Hazardous Levels of Commercial Aircraft Response to Atmospheric Turbulence

Abstract

Jet commercial aircraft in flight are frequently subject to atmospheric turbulence resulting in rapidly varying aerodynamic and flight dynamic characteristics. These varying characteristics not only pose threats to flight safety, but also may cause structural damages and reduce fatigue life. The sudden plunging motion in severe turbulence is the major reason to cause the flight injuries. To express the turbulence intensities as the hazardous levels, the root-mean-square g-load, usually for structural load, has been examined in the past twenty years. The present study is to examine alternative ideas to express the hazardous levels of sudden plunging motion in atmospheric turbulence. The flying-quality parameters of the plunging mode and integrated turbulence-induced downwash will be proposed as more reliable parameters for the turbulence hazard levels.

Structural Health Monitoring of Transport Aircraft with Fuzzy Logic Modeling

“…The present modeling method was first developed by Takagi and Sugeno [9] and Sugeno and Tanaka [10], and later in 1995, Xie et al [11,12] applied the theory to simulate microelectronic processes with very good accuracy. The present paper is based on the modeling technique suggested by Xie et al This technique was first applied to aviation technology in 1997 and later to flight data [13][14][15][16]. A new application of this modeling technique to examine aeroelastic effects of a transport aircraft is presented in this paper.…”

“…By varying the influencing parameters one at a time, the corresponding changes in the aerodynamic coefficients are used to predict the related stability and control derivatives for the analysis of flight dynamic characteristics. All aerodynamic derivatives are computed with central differences [15,16].…”

Structure health inspection for aging transport aircraft

“…The fast-varying characteristics of aircraft response to severe clear-air turbulence not only pose threats to flight safety, but also may cause structural damages and reduce fatigue life. One main type of motion that causes flight injuries in clear-air turbulence is the sudden plunging motion with the abrupt change in flight attitude and gravitational acceleration (Chang et al, 2009(Chang et al, , 2010. In the estimation of gust loads on aircraft, the maximum response to random gust is of main interest, especially for the structural design purpose (Lee and Lan, 2000).…”