Editor's Note

New LEDs, Better Mood

By by Ed McKenna | February 1, 2014
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UTC LED Wash Light WAWB Illumination. Courtesy of UTC.

As Light Emitting Diode (LED) technology improves, Original Equipment Manufactureres (OEMs) and operators are upping their use of the “smart” lighting throughout the aircraft — inside and out. Already in general use on the latest aircraft models, LEDs are being eyed for broader application on legacy aircraft to supply efficiency and aesthetic improvements. The expanded use of technology gives operators an opportunity to harmonize the appearance of their fleet, cut energy costs and even their carbon footprint.

The continuing surge in LED use is driving growth in the aviation lighting market, with cabin light sales alone projected to jump from $1.1 billion to $1.31 billion by 2017, according to the Dallas-based research firm Markets and Markets. This boost in use is “driven by both the operational benefits — less power [use], longer life — as well as the marketing appeal,” says Jim Kramer, senior vice president of Astronics. The East Aurora, N.Y.-based company, offering aircraft lighting through its subsidiary Astronics Luminescent Systems, is one of a cadre of vendors offering LED lighting products including Diehl Aerospace, UTC, Emteq, STG Aerospace and B/E Aerospace.

The market is getting an additional spur from steady technology development. “There have been significant improvements with LED efficiencies in both lumen per watt and dollar per lumen,” says Jake Franke, director, product development at New Berlin, Wis.-based Emteq. In the past, “high power LEDs or a large number of lower power LEDs were needed to produce the desired output,” but now that output can be achieved with a “smaller number … [of] mid-power LEDs,” he said. “The challenge of getting LEDs bright enough has evolved to where now LEDs can be too bright.”

EMTEQ QUASARII interior. Courtesy of EMTEQ.

This boost in efficiency allows operators to not only cut their energy costs but also reduce their carbon footprint. An incandescent navigation light, for example, uses 50 watts of power while an LED replacement would use three watts of power, says Rolf Brölemann, segment leader, business and regional jets interiors at Goodrich Lighting Systems GmbH, a UTC Aerospace Systems Company headquartered in Lippstadt, Germany. Passenger reading lights in halogen technology use 11 watts, while the latest LED products use only one watt, according to Brölemann. “Lighting is still a small power consumer for the overall aircraft operation, but compared to other systems it is relatively easy to upgrade to the latest standard,” he says.

In terms of efficiency LEDs are the first in their class, but the rate of improvement has been slowing down. LED manufacturers are focused more on other fields of improvements, says Brölemann. For instance, LED color and intensity ranks are smaller and stabler when used for interior lighting application and the color rendering of the latest phosphor-mixtures for warm- and neutral-white LEDs provide a better light quality, he adds.

Today more and more LEDs are being used mainly because of their greater flexibility in styling and creating appealing aesthetics. “Due to its [smaller] size and low heat emission, LED technology is entering multiple new areas in aircraft cabins and cockpits,” says Brölemann.

All of these improvements are building on a growing track record for reliability. For example, “our LED lighting products have been flying on production aircraft for close to a decade … are performing even better than expected as actual MTBUR (Mean Time Between Unscheduled Replacement) data is exceeding original predictions,” says Kramer. Astronics provides a range of interior and exterior lighting, and, in the last couple of years, has inked deals to provide exterior lighting for platforms as variable as KC-390 military transport tanker and Hawker Beechcraft King Air family of aircraft.

Meanwhile, B/E Aerospace has been providing the LED-lit Boeing Sky Interiors (BSI) for the manufacturer’s next generation 737s since 2010. Offered as an option on the new platforms, BSI has already been implemented on about 1,000 platforms, according to Stephen Scover, vice president and general manager of the lighting division of B/E Aerospace, Wellington, Fla. Scover credits the success of BSI with boosting interest in the growing lighting refit market.

The aftermarket has also gotten a lift from recent technology and manufacturing advances that have improved general illumination in not only narrow but also now wide-body platforms, Scover says. For the industry, a key goal has been “to get enough power out of the cabin lighting system … to illuminate to a sufficient degree the wide-body cabin,” he says, adding the products that have been used “have been lacking in overall vibrancy.” The chief bottleneck has been the compromises developers have had to make “in terms of package size and power distribution heat,” Scover says. “Now we can package things the way we always wanted to … in a very small footprint, and the thermodynamic properties … are such that we’re no [longer] terribly concerned with getting rid of huge amounts of heat.”

UTC Interior Lighting 8Bit.
Courtesy of UTC.

B/E Aerospace has lined up contracts with as yet unnamed customers for wide body implementations. According to Scover, the company has contracts to put the system on Boeing 737s, 757, 767s and 777s. B/E also has launched its cross-platform Tapestry systems that can be used in everything from wide body platforms to small business aircraft. The product comes in two varieties to handle AC and DC systems.

Of course, B/E Aerospace faces competition in the forward and retrofit cabin lighting markets market from vendors including Emteq, Astronics, UTC and Diehl Aerospace. The latter, a Diehl and Thales joint venture, provided the mood lighting for 787 and A380 and has been tapped to develop LED cabin lighting for Bombardier’s Global 7000 and 8000 Business jets. 

