Lasers and aviation safety

Under certain conditions, laser light or other bright lights (spotlights, searchlights) directed at aircraft can be a hazard. The most likely scenario is when a bright visible laser light causes distraction or temporary flash blindness to a pilot, during a critical phase of flight such as landing or takeoff. It is far less likely, though still possible, that a visible or invisible beam could cause permanent harm to a pilot's eyes. Although laser weapons are under development by armed forces, these are so specialized, expensive and controlled that it is improbable for non-military lasers to cause structural damage to an aircraft.
Pointing a laser at an aircraft can be hazardous to pilots, and has resulted in arrests, trials and jail sentences. It also results in calls to license or ban laser pointers. Some jurisdictions such as New South Wales, Australia have restricted laser pointers as a result of multiple incidents.
Lasers and bright lights.
In addition to lasers, other bright directional lights such as searchlights and spotlights can have the same dazzling, distracting, and flashblinding effects.
Lasers in airspace.
Lasers are used in industry and research, such as in atmospheric remote sensing, and as guide stars in adaptive optics astronomy. Lasers and searchlights are used in entertainment; for example, in outdoor shows such as the nightly "IllumiNations" show at Walt Disney World's Epcot. Laser pointers are used by the general public; sometimes they will be accidentally or deliberately aimed at or near aircraft.
Lasers are even used, or proposed for use, with aircraft. Pilots straying into unauthorized airspace over Washington, D.C. can be warned to turn back by shining eye-safe low-power red and green lasers at them. At least one system has been tested that would use lasers on final approach to help line up the pilot on the proper glideslope. NASA has tested a Helicopter Airborne Laser Positioning System. The Federal Aviation Administration (FAA) has tested laser-projected lines on airport runways, to increase visibility of "hold short" markings. Because of these varied uses, it is not practical to ban lasers from airspace.
Primary hazards of lasers and bright lights.
The photos at right flash because most incidents are of flashes and not of steady illumination. In accidental illuminations there may be just one or a few flashes. Even in deliberate illuminations, it is difficult to keep a hand-held laser focused on a moving target, so there will be a series of longer flashes. With helicopters at close range, it is possible to have a more or less continuous light. The flashes shown greatly exaggerate the duration of a laser flash and use green rather than less visible red light. With a plane traveling hundreds of miles per hour and a laser beam size of only a meter or so, flash durations would be measured in thousandths of a second.
There are some subjects which aviation safety experts agree pose no real hazard. These include passenger exposure to laser light, pilot distraction during cruising or other non-critical phases of flight, and laser damage to the aircraft. The main concerns of safety experts are focused on laser and bright light effects on pilots, especially when they are in a critical phase of flight: takeoff, approach, landing, and emergency maneuvers.
There are four primary areas of concern. The first three are visual effects that temporarily distract or block pilots' vision. These effects are only of concern when the laser emits visible light.
The three visual effects above are the primary concern for aviation experts. This is because they could happen with lower-powered lasers that are commonly available. The fourth concern, eye damage, is much less likely: it would require specialized equipment not readily available to the general public.
It is extremely unlikely that any of the four elements above would cause loss of the aircraft.
Analyzing the hazard.
The exact hazard in a specific situation depends on a number of factors.
Pilot and aircrew factors.
The U.S. FAA has studied some of these factors. They conducted research using pilots in flight simulators to determine the effects of laser exposure on pilot performance; results were released in August 2003 and June 2004.
Example laser safety calculations.
The graphic (right) illustrates laser safety concepts. For example, it shows that the areas of most concern—eye damage, flash blindness and glare—occur relatively close to the aircraft. The distraction risk covers the longest hazard distance, but also presents the least concern. The photos in the graphic also give an idea of what the visual effect looks like to the pilot, at various distances. While the distances given are exact, the laser's brightness is in fact falling off slowly and so effects diminish continuously with increasing distance.
Also, the weaker effects are part of any stronger effect. Even if a laser does not cause eye damage at 25 feet, it can still cause flash blindness, glare and a distraction.
For any given laser, the relative distances shown here may change. For example, an infrared laser can be an eye hazard for hundreds of feet, but presents no flash blindness, glare or distraction hazard. Because of this, each laser must be analyzed individually.
To give another example, of a more powerful laser—the type that might be used in an outdoor laser show: a 6-watt green (532 nm) laser with a 1.1 milliradian beam divergence is an eye hazard to about , can cause flash blindness to about 8,200 feet (1.5 mi/2.5 km), causes veiling glare to about 36,800 feet (), and is a distraction to about 368,000 feet ().
Reducing the hazard.
There are a number of ways that laser users, regulators and pilots reduce the potential hazard from outdoor laser use. These measures include:
Police enforcement.
Police have begun using helicopters to patrol and seek out people using lasers to disrupt aviation.
Active hazard reduction (proposed measures).
Some measures have been proposed to protect aircrews including goggles and windscreen filters. These may work in theory (especially against known wavelengths) and may be useful in some situations such as military operations. However, these measures may not be suitable, practical or recommended for widespread civil air operations.
Regulation and control.
In the United States, laser airspace guidelines can be found in Federal Aviation Administration Order JO 7400.2, Chapter 29 "Outdoor Laser Operations", and bright light airspace guidelines are in Chapter 30 "High Intensity Light Operations".
In the United Kingdom, CAP 736 is the "Guide for the Operation of Lasers, Searchlights and Fireworks in United Kingdom Airspace." 
