This SAE Aerospace Information Report (AIR) describes the design approaches used for current applications of aircraft Brake-by-Wire (BBW) control systems. The document also discusses the experience gained during service@ and covers system@ ergonomic@ hardware@ and development aspects. The document includes the lessons that have been learned during application of the technology. Although there are a variety of approaches that have been used in the design of BBW systems@ the main focus of this document is on the current state of the art systems. Purpose Although the designers and users of aircraft BBW systems are familiar with their functions@ features@ components@ and limitations@ there is no readily available documentation that describes the field in breadth. This document seeks to address this need by providing an overview of the current state of the art with respect to function@ components@ and issues. The experience that has accumulated from existing BBW systems is presented as an aid to those who are embarking on the design of a new application or who are preparing specifications for a BBW system.