【摘要】 2022年1月20日，在陕西及周边地区开展了飞机自然结冰飞行试验，利用机载探测资料对飞机结冰强度及运输类飞机适航标准CCAR 25部附录C包线的符合性进行了分析，并利用常规气象资料、大气再分析资料和卫星云图等给出了该飞行试验过程的结冰气象条件及云层宏微观特征。结果表明：此次飞机自然结冰发生在西南暖湿气流北抬和地面回流强冷空气造成中低空深厚逆温层结的天气背景下。试验区域内的环境温度为-9～-5℃,相对湿度大于80%,水汽通量散度小于-0.9×10^-7 g·s^-1·hPa^-1·cm^-2,有利产生自然结冰。同时，云层上部存在0～5 cm·s^-1的弱上升气流，对过冷云滴的增长起促进作用。机载探测数据显示云内过冷小云滴丰富，且分布较均匀，数浓度平均值为445～956个·cm^-3,LWC平均值为0.28～0.39 g·m^-3,MVD平均值为13.88～15.91μm,呈现典型层状云特征。此外，云中伴有少量的过冷大水滴，无明显冰晶粒子生成，云内贝吉隆过程不显著。飞机共开展8次穿云试验，第6次为重度结冰，其余以中度结冰为主，仅瞬时出现重度结冰。LWC、MVD及环境温度低于CCAR 25部附录C规定的连续最大结冰状态，满足飞行条件。更多还原

【Abstract】 An aircraft natural icing flight test was carried out in Shaanxi and its surrounding areas on January 20, 2022. The aircraft icing intensity and the compliance of Appendix C envelope of CCAR 25 airworthiness standard for transport aircraft were analyzed by using airborne detection data. The meteorological conditions of icing and the macroscopic and microscopic characteristics of clouds during the flight test were given by using conventional meteorological data, atmospheric reanalysis data and satellite cloud images. The results show that the natural icing of the aircraft occurred under the weather background of the north uplift of the southwest warm and humid airflow and the deep inversion stratification of the middle and low altitude caused by the strong cold air backflow from the ground. The ambient temperature in the test area is during-9 and-5 ℃, the relative humidity is more than 80%, and the water vapor flux divergence is less than-0.9×10^-7 g·s^-1·hPa^-1·cm^-2, which is beneficial to the natural icing. At the same time, there is a weak updraft of 0-5 cm·s^-1 in the upper parts of the cloud, which promotes the growth of supercooled cloud droplets. Airborne detection data show that the supercooled small cloud droplets in the cloud are rich and evenly distributed. The average number concentration was 445-956 cm^-3, and the average LWC was 0.28-0.39 g·m^-3, and the average MVD was 13.88-15.91 μm, which presenting typical stratiform cloud characteristics. In addition, the cloud is accompanied by a small amount of supercooled large water droplets, no obvious ice crystal formation, cloud Bergeron process is not significant. The aircraft carried out a total of 8 cloud penetration tests. The sixth time was severe icing, and the rest was mainly moderate icing, with only instantaneous severe icing. The LWC, MVD and ambient temperature are lower than the continuous maximum icing state specified in appendix C of CCAR 25, which meets the flight conditions.更多还原