CS 26.120 Interior emergency lighting and emergency light operation

CAA ORS9 Decision No. 1

Compliance with point 26.120 of UK Part-26 is demonstrated by complying with CS 25.812 (b),(c),(d) and (h) of CS-25 or equivalent and CS 25.812 (a) and (e) of CS-25 or equivalent, or with the following:

(a) An emergency lighting system, independent of the main lighting system, is installed. However, sources of general cabin illumination may be common to both the emergency and the main lighting system if the power supply to the emergency lighting system is independent of the power supply to the main lighting system. The emergency lighting system includes:

(1) Illuminated emergency exit marking and locating signs, sources of general cabin illumination and interior lighting in emergency exit areas.

(2) for aeroplanes that have a maximum approved passenger seating configuration of more than 19, a floor proximity emergency escape path marking provides emergency evacuation guidance for passengers when all sources of illumination more than 1.22 m (4 feet) above the cabin aisle floor are totally obscured. In the dark of the night, the floor proximity emergency escape path marking enables each passenger to:

(i) after leaving the passenger seat, visually identify the emergency escape path along the cabin aisle floor to the first exits or pair of exits forward and aft of the seat;

(ii) readily identify each exit from the emergency escape path by reference only to markings and visual features not more than 1.22 m (4 feet) above the cabin floor.

(b) Except for lights forming part of the emergency lighting subsystems provided in compliance with Part CAT.IDE.A.275 (b)(4) and (5) that serve no more than one assist means, are independent of the aeroplane’s main emergency lighting systems, and are automatically activated when the assist means is deployed, each light required for interior and exterior emergency lighting:

(1) is operable manually both from the flight crew station and for aeroplanes on which a cabin crew member is required, from a point in the passenger compartment that is readily accessible from a normal cabin crew seat;

(2) has a means to prevent inadvertent operation of the manual controls;

(3) when armed or turned on at either station, remains lighted or becomes lighted upon interruption of the aeroplane’s normal electric power;

(4) provides the required level of illumination for at least 10 minutes at the critical ambient conditions after emergency landing;

(5) has a cockpit control device that has an ‘on’, ‘off’, and ‘armed’ position.

(c) In addition to subparagraphs (a), and (b) above, for an aeroplane which had its initial Certificate of Airworthiness issued prior to 1 December 2006, the following conditions are met:

(1) For an aeroplane for which the application for the type certificate was filed prior to 1 May 1972:

(i) Each passenger emergency exit marking and each locating sign has white letters at least 25 mm (1 inch) high on a red background at least 5 cm (2 inches) high. These signs may be internally electrically illuminated, or self-illuminated by other than electrical means, with an initial brightness of at least 0.509 cd/m² (160 microlamberts). The colours may be reversed in the case of internally electrically illuminated signs if this will increase the illumination of the exit. On these aeroplanes, no sign may continue to be used if its luminescence (brightness) decreases to below 0.318 cd/m² (100 microlamberts).

(ii) The sources of general cabin illumination provides enough general lighting in the passenger cabin so that the average illumination when measured at 102 cm (40inch) intervals at seat armrest height, on the centreline of the main passenger aisle, is at least 0.54 lux (0.05 foot-candle).

(iii) The floor of the passageway leading to each floor level passenger emergency exit, between the main aisles and the exit openings is provided with illumination.

(2) For an aeroplane for which the application for the type certificate was filed on or after 1 May 1972, the interior emergency lighting specifications under which the aeroplane was type certificated. On these aeroplanes, no sign may continue to be used if its luminescence (brightness) decreases to below 0.796 cd/m² (250 microlamberts).

(d) In addition to subparagraphs (a) and (b) above, for an aeroplane which had its initial Certificate of Airworthiness issued on or after 1 December 2006, and for which the application for the type certificate was filed prior to 1 May 1972, the following conditions are met:

(1) For an aeroplane that has a passenger seating configuration, excluding pilot seats, of:

(i) 10 seats or more, each passenger emergency exit locator sign and marking sign required by point 26.110(d) of Part-26 has red letters at least 38 mm (1 ½ inches) high on an illuminated white background, and has an area of at least 135 cm² (21 square inches) excluding the letters. The lighted background-to-letter contrast is at least 10:1. The letter height to stroke-width ratio is not more than 7:1 nor less than 6:1. These signs are internally electrically illuminated with a background brightness of at least 86 cd/m² (25 foot-lamberts) and a high-to-low background contrast no greater than 3:1. Other passenger emergency exit signs required by point 26.110(d) of Part-26 have red letters at least 38 mm (1 ½ inches) high on a white background having an area of at least 135 cm² (21 square inches) excluding the letters. These signs are internally, electrically illuminated or self-illuminated by other than electrical means and have an initial brightness of at least 1.27 cd/m² (400 microlamberts). The colours are reversed in the case of a sign that is selfilluminated by other than electrical means. On these aeroplanes, no sign continues to be used if its luminescence (brightness) decreases to below 0.796 cd/m² (250 microlamberts).

  (ii) 9 seats or less, passenger emergency exit signs that are required by point 26.110(d) of Part-26, have red letters at least 25 mm (1 inch) high on a white background at least 5 cm (2 inches) high. These signs may be internally electrically illuminated or self-illuminated by other than electrical means, with an initial brightness of at least 0.509 cd/m² (160 microlamberts). The colours may be reversed in the case of a sign that is self-illuminated by other than electrical means. On these aeroplanes, no sign continues to be used if its luminescence (brightness) decreases to below 0.318 cd/m² (100 microlamberts).

(2) General illumination in the passenger cabin is provided so that when measured along the centreline of the main passenger aisle(s), and cross aisle(s) between main aisles, at seat armrest height and at 102 cm (40-inch) intervals, the average illumination is not less than 0.54 lux (0.05 foot-candle) and the illumination at each 102 cm (40-inch) interval is not less than 0.11 lux (0.01 foot-candle). A main passenger aisle is considered to extend along the fuselage from the most forward passenger emergency exit or cabin occupant seat, whichever is farther forward, to the most rearward passenger emergency exit or cabin occupant seat, whichever is farther aft.

(3) The floor of the passageway leading to each floor-level passenger emergency exit, between the main aisles and exit openings, is provided with illumination that is not less than 0.22 lux (0.02 foot-candle) measured along a line that is within 15 cm (six inches) of and parallel to the floor and is centred on the passenger evacuation path.

(e) Each sign required by point 26.120 of Part-26 may use a universal symbolic exit sign. The design of the signs is chosen to provide a consistent set throughout the cabin (See GM1 26.110(d)).