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.
