The rhythm of light

When it comes to airframe design and construction, LED technology is almost a no-brainer. It is lightweight, energy efficient and long-lasting. And it can be so intricately controlled, that any setting becomes possible.

“We are seeing an increasing trend towards LED,” begins Kim Choate, global mass transportation leader at Sabic (www.sabic-ip.com). “The most interesting trend for us is towards large lighting objects. These require lightweight products that are compliant with industry regulations.

“I think most people recall the first LEDs we installed in our homes many years back. They made people look washed out or unnatural. Today, the quality of LED has improved, leading to increased acceptance. This has opened the door for new lighting designs, such as the 737 Boeing Sky interior. The new LEDs are brighter and allow different colour schemes that will enhance cabin interiors and passenger comfort.”

Virgin Atlantic introduced dynamic LED lighting to the Airbus A330 aircraft to aid relaxation, while making passengers look more attractive using an apricot filter.

Luke Miles, Virgin's head of design, says: “After extensive research, we chose a palette of colours to create a relaxing ambience onboard our aircraft. We aim to help our passengers unwind, sleep and arrive at their destination rejuvenated.”

In conjunction with DHA Designs (www.dhadesigns.com), a soft ‘rose champagne' colour was chosen to de-stress passengers. This shifts to a ‘cosy' purple, then to a warm amber through dinnertime. Finally, a ‘silver moonlight' colour designed to reflect a starry night is chosen to help passengers drift off to sleep.

“It's important to create a relaxing atmosphere,” explains DHA's Desmond O'Donovan. “It is now easy to produce dynamic lighting on board aircraft, but this should be avoided in favour of a more restrained feel so people can relax.”

The cabin is lit with Diehl Aerospace's RGB units, while the bar comprises bespoke AIM Aviation LEDs.
Virgin didn't want to say anything else about the lighting. But how helpful is this lighting for passengers on long-haul flights?

Experiments have been done to test whether chronobiologically-adapted LED lighting can enhance passenger wellbeing. German lighting manufacturer Osram partnered with the University of Wuppertal, the Fraunhofer Institute for Building Physics, Airbus and Diehl Aerospace, to create a model aircraft cabin and investigate the effect of adaptive LED lighting on sleep and mood.

Circadian light

Thirty-two test subjects were put through three overnight ‘flights' over a six-day period. At the start of an overnight flight, warm-white light was found to help stimulate melatonin production and increase passenger relaxation. Blue-rich cold light suppressed melatonin, increasing passenger alertness. The research found lighting was able to aid sleep when needed then increase alertness on arrival.

“Circadian shifting by programmed dimming and CCT adjustment on transoceanic flights is the killer app on planes,” states NliteN's chief innovation officer, Andy Turudic. He reckons jetlag could be cut by a day. The science behind manipulating melatonin levels is still quite new, so there's plenty of debate on the pros and cons.

MechoSystems UK's (www.mechosystems.co.uk) regional sales manager, Grant Carberry notes: “The main benefit would be using cabin lighting to replicate people's natural circadian rhythm to reduce jetlag.”
He adds that by balancing cool and warm light during a flight, you can control when people sleep and how comfortable they feel.

One problem is that everyone will have different requirements. You need to think about the time of day, both in the origin and destination. The temperature and food schedule also needs to be considered.

“The industry attempt has been half-hearted at best,” asserts epigenetic design expert, Deborah Burnett (www.deborahburnett.com). Burnett specialises in designing spaces for the best biological impact on people. She says general understanding of circadian manipulation is still in its infancy.

“They've been using colour changing lights as marketing tools,” she continues. “They need a different approach. For an airline to truly make a difference in a traveller's life, they need to enlist the help of design and sleep experts. Lighting is a drug for the body, so it's important to understand what you're doing.”

Flying through multiple time-zones causes the part of the brain responsible for the body clock to misalign. Memory is impaired, muscle strength drops and one's ability to heal is reduced. Burnett applauds the airlines attempting to help passengers, but thinks they are not going far enough. The lighting needs to be scheduled. It needs to be thought out and researched. One point to consider is direction: in nature, light doesn't come from the top down. The sun is always in the peripheries.

“The lighting needs to be in the vertical sphere as well as the ceiling,” adds Burnett. “And it needs to be timed better; in time with the temperature of the cabin and the serving times for food. Without doing it properly it's nothing more than colour changing light.

“Light is more than what comes out of a light bulb. Light is also reflectivity off surfaces; its glare and colour. There needs to be a paradigm shift in the way we design an aircraft for passengers to be truly circadian correct. It's going to take a lot more than colour changing LEDs in the ceiling going from blue to red. All of the attempts so far are just gimmicks.”

The light bulb moment

The desire to introduce circadian lighting on aircraft is great, but we're still in the research stage; still waiting for the ‘eureka' moment.

When it comes to pilots, NASA has been running a programme for their pilots for years, so we know it can be done. Airlines are able to help pilots maintain the necessary unnatural time scale. Lighting and temperature are key to this. Protocol will dictate the specific wavelengths and time span of light used. Setting the cockpit to a high dose of blue for the entire journey isn't going to do anyone any good, and it's currently unclear what the side-effects of that will be.

“We have to be very careful about how we deliver the blue rich white light,” Burnett concludes. “It's better to have short bursts.” www.sabic-ip.com www.dhadesigns.com www.mechosystems.co.uk www.deborahburnett.com