰雹和阵雨

A. 后设备舱的引气管路 bleed air ducting in the aft equipment bay

B. 中央机身的防冰管路 anti-ice ducting in the center fuselage

C. 发动机吊架的整流罩防冰管路 cowl anti-ice ducting in the engine pylons

D. 空调引气管路air conditioning bleed air ducting

A. 晚上冷空气活跃

B. 晚上近地层气温降低

C. 晚上层状云上部辐射降温

A. 查阅MEL，并与机务人员沟通确认符合放行标准。Refer to MEL and communicate with maintenance personnel to confirm that they meet the release standards;

B. 查阅MEL，可以不与机务人员沟通确认符合放行标准。Refer to MEL and may not communicate with maintenance personnel to confirm whether meet the release standards;

C. 不用确认机务人员按照MEL执行维护程序（M）（如有）；Don＇t need to verify the maintenance personnel conducting the maintenance procedures (M) as per MEL (if any);

D. 不用与机组成员预习MEL的操作程序（O）（如有）；Don＇t need to preview MEL operation procedures (O) (if any) together with the flight crew members;