ATA 33 LIGHTS

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ED Decision 2020/012/R

Summary of the guidance items:

Item	ATA
Flight Crew Compartment Lighting	33-10-1
Passenger Compartment Lighting	33-20-1
Cabin Signs (‘Fasten Seat Belt’, ‘No Smoking’ Signs, Return to Cabin, NO PED)	33-20-2
Navigation/Position Lights	33-41-1
Anti-Collision Light System	33-42-1
Wing illumination lights	33-43-1
Landing Lights	33-44-1
Cabin Emergency Lighting (Aeroplanes)	33-50-1
Cabin Emergency Lighting (Helicopters)	33-50-1
Exterior Emergency Lighting Systems	33-50-2

Aircraft applicability: Aeroplanes & Helicopters

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions

33-10-1	Flight Crew Compartment Lighting
33-10-1A		C	-	0	May be inoperative for daylight operations.
33-10-1B		C	-	-	Individual lights may be inoperative provided:
					(a) Sufficient lighting is operative to make each required instrument, control, and other device for which it is provided easily readable, (b) Sufficient flight crew compartment emergency lighting is operative, and (c) Lighting configuration at dispatch is acceptable to the flight crew.
33-10-1C		C	-	-	Co-pilot’s station instrument lights may be inoperative for single pilot operations, provided no co-pilot’s station instrument is required to be used by the pilot.
33-10-1D	(Helicopters and other than CAT Aeroplanes operations)	C	-	0	May be inoperative for daylight operations under VFR.

Additional considerations:

Based on the aircraft flight crew compartment emergency lighting configuration, condition (b) under 33-20-1B has to be clarified to indicate the lights that remain supplied under emergency power supply (e.g. DOME light, etc.).

Aircraft applicability: Aeroplanes & Helicopters

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions
33-20-1	Passenger Compartment Lighting

33-20-1A		D	-	0	May be inoperative provided passengers are not carried.
33-20-1B	(Aeroplanes)	C	-	-	Individual lights may be inoperative provided:
					(a) Lighting is acceptable for the crew located in the cabin to perform their required duties, and (b) Inoperative lights are not part of the cabin emergency lighting.
33-20-1B	(Helicopters)	C	-	-	Individual lights may be inoperative provided:
					(a) Inoperative lights do not exceed 50 % of the total installed, (b) Lighting is acceptable for the crew located in the cabin to perform their required duties, and (c) Inoperative lights are not part of the cabin emergency lighting.
33-20-1C	(Helicopters)	D	-	0	May be inoperative for daylight operations.

Additional considerations:

If the cabin illumination is used to charge floor mounted emergency photoluminescent lighting system, additional conditions on a minimum of lighting to be provided may be required.

Some lights installed on the aircraft may be part of the cabin emergency lighting equipment. In this case, relief cannot be granted in the MMEL beyond the minimum required configuration.

For cargo and non-passenger carrying operations there must be sufficient lighting for the inspection of cargo for the verification of cargo restraint or for firefighting purposes.

Aircraft applicability: Aeroplanes & Helicopters

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions
33-20-2	Cabin Signs (‘Fasten Seat Belt’, ‘No Smoking’ Signs, Return to Cabin, NO PED)
33-20-2A		C	-	-	(M)/(O) One or more may be inoperative provided affected passenger seats, crew member seats or lavatories from which at least one cabin sign is not readily legible are blocked and placarded ‘DO NOT OCCUPY’.
					Procedures: (M)/(O) to give guidance reference for a practical mean of prohibiting the use of the affected seat. (O) To alert the crew about affected seats/lavatories.
33-20-2B		C	-	-	(O) One or more may be inoperative and the affected passenger seats, crew member seats or lavatories may be occupied provided:
					(a) The passenger address system is operative and can be clearly heard throughout the cabin during flight, and (b) A procedure is used to notify passengers as appropriate.
					Procedures: (O) To provide the alternate procedure to crew located in the cabin to notify passengers and crew members when using crew rest facility – bunk, as applicable.
33-20-2C		C	-	-	May be inoperative provided passengers are not carried.
33-20-2-1	Aural Tone Function	C	-	0	(O) May be inoperative provided a procedure is established and used to verify that visual indications are taken into account by passengers.
33-20-2-2	Automatic Function	C	-	0	(O) May be inoperative provided:
					(a) Manual control function is operative, and (b) An alternate procedure is established and used.

