An engine CU 51 detects an abnormality which has occurred in an engine, and outputs a signal that indicates the occurrence of this abnormality to an SCR-CU 61. The linkage is constructed and arranged to move the door generally rearwardly and upwardly when the door is moved from a closed position to an opened position, so that the door is positioned below and adjacent to the rearward tail portion. The device comprises two sides both of which are fitted with a fitting means for attachment to the helmet. The name of the method to be called on the second object is delivered from the intermediary object to a message queue object.