a first row of vanes disposed about an engine axis, a second row of vanes axially spaced from the first row of vanes, and a row of blades axially between the first row of vanes and the second row of vanes;

a row of blade outer air seal arc segments situated radially outwardly of the row of blades, each of the blade outer air seal arc segments including a ceramic matrix composite (CMC) body defining a core gaspath side facing the row of blades, a non-core gaspath side opposite the core gaspath side, a forward end, an aft end, and circumferential sides, the CMC body having first and second flanges projecting from the non-core gaspath side, the blade outer air seal arc segments being arranged such that the circumferential sides of adjacent ones of the blade outer air seal arc segments mate at respective interfaces; and

a seal system disposed in each of the interfaces, the seal system including a first seal and at least one second seal that partially overlaps the first seal, the at least one second seal configured to bias the first seal into a sealing position, and the at least one second seal includes two second seals, each of the two second seals having an L-shape, the L-shape including first and second legs that meet at a corner, the first leg overlapping and contacting the first seal, and the second leg extending away from the first seal, and the first legs of the two second seals are of unequal length.