Avionics News February 2016 - 71
flashing LEDs to perform the strobe-light functions. And
no weighty, power-thirsty power pack needed to power
the strobe functions.
The individual circuitry hides inside the fixture,
protected from dust, moisture and vibration.
Individual units for recognition/position and anticollision functions also are available, many of them capable
of directly replacing existing old-technology fixtures.
And speaking of anti-collision functions, many of
those LED landing-light replacements offer integral
wig-wag or flashing functions built into the lighting unit
itself. For some, it's only a matter of flipping the switch
an extra time to change between a steady light and the
blinking state to help the aircraft stand out en route, in
the pattern or on approach.
LEDs for inside
The design engineers haven't neglected the needs of
pilots and passengers inside the cabin, just as they've
tackled fulfilling almost every need for outside illumination.
Everything from eyeball lights to post light bulbs and
map lights, reading lights and cabin-interior lights are
available for most applications.
Also worth offering owners, glow stripes and electroluminescent strips can attach to glare shields and
illuminate dark panels and unlighted switches - with full
dimming control available.
LED bulbs that plug into cabin-light fixtures, replacement
units that convert the fixtures to LED-based, and other
advanced systems also are available, and they bring to the
interior the same benefits they deliver as exterior lights.
Durability, versatility, lifespan and low-current draw
translate well for interior needs.
More options for the homebuilt aircraft
Browse the sites of any of the companies offering LED
lighting options, any of the suppliers offering hardware
to owners and maintenance technicians, and you should
notice many options available for experimental and
Lacking the approvals required for some lighting
tasks, these options give the experimental-aircraft
operator options with lower costs, albeit less
documentation about their performance.
The lack of a TSO does not, however, mean the units
lack the performance the owner/pilot or builder wants
or needs, as most technicians know. As they also know,
some equipment tagged for the experimental market can
be legally used in certificated aircraft without voiding
the type certificate - particularly when the aircraft
doesn't fly for hire.
Where available, shop staff can help aircraft owners
recognize and understand those options and perhaps help
cement a stronger relationship with these customers.
With most pilots still waiting for AvGas prices to
fall commensurate with the decline in crude-oil prices,
every little bit that helps keep them flying also keeps the
aviation community healthier.
The shortcomings ... just a few
While LED lights win the contest for brightness,
stability, longevity and being low power consumers, they
do have a couple of drawbacks.
One is that LEDs have to be tailored for visible light
and, in runway environments, supplemented with LEDs
of a different spectrum so they show up on enhancedvision system screens. Ditto for inside cockpits where
the flight crew uses night-vision goggles.
The LEDs produce light in a specific range, according to
their design. Conversely, incandescent and halogen bulbs
produce light across a vastly wider range of frequencies -
much of it wasted in heat and light humans can't detect.
Airport operators learned about this issue after many
started converting to LED runway and taxiway lights,
learning from flight crew that their EVS system could
not detect the specific LED frequency used.
But arguably the biggest obstacle to wide acceptance
rests largely in their cost. As is typical in aviation, units
designed for the experimental, amateur-built market are
less expensive than units built for approved installations.
Across the spectrum, however, LEDs' initial costs
remain well above the expense of sticking with
traditional light sources. Factor in the time, labor costs
and any incidental factors that accompany each bulb
eliminated by an LED replacement, however, and the
outlook shifts toward the LED replacement.
The long-term value of once-and-done light
replacements continues to win converts, particularly as
options grow and the costs of producing individual LEDs
continue to decline.
In the interim, the best arguments for making the
switch remains their long-term value and low current
draw for the application. A staged replacement as needed
is going to be the best approach for many operators.
From all other perspectives, the points all go to the
LED, and the tilt toward them will continue long after
incandescents have gone from production. q