APPENDIX 1

Colours for Aeronautical Ground Lights, Markings, Signs and Panels

 

139.a1.1 General

Introductory Note: The following specifications define the chromaticity limits of colours to be used for aeronautical ground lights, markings, signs and panels. The specifications are in accord with the 1983 specifications of the International Commission on Illumination (CIE). It is not possible to establish specifications for colours such that there is no possibility of confusion. For reasonably certain recognition, it is important that the eye illumination be well above the threshold of perception, that the colour not be greatly modified by selective atmospheric attenuations and that the observer’s colour vision be adequate. There is also a risk of confusion of colour at an extremely high level of eye illumination such as may be obtained from a high-intensity source at very close range. Experience indicates that satisfactory recognition can be achieved if due attention is given to these factors. The chromaticities are expressed in terms of the standard observer and coordinate system adopted by the International Commission on Illumination (CIE) at its Eighth Session at Cambridge, England, in 1931.

 

139.a1.2 Colours for aeronautical ground lights

(a) Chromaticities

(1) The chromaticities of aeronautical ground lights shall be within the following boundaries:

CIE Equations (see Figure A1.1):

(i)
Red

 

 

 

Purple boundary                  

 

y = 0.980 - x

 

Yellow boundary

 

y = 0.335

(ii)

Yellow

 

 

 

Red boundary              

 

y = 0.382

 

White boundary           

 

y = 0.790 - 0.667x

 

Green boundary           

 

y = x - 0.120

(iii)

Green

 

 
 
Yellow boundary                                
 
x = 0.360 - 0.080y

 

White boundary

 

x = 0.650y

 

Blue boundary

 

y = 0.390 - 0.171x

(iv)

Blue

 

 

 

Green boundary

 

y = 0.805x + 0.065

 

White boundary

 

y = 0.400 - x

 

Purple boundary

 

x = 0.600y + 0.133

(v)

White

 

 

 

Yellow boundary

 

x = 0.500

 

Blue boundary

 

x = 0.285

 

Green boundary

 

y = 0.440

 

                                 

and

y = 0.150 + 0.640x

 

Purple boundary

 

y = 0.050 + 0.750x

 

 

and

y = 0.382

(vi)

Variable white

 

 

 

Yellow boundary

 

x = 0.255 + 0.750y

 

 

and

x = 1.185 - 1.500 y

 

Blue boundary

 

x = 0.285

 

Green boundary

 

y = 0.440

 

                         

and

y = 0.150 + 0.640x

 

Purple boundary

 

y = 0.050 + 0.750x

 

 

and

y = 0.382

Note: Guidance on chromaticity changes resulting from the effect of temperature on filtering elements is given in the  EAC 139 -12.

(2) Where dimming is not required, or where observers with defective colour vision must be able to determine the colour of the light, green signals should be within the following boundaries:

Yellow boundary

y = 0.726 - 0.726x

White boundary

x = 0.650y

Blue boundary

y = 0.390 - 0.171x

(3) Where increased certainty of recognition is more important than maximum visual range, green signals should be within the following boundaries:

Yellow boundary

y = 0.726 - 0.726x

White boundary

x = 0.625y - 0.041

Blue boundary

y = 0.390 - 0.171x

(b) Discrimination between lights:

(1) If there is a requirement to discriminate yellow and white from each other, they should be displayed in close proximity of time or space as, for example, by being flashed successively from the same beacon.

(2) If there is a requirement to discriminate yellow from green and/or white, as for example on exit taxiway centre line lights, the y coordinates of the yellow light should not exceed a value of 0.40.

Note: The limits of white have been based on the assumption that they will be used in situations in which the characteristics (colour temperature) of the light source will be substantially constant.

(3) The colour variable white is intended to be used only for lights that are to be varied in intensity, e.g. to avoid dazzling. If this colour is to be discriminated from yellow, the lights should be so designed and operated that:

(i) the x coordinate of the yellow is at least 0.050 greater than the x coordinate of the white; and

(ii) the disposition of the lights will be such that the yellow lights are displayed simultaneously and in close proximity to the white lights.

