Ormosil coating-based oxygen sensor for aircraft ullage

Significant emphasis has been placed on fuel tank safety since the TWA flight 800 accident in July 1996. Upon investigation the National Transportation Safety Board (NTSB) determined that the probable cause of the accident was an explosion of the center wing tank (CWT), resulting from ignition of the flammable fuel/air mixture in the tank. The Federal Aviation Administration (FAA) has focused research to support two primary methods of fuel tank protection -- ground-based and on-board -- both involving fuel tank inerting. Ground-based fuel tank inerting involves some combination of fuel scrubbing and ullage washing with Nitrogen Enriched Air (NEA) while the airplane is on the ground (applicable to all or most operating transport airplanes). On-board fuel tank inerting involves ullage washing with OBIGGS (on-board inert gas generating system), a system that generates NEA during aircraft operations. An OBIGGS generally encompasses an air separation module (ASM) to generate NEA, a compressor, storage tanks, and a distribution system. Essential to the utilization of OBIGGS is an oxygen sensor that can operate inside the aircraft's ullage and assess the effectiveness of the inerting systems. OBIGGS can function economically by precisely knowing when to start and when to stop. Toward achieving these goals, InnoSense LLC is developing an all-optical fuel tank ullage sensor (FTUS) prototype for detecting oxygen in the ullage of an aircraft fuel tank in flight conditions. Data would be presented to show response time and wide dynamic range of the sensor in simulated flight conditions and fuel tank environment.