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Source: Air Force Safety Magazine:
http://afsafety.af.mil/magazine/htdocs/octmag97/pg8.htm

"Blinded by the Light"

(An Old Song With New Consequences)

DOUGLAS J. FREY, SETA TEAM
Optical Radiation Division
Brooks AFB, Texas

The experienced commercial pilot scanned the sky ahead as he reached 5,000 feet during takeoff from McCarran International Airport near Las Vegas. Without warning, he was startled and distracted by a bright green light. Momentarily blinded, he realized he could no longer safely control the airliner. Instantly, he called on his copilot. "Take the controls--I can't see!" Fortunately, the copilot had been looking away when the light passed through the plane's cockpit. While the passengers were unaware an in-flight emergency had just occurred, if the copilot had been glancing in the same direction as the pilot, the result could have been disastrous.

From 1993 to 1995, there were more than 50 laser incidents reported by military and civilian pilots flying near Las Vegas. Similar incidents have occurred at other facilities that are close to outdoor laser light shows or near major tourist sites using lasers to attract attention. In December of last year, for example, the pilot of a Delta flight inbound for a Florida airport was temporarily blinded by a beam from a spectacular outdoor laser light show that was entertaining thousands.

Powerful lasers can cause irreparable eye damage. Scientists have developed procedures that establish minimum safe distances to prevent injuries, and the Federal Aviation Administration has established eye damage hazard zones for outdoor laser shows. Unfortunately, staying beyond this Nominal Ocular Hazard Distance (NOHD) does not solve all the safety problems for pilots. The glare and flash-blindness danger presented by entertainment (laser light shows) and commercial promotion lasers extends far beyond the established NOHD. If a pilot cannot safely control an aircraft because of momentary blindness caused by glare and flash-blindness, there may be much more than damage to one set of eyes involved--lives could be in jeopardy.

The Air Force predicted these problems years ago and began to explore laser exposure hazards and establish laser safety standards. The Optical Radiation Division of Armstrong Laboratory at Brooks AFB, Texas, is the leading Department of Defense element in this area, providing laser safety information to government and civilian agencies for years. In late 1994, the Air Force formed a Tiger Team under the direction of the Flight Standards Agency to address the flight hazards posed by commercial laser light shows. The Tiger Team faced two key challenges: Quantify the flight hazard distances upon which the controlling agencies could base regulatory controls, and develop methods to educate military and other aircrews to the growing flight hazards associated with lasers. As an immediate result of the team's efforts, laser hazard information is being developed for pilot refresher courses, and outdoor commercial laser show information was included in the military NOTAM system.

Because of their laser expertise and experience, Air Force scientists and engineers from the Optical Radiation Division were asked to join the Society of Automotive Engineers (Aerospace Council) G-10 Committee, the Washington DC-based group that has been charged with resolving laser dangers to flight safety. As an interim measure, the committee has prepared a safety video script and coordinated with Walt Disney Studios for production assistance.

Meanwhile, the Federal Aviation Administration has been working with the airline industry and with laser light show presenters to come up with a solution that will be satisfactory for all interests.

"If some of the previous illumination incidents had happened to pilots of single-seat aircraft, the results could have been disastrous," said Lt Col Leon McLin, cochair of the G-10 Committee and a researcher at the Brooks AFB laser lab. "What we want to do is take steps to minimize the risks to flight operations while still making the use of laser technology available to promoters and entrepreneurs."

McLin added that the people who put on laser light shows for a living have been generally cooperative and helpful in the efforts to protect safe flight operations. He warns, however, that serious laser flight hazards still exist. "The FAA considered restricting the output power of the lasers used by promoters, but instead established areas around active runways where promoters must adjust the laser output intensity of any beams that might enter those areas and present a flight safety hazard. These laser protection zones reduce the dangers presented by unintentional exposures that could result in glare and flash-blindness."

As the various agencies work to decrease laser flight hazards, it is imperative that all cockpit exposures get reported. Although there is little chance of permanent eye damage beyond NOHD warning distances, notify your local flight surgeon of any laser incidents. The flight surgeon can coordinate with bioenvironmental engineers and with the laser lab at Brooks AFB to report safety issues and verify exposure limits. Report any incidents of possible laser exposure to your flight safety office.

The possibility of laser exposure during flights is real. "The idea of flying blind during high-risk activities such as takeoff and landing is frightening. To lose a pilot or commercial air carrier because of exposure to a spectacular beam of light that was intended to entertain thousands would be a tragedy," said McLin. "We've been lucky, so far."