Requirements Concerning Design of Taxiing Guidance
Signs
Note: See Subpart H, Section 139.325 for specifications
on the application, location and characteristics of signs.
139.a4.1 Inscription heights: Inscription heights shall
conform to the following: tabulation:
Note:
Where a taxiway location sign is installed in conjunction with a runway
designation sign (see .325(c)(22)), the character size shall be that specified
for mandatory instruction signs.
139.a4.2 Arrow dimensions: Arrow dimensions shall be as
follows:
|
Legend height |
Stroke |
|
200 mm |
32 mm |
|
300 mm |
48 mm |
|
400 mm |
64 mm |
139.a4.3 Stroke width for single letter: Stroke width for single
letter shall be as follows:
|
Legend height |
Stroke |
|
200 mm |
32 mm |
|
300 mm |
48 mm |
|
400 mm |
64 mm |
139.a4.4 Sign luminance: Sign luminance shall be as
follows:
(a) Where operations are
conducted in runway visual range conditions less than a value of 800 m, average
sign luminance shall be at least:
|
Red |
30 cd/m2 |
|
Yellow |
150 cd/m2 |
|
White |
300 cd/m2 |
(b) Where operations are
conducted in accordance with .325(a)(7)(ii) and (iii) and .325(a)(8), average
sign luminance shall be at least:
|
Red |
10 cd/m2 |
|
Yellow |
50 cd/m2 |
|
White |
100 cd/m2 |
Note: In runway visual range conditions less than a
value of 400 m, there will be some degradation in the performance of signs.
139.a4.5. The luminance ratio:
The luminance ratio between red and white elements of a
mandatory sign shall be between 1:5 and
139.a4.6 The average luminance:
The average luminance of the sign is calculated by
establishing grid points as shown in Figure A4.1 and using the luminance values
measured at all grid points located within the rectangle representing the sign.
The average value is the arithmetic average of the
luminance values measured at all considered grid points.
Note: Guidance on measuring the average luminance of a
sign is contained in EAC 139-12.
139.a4.8 The ratio between luminance values of
adjacent grid points:
The ratio between luminance values of adjacent grid
points shall not exceed 1.5:1. For areas on the sign face where the grid
spacing is 7.5 cm, the ratio between luminance values of adjacent grid points
shall not exceed 1.25:1. The ratio between the maximum and minimum luminance
value over the whole sign face shall not exceed 5:1.
139.a4.9 The forms of
characters:
The forms of characters, i.e.
letters, numbers, arrows and symbols, shall conform to those shown in Figure
A4.2. The width of characters and the space between individual characters shall
be determined as indicated in Table 4.1.
139.a4.10 The face height of signs: The face height of signs
shall be as follows:
|
Legend height |
Face height (min) |
|
200 mm |
400 mm |
|
300 mm |
600 mm |
|
400 mm |
800 mm |
139.a4.11 The face width of signs:
The face width of signs shall be determined using
Figure A4.3 except that, where a mandatory instruction sign is provided on one
side of a taxiway only, the face width shall not be less than:
(a) 1.94 m where the code
number is 3 or 4; and
(b) 1.46 m where the code
number is 1 or 2.
Note: Additional guidance on
determining the face width of a sign is contained in EAC 139-12.
(a) The black vertical
delineator between adjacent direction signs should have a width of
approximately 0.7 of the stroke width.
(b) The yellow border on a
stand-alone location sign should be approximately 0.5 stroke width.
139.a4.13 The colours of signs:
The colours of signs shall be
in accordance with the appropriate specifications in Appendix1.
Note 1: The average luminance of a sign is
calculated by establishing grid points on a sign face showing typical
inscriptions and a background of the appropriate colour (red for mandatory
instruction signs and yellow for direction and destination signs)
as follows:
a) Starting at the top left corner
of the sign face, establish a reference grid point at 7.5 cm from the left edge
and the top of the sign face.
b) Create a grid of 15 cm spacing
horizontally and vertically from the reference grid point. Grid points within
7.5 cm of the edge of the sign face shall be excluded.
c) Where the last point in a
row/column of grid points is located between 22.5 cm and 15 cm from the edge of
the sign face (but not inclusive), an additional point shall be added 7.5 cm
from this point.
d) Where a grid point falls on the
boundary of a character and the background, the grid point shall be slightly
shifted to be completely outside the character.
Note 2: Additional grid points may be required to
ensure that each character includes at least five evenly spaced grid points.
Note 3: Where one unit includes two types of signs,
a separate grid shall be established for each type.
Figure A4-1: Grid points for calculating average luminance of a sign
Figure A4-2: Forms of characters
Figure A4-2: (cont.)
Figure A4-2: (cont.)
Figure A4-2: (cont.)
Figure A4-2: (cont.)
Runway vacated sign
NO ENTRY sign
Note. —
Existing NO ENTRY signs not conforming to the above dimensions are to be replaced not
later than 1 January 2012
Arrow, dot and dash
Note 1: The arrow stroke width, diameter of the dot, and both width and length of the dash shall be proportioned to the character stroke widths.
Note 2: The
dimensions of the arrow shall remain constant for a particular sign size,
regardless of orientation.
Figure A4-2: (cont.)
Table A4-1: Letter and numeral widths and space between letters or
numerals
Figure A4-3: Sign dimensions