Aircraft are provided with a pair of auxiliary power units adjacently mounted in parallel relative to one another within the tail cone section of the aircraft’s fuselage. The exposed portion of the first dichroic filter material layer is removed so as to form a plurality of first dichroic filter units. When no users are connected to the server or at other appropriate times, the cellular-telephone-based server may enter a hibernation state to reduce power consumption. More particularly, in accordance with one aspect of the invention, signaling between a baseband portion of a communications apparatus and a radio portion of the communications apparatus is achieved by encoding data units of a given number of bits into codes, each code being a data unit of a number of bits greater than the given number of bits. The plates restrain the sprayed coating to prevent delamination during friction welding.