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Old 07-17-2015, 10:37 AM
Habeed Habeed is offline
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Lasers and planes : risk of eye injury to the pilots and copilots?

There's 318 million or so people in the USA. Every last man, woman, and child can get their hands on a small laser - about 2 watts power seems to be about the limit. More powerful lasers exist but are far harder to obtain.

So out of 318 million people, at any given time, there's a jerk or 2 who wants to aim the laser at a commercial jet. While these people can be caught, eventually, and sent to decades in prison as an example to others, it doesn't sound like law enforcement can ever stop it completely if the lasers can be grabbed from many stores and it's just a matter of pointing it at a jet on a whim.

Anyways, the focusing lens or mirror in a handheld laser is tiny. R^2 law. Isn't the risk of eye injury from a 2 watt or so laser at a jet 5000 feet or more away small?

Distracting the pilots might one day crash the jet. That's what happened in a tom clancy novel - but they also send out a fake airworthiness bulletin so the jet was off autopilot on approach, and used a much more powerful light designed to be a weapon.

So it seems like eye injury is the main risk. Would it be practical to armor the windshields or otherwise provide some kind of protection for the pilot's vision?
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  #2  
Old 07-17-2015, 11:26 AM
LSLGuy LSLGuy is offline
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There has been talk of making the windshields laser resistant. The cost is scary, even by the standard of aviation parts.

The risk is real. Some airliner gets lased someplace in the US every few days. In the daytime it's an incremental risk. At night it's a huge life-threatening risk.

When a laser hits the cockpit area, it rattles around in there bouncing off all the windows & instruments. At least one pilot is effectively blind for 30+ seconds until the dazzle wears off. Since this usually happens when we're hand-flying and close to the ground, the opportunity for disaster is real.

At cruise with the autopilot on would be different. We could sit there for a few minutes if necessary waiting for our vision to return and the odds are very, very slim we'd miss anything truly critical during that time.

Some pilots have experienced retinal damage leading to weeks or months off work. I'm pretty sure somebody has permanently lost his medical clearance over a laser hit, but I can't point you to a cite.

The basic Chinese laser pointer in the bucket by the cash register at the hardware store isn't the main danger. Those have to be pretty darn close to us to inflict damage. But the couple-hundred dollar light-saber lookalikes are a whole different matter. Those can be dangerous at even a couple miles slant range.

Last edited by LSLGuy; 07-17-2015 at 11:27 AM. Reason: tpying is hrad.
  #3  
Old 07-17-2015, 11:33 AM
md2000 md2000 is offline
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I think you overestimate the power. I look for laser pointers and they seem to be in the 2 to 4 mW range. 2W would fry your eyeball or at least make spots on your retina permanently blind, I think. But yes, that's point-blank. I've looked into one of those classroom 1970's HeN lasers (.5mW I think it was, or was it 0.05mW?) with no ill effects. The other issue is spread. If it spreads from 1mm to 1m at 1000m then that's one millionth the power... but then it's times about say, 25 power because it's not a 1mm beam, it's hitting your entire area of (I'm guessing) 5mm pupil.

http://www.lasersafetyfacts.com/3R/
Quote:
For a 4.99 mW Class 3R laser with a less-tight beam that spreads out faster (1 milliradian), the NOHD is 52 feet (16 m). This divergence is more typical of consumer lasers.

If you are closer than the NOHD distance to the laser, there is a possibility of retinal damage if the direct or reflected beam enters your eye longer than about second. The closer you are to the laser and the longer the beam is in the eye, the greater the chance of injury.

http://www.laserpointersafety.com/media/media.html
This says there have been no actual injuries - to pilots.

