7.1 Aircraft lighting systems enable the crew to: see essential flight data and aircraft information in all ambient light conditions, discern external physical conditions/features during operations (particularly during take-off and landing), implement ‘see and avoid’ barriers to airspace conflicts, and so on. For the majority of lighting systems, compliance with the airworthiness design requirements prescribed in an Authority recognised Airworthiness Code satisfies an appropriate benchmark for the safe design and operation of these systems in Defence aircraft. However, some lighting systems requirements associated principally with military operations (such as Night Vision Imaging Systems (NVIS) compatibility, external lighting to support formation flight, air-air refuelling lights and so on) are not, or may be only minimally, covered in civil Airworthiness Codes. Consequently, the Authority prescribes airworthiness design requirements for Defence aircraft lighting systems.
7.2 This Chapter presents Authority prescribed airworthiness design requirements for Defence aircraft lighting systems. Importantly, the design requirements in this chapter are not suitable for application in isolation from an Airworthiness Code. The Authority's requirements for the application of recognised Airworthiness Codes are defined in Section 1 of this manual.
7.3 This Chapter does not include requirements for emergency lighting. These requirements and any associated Authority prescribed supplementation are detailed in Section 2 Chapter 6 Crash Protection. Further, there may be additional systems/equipment required to support NVIS operations (eg radio altimeter for helicopter NVIS operations) that are not included within the scope of this Chapter, but for which compliance must be verified before the aircraft can be certified as being NVIS compatible.
7.4 Lighting systems requirements may be prescribed by civil NAAs on the basis of aircraft type or to support safe operations (for example, operation under Instrument Flight Rules requires fitment of specific external lighting). Lighting systems must also be compatible with aircrew equipment (including NVIS) and support safe flight during military-unique operations such as air to air refuelling.
7.5 Design Requirement (Essential). The lighting systems fitted to Defence aircraft must satisfy the minimum systems/equipment and functional requirements prescribed by any one of the Authority recognised NAAs/MAAs, as follows:
FAA. The relevant FAR Part 23, 25, 27 or 29 lighting requirements, and the requirements prescribed in FAR 91.205 for operations in US civil airspace.
EASA. The relevant CS 23, 25, 27 or 29 lighting requirements, and the requirements prescribed in EU CAT.IDE.A.115 or EU CAT.IDE.H.115 for operations in European civil airspace.
CASA. The relevant FAR/CS Part 23, 25, 27 or 29 requirements, and the requirements prescribed in CASR Part 91 Manual of Standards for operations in Australian airspace
USAF. The relevant lighting requirements of MIL-HDBK-516C, including the requirements for ‘operations in commercial airways’.
UK MoD. The relevant lighting requirements of DEF STAN 00-970.
7.6 Note that the preceding Authority prescribed design requirement includes both the Authority recognised civil Airworthiness Codes defined in Section 1 of this manual, plus additional operational regulations that do not form part of the basic suite of civil NAA prescribed ‘design’ requirements. Military Airworthiness Authorities do not prescribe ‘operational regulations’ for aircraft lighting in the same way as civil NAAs; however, the Authority recognised military Airworthiness Codes inherently prescribe lighting design requirements that satisfy the civil Codes requirements for operations in specified civil airspace.
7.7 Design Requirement (Essential). Lighting systems required for military-unique operations must satisfy the requirements prescribed in an Authority recognised military Airworthiness Code.
7.8 Lighting systems on Defence aircraft support safe operations in shared airspace through enabling the crew to conduct ‘see and avoid’ separation in low visibility and during the conduct of military operations such as formation flight. Failure to install appropriate lighting could pose a hazard to other airspace users. When establishing the lighting systems to be fitted to a Defence aircraft, the minimum systems required to support proposed operations (eg air-air refuelling, formation flight and so on) must be installed and satisfy the applicable design standards.
7.9 Design Requirement (Essential). Where NVIS is intended for use in a Defence aircraft, the aircraft lighting systems must satisfy the compatibility requirements for the relevant NVIS Type and Class specified in:
MIL-STD-3009, Lighting, Aircraft, Night Vision Imaging System (NVIS) Compatible, or
STANAG 3224 Aircraft Interior and Exterior Lighting Night Vision Goggle (NVG) and Non-NVG Compatible.
7.10 Aircraft NVIS generally use helmet mounted, binocular, image intensifier tubes to produce an enhanced image of the environment outside the aircraft in light conditions too low for normal flying operations or navigation by visual means. Aircraft cockpit lighting that is incompatible with NVIS can interfere with the proper operation of NVIS in two ways. Firstly, incompatible light may be reflected into the field of view of the NVIS, leading to obscuration of the outside environment by a false image. Secondly, incompatible light (either direct or reflected) can trigger the automatic gain control function of the NVIS, reducing image contrast.
7.11 Authority recognised civil Airworthiness Codes do not prescribe comprehensive NVIS airworthiness design requirements. While two published RTCA documents define functional and performance requirements for NVIS use and operations in civil aircraft, neither standard provides a comprehensive basis for establishing the compatibility of aircraft lighting with NVIS. Consequently, where NVIS is intended for use in Defence aircraft, the aircraft lighting must satisfy the NVIS compatibility requirements prescribed in the associated military standards. While the military standards only require ground test (or do not specify testing) to be conducted to demonstrate NVIS compatibility, FAA guidance includes a requirement for flight test to be conducted, particularly for helicopter NVIS operations. Designers should consider whether flight test is warranted to support verification of compliance with NVIS compatibility standards.
7.12 Authority prescribed design requirements for NVIS equipment are presented in Section 5 Chapter 2, Aeronautical Life Support Equipment, of this manual.
7.13 Further guidance on implementing the lighting systems design requirements prescribed in this chapter can be provided by the chapter sponsor.