This SAE Aerospace Recommended Practice (ARP) contains methods used to measure the optical performance of airborne binocular Head Up Displays (HUDs). This document covers methods for conformal and non-conformal HUD systems that are intended for use in the cockpit by the pilot or copilot. The focus of this document is on displays that generate the HUD information using a cathode ray tube (CRT), however, the majority of the methods can be applied to other display technologies. These measurement methods are provided for testing to the requirements of AS8055. This document does not address measurement methods for sensor imaging systems, or displays worn by the pilot (goggles, helmet mounted displays).