FIBER OPTIC EXIT AREA SENSING FOR GAS TURBINE ENGINE NOZZLES

A gas turbine engine (90) has a fan case exit (94) and an inner core housing exit (97), at least one of which is provided with a fiber optic sensing unit (85, 185). that includes a fiber optic sensing member (98, 100) surrounding a circumference of the exit(s). A control (98C, 100C) is programmed to calculate a nozzle area (99, 101) at the exit(s) based upon the displacement of the fiber optic sensing member (98, 100). The calculated nozzle area is utilized to update nozzle area information at an electronic engine controller (86) that is programmed to control at least one associated component on the engine based upon the updated nozzle area.