PT6A发动机反桨失效分析  

Analysis on Propeller Reverse Pitch Control Failure for the PT6A Engines

作　　者：明卉 周恒宇 MING Hui;ZHOU Heng-yu(Aviation Maintenance Department of Shanghai Civil Aviation College,Shanghai 200235,China)

机构地区：[1]上海民航职业技术学院民航维修学院,上海200235

出　　处：《机械研究与应用》2024年第6期121-125,共5页Mechanical Research & Application

摘　　要：针对一起运12IV飞机着陆后偏出跑道的事件,为了确定故障原因,通过现场勘察与系统测试对故障原因进行了初步分析与隔离。首先对PT6A-27发动机的螺旋桨反桨系统工作原理进行了研究,从液压和机械两方面叙述了反桨系统的运行。通过理论分析,按照由易到难的故障隔离顺序,确定了故障原因为:夹紧螺栓断裂导致左发反桨失效,造成左右发产生不对称推力,从而使飞机偏出跑道。然后从宏观、微观、材料成分、金相组织与硬度这几个方面分析出夹紧螺栓断裂的原因为应力腐蚀。结合该事故飞机海监作业的特点分析得出,由于长时间近海低空飞行,海洋大气环境造成夹紧螺栓的螺纹孔区域形成了应力腐蚀。最后提出了针对该故障的预防性维护措施,即通过加强外部水洗与定期检查来降低类似故障的发生概率。In response to an incident that a 12IV aircraft deviated from the runway after landing,to determine the cause of the malfunction,preliminary analysis and isolation of the cause of the malfunction was conducted through the field investigation and system test.The working principle of the propeller reverse system of the PT6A-27 engine was studied,and operation of the propeller reverse system was described from both hydraulic and mechanical aspects.With the help of theoretical analysis,and in the order of easy to difficult inspection,the cause of the fault was determined to be the failure of the left engine propeller reverse system caused by the fracture of the clamp bolt.The asymmetric thrust generated by the left and right engines caused the aircraft to deviate from the runway.The reasons for the fracture of the clamp bolt were analyzed from the aspects of macro,micro,material composition,metallographic structure,and hardness.The above characteristics indicate that the fracture is caused by stress corrosion.Based on the analysis of the characteristics of the aircraft's marine surveillance operation,it is found that due to long-term low altitude flight near the sea,stress corrosion is formed in the threaded hole area of the clamp bolt.Finally,preventive maintenance measures for this failure are proposed,namely strengthening external wash and scheduled inspections.

关 键 词：反桨 PT6A-27发动机 涡桨发动机 螺旋桨桨距 夹紧螺栓 

分 类 号：V235.12[航空宇航科学与技术—航空宇航推进理论与工程]