For all laser users, the ANSI Z136.6 document gives guidance for the safe use of outdoor lasers. While this document is copyrighted by ANSI and is relatively costly, a flavor of its recommendations can be seen in NASA's Use Policy for Outdoor Lasers.
Airspace zones.
The U.S. FAA has established airspace zones. These protect the area around airports and other sensitive airspace from the hazards of safe-but-too-bright visible laser light exposure:
For non-visible lasers (infrared and ultraviolet), the irradiance at the aircraft must be eye-safe—below the Maximum Permissible Exposure level for that wavelength. For pulsed visible lasers, the irradiance at the aircraft must be both eye-safe and must be at or below any applicable FAA laser zone.
In the UK, restrictions are in place in a zone that includes a circle in radius around an airport, plus extensions from each end of each runway. The runway zones are rectangles in total length and wide, centered about each runway.
Reporting.
In the U.S., operators of outdoor lasers are requested to file reports with the FAA at least 30 days in advance, detailing their location and laser power. It is permitted to use lasers whose output exceeds the limits of these zones, if other control measures are in place. For example, spotters could be used to watch for aircraft, and turn off the laser if a potential conflict is sighted. The FAA does not approve or disapprove requests, as it does not have the regulatory authority for this, but rather indicates whether it objects or does not object. If the laser use is for a show or display, approval from the Food and Drug Administration (FDA) Center for Devices and Radiological Health is required. A prerequisite for this approval is a letter of non-objection from the FAA. Laser activity in a given area is communicated to pilots before their flight via a NOTAM.
UK laser operators report outdoor laser, searchlight or firework operations at least 28 days in advance.
Regulatory and standards development.
A key group inside the U.S. working on laser and aviation safety is the Society of Automotive Engineers (SAE) G-10T, Laser Safety Hazards Subcommittee. It consists of laser safety experts and researchers, pilots and other interested parties representing military, commercial and private aviation, and laser users. Their recommendations have formed the basis of the FAA laser and bright light regulations and forms, as well as standards adopted in other countries and by the ICAO.
The ANSI Z136.6 standard is the "American National Standard for Safe Use of Lasers Outdoors." The Z136.6 committee has worked closely with SAE G-10T and others, to develop recommended safety procedures for outdoor laser use.
History.
Until the early 1990s, laser and bright light aviation incidents were sporadic. In the U.S., NASA's Aviation Safety Reporting System showed only one or two incidents per year. The SAE G-10T subcommittee began meeting around 1993 as the number of incidents grew. Almost all of the incidents were known or suspected to be due to outdoor laser displays. Almost all of the concern was over potential eye damage; at the time visual effects were felt to be a minor consequence.
In late 1995, a number of illumination incidents occurred in Las Vegas due to new outdoor laser displays. Although the displays had been approved by the FDA as eye-safe for their airport proximity, no one had realized that the glare and distraction hazard would adversely affect pilots. In December 1995 the FDA issued an emergency order shutting down the Las Vegas shows.
Within the SAE G-10T subcommittee, there was some consideration about cutting back or banning laser shows. However, it became apparent that there were a large number of non-entertainment laser users as well. The focus shifted to control of known laser users, whether shows or industry/research. New policies and procedures were developed, such as the FAA 7400.2 Chapter 29, and Advisory Circular 70-1. Although incidents continued to occur (from January 1996 to July 1999, the FAA's Western-Pacific Region identified more than 150 incidents in which low-flying aircraft were illuminated by lasers), the situation seemed under control.
Then in late 2004 and early 2005 came a significant increase in reported incidents linked to laser pointers. The wave of incidents may have been triggered in part by "copycats" who read press accounts of laser pointer incidents. In one case, David Banach of New Jersey was charged under federal Patriot Act anti-terrorism laws, after he allegedly shone a laser pointer at aircraft.
Responding to the incidents, the Congressional Research Service issued a study on the laser "threat to aviation safety and security." Because there was no federal law specifically banning deliberate laser illumination of aircraft, Congressman Ric Keller introduced H.R. 1400, the "Securing Airplane Cockpits Against Lasers Act of 2005." The bill was passed by the U.S. House and Senate, but did not go to conference and thus did not become law. In 2007, Keller re-introduced the bill as H.R. 1615. Although passed by the House in May 2007, it was not acted on by the Senate before the end of the 110th Congress and never became law.
On March 28, 2008, a coordinated attack took place using four green laser pointers aimed at six aircraft landing at Sydney airport in New South Wales, Australia. As a result of this attack plus others, a law was proposed in mid-April 2008 in New South Wales to ban possession of handheld lasers, including low-power classroom pointers. The Australian state of Victoria has had a similar ban since 1998, but press reports state that it is easy to buy lasers without a permit.
On February 22, 2009, a dozen planes were targeted with green laser beams at Seattle-Tacoma International Airport. An FAA spokeswoman said there were 148 laser attacks on aircraft in the U.S. from January 1, 2009 to February 23, 2009.
During the July 2013 protests against the presidency of Mohamed Morsi in Egypt and later celebration of his removal, thousands of protesters and revelers aimed laser pointers at government helicopters.
On February 2016 a Virgin Atlantic flight from Heathrow to New York JFK Airport was forced to turn back when a laser beam was shone into the cockpit. The incident led the British Airline Pilots' Association to call for lasers to be classified as offensive weapons.
In the first seven months of 2018, United States Armed Forces pilots were targeted with laser points in multiple regions, but particularly in the Middle East.