The US Army Aviation RDEC's Aeroflightdynamics Directorate (AFDD) in cooperation with the Department of Defense Flight Symbology Working Group, the United Kingdom's Defense Research Agency (DRA), and The Technology Cooperative Program Helicopter Technical Panel 6 (HTP6), conducted a Helmet Mounted Display (HMD) symbology investigation using AFDD's Crew Station Research and Development Facility helicopter simulator located at the Ames Research Center, Moffett Field, California. The objectives of the experiment were to examine HMD symbology stabilization, pitch ladders, flight path presentations, and tasks and measures that capture objective and subjective performance differences. Symbology presentation techniques closely modeled specific presentations found in the US Army's AH- 64D Apache helicopter and proposed symbology techniques for the RAH-Comanche and Longbow Apache rotorcraft. Eight helicopter pilots from DOD and DRA participated in the study flying simulated low-altitude rotorcraft maneuvers. This paper describes the simulation flight tests, test results, implications of test findings and recommendations for future HMD investigations.