Aircraft are flight tested in which conditions?

Aircraft are flight tested in conditions represented by FZRA (Freezing Rain) and FZDZ (Freezing Drizzle) because these conditions are critical for assessing the performance and safety of an aircraft in adverse weather. Testing in freezing rain and drizzle scenarios helps engineers and pilots understand how an aircraft handles ice accumulation, affects aerodynamics, and the operation of systems like de-icing mechanisms. It is essential to ensure that an aircraft can safely operate in a range of adverse weather conditions, especially since flying in icy environments is a common scenario in the aviation industry.

While clear air testing is fundamental for evaluating basic flight characteristics, it does not provide insights into an aircraft's performance under the more perilous conditions created by icing phenomena. Similarly, limiting testing to only one type of precipitation, either freezing rain or freezing drizzle, would not provide the comprehensive data needed to evaluate the aircraft's resilience and capabilities. Thus, flight testing in both FZRA and FZDZ offers a broader understanding of aircraft performance in challenging weather scenarios.