Last edited by md2000; 07-17-2015 at 11:35 AM.
  #4  
Old 07-17-2015, 11:35 AM
Habeed Habeed is offline
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Quote:
Originally Posted by LSLGuy View Post
When a laser hits the cockpit area, it rattles around in there bouncing off all the windows & instruments. At least one pilot is effectively blind for 30+ seconds until the dazzle wears off. Since this usually happens when we're hand-flying and close to the ground, the opportunity for disaster is real.
What would you do in this situation? Is there a switch or control setting you could enable with impaired vision to basically go into a shallow climb and increase power? (to buy you enough time on a go-around for your vision to return)

My 2 watt estimate came from a certain website that is well known that sells them. Technology has changed and it is now practical to build multi-hundred watt lasers relatively inexpensively, using similar LED drivers to what we're replacing lightbulbs with. Presumably, once you're talking about hundreds of watts of lasing power, you're talking about something that could cut metal or be used as a real weapon. (military wants 100 kilowatts or more, but they want a lot more range)

Last edited by Habeed; 07-17-2015 at 11:38 AM.
  #5  
Old 07-17-2015, 11:58 AM
Broomstick Broomstick is online now
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Quote:
Originally Posted by Habeed View Post
What would you do in this situation? Is there a switch or control setting you could enable with impaired vision to basically go into a shallow climb and increase power? (to buy you enough time on a go-around for your vision to return)
You know, a lot of airports have obstacles around them - buildings, towers, mountains, whatever. A random shallow climb will get you away from the ground, but not necessarily other obstacles.

This sort of thing is, of course, why passenger planes still carry more than one pilot. The odds of both pilots being dazzle-blinded are lower than just one being dazzled.
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Old 07-17-2015, 12:01 PM
LSLGuy LSLGuy is offline
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md2000: As I said, the issue isn't laser pointers. It's things like this: http://www.armlaser.com/

Habeed: There's no magic button. yet. Procedure calls for the pilot seeing it to shout a warning and the other pilot to close eyes & duck down below the glareshield.

Typically you can see it coming a second or so early as the bad guy tries to swing the beam onto the airplane. The good news is there's more warning at night when the risk is larger.

Obviously if he had it attached to a scope like a laser rifle, and could accurately aim before firing we'd get no warning. But so far it's just dummies playing in their backyard who act on a stupid impulse. Or maybe folks tired of the noise and thinking somehow that them doing a little minor vandalism will change things or at least make them feel better.

The other good news is it's difficult to track the jet for long. the beam size isn't that big and in many cases I doubt the bad guy can even tell if he's getting a hit or not. So the typical encounter lasts a few seconds at most. Again somebody with a rifle-and-scope-like arrangement could keep us illuminated a lot longer with much more serious consequences.

Last edited by LSLGuy; 07-17-2015 at 12:03 PM. Reason: tpying is still hrad.
  #7  
Old 07-17-2015, 01:16 PM
MichaelEmouse MichaelEmouse is online now
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Quote:
Originally Posted by LSLGuy View Post
md2000: As I said, the issue isn't laser pointers. It's things like this: http://www.armlaser.com/
What functions do those serve besides being used as weapons?


Can infrared laser pointers dazzle too?
  #8  
Old 07-17-2015, 01:57 PM
GusNSpot GusNSpot is offline
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Green & blue are the most powerful & dangerous as a general rule?

Any color that would stop the lasers light being damaging to the eyes that could be made into safety glasses that at least one of the pilots in airliners could wear, from 3000 AGL and below to touchdown say, that would protect & yet allow reasonable ability to function at night?

Also serious effort to catch these idiots.
  #9  
Old 07-17-2015, 01:57 PM
hopesperson hopesperson is offline
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Just curious how this works -- It would seem to me that, for a commercial airliner at cruise flight level, the geometry is such that someone on the ground with a laser would have to be off at a pretty great distance in order to angle a straight laser beam into the eyes of the flight crew. From most angles on the ground, all you see is the bottom (or at best, some of the side) of the plan in profile. Obviously it happens with some frequency, but I've never been able to visualize how. Is it typically during descent, when the cockpit is angled downward?

Edit: Just saw GusNSpot's post. Makes more sense to me at 3000 AGL, but does it happen at higher altitudes AGL?

Last edited by hopesperson; 07-17-2015 at 02:00 PM.
  #10  
Old 07-17-2015, 02:03 PM
Broomstick Broomstick is online now
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As I mentioned - it's not uncommon for airports these days to be surrounded by objects and terrain with some elevation. Why are you assuming all of this is coming from ground level? Skyscraper... mountain side... another airplane... a drone...

