Claims inaccurate statements about lasers exaggerate threat to
pilots
The recent wave of reports of US aircraft illuminated by lasers
has highlighted the need for the public and safety officials to
better understand laser technology, says the International Laser
Display Association (ILDA), which claims a number of inaccurate
statements have been repeated by government authorities and the
media regarding the hazard level posed by lasers. "I'm worried that
much of the reaction to date has been based on fear rather than
fact," said David Lytle, ILDA Executive Director. The group
represents over 100 companies, including manufacturers of laser
equipment and producers of laser shows.
A joint memo by the Department of Homeland Security and FBI, for
example, recently warned that terrorists might use inexpensive,
off-the-shelf lasers to blind airline pilots in flight. Safety
calculations performed using internationally accepted exposure
levels show this is not the case. The energy necessary to cause a
permanent eye injury at a distance of 1,500 meters would require an
unusually high-powered laser and the use of highly specialized
optics to focus the beam. "This type of equipment can cost more
than $100,000 and is decidedly not off-the-shelf or easy to
operate," said safety expert Greg Makhov, Chair of the ILDA Safety
Committee.
Although federal authorities initially sounded a warning about
terrorists, an FBI spokesman subsequently stated that the rash of
recent illuminations of aircraft by lasers all involved pranks. He
described the exposures as a "nuisance." An official of the Airline
Pilots Association discounted the threat lasers posed to aviation,
saying lasers would not be a highly effective weapon against
aircraft.
High-powered entertainment laser systems are not involved in any
of the recent incidents. Laser entertainment companies must inform
state and federal officials of shows in advance and outdoor shows
must comply with strict rules that keep laser beams away from
airports. Spotters are used to monitor the skies and shut down the
laser show if a plane approaches the display.
Although a New Jersey man recently confessed to aiming a laser
pointer at an aircraft flying at an altitude of 3,000 feet, it
would have required the combined output of several thousand of
these pointers, all focused in a single beam, to cause eye damage
to the pilot. The common 5.0 milliwatt laser pointer cannot cause
eye damage beyond fifty feet. Even at distances of 300 feet, a
pointer constitutes a hazard -- under the worst of circumstances --
similar to the glare from an oncoming car's headlights or the flash
from a point-and-shoot camera. While this can impair the vision of
some people, the effect is temporary and does not cause permanent
damage.
A recent Federal
Aviation Administration analysis of 150 incidents involving lasers
that illuminated aircraft found no cases of injuries or accidents
caused by lasers. Although there have been anecdotal reports of
permanent injuries suffered by pilots, there has never been a case
supported by an ophthalmologic examination.
The laser display industry joins other safety officials in
urging the public to never aim a laser pointer at anyone's eyes or
at the operator of a vehicle. Laser pointers are visual distraction
but will not cause eye damage unless a person stares directly into
the beam for an extended period.
ILDA continues to study lasers and air safety and offers to work
with safety authorities to further explore the issue. "Once the
public and pilots better understand the nature of the technology,
we think the reaction will be more proportionate to the risk," said
Lytle.