民用飞机临界冰型确定策略浅析

Determination Method of Critical Ice Shapes for Large Civil Aircraft

分析了适航规章第25部121修正案中关于民机临界冰型的修订内容,提出大型客机结冰适航验证所用临界冰型的确定策略。针对飞机不同飞行阶段分析飞机结冰特征,对飞机不同部件开展结冰参数临界性分析,确定临界结冰条件,结合结冰数值预测和冰风洞试验手段提出相应的临界冰型确定方法;同时提出适航验证所需失效冰型、延迟冰型等特殊冰型的确定方法。根据性能、操稳和动力专业对于结冰临界性的不同要求,对比评估各种冰型对飞机影响的严重程度,最终确定飞机用于适航验证的临界冰型。本文可为大型客机的结冰适航验证工作提供参考。

The content about airplane critical ice shapes in Amendment No. 25-121 of 14 CFR Parts 25 is analyzed. We presented the determination method of the critical ice shapes on large airplanes used in icing airworthiness validation. The study is conducted on the ice accretion characteristics within the different flight phases. The critical analysis about icing parameters is conducted based on the different parts of aircraft to determine the critical icing condition. The critical ice shapes is determined using the numerical simulation and icing wind tunnel test.The method to determine the disabled ice and delayed turn on( DTO) ice accretion is also presented. According to the different needs about icing criticality of the flight performance,maneuver and stabilization and engine design,the effects to the aircraft of all ice shapes are compared and evaluated. Then the critical ice shapes used in airworthiness validation is determined. The contents of this paper can be be consulted in large aircraft airworthiness validation.