If I've thought of it I assume other people have, too.

Last edited by Broomstick; 07-17-2015 at 02:04 PM.
  #11  
Old 07-17-2015, 02:13 PM
Gary T Gary T is offline
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Quote:
Originally Posted by hopesperson View Post
...someone on the ground with a laser would have to be off at a pretty great distance in order to angle a straight laser beam into the eyes of the flight crew.
Okay, but apparently that isn't necessary to do harm. Read post #2.
  #12  
Old 07-17-2015, 02:16 PM
hopesperson hopesperson is offline
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Quote:
Originally Posted by Broomstick View Post
As I mentioned - it's not uncommon for airports these days to be surrounded by objects and terrain with some elevation. Why are you assuming all of this is coming from ground level? Skyscraper... mountain side... another airplane... a drone...

If I've thought of it I assume other people have, too.
I'm not assuming "all of this" comes from ground level, but I am assuming most of it does, which seems to be a reasonable assumption:

http://www.laserpointersafety.com/ne...ry-arrests.php

Lots of the incidents listed are police helicopters, the mechanics of which make more sense to me. But I am aware that commercial airline flights have also been affected. Don't mean to hijack the thread.

To repeat, I'm not doubting anything anyone has posted, just curious.

Last edited by hopesperson; 07-17-2015 at 02:16 PM.
  #13  
Old 07-17-2015, 02:23 PM
beowulff beowulff is offline
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Quote:
Originally Posted by MichaelEmouse View Post
What functions do those serve besides being used as weapons?


Can infrared laser pointers dazzle too?
By definition, infrared is invisible.

And, I don't know of anyone making an infrared laser pointer - it would be sort of a special-purpose device.

I have a 30W infrared laser. It won't dazzle you, but it will blind you...
  #14  
Old 07-17-2015, 04:48 PM
LSLGuy LSLGuy is offline
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Most shots against airliners take place at fairly low altitude, say below 3000 feet. We have a pretty panoramic view to the sides and below; much more so than the passengers do through their tiny windows.

The typical shot is from a couple miles ahead and a couple miles off to one side. And again we're around 1/2mile altitude. So slant range from them to us is anywhere from <1 to, say, about 5 miles. All they need to do is have line of sight to the cockpit windows; hit that and the light will rattle around in the cockpit until it gets us.

Right now green are the most dangerous. That's a combination of the greatest radiated power for the cheapest price, meaning Bubba with a $200 toy budget can get the most beam for the buck by buying green. And the green ones by their physics happen to be tuned to very close to the frequency that the eye has the very best response to. So green is the biggest stick hitting us in our softest spot.

The danger is not so much permanent blinding eye damage. We worry about eye damage because it only takes a tiny retinal lesion from any source to end our career even though we could see just fine to work in an office for the rest of our lives.

