飞机前座舱盖故障分析

Analysis on Dropping-out Failure of an Airplane Front-canopy

本文是针对一起飞机飞掉前座舱盖的事故征候的综合分析。通过对抛舱盖薄膜活门膜片的断口和痕迹分析,对不同生产厂家的衬套R角加工质量进行对比以及用原机前舱盖薄膜活门进行地面耐压试验等分析验证工作,确定飞机发生飞掉前座舱盖的事故征候是由于抛盖薄膜活门的膜片异常爆破造成。膜片爆破的主要原因是二次装配造成的挤压伤。膜片挤压伤处形成应力集中,在高压冷气作用下爆破,造成应急抛盖作动筒工作,空中飞掉前座舱盖。另外衬套的加工质量不好也是膜片爆破的原因之一。

In this paper, the accident that the airplane front-canopy dropped was synthetically analyzed. According to the fracture and trace analysis of the failed diaphragm membrane, contrasting the bushes that were made by different factories, and ground compression test of the normal diaphragm membrane, it is found that, the accident that the airplane front-canopy dropped was caused by the abnormal break of membrane. Extruding injure of membrane caused in the second assembly was the main reason for the failure. The break of membrane under the high pressure and low temperature because of stress concentration in the position of the extruding injure of membrane, caused that the emergency actuating cylinder started running, and the airplane front-canopy dropped in the air. In addition the poor machine quality of the bush was attributed to this failure.