本手册取代了第205号通告，旨在帮助各国使用最新的程序和可用的最新飞机噪音和性能信息，计算机场周围的噪音等值线。它包括三种不同的方法，最实用的噪音模型计算飞机单事件噪音水平，旨在利用在线国际飞机噪音和性能（ANP）数据库。

This manual, which replaces Circular 205, is intended to assist States in the computation of noise contours around airports, using the most up-to-date procedures and the most recent aircraft noise and performance information available. It includes three different ways in chich most practical noise models calculate aeroplane single event noise levels and is designed to make use of an online international aircraft noise and performance (ANP) database.