一、概述据民航总局运行管理中心报告:2005年4月20日13:00～14:15时(世界协调时UTC,下同),上海虹桥、浦东机场同时出现了低空风切变(以下简称“04.20”低空风切变),影响三个航班备降杭州,八个航班复飞,二十五个航班盘旋等待。浦东机场报告,低空风切变主要出现在五边区域上空200 I. Overview According to the Civil Aviation Administration operation and management center report: April 20, 2005 13: 00 ~ 14: 15 (UTC UTC, the same below), Shanghai Hongqiao, Pudong Airport at the same time a low-level wind shear (hereinafter referred to as “04.20” low-altitude wind shear), affecting the three flights standby Hangzhou, eight flights go around, twenty-five flights circling wait. Pudong Airport reported that the low-level windshear occurred mainly in the areas above the five sides 200