桃園國際機場執行持續下降操作之研究

Implementation of Continuous Descent Operations at Taoyuan International Airport

面對全球暖化威脅，航空運輸體系積極改善作業流程，配合綠色運輸之總體發展目標。航機降落前之「持續下降操作」（Continuous Descent Operation, CDO）已被證實可減少二氧化碳排放與噪音汙染，全球許多機場均已公告相關操作程序。桃園國際機場CDO執行成效或相關分析之探索相對較少，本研究利用Flightradar24網站蒐集潛在可執行CDO航班，進行資料判讀和研析。桃園機場在108年4月CDO的執行率達46.89%左右，其中長榮航空航班和波音777機型皆擁有較高的執行率。來自不同洲際執行CDO航班之平面軌跡，與標準進場程序的互異性較為明顯。航班起始下降點（Top of Descent, TOD）的高度，則遵循空層垂直間隔原則。至於執行CDO程序的降落時間大部分少於30分鐘，僅澳洲航線高於此一門檻，並在統計上與其他航線有顯著差異。

Facing various kinds of threat from global warming, air transport system also aggressively implemented some improvement on operation procedures for coping with the ultimate target of green transport. Flights conducting the continuous descent operations (CDOs) have been proved effective on carbon and noise pollution abatement already. Many airports also announced the related operation procedures. However, the implementation reports or studies for Taoyuan International Airport (TPE) were limited. This study, based on the records of Flightradar24 database, collected the flights of conducting CDOs at TPE to analyze their characteristics. The CDO execution rate at TPE was 46.89% in April 2019. Flights of EVA AIR and B777 had higher execution rates. The aircraft lateral trajectories of different routes appeared more significant deviations with the standard approach procedures. The altitudes of top of descent (TOD) followed the vertical separation principles on flight levels. Time durations from TOD to aircraft landing for most flights were less than 30 minutes, but flights from Australia spent much time than this threshold and with statistical significance.