The immediate danger is the dazzle effect can prevent either of us from seeing well enough to fly for many minutes worst case, and for a couple minutes minimum. And that could snowball badly if both of us took a good strong hit.
  #15  
Old 07-17-2015, 09:11 PM
Canadjun Canadjun is offline
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Quote:
Originally Posted by LSLGuy View Post
md2000
Typically you can see it coming a second or so early as the bad guy tries to swing the beam onto the airplane. The good news is there's more warning at night when the risk is larger.
That puzzles me. Assuming the day or night is clear (no fog or significant pollution) I wouldn't have thought the laser would be visible until the bad dude got the beam pointed at you. Is there enough crud even in clear air to get a good view of the beam from one side of it?
  #16  
Old 07-17-2015, 09:27 PM
LSLGuy LSLGuy is offline
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Originally Posted by Canadjun View Post
That puzzles me. Assuming the day or night is clear (no fog or significant pollution) I wouldn't have thought the laser would be visible until the bad dude got the beam pointed at you. Is there enough crud even in clear air to get a good view of the beam from one side of it?
It takes very little dust or haze to create a visible bloom around the beam. The amount over a typical city is usually more than enough.
  #17  
Old 07-17-2015, 09:35 PM
Habeed Habeed is offline
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If this becomes a big enough problem, maybe airliners need laser recorders or detectors. A good quality camera mounted in the right place could detect the beam, and from GPS and plane orientation data, let you figure out the exact location it came from. If the police can actually consistently get to and punish laser rednecks, maybe they wouldn't do it very often.
  #18  
Old 07-17-2015, 11:15 PM
GusNSpot GusNSpot is offline
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Quote:
Originally Posted by Habeed View Post
If this becomes a big enough problem, maybe airliners need laser recorders or detectors. A good quality camera mounted in the right place could detect the beam, and from GPS and plane orientation data, let you figure out the exact location it came from. If the police can actually consistently get to and punish laser rednecks, maybe they wouldn't do it very often.
What I was thinking also. Good idea IMO. Cost, could be too high.
  #19  
Old 07-17-2015, 11:18 PM
GusNSpot GusNSpot is offline
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Quote:
Originally Posted by Broomstick View Post
As I mentioned - it's not uncommon for airports these days to be surrounded by objects and terrain with some elevation. Why are you assuming all of this is coming from ground level? Skyscraper... mountain side... another airplane... a drone...

If I've thought of it I assume other people have, too.
Unfortunately.....
  #20  
Old 07-22-2015, 01:58 PM
LSLGuy LSLGuy is offline
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Late bump:

Here's the latest from the FAA on the topic: https://www.faa.gov/about/initiatives/lasers/
  #21  
Old 07-22-2015, 05:39 PM
Quartz Quartz is offline
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I suggest the OP reads this thread on Pprune where he'll read of lots of experiences of many pilots.
  #22  
Old 07-22-2015, 06:35 PM
Morgenstern Morgenstern is offline
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Too bad jet liners don't carry even bigger lasers. That's teach those miscreants a lesson or two.

Zaaapppppppp!
  #23  
Old 07-23-2015, 07:13 AM
Machine Elf Machine Elf is offline
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Quote:
Originally Posted by Habeed View Post
Anyways, the focusing lens or mirror in a handheld laser is tiny. R^2 law. Isn't the risk of eye injury from a 2 watt or so laser at a jet 5000 feet or more away small?
I think you misunderstand the nature of lasers. The beam is highly collimated, so the intensity does not fall off with distance in the same way that a light bulb does; the beam can retain high levels of intensity for very great distances. Cheap handheld lasers may have high divergence (compared to expensive research/industrial lasers), but damage to pilots' retinas by them has been documented.
  #24  
Old 07-23-2015, 10:37 AM
Habeed Habeed is offline
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Originally Posted by Machine Elf View Post
I think you misunderstand the nature of lasers. The beam is highly collimated, so the intensity does not fall off with distance in the same way that a light bulb does; the beam can retain high levels of intensity for very great distances.
It's you who misunderstand. They are absolutely subject to the same laws as any other form of light.
  #25  
Old 07-23-2015, 11:03 AM
Habeed Habeed is offline
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My sources : reading about an article to bounce a laser off the reflectors on the moon (the beam spread was enormous by the time it got there), the air force's airborne laser (if laser light wasn't subject to optics equations, the laser wouldn't need that enormous focusing mirror at the nose), reading about a method to launch spacecraft with lasers (same deal : big focusing mirrors), reading about the theory behind spacecraft armed with lasers (same thing), and so on. Basically it's an undisputed fact of nature.
  #26  
Old 09-05-2016, 07:31 PM
Elendil's Heir Elendil's Heir is online now
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Bumped.

I just read One Hundred Days by Adm. Sandy Woodward, who commanded the British battle group during the 1982 Falklands War. He mentions in passing that the frigate HMS Plymouth "was fitted with the new laser equipment known locally to us as 'Flasher' - which could well have stopped [an Argentine Air Force] attack in its tracks, because it literally forces any incoming pilot to pull up sharply during the forty-second period in which he cannot see."

The ship evidently never had the chance to use it, however.
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