Purpose of this Document

This document sets forth the desired characteristics of a new Distance Measuring Equipment intended for installation in commercial transport aircraft. The intent of this document is to provide general and specific design guidance for the development of the DME. It will describe the desired operational capability of the equipment and the standards necessary to ensure interchangeability.

Equipment manufacturers should note that this document encourages them to produce maintenance-free, high performance equipment rather than that of minimum weight and size. They are at liberty to accomplish this objective by means of the techniques they consider to be the most appropriate. Their airline customers are interested primarily in the end result rather than the means employed to achieve it.