the device is in use if the door is open or in the process of being opened or closed or if the control means are not electrically isolated u201c in use u201d message or that the device is in a state corresponding to a configuration consistent with take off for the control means i e at the end of the so called isolation sequence u201c flight u201d message preferably the u201c gdo status u201d indicator 35 is an indicator having two stable states which only consumes power during the transition from one state to the other according to a particular aspect of the invention the u201c gdo status u201d indicator 35 is linked with a marker 45 which can be seen in fig1 which can be moved between a retracted position wherein it enables the panel 15 for accessing the control board 17 to be closed and which corresponds to the u201c flight u201d position of the u201c gdo status u201d indicator 35 and a projecting position shown here wherein it prevents the panel 15 for accessing the control board 17 from being closed which corresponds to the u201c in use u201d position of the u201c gdo status u201d indicator 35 therefore the pilot can check during the pre flight inspection which state the device of the invention is in and be warned by the panel 15 remaining open that the device of the invention has not been returned to the u201c flight u201d status according to another particular aspect of the invention the control board 17 comprises a second push to test button 41 for checking via a pressing action that additional equipment operates correctly in particular it.