China Civil UAV Theory Questions — Questions 521–530
Unofficial study reference only. Not affiliated with or endorsed by any civil aviation authority — the official syllabus and regulations prevail.
UAV-Q0521. For visually judging wind shear, the INCORRECT reference is
Explanation
Cumulonimbus clouds generally do not bring rainfall and are not visual references for wind shear; dust devils (clouds) from thunderstorm cold outflow and rain shafts under thunderstorm clouds can serve as wind shear references.
UAV-Q0522. Aircraft icing is mainly caused by the presence in clouds of
Explanation
Aircraft icing is mainly caused by supercooled water droplets in clouds freezing upon contact with the airframe; supercooled droplets are the main cause.
UAV-Q0523. A typical thunderstorm cell's life cycle, by vertical airflow conditions, has three stages:
Explanation
A thunderstorm cell's life cycle is divided into the cumulus stage (updrafts), mature stage (updrafts and downdrafts coexisting), and dissipating stage (downdrafts).
UAV-Q0524. Temperature, pressure, and air humidity changes all affect aircraft performance and instrument indications, mainly through their effect on air density. Which description is correct?
Explanation
Study note: higher pressure means more air molecules and greater density (direct proportion); higher temperature means air expands and density decreases (inverse proportion).
UAV-Q0525. Warm fronts and cold fronts are very different in character:
Explanation
Study note: when warm and cold fronts appear together, look for the option containing both. Warm fronts move slowly (10–25 mph) and easily produce low visibility and rain; cold fronts move fast (20–35 mph) and easily produce gusts and turbulence.
UAV-Q0526. When an aircraft suddenly encounters headwind shear on landing, what phenomenon occurs?
Explanation
Headwind shear makes the wind oppose the heading, so airspeed increases, lift increases, and the aircraft pitches up and rises above the glide path.
UAV-Q0527. The atmosphere is composed of:
Explanation
Study note: atmosphere 78/21/1. Memorize the fixed ratio: 78% nitrogen, 21% oxygen, 1% other gases.
UAV-Q0528. For instrument-based wind shear judgment, which is INCORRECT?
Explanation
Wind shear mainly affects airspeed, altitude, vertical speed, and pitch angle; engine RPM does not change rapidly as a direct result of wind shear, and ground speed does not change significantly.
UAV-Q0529. In a thunderstorm's life cycle, which stage is characterized by downdrafts filling the cloud?
Explanation
In the dissipating stage, downdrafts fill the thunderstorm cloud, and cloud temperature is lower than surrounding air.
UAV-Q0530. The pressure entered on a surface weather chart is:
Explanation
Surface weather charts show sea-level pressure, so pressure distributions at different locations can be analyzed uniformly.