A foreign object debris (FOD) detection system for a gas turbine engine comprises a light detection and ranging (LiDAR) sensor assembly. The LiDAR sensor assembly is configured to scan a pre-determined volume within an inlet of the gas turbine engine. The inlet may be defined by a nacelle of the gas turbine engine. The LiDAR sensor assembly may comprise a single transceiver, a transmitter and a receiver, a plurality of transmitters and a receiver, or a plurality of receivers and a transmitter.