A comprehensive resource for safe and responsible laser use

Laser hazards to aviation

Laser and aviation safety experts such as the SAE G10OL and G10T committees, and the ANSI Z136.6 committee, agree that there are two potential hazards to pilots from laser light: visual interference, and eye effects or injuries:

Visual interference

The primary hazard is visible-light lasers aimed at aircraft that results in “visual interference” with pilot performance, during critical phases of flight such as takeoff, landing, emergency maneuvers, and low-altitude flight (helicopters).

Fortunately, it is unlikely that exposure to the light alone could cause an accident. In over 80,000 reported laser illuminations worldwide from 2004 through mid-2020 there have not been any accidents. However, experts are concerned that bright light occurring at the wrong time — such as during an emergency, or when there is another problem for pilots to deal with — could be the “straw that breaks the camel’s back.”

Eye effects or eye injuries to pilots

The secondary hazard is the potential for a laser to cause eye effects or injuries to pilots (or anyone onboard looking out a window towards strong laser light).

There have been documented eye effects such as watering eyes; these occur in less than 1% of reported laser illuminations of aircraft.

However, pilot exposure in flight to laser light is highly unlikely to result in significant or permanent eye injury. In fact, as of February 2019, there have been no documented or proven cases of permanent eye injury to pilots, according to aviation agencies such as the U.S. FAA, U.K. CAA, and Transport Canada.

Laser light is visible at great distances

Here is a photo showing how a 1 milliwatt laser is visible at a distance of 20 kilometers (12 miles) across Tokyo. Although the laser’s irradiance is below the FAA distraction limit of 50 nanowatts per sq. cm. -- it is approximately as bright as other city lights -- you can see that the light is still visible.

Tokyo - 1 mW laser from 20 km

A 5 milliwatt laser: a distraction 2 miles away

In the United States, lasers sold for pointing uses cannot exceed 5 mW. The diagram below shows the hazard distances for a 5 milliwatt “U.S. legal” green laser pointer with a 1 milliradian beam divergence:
  • It is a potential eye hazard from the pointer to about 52 feet.
  • It is a temporary flashblindness hazard from the pointer, out to about 260 feet. On the diagram, this is illustrated in the inset photo “Near-flashblindness” which shows what a 5 mW laser looks like at 350 feet.
  • It is causes glare and is a disruption hazard from about 260 feet to about 1,200 feet. This is shown in the “Glare” inset photo where the runway is not visible.
  • It is a distraction hazard from the pointer to over two miles (11,700 feet). The distraction can be dangerous during a critical phase of flight, such as takeoffs and landings. Note that this is not truly “visual” interference, since a pilot can see despite the light. Instead, it is a mental distraction, interfering with the pilot’s attention. This can be overcome if a pilot is aware of laser hazards, and how to react to them (e.g., ignoring low-level laser distractions).

The laser’s light is not truly safe until it is indistinguishable from background lights on the ground. A pilot may notice a flashing dot of light, but it should not be enough to cause a distraction. (This does not mean that anyone should aim a 5 mW laser at a plane if it is over 2 miles away. For one thing, it is very difficult to gauge aircraft distances at night. Even more important, there simply is no reason to aim a laser at an aircraft except in an emergency situation such as a wilderness rescue.)

Click on the diagram for a larger version

For more info on the inset photos (cockpit views of laser light), see the “2004 FAA simulator” page

A 125 milliwatt laser: a distraction 11 miles away

More powerful lasers are hazardous at greater distances. The hazard distance increases as the square root of the power increase.

For example, a 125 mW laser is 25 times more powerful than a 5 mW laser. The square root of 25 (the power increase) is 5 (the hazard distance increase). Therefore, multiply the hazard distances for a 5 mW laser by 5, to find the hazard distances for a 125 mW laser. For example, if a 5 mW laser is an eye hazard out to 52 feet, a 125 mW laser is an eye hazard out to 5*52 or 164 feet.

The table below does the multiplications for you. It provides some sample laser powers and the corresponding hazard distances measured from the laser output. (Note that these distances are approximations. It is not as if a 5 mW laser is an eye hazard at 52 feet but is not an eye hazard at 53 feet. The distances give approximations where one hazard zone shades into another.)

Click on the table for a larger version showing additional data

We also have an online laser hazard distance calculator, and a page that explains the hazard distances in depth.

How to be safe when using lasers at night

If you absolutely must point something out in the night sky (e.g., at a star party), use the laser to circle the object -- don’t aim directly at it. Additional suggestions are on the Tips for star pointing page.

Additional information

  • Articles from other aviation sources, and presentations to laser safety groups, are on the Links page.