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Laser Injures Delta Pilot's Eye
stormfish writes "The Washington Times is reporting that laser light from an unknown source injured a pilot's eye as he was flying a Boeing 737 from Dallas to Salt Lake City. A 5 milliwatt laser pointer is strong enough to damage a person's eye, and stronger laser's are not that hard to come by. Unfortunately, having pilots wear colored laser safety glasses would be impractical as that would make it impossible to interpret the colored symbols on paper maps and cockpit displays."
Class IIIa (>5mW) 532nm green laser pointer (ThinkGeek)
Class IIIb (>15mW) 532nm green laser pointer (MegaLaser)
Class IIIb 200mW handheld green laser (Information Unlimited)
It's even possible to get small, portable Class IV (potential instant severe eye damage, even from diffuse or reflected beams; this is the class of laser which also includes burning and cutting beams) lasers:
Various Class IV portable lasers, including a small battery powered 2W diode laser (Information Unlimited)
The front windows of a commercial aircraft and objects in the cockpit could easily reflect and refract a beam from the ground in ways that would be at a minimum very distracting and unsafe, and potentially damaging to eyesight.
Information about laser classes.
... at least we know the laser wasn't fired by GI-JOE or COBRA.
Did anyone think to check the frickin' sharks in the Great Salt Lake?
"Lasers are easily obtainable and can be self-manufactured weapons in the terrorist arsenal, which essentially can effect a soft-kill solution and leave virtually no detectable evidence," he said.
I'm a private pilot, so I certainly won't make light of this problem. But please...is every new way to hurt somebody going to be another weapon in the terrorist arsenal? Are we going to assume that everytime something happens to someone, a terrorist is behind it? I for one am tired of our leaders trying to make us afraid.
And yeah, this is a rant. Mod me down if you will, before I strike again.
Can the cockpit windows have a safety coating applied instead of the pilot wearing glasses. Would tint the look of the world outside the plane, but wouldn't hinder looking at the interior all that much.
Yep, I never spell check.
More incorrect spellings can be found he
Do not look at laser with remaining eye.
How many times do we need to tell people that
500 dollar reward for tip(s) leading to the arrest of the person(s) who stole my sig.
Thinkgeek wanted for questioning.
Since when has this country used intellectual elite as a pejorative term?
I, for one, welcome our new flying shark overlords
*cringes in terror*
How can they be sure it's a laser? Can't directional intense light come from a number of places... like, for example, the sun? (Yeah yeah, the sun is anything but directional, but you get my point..)
Is there any way to make glass opaque to coherent light while still passing visible light? Or are pilots going to have to fly by instruments and video screens to protect themselves? (Can a readily available laser damage a CCD?)
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
The goggles do nothing!
Having pilots wear coloured safety glasses wouldn't be impractical, it would be impossible; the only colour that would block all laser frequencies is black.
Couldn't a laser from that high up only be directed from some place in front of the plane or above it (ie satellite)??
This is my sig. There are many like it but this one is mine.
First off the laser needs to be of significant power to do that from a distance.
Secondly it needs to be mounted to a telescope for aiming.
The articel does not mention any laser facts but uses the word "laser" in an ominous way as to induce fear in the readers.
to cause that kind of damage to an eye, it either needs to be high enough power to cause damage and hit directly, if it's indirect, then it needs to be significantly higher power.
no your laser pointer will not blind a pilot from 5 miles away after it's power was reduced from the beam splitting effects of the windshield.
Do not look at laser with remaining good eye.
I think it was "Debt of Honour" where CIA operatives near the airport use lasers to blind japanese (don't ask) AWACS pilots, making them crash their planes. Coincidentally, that book ends with a airliner being crashed into the White House. Soo, what does this mean? It's obvious - Tom Clancy is providing The Terrorists (tm) with ideas and needs to be put in jail ASAP!
It would not be impractical for the pilot to wear safty glasses during the takoff and landing phases of flight, and have the copilot dictate to the pilot important information and peform tasks (ie. airspeed, gear down, flaps out). This is how it is done to a certain extent already. And after takeoff, the pilot could remove his safty glasses. In fact, this is how the C-130 crews do it when landing in the arctic. The snow is so bright that the pilot must look outside the whole time while the copilot reads things off the instruments.
I must be missing something here. Is it really feasible to hit a pilot in the eye a few thousand feet in the air in a moving plane? Even if you could get a lock on the plane, the pilot could always move a few inches to avoid the beam? I'm very confused here.
