A firearm includes a receiver, a lower receiver, a magazine supported by a magazine catch, a grip, a bolt and a bolt-slide, and a slide catch lever. In one advantageous embodiment, the aircraft structure may have a rib, a plurality of stringers, and a set of shear ties. The method employs a cleaning composition containing a nitrogen containing material and an oxygen containing material and also optionally a hydrogen containing material to remove the copper oxide film on copper surfaces in the structure. The control apparatus sets a mode for causing the injection valves to increase the amount of supplied fuel according to an operational state of the engine.