Boeing B737cl Aircraft Bs727 Strengthen The Center Of The Frame Edge Damage Repair

The structure damages on the BS727 bulkhead center chord in Boeing B737CL aircraft have not only jeopardized the aircraft continued airworthiness, but have also caused long time unscheduled structure repair and huge economic loss.Corrosion and Crack are the most common damage on the BS727 bulkhead center chord. This paper has affirmed the damage rules and the crack type, which are SCC (Stress Corrosion Crack) and corrosion-fatigue, after more than one year's investigation and study.According to the root of the corrosion, SCC and corrosion-fatigue, this paper has analyzed the stress level, stress distributing character, structure designing and maintenance defects. Based on those analysis, this paper has concluded the BS727 bulkhead center chord damage root and has provided the damage prevention & control countermeasures, which satisfy the airframe designing principle and MSG-3 airframe maintenance theory.SCC and corrosion-fatigue crack are the main sources which endanger the aircraft continued airworthiness. The damage prevention & control countermeasures in this paper are crucial to ensure the B737CL aircraft safety and can greatly decrease the maintenance cost. Those countermeasures have gained the approval of Boeing, Civil Aviation Administration of China and Hainan Airlines. They have also been using in Hainan Airlines and have gained great success.This paper includes seven chapters, which have detailed the SCC and corrosion-fatigue crack causes, identify measures and the prevention & control measures. We have also analyzed the stress distribution character by Limited Model to explain the BS727 bulkhead center chord damage rules. The first chapter introduces the background of this study. The second chapter introduces the main function, designing and load character of the BS727 bulkhead and its center chord. The third chapter briefs the BS727 bulkhead center chord damage investigation and the damage rules. The fourth and fifth chapters are the core of this paper. The damage type and roots have been clarified in the two chapters. The sixth chapter is the fruit of the study, which has detailed the damage prevent & control countermeasures. The seventh chapter briefs the value of the study, the study fruit application and its outlook.