Night vision goggles may not detect certain red LEDs, says FAA
Some LED lighting systems fall outside the combined visible and near-infrared spectrum of night-vision goggles, says the US Federal Aviation Administration.
This SAFO advises operators using NVGs that certain LED lighting systems fall outside the combined visible and near-infrared spectrum of NVGs, and thus will not be visible to them.
FAA requirements for "Aviation Red" light ranges from about 610-700 nm, and NVGs approved for civil aviation (having a Class B Minus Blue Filter) are only sensitive to energy ranging from 665 to ~930 nm, the alert says.
Crews that fly using NVGs are warned to use extra caution when flying near obstacle areas. The FAA recommends training for NVG users, to advise pilots of the limitations outlined in this SAFO.
In 2008, a Flight Safety Flash was issued by the Canadian Air Force’s Directorate of Flight Safety that identified some red obstruction LED lighting systems that were clearly visible to the naked eye but not visible to NVGs, the alert adds.