The &quot; cut-off &quot; must be substantially horizontal and shall be as straight as possible from at least 3° L to 3° R. In case the visual aim leads to problems or ambiguous positions, the instrumental method as specified in Annex 9, paragraphs 2. and 4., shall be applied and the quality or rather the sharpness of the &quot; cut-off &quot; and the linearity shall be checked on performance.
The &quot; cut-off &quot; must be substantially horizontal and shall be as straight as possible from at least 3° L to 3° R. In case the visual aim leads to problems or ambiguous positions, the instrumental method as specified in Annex 9, paragraphs 2. and 4., shall be applied and the quality or rather the sharpness of the &quot; cut-off &quot; and the linearity shall be checked on performance.