This document provides information regarding ice detector technology, and design and operating requirements. Icing rate information is included where applicable. The primary application is associated with ice forming on the leading edges of airfoils and inlets with significant forward velocities. Information related to detection of ice at static conditions, ice over cold fuel tanks, and icing at low velocity operation is also included. The material is primarily applicable to transport and light aircraft. Special consideration for rotorcraft is appended separately. The purpose of this document is to provide information and guidelines related to the method of operation, performance, design, verification, and installation of aircraft ice detectors and icing rate indicators.