China Civil UAV Theory Questions — Questions 481–490

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UAV-Q0481. On satellite cloud images, which of the following is NOT a stratus (fog) characteristic?

Explanation

Stratus (fog) is low, with cloud-top temperatures close to ground temperature, so on infrared images its tone is dark and close to the ground tone. Option C is therefore wrong.

UAV-Q0482. Icing frequency differs with flight altitude. Which is correct?

Explanation

Study note: the lower, the easier to ice. In winter, icing frequency is high below 3000 meters, almost 56%; above 6000 meters, icing accounts for a high proportion in summer.

UAV-Q0483. The troposphere can be divided by airflow and weather distribution into lower, middle, and upper layers. The basic trend of mid-troposphere airflow is

Explanation

The mid-troposphere (1500–6000 m) is less affected by the surface, with relatively stable airflow, representing the basic tropospheric airflow trend.

UAV-Q0484. Which statement about mountain effects on wind is WRONG?

Explanation

Study note: for mountains, look at the summit; for mountain areas, look at the base. Mountains obstruct airflow; wind speeds increase at summits and canyon outlets, while winds at mountain bases are usually not strong. So option C is wrong.

UAV-Q0485. En route weather forecasts are usually provided to crews by the flight station weather office how many hours before takeoff?

Explanation

En route weather forecasts are usually provided 1 hour before takeoff, with validity set according to flight time, allowing for early or delayed landings.

UAV-Q0486. After a thunderstorm reaches maturity, as rapidly descending cold air in the cumulonimbus reaches the ground, wind direction shifts abruptly and wind speed rises rapidly. Gust speeds are commonly:

Explanation

In a thunderstorm's mature stage, gust wind speeds commonly reach 20 m/s (equivalent to force 8 winds).

UAV-Q0487. Visibility reflects atmospheric transparency. The WRONG method for measuring atmospheric visibility is

Explanation

Visibility measurement methods include visual observation (without a telescope), atmospheric transmissometers, and laser visibility meters. Measuring by eye through a telescope is wrong.

UAV-Q0488. Airports commonly use windsocks to estimate wind speed. When a windsock blows fully horizontal, wind speed has reached:

Explanation

According to the Civil Aviation Administration's “Windsock Technical Requirements”, a windsock fully extended from inlet to tail indicates a wind speed of 7.8 m/s, within the 6–10 m/s range.

UAV-Q0489. When flying in mountainous areas, note that the strongest turbulence occurs on the

Explanation

Study note: the strongest turbulence is on the leeward slope.

UAV-Q0490. The cause of heat thunderstorms is

Explanation

Heat thunderstorms form when uneven ground heating causes warm air to rise and create convection.