A GASEOUS OXYGEN FIBER OPTIC CHEMICAL SENSOR (FOCS) FOR ON-BOARD AIRCRAFT USE

A FIBER OPTIC CHEMICAL SENSOR (FOCS) IS PROPOSED TO MEASURE THE BREATHING OXYGEN CONCENTRATION ON-BOARD AIRCRAFT. THE FOCS WILL MONITOR AND CONTROL THE OUTPUT OF THE ON-BOARD OXYGEN GENERATING SYSTEM (OBOGS) SO THAT OXYGEN CONCENTRATIONS REMAIN WITHIN THE DESIRED LIMITS. THE FOCS WILL BE DESIGNED SO THAT IT SEES REPRESENTATIVE VOLUMES (SELECTABLE) AND CONCENTRATIONS OF OXYGEN. THE OXYGEN SENSOR WOULD BE A COMPLETELY SOLID STATE DEVICE WITH NO MOVING PARTS. IT WILL BE: SIMPLE, SPECIFIC, SENSITIVE (DESIGNATED DYNAMIC RANGE), LIGHT-WEIGHT, LOW POWER, LONG-LIVED, RELIABLE, TEMPERATURE AND PRESSURE INSENSITIVE, UNAFFECTED BY ACCELERATION, FAST RESPONDING AND HAVE A FEED-BACK CIRCUIT TO CONTROL THE OBOG. WITH THE EXCEPTION OF RIDGED TIPS, I.E. THE SENSOR (<2 CM LONG), THE FIBER OPTICS ARE FLEXIBLE FOR EASY PLACEMENT. THE SENSING CHEMISTRY IS REVERSIBLE SO THAT NO ROUTINE SERVICE OF THE SENSOR IS REQUIRED. THE SUPPORT INSTRUMENTATION IS SIMPLE AND CAN BE VERY SMALL BECAUSE SPECIFICITY AND SENSITIVITY ARE RELEGATED TO THE FOCS.