"The plane's two pilots reported that the Boeing 737 had been five miles from the airport when they saw a laser beam inside the cockpit, said officials familiar with government reports of the Sept. 22 incident."
Next thing you know, they're smearing vaporub on each other and are struggling to find words to describe how awesome their faces feel right now.
-Randy
The story said they saw a laser beam inside the cockpit. To do that from the ground would take some pretty quick targeting work.
Could a first class prankster have used a pointer through a small hole or something similar? Maybe the door was open?
Grasping at straws here.
They used bright spotlights during WWII to blind and confuse Nazi pilots. It worked, many of them crashed, and none knew where to drop their bombs.
They also "hid" entire squadrons using smoke and mirrors.
If I could remember the name of the magician and his special squad of effects dude, I'd google for some links. Cool stuff though. David Copperfield-style illusions to fool the Nazis into seeing forces where there were none, and seeing nothing where the forces are, mostly in the desert theatre.
I don't need no instructions to know how to rock!!!!
A multi-watt laser with a decently large aperture and a TEM 00 spatial mode would be a different story.
On approach for landing in Seattle (I was just a passenger, not pilot) I was looking out the window into downtown Bellevue. From an area near the Bellevue main mall (hard to tell where exactly from 5000 feet, and 3 miles over) was some kind of laser light show, and the laser in describing its pattern for the show occasionally and momentarily came directly through the window, and directly in my eyes. Even this very brief exposure was painful, and my eyes had after-images for hours! The laser was green, so I assume an even higher energy than a red laser (don't know for sure).
Ever since that encounter I've always wondered if it was just an incredible fluke, or something that could happen easily again. Now I know.
I bet the navigator sitting behind the pilot is hiding his laser keychain about now.
oops.
I remember reading something similar in a Reader's Digest a few years ago:
Apparently the US was tracking a Russian "Laundry Ship" north of Canada because they somehow found it suspicious. A while later, the helicopter pilot that had been filming the ship came to the doctor having vision problems. Upon close examination, there was a grid of little damaged, scar-tissue-surrounded holes in his retina. Upon examination of the video, they found a brief flash that when freeze-framed proved to be a grid of bright little laser points that had flashed at the helicopter from the boat! So it's nothing new to use lasers to destroy the vision of expensive-to-train pilots. The question is, was this stray laser light or something intentional as was the case with the "laundry ship"?
~Ben
This has been debated for a while, but recent studies have borne out the idea that class IIIa lasers, up to 5mW, don't cause permanent injury to the retina.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd= Retrieve&db=pubmed&dopt=Abstract&list_uids=1111526 6
We need to add Laser Detection Systems to the planes, that will fire a laser back in the same direction as the incoming one, a little offset so as to hit the terrorist in the eye. An eye for an eye.
I thought I had a reasonable grasp on basic physics, but obviously not. The plane's two pilots reported that the Boeing 737 had been five miles from the airport when they saw a laser beam inside the cockpit
1. The pilots saw the beam? Was the cockpit full of smoke? Or did they see a red dot jumping around the cockpit?
2. Also, from what I know of airliners, the windows are more or less pointing forward as opposed to down - and I'm guessing at five miles out from the airport the plane was still high enough that no-one was going to be able to shine a laser in from a source at the same level as the place itself. So given the angles, the red dot must have been jumping around the ceiling of the cockpit, if anywhere at all. That's some shot.
3. It was an even better shot to hit the pilot in the eye with the thing. Presumably that's hitting a moving target the size of a dime from hundreds of yards.
4. And another thing, I always learned that lasers were beams of coherent light. Can a laser pass through regular glass and come out the other side still coherent enough to do damage? Especially that thick glass you get on airliners?
Somebody please explain. I'm confused.
There is no way a laser from the ground could get in through the window, given the angles.
While I agree that a ground-based attack seems highly unlikely, and that the Washington Times is looking for any angle on terrorism, the angle from the ground to a cabin during decent is not that unlikely.
Salt Lake City is surrounded by the Washatch Mt Range. They are approximately 4K-5K feet above the basin floor surrounding the city and the approach to SLC takes flights to elevations where it would be possible to point a laser directly into the cabin.
Also, considering the velocity,..
There's the kicker. The terrorist, or dumbass prankster, would have to be extremely lucky to get a laser into a pilots eye, at extreme distance, and into a plane that is traveling in excess of 160 mph.