Additional considerations:

The requirement of condition 33-20-2B (a) may not apply to aircraft which are not required to install a passenger address system.

Aircraft applicability: Aeroplanes & Helicopters

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions

33-41-1	Navigation/Position Lights

33-41-1A		C	-	0	One or more may be inoperative for daylight operations.
33-41-1B		C	-	-	Any in excess of those required may be inoperative for night operations.
33-41-1C	(Helicopters)	A	-	-	(O) One or more may be inoperative for a single night flight when departing from an offshore or remote installation provided:
					(a) The appropriate Air Navigation Service Provider (ANSP) has been informed before departure, (b) The anti-collision light system is operative, and (c) The landing light system is operative.
					Procedures: (O) To provide guidance to the crew for operations of anti-collision and landing lights.

Additional considerations:

For the purpose of compliance with 33-41-1B for night operations, all except the following minimum may be inoperative:

— One stationary red forward/wing tip light,

— One stationary green forward/wing tip light, and

— One stationary white light on the tail or on each wing tip.

A light composed of more than one bulb or LED, may be partially degraded, but still considered operative for the purpose of the associated requirement, provided that the degraded configuration has been demonstrated acceptable to meet the requirements.

Aircraft applicability: Aeroplanes & Helicopters

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
Item			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions
33-42-1	Anti-Collision Light System				Note: This guidance may be subject to additional restrictions in accordance with the applicable Rules of the Air.
33-42-1-1	Fuselage Lights (Beacon or Strobe Type)				Note: If the fuselage anti-collision light is inoperative, alternate procedures are established and used when the aircraft is on the ground with engine(s) running.
33-42-1-1A	(Aeroplanes)	C	-	1	(O) Either the upper or the lower fuselage lights may be inoperative provided an acceptable number of white wing-tip strobe lights are operative.
					Procedures: (O) to provide guidance to the crew for operations of anti-collision and strobe lights.
33-42-1-1B	(Aeroplanes)	C	-	0	(O) May be inoperative for daylight operations provided all white wing-tip strobe lights are operative.
					Procedures: (O) To provide guidance to the crew for operations of anti-collision and strobe lights.
33-42-1-1C	(Helicopters)	C	-	1	Any in excess of one may be inoperative.
33-42-1-1D	(Helicopters)	A	-	0	(O) One or more may be inoperative for a single night flight when departing from an offshore or remote installation provided:
					(a) The appropriate Air Navigation Service Provider (ANSP) has been informed before departure, (b) The navigation light system is operative, and (c) The landing light system is operative.
					Procedures: (O) To provide guidance to the crew for operations of remaining lights.
33-42-1-1E	(Helicopters and other than Commercial Air Transport operations of aeroplanes)	B	-	0	May be inoperative for daylight operations.
33-42-1-2	Wing-Tip/Tail Strobe Lights (if installed)
33-42-1-2A		C	-	0	One or more of these may be inoperative.

Additional considerations:

An anti-collision light system is required for Commercial Air Transport (Part-CAT) operations and for other than Commercial Air Transport (Part-NCC) operations under night VFR or IFR.

Additional airspace requirements may apply.

33-42-1-1A:

The acceptable number of white strobe lights has to be defined by the applicant according to the requirements applicable for anti-collision light system.

