將志才

A Disscussion of the Flight Accident of CAL over Clark USAFB in Philippines

Chih T. Chiang

Abstract

　　According to the report of daily news, a Beoing passenger’s airplane of China Air Line met with an accident by clear air turbulence over Clark Air Force Base of United States (USAFB) in Philippines of August 23, 1977. The airplane dropped down over one thousand feet suddenly when it clambered up to 27,000’high, and 32 passengers hurted who had never been fastened their own safe belt.

　　The cause occurred flight accident has been made a meteorological analysis as follow：

1.The position of the flight accident had a deep trough over 500mb constant pressure chart during that time.

2.Airplane passed under right side of a equatorial jet stream where had a great number of horizontal wind shear index, and wind direction ahead the airplane moving was changed ripidly.

3.The vertical wind shear cross section shown that air clear turbulence would be occurred by the vertical wind shear between 24,000′ and 30,000′ over Clark USAFB.

4.The temperature difference between 500mb and 300mb constant pressure level was a high value over Philippines Island, which means a great temperature lapse rate caused the clear air turbulence to occur.