In May 2024 the joint European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) mission EarthCARE was launched. A similar payload as on the satellite was set up on the German research aircraft HALO, and deployed during an extensive measurement campaign to validated the satellite. We present our instrumentation, the measurements, and its potential for the validation of EarthCARE. We show first validation results and assessments of the EarthCARE data quality.