Radar equipment mounted on an aircraft for purposes of weather avoidance or weather observation. Airborne weather avoidance radars are usually mounted in the nose of the aircraft, scanning ahead of the aircraft for weather hazards. Airborne research radars are frequently Doppler radars that provide measurements of radial wind or turbulence in addition to radar reflectivity. Such radars are typically side-pointing or helical scanning and may use dual beams to enable dual- Doppler analysis of storm motions. Airborne weather radars ordinarily operate at wavelengths of C-band or shorter to keep the physical size of the equipment small.