# What is the effect of non-LASER light sources on pilots?

After all the media coverage about people pointing lasers at commercial aircraft, I started to wonder what was so special about lasers.

It seems to me that the amount of distraction that could be done with a 5mW laser is significantly less than what could be done with something else.

For example, if I bought/borrowed the light beam from the Luxor hotel, put it in my backyard, turned it on, and pointed it at the planes flying out of a major airport, I would expect that pilots might have some more issues with a 4.3 Billion candela beam than with a 5mW laser (right?)

However, I can't find any laws against it, so would this technically be legal?

Alternatively, what if I just wanted to swing that beam around in the sky, and it accidentally crossed the path of a plane? Are there different laws regarding unintentionally hitting a plane with something like this?

• Both of those questions relate to lasers. I am interested in non-laser sources. I have edited to clarify. – Stack Tracer Sep 3 '15 at 15:25
• In the UK, there are generic laws which relate to endangering the safety of an aircraft. They could you used to prosecute someone for doing something stupid such as this without having to specifically mention what the stupid is. There are also laws laid down in the AIP that using such a beam of light pointed upwards requires the permission of the CAA and the publication of a NOTAM. This is required in my home town where cruise ship departures often have ceremonies which include sweeping search lights across the sky. I would imagine that US federal law includes similar provisions. – Simon Sep 3 '15 at 16:03
• What is different with laser is that they remain focused at long distances, hence the power is concentrated on a small area and the energy falls off very slowly with distance, by contrast a non-laser light intensity decreases with the square of the distance. Lasers don't require a powerful source or a lot of electric energy to hurt. But using the Luxor beam at home will need prior contact with your power supplier to increase your capacity. Whatever is made to create a hazard and endanger other's life can result in severe penalties, even if you are just reckless. – mins Sep 3 '15 at 16:25
• @mins Yeah, supplying 315 kW might be a bit of a problem in your backyard. It's not out of the realm of possibility, but it's certainly a lot more expensive to operate than a 0.000005 kW laser pointer. – reirab Sep 3 '15 at 16:25
• @reirab, I wasn't particularly concerned with the details of HOW to take the Luxor to your backyard... That's fairly difficult. – Stack Tracer Sep 3 '15 at 19:52

The short answer is "If you intentionally pointed the Luxor beam at an aircraft (flying low enough for it to constitute a hazard) you would probably be arrested". The real question is What would they charge you with?, and the FAA regulations aren't where you want to look for that: You need to look in the "United States Code".

18 U.S.C. 39A makes it an offense to aim a laser pointer at an aircraft. It goes on to define "laser pointer" as:

any device designed or used to amplify electromagnetic radiation by stimulated emission that emits a beam designed to be used by the operator as a pointer or highlighter to indicate, mark, or identify a specific position, place, item, or object.

The Luxor beam certainly isn't that, so you're safe there.

Instead you will probably be charged under a creative application of 18 U.S.C. 32(a)(5), which says

Whoever willfully … interferes with or disables, with intent to endanger the safety of any person or with a reckless disregard for the safety of human life, anyone engaged in the authorized operation of such aircraft or any air navigation facility aiding in the navigation of any such aircraft … shall be fined under this title or imprisoned not more than twenty years or both.

While this law was originally conceived to deal with in-person threats (kicking down the cockpit door and clobbering the captain with a frying pan) it would not take a very creative US Attorney to make the argument that shining a 40 billion candela light at an aircraft's cockpit would "interfere with or disable" the flight crew, and shows a "reckless disregard for the safety of human life".
Similarly it would not take much creativity to argue that swinging such a beam around in the sky in an area where it may interfere with aircraft operations would also show a "reckless disregard for the safety of human life", unless you took the time to file an appropriate hazard NOTAM.

Note that in my initial statement I said that you would be charged if the aircraft were flying "low enough for it to constitute a hazard" -- as has been pointed out non-coherent light source intensity falls off according to the inverse square law, and with sufficient altitude the Luxor beam is just a bright spot on the ground and doesn't have anywhere near the effects of laser illumination.

The Luxor's beam was in fact part of a study on the effect of lasers and high intensity lights in relation to air traffic safety. That section of this report (and indeed the entire thing) makes for interesting reading.

• Alternatively, what if the beam were pointed into the sky, and a plane happened to be in the area where it was pointed? Are there laws against that? – Stack Tracer Sep 3 '15 at 19:55
• @StackTracer A beam pointed directly up is not likely to be a hazard to air navigation. If you're doing it right near an airport it would be a nice courtesy to call the tower and advise them (they may publish a NOTAM), but as best I can tell there's nothing specifically illegal about it in the United States as long as you're not violating the laws above. (Note however that there may be local laws on the issue. For example, using any kind of searchlight/beacon in my county requires a permit.) – voretaq7 Sep 3 '15 at 20:10
• Even with lasers brightness at non-trivial distances follows the inverse square law. It's just that the initial beam is far more intense than non-laser sources. – Peter Green Oct 1 '18 at 18:20

The comment by @mins is right on the money by indicating that lasers require much less power to damage and distract than typical lights (whose power density falls off with the square of the distance). An additional consideration is that, while a Luxor-style beam shining from your yard will certainly get the attention of pilots, it will likely be much easier to trace to its source than a laser beam. You will likely be contacted. They may ask you to turn it off, and they may ask you to leave it on, because, while it may be obnoxious, such things are often labeled on the chart because they are uniquely identifiable visual checkpoints. Such visual checkpoints are named, recorded in the FAA database, and depicted on Terminal charts.

Speaking of the Luxor, I believe there was a visual approach procedure that actually used the Luxor as a visual fix, although I do not see it published with the current procedures.

A simple pointer-type laser will not be as bright as a search light, however, there are more powerful lasers, such as those used in light shows that can be quite dangerous. High power lasers at 500 mW are 100x stronger than a 5mW laser pointer and can seriously dazzle a cockpit, filling it with sparkling light so that nothing else can be seen. Lasers of this power can also burn the retina of the eye if the aircraft is flying low enough.

• A simple pointer-type laser will not be as bright as a search light, At what range? – Simon Sep 4 '15 at 7:39
• @Simon At any range. Contrary to popular belief, a 5mW laser will not actually damage your eyes (though some lasers marketed as 5mW are actually a fair bit more, unfortunately) unless you stare at it intently for a while. A search light, on the other hand, will cause severe damage if you look directly into it. – forest Apr 30 '19 at 6:13