The Federal Aviation Administration (FAA) recently published a memo announcing the approved use of Audio Visual Warning Systems (AVWS) in the National Airspace System (NAS) and the administration's intentions to update Advisory Circular 70/7460-1K, Obstruction Marking and Lighting, the recommended marking standards for obstacles that penetrate the NAS. An AVWS is a system that activates obstruction lighting and audio signals to alert the pilot of potential collisions with obstacles. OCAS is the first AVWS to be installed, tested, and approved in the NAS. An AVWS is designed to significantly reduce the potential for a wire strike or obstacle collision for low flying aircraft. There are over 5000 such incidents/accidents in the National Transportation Safety Board database.