"Rocky Rococo, at your cervix!"
Picture the pilot wearing light filtering goggles, tin foil hat, anti meteorite system and trusty handgun strapped to hip.
Speaking as a private pilot, you are in far more danger from ducks, geese, sea gulls than any number of laser wielding boogey man terrorists.
From personal experience, a flock of 25 pound Canada geese passing around your Cessna 172 at a combined speed of 200 mph or so is pretty impressive.
I'd take my chances with a laser any day over that.
Laser pointers of any type have really shitty focus on them. By the time it goes 1000 feet, the beam has diverged to the point where it's not even a problem.
Point the sucker at a fence across a street, or over any distance where you can see the resulting spot. Notice how it's not exactly a pinpoint spot anymore? That's divergence of the beam. Now imagine how big that beam is over 6 miles (planes flying at around 30000 feet or so), and how little light from it is actually visible from that kind of distance.
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
The article lacks enough information... Often times direct exposure from handheld pointers has been cited and hyped as if it was a 40 watt 523nm YAG laser.
There are rules and restrictions for directing coherent laser light up into the sky at night. You generally file a report with the center for disease and radiological health.
In addition to all of this, even with a 5 watt argon, at a great distance the beam will fall out of coherency. There is a big difference between a beam that is tightly focused / coherent, and one where the output is spread on a 12" circle (temOO?).
Another big factor is if the laser is moving real fast, once again the light is spread out...
The US has pretty strict laws on this stuff, where as other countries do not. You will see pictures of crowd scanning from high powered lasers in other countries, but you won't generally find crowd scanning above 5mw here.
There is more information about lasers at the laser faq site (google for Sam's Laser Faq). Laser-FX International also has a bit of information about laser show setups. I have some pictures of my 150mw argon-ion and large frame argon that puts out somewhere between 2.5 and 5 watts of power at my homepage ( http://users.757.org/~ethan )... Lots of pictures.
Without colimating optics, the laser beam from the 150mw argon spreads to 6" or more across at a distance of 1000'.
Southeastern Virginia REPRESENT!
So exactly why would closing of the outside world be such a bad idea?
Aircraft instruments ain't failsafe. There have been countless incidents where instruments have failed not totally, easily spotted, but slightly (a direction finder slightly off, an altitude meter reading to high) off. Sure aircraft have redundant instruments and pilots are supposed to check but they don't. Even the fact that a plane got two pilots each with their own instruments has not proven enough in the past to prevent a disaster when the captain decides to follow his instrument readout.
So what does this have to do with windows? Well a look at the outside will quickly tell you a lot that you would take several instruments. Altitude, attitude, weather, air traffic, ground traffic. All pretty damn important.
Worse while pilots are trained to fly without outside references it does have the danger of the pilot loosing orientation. Thinking that up is down and such. I remember at least one crash investigation where the pilot was following his instruments into trying to correct the aircraft while he was in fact flying it straight into the ground.
So the above post is not informative. It is totally mis-informed. Pilots need their windows.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
Any angle from the ground in order to hit the pilots eyes had to be shot from a LONG way away you would think. The closer the shooter was, the steeper the angle, making it near impossible to hit the windshield, let alone the pilots eyes. It certainly seems to make more sense that it came from another aircraft, and that in itself is rather alarming.
I am thinking of a few scenarios, all of them suck if that is the case.
1- really lame practical joke gone really bad from a random person in another plane.
2- delibarate terrorist attack by joe "real" terrorist, a proof of concept effort maybe
3-agent provocateur attack by shadow government/rogue faction to induce a reaction to put pressure on reducing lasers in civilian hands, because of their potential self defense against a junta potential perhaps, or for some other reason, such as borking surveillence cameras, or any number of reasons
Of course it still could have come from the ground, but it seems just like an amazingly lucky shot with a pretty powerful laser.(anyone knowledgeable want to comment on probable laser used and how to aim it accurately in this scenario?) Not only to hit, but to see where the hit is to correct the aim. Try it with a simple handheld rifle scope with integral laser(maybe that's what was used, but a model not available readily for civilians), and you can see the wiggle you get and how hard to see it at a relatively close couple hundred yards against a stationary target, against something moving really fast and pretty far away indicates a pretty sophisticated and powerful setup. The news articles (I have read several before slashdot got it) don't really have much in the way of details yet.
