本SAE航空航天标准（AS）规定了最大坡道重量大于50000 kg（110000磅）的商用民用运输飞机的常规三轮车式起落架的前起落架（当从前起落架执行牵引操作时）上牵引杆连接配件的接口要求，通常称为“主线飞机”。其目的是通过飞机重量类别（确定牵引杆力）实现牵引杆连接配件接口标准化，以确保一种带有标准连接的牵引杆可用于该重量类别内或附近的所有飞机类型，以协助运营商和机场地勤公司减少使用不同类型牵引杆的数量。

This SAE Aerospace Standard (AS) specifies the interface requirements for tow bar attachment fittings on the nose gear (when towing operations are performed from the nose gear) of conventional tricycle type landing gears of commercial civil transport aircraft with a maximum ramp weight higher than 50,000 kg (110,000 pounds), commonly designated as “main line aircraft”.Its purpose is to achieve tow bar attachment fittings interface standardization by aircraft weight category (which determines tow bar forces) in order to ensure that one single type of tow bar with a standard connection can be used for all aircraft types within or near that weight category, so as to assist operators and airport handling companies in reducing the number of different tow bar types used.