LED Cabin Lighting Systems
Kim O'Neil
Advanced Aviation Technology
Ltd.
www.aatl.net
Abstract
LED lighting technologies hold out the promise of
significant improvements in cabin lighting systems. These improvements include
more reliable and robust lighting systems, greater flexibility in installation
and a much wider range of lighting effects. These benefits can lead to direct
improvements in safety and in day to day benefits, as well as significant
improvements in cabin ambience. Yet LED lighting also offers significant
benefits in terms of ease of installation, maintenance and operating costs.
1. Introduction
It may seem somewhat odd to open the discussion about
LED Lighting Systems with an immediate reference to passenger safety, yet this
is an appropriate point to make about new onboard systems that will
significantly affect the operation of aircraft in the future. Lighting already
holds a significant position in terms of general passenger Health and Safety
and in ergonomic issues e.g. management of passengers by flight crew, and in
the emergency evacuation of passengers. This is where lighting safety
functionality currently stops. Yet LED Lighting systems offer far more than
mere cosmetic improvements in cabin ambience, colour schemes or small
improvements in lighting functionality.
LED Lighting Systems are likely to become one of the
most robust systems onboard, surviving throughout the lifetime of the airframe
with minimal maintenance and even surviving the destruction of the aircraft
itself. This is perhaps an overly dramatic statement, but nevertheless the fact
is that we can engineer LED Lighting to continue normal operation even in the
most adverse circumstances.
Compare that to the fragility of existing lighting
systems. We assume these systems will fail - even when relatively minor mishaps
occur to the aircraft such as heavy landings. Indeed, we expect to evacuate the
aircraft in the dark, precisely because of our conventional experiences with
current lighting systems. We expect aircraft power to fail, the fluorescent
tubes to be destroyed and the wiring to become an impediment to escape. Then we
shrug our shoulders as if to say "what do you expect"?
Yet we should expect more. Far more. We can
significantly improve general health and safety with more ergonomically useful
lighting systems, and we can also improve safety when things go drastically
wrong.
2. Comparing Lighting Technologies
Most discussion on LED lighting begins with
comparisons between the obvious characteristics of LED's and incandescent or
fluorescent lighting as they are supplied today. LEDs are small and their use
is currently confined to 'spot beams', rather than say lighting the interior of
a cabin. Yet this is more a limitation in the way LEDs are deployed than a
limitation in LEDs themselves. LEDs are supplied as spot beams because these
are easy to manufacture and represent an obvious niche in the market (the sun
is a rather significant 'spot beam' too!). LEDS appear relatively expensive
compared to fluorescent tubes, but this is again because the true costs and
benefits are rarely laid side by side (and is related to market volume and
demand).
The fact is, we expect to see fluorescent tubes
because they are a part of everyday life at home, in the Mall and onboard - and
fluorescent tubes have served us very well indeed - we are comfortable with
them. As a result, we accept their limitations, almost as a fact of life, even
if these shortcomings are (in the cold light of day) not really so acceptable.
In practice, it may be hard to shake the fluorescent 'habit'. LEDS, on the
other hand, appear to be annoyingly bright spots of monochromatic light.
Yet our experience of fluorescent tubes isn't always
happy and they do little to improve the ambience of the places we live, work
in. For that we often prefer incandescent lighting, which provides more 'spread
spectrum' lighting and a warmer feel to our colour schemes. However,
incandescent lighting is not best suited for aircraft lighting, due to its
general inefficiency and high heat output. It is probably about time their use
in aircraft was completely reviewed.
3. A Shift in Technology
There is no doubt that LEDs are creating a lot of
excitement with all the possibilities on offer. LED lighting is a fast moving
area, with new LED technologies appearing almost daily. The range of colours,
light output, efficiency and many other characteristics - improving almost on a
par with the frequency of Pentium and graphic card upgrades in our PCs.
Therein, of course, lies the rub. We are waiting to see what pops up next over
the horizon. Thus LEDs appears to be a technology in flux.
Yet this is missing the point. LEDs are here today and
we should be planning to install the systems that will allow us to gain
benefits that are available now and those we know will be available in the very
near future. We should invest in the infrastructure of our aircraft in such a
way that it becomes economic to upgrade should we wish to design and change
colour schemes, corporate colours (e.g. on transfer of ownership) or
functionality and use (e.g. changes in cabin class configurations).
This is probably especially true for leased aircraft,
where quite dramatic changes can be made quickly and without physically
changing so many cabin fixtures, and for airlines operating large fleets that
may wish to improve aircraft utilisation, rather than dedicating specific
aircraft to specific routes.