Aircraft applicability: Aeroplanes

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions

33-43-1	Wing Illumination Light
33-43-1A		D	-	0	One or more may be inoperative for daylight operations.
33-43-1B		C	-	0	One or more may be inoperative provided operations are not conducted at any time into known or forecast icing conditions.
33-43-1C		B	-	0	(O) One or more may be inoperative provided a portable lamp/light of adequate capacity for wing and/or control surface inspection is available and used for night operations in icing conditions.
					Procedures (O) To provide crew procedures in accordance with the above conditions.
33-43-1D		C	-	0	One or more may be inoperative provided ground de-icing procedures do not require their use.

Additional considerations:

Further relief might be granted when the wing illumination lights are not required to ensure ice accretion monitoring (flight/ground).

33-43-1D: For passenger and cargo aeroplanes where view of the wing surfaces from the flight crew compartment is restricted (due to the sweep of the aircraft wing) or for cargo aircraft where access to the aircraft cabin to view ice formation on the wings is not possible, the wing illumination lights may be inoperative provided ground deicing procedures do not require their use.

Aircraft applicability: Aeroplanes & Helicopters

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions

33-44-1	Landing Lights

33-44-1A	(Aeroplanes)	B	-	-	50 % of landing lights may be inoperative for night operations.
33-44-1B		C	-	0	One or more may be inoperative for daylight operations.
33-44-1C	(Helicopters)	C	-	1	(O) Any in excess of one adjustable landing light may be inoperative for night operations.
					Procedures: (O) To provide guidance to the crew for operations of remaining lights

Additional considerations:

The above guidance does not cover the landing light extension/retraction system. Alternate dispatch conditions may be proposed based on the use of Taxi lights, if adequate for the purpose.

Aircraft applicability: Aeroplanes

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions

33-50-1	Cabin Emergency Lighting

33-50-1-1	Overhead Emergency Lighting (each aisle)
33-50-1-1A		B	-	-	A maximum of one in four consecutive overhead emergency lights (or light assemblies) may be inoperative.
					Note: For aeroplanes which have two rows of lights per aisle (i.e. mounted on the overhead bins), then the above alleviation is acceptable for each row of lights but the inoperative lights must not be directly opposite each other.
33-50-1-2	EXIT Marking Signs
33-50-1-2A		C	-	-	Up to 50 % of the bulbs/LEDs may be inoperative in one or more signs provided the sign remains legible.
33-50-1-2B		-	-	-	One may be inoperative provided the associated door/exit is considered inoperative. Refer to item 52-22.
					Note: If any twin overwing exits are served by a single sign, both exits should be considered inoperative.
33-50-1-3	EXIT Locator Signs
33-50-1-3A		C	-	-	Up to 50 % of the bulbs/LEDs may be inoperative in one or more signs provided the sign remains legible.
33-50-1-4	Exit Area Lighting
33-50-1-4A		-	-	-	May be inoperative provided that the associated door/exit is considered to be inoperative. Refer to item 52-22.
(continued)

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions
(continued)

33-50-1-5	Floor Proximity Lighting (Electrical or photo luminescent systems)
33-50-1-5-1	Individual Lights/ strips
33-50-1-5-1A		B	-	-	Lights/strips may be inoperative provided that:
					(a) All lights/strips marking right-angled intersections, including cross aisles and overwing exits, are operative, (b) Along each aisle axis, all lights/strips within one metre of lights/strips marking right-angled intersections are operative, and (c) A minimum of lights/strips evenly distributed along each aisle axis to provide the required escape guidance are operative.
33-50-1-5-2	EXIT Markers/Identifiers
33-50-1-5-2A		C	-	-	Up to 50 % of the bulbs/LEDs may be inoperative in one or more signs provided that the sign remains legible.
33-50-1-5-2B		-	-	-	One item may be inoperative provided that the associated door/exit is considered to be inoperative. Refer to item 52-22.

Additional considerations:

The proposed guidance is provided as examples of relief generally accepted in MMELs and should be validated on particular cabin design configuration. Different levels of relief may be validated through test showing compliance to requirements even in a degraded configuration. Such relief could then be granted ‘C’ interval relief.

Item 33-50-1-2 Cabin Emergency Lighting - EXIT Marking Sign covers those lights required by CS 25.811(d)(2).

