Structural Health Monitoring and Flight Safety Warning for Aging Transport Aircraft

Abstract

Through the assessments of stability derivatives to indirectly determine the structural health of transport aircraft, a method based on static aeroelasticity theory is presented. The flight data of two twin-jet transport aircraft encountering severe clear-air turbulence at transonic flight will be the study cases. One of these two twin-jet transport aircraft is an aging one and the other is a new one. The nonlinear unsteady aerodynamic models are established through flight data mining and fuzzy logic modeling techniques based on flight data. The pitch damping in oscillatory motion, controllability in longitudinal aerodynamics, and static aeroelastic characteristics in terms of the first and second aerodynamic derivatives are then estimated by using these aerodynamic models. A comparative analysis of static aeroelastic behaviors in severe clear-air turbulence for these two twin-jet transport aircraft will be assessed. The static aeroelastic effect of aging transport aircraft is more significant than that of the new one and has a larger impact on the empennage structures. The root cause of the larger static aeroelastic effects and irregular deviations of stabilizer with obvious problems of screw jack assembly will be discussed. This method can be used to assist certificate holders of aircraft maintenance factories to monitor the variations of static aeroelastic behaviors and issues of flight safety warnings for aging transport aircraft. This is used as a complementary tool for the structural maintenance program to improve aviation safety, operation, and operational efficiency.