(4) The colour of aeronautical ground lights shall be verified as being within the boundaries specified in Figure A1.1 by measurement at five points within the area limited by the innermost isocandela curve (isocandela diagrams in Appendix 2 refer), with operation at rated current or voltage. In the case of elliptical or circular isocandela curves, the colour measurements shall be taken at the centre and at the horizontal and vertical limits. In the case of rectangular isocandela curves, the colour measurements shall be taken at the centre and the limits of the diagonals (corners). In addition, the colour of the light shall be checked at the outermost isocandela curve to ensure that there is no colour shift that might cause signal confusion to the pilot.

Note 1: For the outermost isocandela curve, a measurement of colour coordinates should be made and recorded for review and judgement of acceptability by the ECAA.

Note 2: Certain light units may have application so that they may be viewed and used by pilots from directions beyond that of the outermost isocandela curve (e.g. stop bar lights at significantly wide runway-holding positions). In such instances, the appropriate authority should assess the actual application and if necessary require a check of colour shift at angular ranges beyond the outermost curve.

(5) In the case of visual approach slope indicators and other light units having a colour transition sector, the colour shall be measured at points in accordance with 139.a1.2(b)(4), except that the colour areas shall be treated separately and no point shall be within 0.5 degrees of the transition sector.

 

139.a1.3 Colours for markings, signs and panels

Note 1: The specifications of surface colours given below apply only to freshly coloured surfaces. Colours used for markings, signs and panels usually change with time and therefore require renewal.

Note 2: The specifications recommended in 139.a1.3(d) below for transilluminated panels are interim in nature and are based on the CIE specifications for transilluminated signs. It is intended that these specifications will be reviewed and updated as and when CIE develops specifications for transilluminated panels.

(a) The chromaticities and luminance factors of ordinary colours, colours of retro-reflective materials and colours of transilluminated (internally illuminated) signs and panels shall be determined under the following standard conditions:

(1) angle of illumination: 45°;

(2) direction of view: perpendicular to surface; and

(3) illuminant: CIE standard illuminant D65.

(b) The chromaticity and luminance factors of ordinary colours for markings and externally illuminated signs and panels should be within the following boundaries when determined under standard conditions.

CIE Equations (see Figure A1.2):

(1)

Red

 

 

Purple boundary

y = 0.345 – 0.051x

 

White boundary

y = 0.910 – x

 

Orange boundary

y = 0.314 + 0.047x

 

Luminance factor

b = 0.07 (mnm)

(2)

Orange

 

 

Red boundary

y = 0.285 + 0.100x

 

White boundary

y = 0.940 – x

 

Yellow boundary

y = 0.250 + 0.220x

 

Luminance factor

b = 0.20 (mnm)

(3)

Yellow

 

 

Orange boundary

y = 0.108 + 0.707x

 

White boundary

y = 0.910 – x

 

Green boundary

y = 1.35x – 0.093

 

Luminance factor

b = 0.45 (mnm)

(4)

White

 

 

Purple boundary

y = 0.010 + x

 

Blue boundary

y = 0.610 – x

 

Green boundary

y = 0.030 + x

 

Yellow boundary

y = 0.710 – x

 

Luminance factor

b = 0.75 (mnm)

(5)

Black

 

 

Purple boundary

y = x – 0.030

 

Blue boundary

y = 0.570 – x

 

Green boundary

y = 0.050 + x

 

Yellow boundary

y = 0.740 – x

 

Luminance factor

b = 0.03 (mnm)

(6)

Green

 

 

Yellow boundary

x = 0.313

 

White boundary

y = 0.243 +0.670 x

 

Blue boundary

y = 0.493- + 0.524x

 

Luminance factor

B=0.10(mnm)

Note: The small separation between surface red and surface orange is not sufficient to ensure the distinction of these colours when seen separately.