Item 33-50-1-3 Cabin Emergency Lighting - EXIT locator Sign covers those lights required by CS 25.811(d)(1) and (d)(3).

Item 33-50-1-4-1 Floor Proximity Lighting (Electrical or photoluminescent systems) - Individual Lights/ strips option 33-50-1-4-1A condition (b) & (c) are example proposals that require validation based on the specific system design and installation. The objective is to ensure the minimum certification requirements in terms of escape guidance are still complied with. If demonstrated by adequate substantiations, a rectification interval C could be granted.

Item 33-50-1-4-2 Floor Proximity Lighting (Electrical seat mounted or photo luminescent floor mounted systems) EXIT Markers/Identifiers covers those lights required by CS 25.812(e)(2) and (d)(3).

Aircraft applicability: Helicopters

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions
33-50-1	Cabin Emergency Lighting
33-50-1-1	Cabin Emergency Lighting System	-	-	-	May be inoperative provided it is in accordance with the arrangements agreed with the national authority.
33-50-1-2	EXIS Lighting
33-50-1-2A		B	-	0	May be inoperative for flights over land or for flights over water at a distance from land not beyond 10 minutes flying time at normal cruise speed.
33-50-1-2-1	EXIS 1 Standard Length (24 LEDs)
33-50-1-2-1A		B	-	0	A maximum of 3 LEDs may be inoperative with no more than 2 adjacent inoperative LEDs.
33-50-1-2-2	EXIS 1 Half Length (12 LEDs)
33-50-1-2-2A		B	-	0	A maximum of 1 LED may be inoperative.
33-50-1-2-3	EXIS 1 One Third Length (8 LEDs)
33-50-1-2-3A		B	-	0	A maximum of 1 LED may be inoperative.
33-50-1-2-4	EXIS II
33-50-1-2-4A		B	-	0	A maximum of 2 LEDs per corner strip, one in each arm, may be inoperative.
33-50-1-2-5	EXIS III
33-50-1-2-5A		B	-	0	A maximum of 4 LEDs per light assembly may be inoperative; no more than 1 LED is inoperative per band along any side.
33-50-1-3	Helicopter Emergency Egress Lighting System (HEELS)
33-50-1-3A		B	-	0	May be inoperative for flights over land or for flights over water at a distance from land not beyond 10 minutes flying time at normal cruise speed.
33-50-1-3B		A	-	-	One element on each side of the passenger compartment and/or cockpit may be inoperative for 3 calendar days.

Additional considerations:

N/A

Aircraft applicability: Aeroplanes

ATA Chapter: 33 Lights

(1) System & Sequence Numbers		(2) Rectification Interval
ITEM			(3) Number installed
				(4) Number required for dispatch
					(5) Remarks or Exceptions

33-50-2	Exterior Emergency Lighting Systems

33-50-2A		B	-	0	One or more may be inoperative for daylight operations.

33-50-2-1	Escape Slide Lighting
33-50-2-1A		B	-	0	One or more may be inoperative for daylight operations.
33-50-2-1B		-	-	-	One may be inoperative for night operations provided the associated door/exit is considered inoperative. Refer to item 52-22-1.

33-50-2-2	Overwing Escape Route Lighting
33-50-2-2A		B	-	0	One or more may be inoperative for daylight operations.
33-50-2-2B		-	-	-	One may be inoperative for night operations provided the associated door/exit is considered inoperative. Refer to item 52-22.

Additional considerations:

N/A

Issue No: MMEL/2

Details

Source-Title: ATA 33 LIGHTS

Erulesid: ERULES-1963177438-4157 Compare versions

Domain: Initial airworthiness

Amendedby: CS Issue 2

Applicabilitydate: 1 February, 2021

Entryintoforcedate: 18 August, 2020

Regulatorysource: ED Decision 2020/012/R Navigate

Regulatorysubject: CS-MMEL

Typeofcontent: GM to CS (Guidance material to certification specification)

Origin: EASA

Category: EAR