Generally, “we are seeing two different trends in the airline market,” says Ed Callahan, Emteq’s director, global business development. “Some airlines are seeking extreme differentiation and enhanced passenger experience, where others are [concentrating on] extending the competitive life of their aircraft and staying in the game.”
The company offers its Quasar II LED mood lighting for customers seeking “extreme differentiation.” “Instead of transitioning an entire cabin from blue to purple to pink — although it certainly can do this — it allows airlines to add another dimension throughout the cabin eliciting a feeling of movement and openness,” says Callahan. The system’s 2-inch node resolution delivers customizable scenes with varying colors and intensity levels; by making it a “smart light,” Emteq has also simplified integration, eliminating the need for a separate control box, says Callahan. One of the company’s more unique projects “has been working … with Icelandair creating a Northern Lights dynamic effect unique to their fleet.”

For those carriers looking to “stay in the game,” the company offers a lower cost eFIT product or a drop-in, plug and play LED lighting system. The eFit system replaces outdated fluorescents including ballasts and power supplies, uses existing mounting provisions and connectors and also interfaces with existing controls and attendant switch panel, says Callahan. Available in a dual color system white and blue lighting, eFIT can also provide color combinations that mimic the sky’s white and blue effects.
Originally designed for 737 and Airbus A320 family of aircraft, Emteq is expanding the system to address a majority of Airbus aircraft including A318, A319, A321, A330 and A340. The company “will be unveiling an LED drop in for fluorescent systems common on many business aviation aircraft at the 2014 AEA Annual Convention & Trade Show in March,” says Callahan.

Meanwhile, Swaffham, U.K.-based STG Aerospace has deployed its “swap-out/swap-in” system, replacing fluorescent with LED lighting on the Swiss International Air Line fleet of 20 Avro RJ100s. Now available on Boeing 737-600/700/800/900, the technology reduces complexity and cost of retrofit by using “existing wiring and control mechanisms,” according to the company. The new systems can be installed in an overnight shift, the company claims.

On the flight decks, LEDs are primarily being used to backlight switches and displays. The steady improvements in LED efficacy “are enabling thin, high performance backlights for displays used in military and civil aircraft … [yielding] improvements in weight and power consumption for new display designs,” says Rick Johnson, principal engineering manager, display core at Rockwell Collins.

Newer LED technology is also at least helping to address issues concerning color consistency and uniform dimming in retrofits that may include mixing newer and older displays being addressed in the newer LED technology, Johnson says. “White LEDs are available in a number of different color options … from cool white with more blue to a warm white with more yellow,” he says. “Backlight design can use a mix of LEDs of various colors to produce an overall desired display color, by tuning the backlight color, newer and older display technologies can maintain a similar look.”

As they evolve, “LEDs are continuing to become more reliable and cost effective,” and are giving system developers greater design flexibility, says Mike Glover, director, Atlanta region commercial air transport & business/general aviation at Innovative Solutions and Support (IS&S). The lighting can be used on a variety of sizes of aviation glass allowing for customization opportunities.

With few exceptions, LEDs can be used for exterior lighting applications. For example, currently, UTC Aerospace Systems is offering all aircraft lights, with exception of the APU bay light, in LED technology says Brölemann. “The APU bays of aircraft may reach temperatures of up to 180°C (depending on the aircraft platform); LEDs currently will not withstand that temperature for a reasonable time,” he says. Like in interior, exterior lighting is increasingly being used for not just its technical function but also for marketing and aesthetic purposes. For example, a new “LED logo light may support the visibility of the owners logo … and look very modern and cool,” says Brölemann. Together, those characteristics support airline branding and customer targeting.

“Along with the implementation of LEDs in aircraft interiors, we have been able to achieve big steps in exterior lighting products for retrofit as well as for new aircraft,” says Brölemann. At UTC, key improvements during the past year using different LED strobe lights now offer visual attraction similar to previous Xenon flash tube technology.
 Emteq can now improve lighting output with the same envelope size as flashtubes, says Franke. “More impressive are the increases to output for the landing and taxi light applications,” he says, maintaining that Emteq’s replacement fixtures for PAR 36, 46 and 64 bulbs offer cleaner light enhancing visibility.

While momentum for the use of LEDs seems unstoppable, challenges to managing and deploying the lighting remain. For example, “the rapidity of the LED lifecycles requires designers … to be creative and responsive to issues of obsolescence,” says Kramer. “The products developed just a few years ago, while still performing well in the market, often used LEDs that are now obsolete … These lights have been designed into aircraft that will be flown for decades to come, so the lighting fixture manufacturers need to have a robust obsolescence management plan to ensure continued support of fielded product.”

On the positive side, today new products are being introduced with a similar footprint as the earlier technologies, “so they are in a broad sense backward-compatible which is what we are trying to achieve,” says Scover. “There have been times not in the far past … when LEDs would change so dramatically that you could not even use them in the same application.”

On another front, implementation, especially in the case of total cabin lighting refresh, can still be complex and time consuming. When installing LED lighting spacing and angling of fixtures are important considerations for optimizing the light’s output and performance as well as materials such as panels, fabric and to match the quality of the new lights, says Callahan. The company’s “drop in” LEDs offer “a quick upgrade and are often less costly to integrate … [but] are not always the best approach … because you are limited to the existing controls and dimming options, and they can be more difficult to optimize the light pattern within existing spacing, (and) you can also limit the life of the system to that of the existing power supply,” says Callahan. Meanwhile, exterior lighting upgrades can be “more difficult as power supplies are buried making the installation more complicated,” he adds. “Many of the exterior lighting upgrades to LED are targeted to platforms that have recurring maintenance issues or problem lights.”

For commercial operators, “turnaround time is of paramount importance” because the downtime required to deploy, for example, a general cabin lighting system, hits the bottom line. With that platform out service, the operator loses a revenue stream.

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