I was on a Search and Rescue mission in CAP and we were targeted by a strong green laser. I was the mission observer and instructed the pilot to look away. Initially it passed by us fast but then it illuminated the cockpit. We got closer but it stopped.
If we had a better location on the source we would have been more active tracking it down. I would not want to be the person caught interfereing with an Air Force assigned SAR mission.
A 5mW laser does not seem to damage a person's eye even when they look directly into it for 15 minutes (see here for example).
From a distance of what must be miles away, aimed at a moving aircraft, you would need a laser that was orders of magnitude more powerful in order to damage someone's eye. Even with a powerful laser, you'd generally have to look directly into the optical axis to cause serious vision impairment. And while I haven't gotten injured by a laser, the few times I looked into one accidentally, there was little doubt about when it happened or where the light came from.
Even more implausible is the claim in the article that someone would "[continue] to suffer eye pain and deteriorating vision"; laser injuries to the eye do not cause continued deterioration and they do not cause chronic pain (here).
The whole thing strikes me as wildly implausible. As the article above shows, apparently erroneous claims of laser injuries are fairly frequent. A more likely explanation is that someone is lying, perhaps because he wants to retire early or did something else stupid and wants it covered.
Now, please let me be the first pedant to point out that for them to have actually seen the beam inside the cockpit, then it must have been helluva dusty or smokey in there. Who were the pilots? Cheech and Chong?
After a couple of hours on ebay, I was pretty shaken. Laser heads in the multi-hundred WATT (not MW) range are readily available to the public, no liscense no oversight. I asked a friend who does laser research about this, and he told me that while it was illegal to sell a high-powered laser to the public, the parts weren't restricted. So, a company can sell you a high power laser head, and next week the power supply, columnating lenses and whatever else you need, they just can't assemble it for you.
This is like saying that gun shops can sell all the parts for RPG's, but they can't actually load it for you!
Generally, I'm in favor of minimal govt. oversight, and I don't care for most gun-control laws etc. But NOBODY needs a 1500 watt UV laser for 'personal use' any more than I need tanks and howitzers for deer hunting! The add linked in previous responses showing a 200W laser-pointer shaped like a gun are just frightening. That's not a laser-pointer, it's a weapon, and I certainly don't want it pointed at me by some pimply-faced wanna-be geek trying to impress his friends!
"It starts with a slight fever and dryness of the throat. When the virus penetrates the red blood cells, the victim becomes dizzy, begins to experience an itchy rash, then the poison goes to work on the central nervous system, severe muscle spasms followed by the inevitable grueling. At this point, the entire digestive system collapses accompanied by uncontrollable flatulence... until finally, the poor bastard is reduced to a quivering wasted piece of jelly."
Attndnt : Excuse me sir, there's been a little problem in the cockpit
Striker : The cockpit
Attndnt : It's the little room in the front of the plane where the pilots sit, but that's not important now.
From the article:
The plane's two pilots reported that the Boeing 737 had been five miles from the airport when they saw a laser beam inside the cockpit
If I read this right it says there was a beam (a visible point of light) inside the cockpit. This may not be the case, but it is one possible interpretation.
If this is the case it's pretty serious. Think about it. What kind of tracking system is necessary to get a laser beam into a cockpit window of a flying plane from the ground and keep it there long enough to be seen by the pilots?
I served in an infantry battalion alongside two tank battalions in Germany in 1982, and shortly after I got there, some moron in one of the then-new M1 tanks decided to test the new-fangled laser rangefinders on an automobile speeding along a nearby country road. He succeeded in permanently blinding the driver, who suffered further devastating injuries in the subsequent crash. If I remember correctly, the tank gunner was convicted at his court-martial and got twenty years in Fort Leavenworth military penitentiary. The point is that the M1's laser rangefinder was orders of magnitude more powerful than any commercial laser pointer, the gunner was using a powerful magnifying optical instrument on a gyro-stabilized tank turret to track an object moving much slower than an aircraft in flight.
From my limited contact with the optics in an M1 (courtesy a tanker buddy), I appreciate the extreme difficulty of keeping cross-hairs on a fast-moving target, and I seriously doubt that anyone could have hit the windshield of an aircraft in flight with a handheld laser. They would have to have been using some sort of stabilized mount and telescopic rig. Were there any military units on exercises in the area? Bored soldiers will do the stupidest shit. