Radar, Airfield, and Weather Systems (RAWS) CDC Volume 3 Practice Test 2026 - Free RAWS Exam Questions and Study Guide

Radial velocity is the rate at which the aircraft is moving toward or away from the radar along the line of sight. The radar’s Doppler shift reveals this line‑of‑sight speed, which depends on both how fast the aircraft is actually going and how aligned its flight path is with the radar line to the aircraft. If the aircraft heads straight at the radar, the radial velocity equals the full speed. If it travels at an angle, only the component of speed along the line to the radar contributes to the radial velocity (radial velocity = speed × cos(angle)). If the motion is perpendicular to the line of sight, radial velocity is zero—even though the aircraft may be moving fast sideways. This is why radial velocity is the measure tied to speed and angle relative to the radar. The other terms describe location (where the aircraft is) or a different kind of speed (ground speed), not the line‑of‑sight speed detected by Doppler.