Manual 814-1 OPERATION N° DX. 540-0 : Checking and adjusting the headlamps and controls. Op. DX. 540-0 5 1817 1503 NOTE : If this is done too quickly, the timing device in the front R.H. wing will slow down the movement of the headlamp. In this way, it is possible to check the front and rear headlamp controls. If one or the other is faulty, the liquid does not remain opposite the mark during the corresponding phase of descent.