An arrangement for removably fixing a thermal protection tile on the inside of a combustion chamber wall is described. In one form the tile is provided with a fixing stud which is arranged to pass through a hole in the wall, and a split washer is inserted under the head of the stud to lock the assembly to the wall. In another form the tile is provided with a fixing stud having a head which is arranged to be inserted in a socket welded to the inner surface of the wall and which is locked in place by a stop inserted through a hole in the wall to abut the edge of the head and prevent its removal from the socket.