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Another answer pointed out that laser illumination of a cockpit may be considered an emergency, and that pilots may take evasive action when under laser illumination.

Why is laser illumination considered an emergency?

Have any documented instances of laser illumination resulted in injury to or loss of crew, passengers, or plane?

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Adam Davis
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    @AbraCadaver You might be joking, but laser guided munitions rely on lasers outside the visible spectrum, to avoid warning the enemy primarily. They won't be visible to the pilot of the aircraft. – Adam Davis Mar 27 '14 at 19:33
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    OK, maybe laser "sighted" ;-) I have plenty of weapons with this feature. – AbraCadaver Mar 27 '14 at 19:37
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    I suggest laser-guided missiles for these scenarios. But they start at the plane and aim for the laserpointer ;) –  Mar 27 '14 at 22:55
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    For further perusal: http://www.technologyreview.com/view/420214/the-danger-of-green-laser-pointers/ – Adam Davis Mar 28 '14 at 14:34

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Let me posit a hypothetical game ("Don't Try This at... well Anywhere").
It's simple - there are just 3 rules:

  1. Give your friend a nice laser pointer and have them stand at the end of a road
    A half-mile or so should be plenty.
  2. Get in your car at the other end of the road and drive toward your friend.
  3. Your friend's goal is to shine the laser in your eyes. Your goal is simple: try not to crash.

Clearly this is not a very safe game.
It should be clear that playing the same game with aircraft is substantially less safe. Someone attempting to "play" without your consent certainly rises to the definition of "emergency" in my book.

If you actually play this game you'll note that the laser isn't a neat pinpoint when it's shining at you.
Between scratches in the aircraft's window and the way your eye perceives light the laser pointer can completely blind the victim - check out the examples in the graphic below.

[Laser Effects[1]

To date I don't believe any accidents have been attributed to laser illumination, but it is well within the realm of possibility, and the upward trend in laser illuminations of aircraft means the likelihood of such an accident is also increasing.

For more information check out the FAA's Laser Safety Initiative -- and particularly the video here.

voretaq7
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    and if a pilots eye is permanently damaged he may be unable to fly anymore – ratchet freak Mar 27 '14 at 20:03
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    A 5 mW laser pointer even with minimal dispersion is highly unlikely to permanently blind a pilot beyond a few hundred feet, but unfortunately they sell ~500 mW lasers for <$100 nowadays... – Nick T Mar 28 '14 at 03:54
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    An "accident" is (by definition) an event where aircraft is seriously damaged or anybody is injured. I believe there were some events where pilot had eye problems afterwards. Not sure if permanent, but if they can't continue their duty immediately afterwards, it is necessarily classified as injury (and therefore the event as accident). – Jan Hudec Mar 28 '14 at 05:58
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    @JanHudec I agree with you (as does the NTSB, though they qualify it as "seriously" injured), but in practice there is no NTSB or FAA document I'm aware of that I can point to saying "These are accidents where laser illumination was a causal or contributing factor" - as far as I know they're all classified as "incidents" right now. – voretaq7 Mar 28 '14 at 15:47
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    @voretaq7: Quick search on The Aviation Herald shows 8 accidents where pilot was "injured" or "incapacitated", the most recent being Accident: Kelowna B722 at Regina on May 13th 2013, laser beam incapacitates first officer. Avherald uses the classification assigned by the investigating authority. – Jan Hudec Jun 06 '14 at 22:41
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    I would add that now there definitely is at least one accident in USA too. – Jan Hudec Feb 10 '15 at 11:03
  • @NickT Green lasers are a lot more dangerous at the same output level than red lasers, but you're right that 5 mW is not going to do permanent damage. But why is it unfortunate that people sell high-power lasers? They have legitimate uses. – forest Apr 30 '19 at 06:16
  • Note that 5 mW is the top end of the range that can be legally classified as a "laser pointer". The more typical (usually red) laser pointers that you buy to point at slides in a business meeting or annoy your cat are considerably less powerful. Not that you should point even those at airplanes or other people, but it's not quite as bad. – Darrel Hoffman Apr 26 '21 at 16:21
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Even if the laser doesn't cause temporary or permanent injury to the pilots' eyes, it causes them to lose night vision.

The most well-known cause of this is the pupils of your eyes. In the dark, the pupils open up to allow in as much light as possible. When they're exposed to a sudden bright light, they close up again. If the bright light goes away, it takes your eyes some amount of time (say, a minute or two) for your pupils to open again. During that time, you can't see very well at all. Not good, if you're trying to land a plane. You can experience this for yourself by playing around with the lights indoors at night: if you turn the lights off, you can see very little but, gradually, you begin to make things out as your pupils open. If you then turn the light back on, it feels uncomfortably bright until you get used to it again.

