Commonwealth Numbered Regulations

1988 NO. 158 CIVIL AVIATION REGULATIONS - REG 18

18. (1) The type of letters for nationality marks and registration marks and
their measurements shall, subject to regulation 19, be as follows:

   (a)  the letters shall be capital letters in Roman characters without
        ornamentation;

   (b)  the letters in each separate group of marks shall be of equal height;

   (c)  the width of each letter (except the letter I) and the length of a
        hyphen shall be two-thirds of the height of a letter;

   (d)  the letters and hyphens shall be formed by solid lines the thickness
        of which shall be one-sixth of the height of a letter and which shall
        be of a colour contrasting clearly with the background;

   (e)  each letter shall be separated from that which it immediately precedes
        or follows by a space of not less than one-quarter of the width of a
        letter, and, for the purpose of this paragraph, a hyphen shall be
        regarded as a letter;

   (f)  in the case of a lighter-than-air aircraft, the height of the marks
        shall be at least 500 millimetres;

   (g)  in the case of a heavier-than-air aircraft:

        (i)    the height of the marks on the wings shall be at least 500
               millimetres; and

        (ii)   the marks on the fuselage (or equivalent structure) and on any
               vertical tail surface shall be as nearly as possible parallel
               to the longitudinal axis of the aircraft and shall be as large
               as practicable, but shall not interfere with the visible
               outlines of the fuselage (or equivalent structure) and shall
               leave at least a 50 millimetre margin along each edge of any
               vertical tail surface.

(2) Subparagraph (1) (g) (ii) shall not be interpreted as requiring the use of
marks exceeding 150 millimetres in height.