A compressor blade for an aircraft engine includes a blade core made of a fiber compound material and a metallic enclosing structure. This arrangement causes a uniform volume magnetic charge density, which results in a magnetic field normal to the laminae of the magnitude. Power is supplied from different second power supplies respectively to two or more load groups to which power is supplied from the first power supply through two or more first paths. The downstream module passes the identifier from the signal command to the upstream module at a time corresponding to the downstream module reaching an idle state, thus ceasing access to the memory. When the temperature of the lamp is reduced to be lower than a second predetermined temperature, the fan device is enabled again.