Less well-known is a chemical called rhodopsin, in the rod cells in your retina. Rhodopsin is extremely sensitive to light (even to single photons), and light makes it change shape. Other proteins bind to this new shape and a few little chemical reactions result in an amplified signal being sent to your brain. Most of your vision in the dark comes from the rod cells because of their high sensitivity; the other cells (the cones) require tens to hundreds of photons to fire so they're great for colour vision in decent light but not much use in the dark.

However, being bound to other proteins means that the rhodopsin in your eyes is "used up" as light comes into your eyes. When its dark, this happens slowly enough that the rhodopsin can be regenerated but a sudden burst of bright light, such as from a laser, consumes all the rhodopsin in your eyes almost immediately. Now, you're only seeing with the cones, and you're not seeing much. The really bad news is that it takes at least 5–10 minutes for a decent amount of rhodopsin to regenerate and 30–45 minutes to get back to the full amount. So now, your pilots are operating on quite seriously decreased vision for a substantial amount of time.

David Richerby
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  • This is not true for red lasers, since rhodopsin is not particularly sensitive to red. That's why submarines will use red lighting at times, so if they have to surface in an emergency, their rods will not be saturated and they will not need to adjust. – forest Apr 30 '19 at 06:17
  • @forest Do you have any data on that? Even though rods aren't very sensitive to red, we're still talking about a very intense red light here. Presumably red lasers aren't as bad, but that doesn't mean they're not a problem. – David Richerby Apr 30 '19 at 09:19
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    See https://en.wikipedia.org/wiki/File:CIE_1951_scotopic_luminosity_function.svg for the wavelength responses of various human photoreceptors. A red laser of 635nm would barely excite a rod cell, and 640nm would not affect it whatsoever. The amount of energy required to saturate a rod cell at 635nm would likely burn your retina. There's a little more information at https://en.wikipedia.org/wiki/Scotopic_vision and https://en.wikipedia.org/wiki/Luminosity_function as well. – forest Apr 30 '19 at 17:07
  • @forest OK but egid's answer says that pilots have had their retinas burnt by lasers, – David Richerby Apr 30 '19 at 17:16
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    Those cases were all green lasers, which the eye is very sensitive to. – forest Apr 30 '19 at 17:17
  • Retinal burning is just a matter of the intensity of the light. Your retinas can be burnt by UV, which they're not sensitive to at all. – David Richerby Apr 30 '19 at 17:23
  • That's true, but you were talking about loss of night vision. I was just pointing out that this would not be true for red lasers, which are very common. Of course a powerful enough light will burn your retinas at any wavelength, but at that point you're blinded due to photic retinopathy, not loss of night vision. – forest Apr 30 '19 at 17:25
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Some of the cheap, powerful lasers available now are capable of blinding pilots and in some cases causing lasting injury. Even temporary blindness, however, is something I think any pilot would consider an emergency.

A fairly recent Daily Mail article states that "the FBI noted that several commercial pilots earlier this year suffered significant injuries including a burnt retina." There are over 4000 reported incidents a year, and the number is apparently increasing rapidly. It is now a federal crime that has at least in one case resulted in prison time.

egid
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You can legally buy lasers that are certainly able to damage someone's eyes. They come with laser warnings for a reason, and being lasers, the intensity does not decrease much with distance. People with more powerful lasers could do even more damage.

This laser safety site has good info about the effects it has on the pilot and what can happen to you if you are caught doing this. Here is another article where the pilot suffered injury.

Laser illumination has not been identified as a factor in any accidents involving loss of life so far, but considering how many happen and the fact that they happen more and more often, it is certainly a hazard to safety and cause for declaring emergency.

Although many people charged with this crime claim their intentions were not malicious, that is certainly not always the case. Police helicopters are often targets, and this recent incident in Egypt is a notable example.

fooot
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    Now why buy, when you can make much, much more powerful lasers? – haneefmubarak Mar 28 '14 at 04:38
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    An incident where anybody is injured is classified as "accident", so in this sense they certainly were identified as cause of some. – Jan Hudec Mar 28 '14 at 06:02
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    @haneefmubarak I'd venture that most of the people who shine lasers on aircraft pilots aren't the kind capable of building their own laser :) – Luaan Mar 28 '14 at 07:35
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    @Luaan *that* many people lack basic physics skills? Five minutes later... "Okay, so boys and girls, this is how you make a 5W laser..." XD – haneefmubarak Mar 28 '14 at 08:06
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    @haneefmubarak I think his point wasn't that so many people lack basic physics skills, but rather that so many people possess an understanding of right and wrong that includes potential outcomes here and excluding the few Dr. Evil's in our world, being capable of building your own laser likely puts you in the "smart enough to know not to do that" group. – mah Mar 28 '14 at 11:32
  • @mah I suppose that makes sense... – haneefmubarak Mar 28 '14 at 16:39
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    @fooot I don't believe it is illegal (at least in the US) to possess a high power laser or that you needed a permit. – haneefmubarak Mar 28 '14 at 16:40
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    @fooot Perfect. After reading that, I was sweating bricks for a few minutes while I searched for laws about lasers :) – haneefmubarak Mar 28 '14 at 18:05