ISO 20894-2018 PDF

Full title and description

ISO 20894:2018 — Aircraft — LED based taxiing lightsystem — General requirements. This international standard specifies characteristics and interface requirements for LED‑based taxiing (taxi and runway turn‑off) lighting systems used on aircraft, covering functional, photometric, chromaticity, thermal, environmental and electromagnetic aspects of the luminaire and associated control interfaces.

Abstract

ISO 20894:2018 defines the general requirements for LED taxiing light systems, including initial photometric performance, chromaticity limits, illuminance/distribution criteria, thermal management and operating‑life considerations. The standard also addresses electromagnetic compatibility, environmental durability and test/qualification practices needed to demonstrate compliance over the life of the installation.

General information

• Status: Published (International Standard, confirmed).
• Publication date: September 2018 (2018‑09).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 49.060 — Aerospace electrical equipment and systems.
• Edition / version: Edition 1 (2018).
• Number of pages: 10 pages.

Scope

Specifies characteristics and interface requirements for LED‑based taxiing light systems fitted to aircraft. The scope covers photometric performance (initial and degraded over life), chromaticity limits for white taxi lighting, illuminance distribution requirements for taxi and runway turn‑off (RTO) functions, thermal and mechanical constraints for LED modules and optics, electromagnetic compatibility (EMC) considerations for power/control electronics, and methods for sampling, testing and verifying compliance. The standard is intended to support the transition from legacy sealed‑beam and incandescent systems to LED technology and to ensure safe, durable and interoperable installations.

Key topics and requirements

• Photometric performance: initial luminous intensity, illuminance distribution and measurement points; requirements to demonstrate minimum usable illumination across specified angles.
• Colour/chromaticity: limits and maintenance of white chromaticity to ensure adequate perception of runway/taxi markings throughout service life.
• Operating life and degradation: definition of effective operating life based on photometric minimums and procedures to account for LED lumen depreciation and optical/connector aging.
• Thermal management and mechanical durability: limits on LED junction temperature, environmental resistance of lenses and housings, and mechanical mounting/interface requirements.
• Electromagnetic compatibility (EMC): conducted and radiated emission and immunity requirements for control and power electronics (references to relevant EMC test methods and limits).
• Quality assurance and test methods: component and system‑level tests, warm‑up and stabilization procedures before photometric measurement, and sample conditioning to represent installed configuration.

These topics are summarized from the standard's requirements and guidance for design, test and verification of LED taxiing light systems.

Typical use and users

Primary users include aircraft manufacturers, avionics and lighting suppliers, certification and compliance teams, and maintenance/MRO organizations. The standard is used when designing, specifying, procuring or certifying LED taxi and RTO lighting systems to ensure they meet photometric, environmental and EMC performance expectations for operational safety and interoperability.

Related standards

ISO 20894:2018 was prepared by ISO/TC 20/SC 1 (aerospace electrical requirements) and references other aerospace and EMC test standards where relevant. The standard cites EMC test requirements (for example ISO 7137 category/limits referenced for conducted emissions) and aligns with other aerospace electrical/lighting test practices used for aircraft equipment qualification. Users should consult the ISO/TC 20/SC 1 suite and applicable EMC, environmental and aeronautical installation standards when applying ISO 20894.

Keywords

LED taxiing light system, taxi lights, RTO lights, aircraft lighting, photometric performance, chromaticity, illuminance distribution, EMC, thermal management, ISO 20894.

FAQ

Q: What is this standard?

A: ISO 20894:2018 is an international standard that defines general requirements for LED‑based taxiing (taxi and runway turn‑off) lighting systems on aircraft, covering performance, interface and test considerations.

Q: What does it cover?

A: It covers photometric and chromaticity requirements, illuminance/distribution criteria, operating life and degradation considerations for LEDs and optics, thermal/mechanical limits, EMC expectations for electronics, and appropriate test/verification methods.

Q: Who typically uses it?

A: Aircraft OEMs, lighting and avionics suppliers, certification authorities, test laboratories and MRO organizations use the standard when designing, testing, certifying or maintaining LED taxiing lighting systems.

Q: Is it current or superseded?

A: As published in September 2018 (Edition 1), ISO lists the standard as published and confirmed; ISO standards are reviewed periodically (typically every five years) for confirmation, revision or withdrawal. Users should check with the publisher or their national standards body for any amendments or newer revisions since 2018.

Q: Is it part of a series?

A: It is part of ISO work produced by ISO/TC 20/SC 1 on aerospace electrical equipment and systems; it complements other aerospace lighting, EMC and equipment qualification standards rather than being a numeric series of directly linked parts.

Q: What are the key keywords?

A: LED taxiing light system, taxi/RTO lights, photometry, chromaticity, illuminance distribution, EMC, operating life, aircraft lighting.