One of which is much more deeds given as much as possible.

The new forecast analysis method on the flight accident-rate and the flight incident-rate is discussed by using the forecast method based on grey control principle.

Summarizing investigations on several flight accidents of CRJ-200 and its former type,the Challenger,caused by aerodynamic stall,analyses QAR data of an accident happened in the course of taking off,and conduct an analysis focusing on their contributing factors,the characteristics seen after the accident,the way of how to identify the aerodynamic stall and of how to get rid of it.

The paper presents the concept of safety fluctuation,arid with the spectrum analysis of flight accident rate da- ta through past 57 years,we prove that the safety fluctuation exits and measure its wave cycle,so as to provide useful references and inspiration for civil aviation units in taking effective measurement to prevent flight accident.

Method The human factor accident/incident classification standard is developed on the basis of Reason's Model, combining with CAAC’s traditional classifying method, and applied to the classified statistical analysis for 361 flying incidents and 35 flight accidents of China civil aviation, which is induced by human factors and occurred from 1990 to 2001.

Measures to avoid navigational accident;