The FAA has released an updated Obstruction Marking and Lighting Advisory Circular (70/7460-1L Change 2) requiring that LED L-810, L-864 and L-885 obstruction light fixtures include Infrared (IR) emitters to make obstruction lighting systems more visible to pilots who use Night Vision Imaging Systems (NVIS). NVIS and Night Vision Goggles (NVGs) are used in civilian aviation for search-and-rescue, emergency medical transport, and other flight operations to increase situational awareness. According to the FAA, tower owners with FAA determinations issued after the updated advisory release date must include IR LEDs in lighting fixtures. As incandescent obstruction light fixtures are replaced with LED light fixtures, pilots using NVIS equipment that filters the adverse effects of cockpit lighting cannot see red LED-based obstruction lighting because the light generated is outside of the combined visible and near-infrared spectrum of NVGs. In response to a Safety Risk Assessment of LED Lighting in Aircraft Operations, the FAA established IR specifications for LED-based red obstruction lights in Airport Engineering Brief 98, Infrared Specifications for Aviation Obstruction Light Compatibility with Night Vision Goggles (NVGs), published in December of 2017. This brief provides information about the interaction of LEDs used in obstruction lighting fixtures with NVGs, and provides performance specifications for IR emitters to ensure compatibility with NVGs.