4. The benefits of LED Technology
LEDS are indeed useful for spot beam applications,
where light can be focussed directly where it is needed, in a range of colours
and without disturbance to other passengers, in a word - control. But this is
only the beginning, and LEDs are quite capable of providing much, much more.
LEDS can provide colour wash to surfaces, creating
sophisticated ambient and indirect lighting effects. It can do this by
employing a range of colour LEDs singly or in combination or by employing
tunable colour LEDs. This can be done with great precision, providing
sophisticated control over colour, tone and brightness to generate an infinite
variety of mood, brand or corporate effects.
The only limit is in our imagination. This is not just
fanciful stuff, but is genuinely productive and useful. To see this, it is only
necessary to compare the functional benefits of LED lighting systems to the
alternatives:
The "Lows":
- Low Heat
- Low Failure rates
- Low Maintenance
- Low Weight
- Low Power
- Low Radio Output
- Easy Installation, Anywhere!
The "Highs":
- High Efficiency
- Long Life
- Flexibility
- Control
- Reliability
- Robustness
- Redundancy
- Battery backup
- Safety
LEDs are vibration, switching and temperature tolerant
with extremely rapid response times. LED lighting can be installed in places
currently unserved (i.e. virtually anywhere) and without the nightmare of
wiring and power that currently accompanies existing lighting systems
(difficulties with installation and reliability of existing lighting systems
has resulted in compromises - even in emergency lighting - that should be
eliminated).
It is possible to control LED lighting in a way not
possible with fluorescent lighting and to do this in a redundant, fault
tolerant way that drastically improves reliability, significantly reducing the
risk of an aircraft 'going tech' and increasing the intervals between essential
maintenance, as well as generally reducing maintenance effort.
LEDs do not generate radio interference, as does
fluorescent lighting.
Positive lighting and directional guidance can be
provided in emergencies.
The low power requirements of LEDs, also means that it
is possible to continue to light the cabin even when aircraft power has failed
(how many times have you sat in an aircraft when the lights failed due to a
flight deck mishap with the APU?). The ability to continue to provide full
cabin lighting in an emergency may be the single most important application
yet.
5. Subtlety and Power
Subtle and sophisticated lighting effects delivered
with power and control - this is the promise of LED lighting. Programmable
effects simulating the changes in the day from morning through to evening, and
mood lighting matched with the in-flight service, providing subtle passenger
prompts easing both crew tasks and passenger management as well as providing a
more fulfilling experience for all.
Many atmospheric and zoning effects can be created
which can be tried out using 3D modelling and simulation and then programmed
into the aircraft with complete safety and reliability.
6. Key Issues
Essential to the successful long-term implementation
of the full range of possibilities offered by LED lighting, is the need to
address key issues:
- Modular Design, with agreed control and
communication protocols.
- Flexibility and adaptability in electronic systems
design.
- 'Plug and Play' upgradability.
7. Classic Conflicts
As might be expected, the usual classic conflicts will
always occur as with any change of technology:
Customers:
- With investments in existing solutions
- Commitments and agreements with existing suppliers
Airframe Manufacturers:
- Inertia
- Preferred suppliers
- Production line commitments
Suppliers, happy with:
- Existing supply chain
- Economics (price, MTBF etc. whether good or
bad)
- Maintenance and support arrangements
8. Conclusions
LEDs means significant long-term change for aircraft
cabin lighting - and with a potential shift to s/w development. Existing
suppliers will resist change, basing their position on market dominance. More
enlightened manufacturers will develop strategies to migrate to the new
technology without undermining existing products and markets. This does not
mean that fluorescent tubes are dead, as there will be a significant retrofit
and support market, purely due to the long life of our aircraft. Hence,
aircraft will continue to be delivered with existing lighting technologies for
some time.
Rather than dramatic change, we should expect the
market to be "LED" by the regional and corporate jet manufacturers (as is so
often the case with new technology), to incorporate LED lighting in their new
aircraft deliveries - perhaps piecemeal at first in spot, accent and safety
lighting (as is already happening), until momentum gathers pace. Enlightened
airlines (pun intended) undergoing fleet replacements, Lessors or those
intending to strengthen their brands will specify new high performance lighting
systems that can only be delivered by LEDs. They will do this without expecting
a price hike - for there is no need for one. Rather, the economics of LEDs
should light the way for many other much-needed improvements, perhaps the most
significant of which is safety.
We should all certainly try our hardest to provide
environments in our aircraft that encourage positive feelings in our passengers
and so help make the whole experience of flying more comfortable and edifying -
especially in these difficult times. LEDs offer one of the most straightforward
and powerful ways to change the look and feel of aircraft cabins - literally in
an instant. We should also remember that all of us as human beings devote 90%
of our attention to what enters our eyes - and make the most of this simple
fact. |