(c) The chromaticity and luminance factors of colours of retro-reflective materials for markings, signs and panels should be within the following boundaries when determined under standard conditions.

            CIE Equations (see Figure A1.3):

(1)

Red

 

 

Purple boundary

y = 0.345 - 0.051x

 

White boundary

y = 0.910 - x

 

Orange boundary

y = 0.314 + 0.047x

 

Luminance factor

b = 0.03 (mnm)

(2)

Orange

 

 

Red boundary

y = 0.265 + 0.205x

 

White boundary

y = 0.910 - x

 

Yellow boundary

y = 0.207 + 0.390x

 

Luminance factor

b = 0.14 (mnm)

(3)

Yellow

 

 

Orange boundary

y = 0.160 + 0.540x

 

White boundary

y = 0.910 - x

 

Green boundary

y = 1.35x - 0.093

 

Luminance factor

b = 0.16 (mnm)

(4)

White

 

 

Purple boundary

y = x

 

Blue boundary

y = 0.610 - x

 

Green boundary

y = 0.040 + x

 

Yellow boundary

y = 0.710 - x

 

Luminance factor

b = 0.27 (mnm)

(5)

Blue

 

 

Green boundary

y = 0.118 + 0.675x

 

White boundary

y = 0.370 - x

 

Purple boundary

y = 1.65x - 0.187

 

Luminance factor

b = 0.01 (mnm)

(6)

Green

 

 

Yellow boundary

y = 0.711 - 1.22x

 

White boundary

y = 0.243 + 0.670x

 

Blue boundary

y = 0.405 - 0.243x

 

Luminance factor

b = 0.03 (mnm)

(d) The chromaticity and luminance factors of colours for luminancent transilluminated (internally illuminated) signs and panels should be within the following boundaries when determined under standard conditions.

CIE Equations (see Figure A1.4):

(1)

Red

 
 
Purple boundary
y = 0.345 - 0.051x

 

White boundary

y = 0.910 - x

 

Orange boundary

y = 0.314 + 0.047x

 

Luminance factor (day condition)

b = 0.07 (mnm)

 

Relative luminance

5% (mnm)

 

to white (night condition)

20% (max)

(2)

Yellow

 

 

Orange boundary

y = 0.108 + 0.707x

 

White boundary

y = 0.910 - x

 

Green boundary

y = 1.35x - 0.093

 

Luminance factor (day condition)

b = 0.45 (mnm)

 

Relative luminance

30% (mnm)

 

to white (night condition)

80% (max)

(3)

White

 

 

Purple boundary

y = 0.010 + x

 

Blue boundary

y = 0.610 - x

 

Green boundary

y = 0.030 + x

 

Yellow boundary

y = 0.710 - x

 

Luminance factor (day condition)

b = 0.75 (mnm)

 

Relative luminance to white (night condition)

100%

(4)

Black

 

 

Purple boundary

y = x - 0.030

 

Blue boundary

y = 0.570 - x

 

Green boundary

y = 0.050 + x

 

Yellow boundary

y = 0.740 - x

 

Luminance factor (day condition)

b = 0.03 (mnm)

 

Relative luminance

0% (mnm)

 

to white (night condition)

2% (max)

(5)

Green

 

 

Yellow boundary

x=0.313

 

White boundary

y=0.243+0.670x

 

Blue boundary

y=0.493-0.524x

 

Luminance factor: (day conditions)

β=0.10 minimum

 

Relative luminance

5% (minimum)

 

to white conditions)

(night 30% (maximum)

 

 

Figure A1-1: Colours for aeronautical ground lights

 

 

 

 

 

 

 

 

Figure A1-2: Ordinary colours for markings and externally illuminated signs and panels

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure A1-3: Colours of retro-reflective materials for markings, signs and panels

 

 

 

 

 

 

Figure A1-4: Colours Luminescent or transilluminated (internally illuminated) signs and panels