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Lasers have been in the news in late 2004 and early 2005,
due to incidents in the U.S. where laser beams were aimed at airplanes. (This is
discussed in great depth on the Lasers and aviation
safety page.)
None of these incidents appear to have been from light shows.
This is to be expected, since the laser light show industry is
the most heavily regulated of any
outdoor user of lasers in airspace.
Shows are designed for
aviation safety
Outdoor show producers take many steps to ensure aviation
safety. If possible, they aim the lasers onto nearby buildings or structures, so
the beams are terminated (stay within the show area). Any unterminated beams are
aimed away from airports and flight paths.
Control measures such as airplane spotters are used to turn off the laser if any
aircraft approach unterminated beams. The goal is to keep all laser light away
from pilots and aircraft, no matter how bright or dim the light.
It was not
always like this. In the mid-1990s, U.S. regulators (both
FDA and FAA) approved lasers in the flight
path of Las Vegas's main airport. At the time, all parties thought the only
concern with planes was to keep the beam power at an eye-safe level. But pilot
complaints made it clear that distraction, glare and even temporary
flashblindness were valid concerns during critical flight phases.
As a result
of the mid-1990s episodes, the outdoor shows in Las Vegas were ended.
Representatives from the International Laser Display Association worked closely
with government, industry and aviation groups such as the
ANSI Z136 and
SAE G-10T
committees, to develop safety techniques for all outdoor laser users.
Laser shows have an excellent
safety record
Since that time,
professionally-run laser shows have had an excellent safety record. ILDA members
understand the potential hazards. They support the recent crackdown on
irresponsible use of laser pointers.
ILDA also
supports the responsible reporting of potential laser hazards. Some inaccurate or
sensationalistic reports have appeared in the news media and elsewhere.
Everyone, including pilots, law enforcement, and the public should understand
the very limited circumstances under which lasers could present a hazard.
And they
should understand how laser professionals working on shows, at observatories and
in industries nationwide, are working to keep skies safe and pilots reassured.
Frequently asked questions
Can laser
shows and other uses be done within the FAA's zones?
Yes, lasers can be used
with the FAA Laser-Free, Critical and Sensitive Zones in two cases. One is if
the beam power and characteristics are lower (safer) than the limits for a
particular zone. The other is if "mitigation" is done using effective control
measures. This allows high laser power levels to be used, as long as aircraft
are not illuminated. In both cases, those using lasers outdoors must report
their usage to the FAA, usingAdvisory Circular 70-1
[caution: 2.2 MB download]. The FAA will review the provided data and determine
whether or not they will object to the laser use.
What control measures are available?
The following are some
"physical, procedural and automated control means to ensure that aircraft
operations will not be exposed to levels of illumination greater than the
maximum irradiance level considered as acceptable in each affected flight zone:"
-
Physical
beam stops used to prevent laser light from being directed into protected
airspace. Example: Barriers surrounding laser show bounce mirrors, so that if
the laser misses the mirror, it does not go off into airspace.
-
Adjusting
beam divergence and output power to meet the appropriate irradiance
distance. In other words, making the beam wider and/or less powerful, so it does
not exceed the laser power for a particular FAA zone.
-
Directing
beams into a specific area. Example: Aiming beams away from an airport so
they do not enter a particular zone.
-
Using
airspace observers (spotters), who can shut down the beam if they spot an
aircraft. This topic is a complex one, which depends on observer abilities,
distance to planes, aircraft visibility, communications to ensure shutdown
occurs, etc.
At Walt Disney World, EPCOT's nightly laser show relies partially on laser
spotters to keep the show safe and legal. Incidentally, in the past, EPCOT has
been buzzed by
small planes during the show, causing the beams to be prematurely turned off and
thus spoiling the show for the ground-based observers.
-
Automated
detection/avoidance systems, which shut down the laser or move the beam in
case a plane is detected. These are complex, must be proven to work, and must be
approved.
Is it true that laser shows are
the only laser users who are regulated in airspace?
Yes. Of all
outdoor laser uses, the only one which is legally regulated is laser shows.
All others are requested, but not required, to submit to FAA review. Here's how
this works:
Only three laser uses
are regulated by the U.S. federal government: medical, construction and laser
shows. The Food and Drug Administration (FDA) requires outdoor laser show
operators to submit their shows to the Federal Aviation Administration (FAA) for
review. If the FAA objects, then FDA will not give permission (called a
"variance") for the show.
Normally, the FAA has
no authority or jurisdiction over outdoor lasers. Anyone can shine lasers into
the air without seeking FAA approval. The FAA certainly encourages people to
file reports (using
Advisory Circular 70-1 [caution: 2.2 MB download]). The FAA will
review the reports and will send back a letter saying whether they object to the
laser use.
However, no one is
required to file this report with the FAA, and there are no penalties if you
ignore an FAA letter of objection. The only exception is, of course, laser light
shows. This is because if the FAA objects, then the FDA will not give its
permission (variance).
This
is one reason why legal laser shows, those reported to the FDA and FAA, have
had an excellent safety record since new requirements were developed in the
late 1990s.
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