Gas turbine engine liner

A liner for a gas turbine engine is provided that includes a first liner section and a second liner section. The first liner section includes a first flange having a first contact surface. The second liner section includes a second flange having a second contact surface and a plurality of apertures. The first and second flanges axially overlap one another, and in a circumferential liner the second flange is disposed radially outside of the first flange. A channel is formed by the two liner sections that is open to the core gas path. In a first position, the first flange axially overlaps the second flange by a first distance and the apertures are misaligned with the first flange and disposed within the channel. Cooling air entering apertures within the second flange subsequently passes into the channel. In a second position, the first flange axially overlaps the second flange by a second distance. The second distance is greater than the first distance and in the second position the apertures in the second flange are substantially aligned with the first flange. Cooling air entering the second flanges apertures subsequently impinges on the first flange.