Patent ID: 7207768

Claim:
A system for providing advance warning of contact of neighboring turbine engine components comprising: a stationary turbine engine component; a rotating turbine engine component substantially proximate to the stationary turbine engine component so as to define a gap therebetween; and a contact sensor extending from one of the stationary component and the rotating component into the gap toward the opposing component, wherein contact sensor is responsive to contact with the opposing component by generating a warning signal, wherein the pad comprises at least two layers, wherein an outer layer produces a first acoustic warning signal upon contact with the opposing turbine engine component and an inner layer produces a second acoustic warning signal upon contact with the opposing turbine engine component, wherein the first acoustic warning signal is acoustically distinct from the second acoustic warning signal, wherein the contact sensor is a pad secured to one of the stationary component and the rotating component, whereby the signal provides advance warning of impending contact between the stationary and rotating turbine engine components.