China Civil UAV Theory Questions — Questions 661–668
Unofficial study reference only. Not affiliated with or endorsed by any civil aviation authority — the official syllabus and regulations prevail.
UAV-Q0661. A front is a three-dimensional weather system. The frontal zone is very narrow compared with air mass width, so it is often treated as a geometric surface called the frontal surface. Which description is WRONG?
Explanation
Fronts extending into the upper troposphere are called upper-air fronts or upper-troposphere fronts; the term “laminar front” is wrong.
UAV-Q0662. The main reason ground wind has marked daily variation is ( )
Explanation
During the day, strong solar radiation raises temperatures, air rises, and near-surface pressure falls; at night the reverse occurs, and pressure changes cause daily ground wind variation.
UAV-Q0663. An aircraft flying at a pressure-altimeter-indicated altitude, when flying toward a low-pressure area, its actual altitude will ( )
Explanation
When flying toward a low-pressure area, pressure falls and the altimeter reads higher, so the pilot lowers flight altitude to maintain indicated altitude; actual altitude gradually decreases.
UAV-Q0664. Flying at low altitude in warm weather, turbulent air is sometimes encountered. Which description is correct? ( )
Explanation
Roads and barren land warm fast during the day, and near-surface air above them heats and rises, easily producing turbulence; water bodies and vegetated areas warm slowly, with sinking air.
UAV-Q0665. When an aircraft enters a microburst (downburst) area:
Explanation
When wind shear airflow plunges and spreads outward, the aircraft first encounters a strong headwind, enters the downdraft zone, and then encounters a strong tailwind.
UAV-Q0666. Atmospheric stability is the stability of an entire air layer, sometimes called vertical atmospheric stability. It is judged by which motion?
Explanation
Study note: look for acceleration. Atmospheric stability is judged by the vertical acceleration motion of air temperature — the tendency of disturbed air to return to or move away from its equilibrium position.
UAV-Q0667. Atmospheric convection is caused by uneven surface heating. Heated air expands and rises; cooled air sinks, producing strong, fairly regular vertical motion. The higher the temperature, the more pronounced convection. Convection is therefore most pronounced in ( )
Explanation
Equatorial regions receive intense sunlight and high temperatures, with the most marked uneven surface heating, so atmospheric convection is most pronounced there.
UAV-Q0668. When temperature is higher than standard atmosphere temperature, aircraft payload will ( )
Explanation
High temperature means low air density and less lift, so aircraft payload decreases.