China Civil UAV Theory Questions — Questions 962–971

The aircraft approaching the runway extended centerline quickly while the remaining turn angle decreases slowly means the aircraft entered the turn late, and at the current turn rate the turn cannot be completed in time. The bank and turn rate must be increased to speed up the change of turn angle.

With a normal glide path, a high speed means the aircraft will fly farther in the descent, delaying touchdown, so the visual estimate is high. High speed needs to be reduced by closing the throttle.

The causes tested here are all pilot-caused. There are three main causes of deviation: (1) failure to check the attitude indicator position promptly, resulting in flight with a bank; (2) rough actions and large control inputs, causing an unstable flight state; (3) when switching among level flight, climb, and descent, push and pull directions that are not straight, interfering with other channels.

Coordinated turn (with bank): press the stick and twist the rudder toward the turn. Unbanked turn (for orthomosaic missions): press the rudder toward the turn, with opposite aileron to keep the wings level.

Study note: pressing the stick and rudder increases the bank; returning the stick and rudder decreases it. When the bank is too large, reduce it by returning the stick and rudder; when the bank is too small, increase it by pressing the stick and rudder.

Because of inertia, changing from a turn to level flight takes time. When rolling out of a turn, therefore, begin returning the stick gradually when 10°-15° away from the target direction.

In a level turn, the wing tilts toward the turn, and the horizontal component of lift completes the turn; at that point the vertical component of lift is less than the weight. To obtain enough lift, the throttle must be increased, so that higher speed produces greater lift, and the greater lift's vertical component offsets the weight.

If the visual estimate is high, height must be lost quickly; if the visual estimate is low, the descent rate must be slowed. When visually low, increase the throttle while appropriately increasing the pull and decreasing the glide angle, leveling off for a stretch if necessary. Waiting until the aircraft has descended to a low altitude to correct may leave too little time.

A height at the fourth turn above the planned height means height must be lost quickly. Height can be lost by increasing the glide angle and closing the throttle to slow down.

Study note: leveling off is always started before the planned altitude. Because of inertia, transitions among level flight, climb, and descent take time. When changing from a climb to level flight, therefore, begin leveling off 10-20 m before reaching the planned altitude.