A new European Standard for LED cabin lights is among recent tech breakthroughs Lufthansa Technik (LHT, Booth H71) is touting at EBACE 2019. The tech spec, DIN EN 4731, is aimed at fostering illumination commonality among next-generation interior systems.

The issue: LED lights, unlike the fluorescent fixtures they often supplant, have highly individual light spectrums, generally determined by the manufacturers’ specifications. Cabin lighting systems with mood lights, for example, have an almost infinitely variable light spectrum. These variations affect the appearance of interior colors, among other impacts.

Additionally, charging times for the LED systems can also vary widely, and this can be a safety issue when used for photoluminescent floor path marking. To ensure they meet performance needs, LED floor path lights have required extensive testing before installation to confirm their charging capability.

As a major player in cabin lighting for two decades, LHT saw a need for the LED lighting standard, supported its development, and served on the expert committee that drafted it.

Published last year, DIN EN 4731 (Aerospace series – Spectral quality of LED luminaires used with photoluminescent marking systems) can be used to calculate the charging efficiency (Ce) value of LED light sources for photoluminescent products, and the charging time for LED cabin lighting systems, eliminating the need for pre-installation testing, said LHT senior engineer Wolfgang Sutter, who led LHT’s standards team. The benchmark creates a tool that can help all individuals involved in designing cabin lighting systems achieve standardized levels of luminosity. It is “easy to use” and is "already being applied in practice and proving to be very useful,” Sutter said.

The standard applies specifically to LED lighting systems used in aircraft equipped with photoluminescent floor-path marking and is officially recognized only in Europe, but DIN EN 4731’s adoption is expected to affect interior LED lighting used in other aircraft and beyond the Continent, as well.

In addition to improved illumination, LED lights can be significantly cheaper to maintain than conventional lighting, owing to the fixtures’ longer life. But more LEDs may be required to provide a lighting level equivalent to conventional lighting and the lighting levels and color of first-generation LED systems were prone to dim and change over time. LHT previously teamed with German optical products specialist Schott to develop an LED system for commercial aircraft, HelioJet, that uses LED chips to generate light transmitted via fiber optic cable, delivering homogenous light that earlier strip-light LED systems couldn’t produce.