A fiber-optic sensor provides feedback control of onboard inert gas generation systems (OBIGGS) and reduces aircraft operational costs.

A fiber-optic sensor system has been developed that can remotely measure the concentration of molecular oxygen (O₂), nitrogen (N₂), hydro- carbon vapor, and other gases (CO₂, CO, H₂O, chlorofluorocarbons, etc.) in the ullage of a liquid-fuel tank. The system provides an accurate and quantitative identification of the above gases with an accuracy of better than 1 percent by volume (for O₂ or N₂) in real-time (5 seconds). In an effort to prevent aircraft fuel tank fires or explosions similar to the tragic TWA Flight 800 explosion in 1996, OBIGGS are currently being developed for large commercial aircraft to prevent dangerous conditions from forming inside fuel tanks by providing an “inerting” gas blanket that is low in oxygen, thus preventing the ignition of the fuel/air mixture in the ullage.