Adjustable fan track liner with dual grooved array active fan tip treatment for distortion tolerance

A fan case assembly adapted for use with a gas turbine engine, the fan case assembly comprising

• a case that extends circumferentially at least partway about a central axis of the fan case assembly to define an outer boundary of a gas path of the gas turbine engine, the case formed to define a channel that extends circumferentially at least partway about the central axis,
• a plurality of drums arranged in the channel and spaced circumferentially about the central axis, each drum of the plurality of drums including a first groove and a second groove spaced axially along the drum form the first groove that each extend partway into the corresponding drum, each drum of the plurality of drums is configured to rotate about a respective drum axis between a closed position in which the first groove and the second groove of the corresponding drum both face away from the gas path so that the outer surface of the corresponding drum cooperates with an inner surface of the case to define the outer boundary of the gas path, a first open position in which the first groove of the corresponding drum faces radially inward towards the gas path while the second groove remains facing away from the gas path, and a second open position in which the second groove of the corresponding drum faces radially inward towards the gas path while the first groove remains facing away from the gas path, and
• a control unit configured to rotate the plurality of drums about the respective drum axis between the closed position, the first open position, and the second open position in response to preselected operating conditions to minimize negative effects pressure and swirl distortions in the gas turbine engine to improve stall margin.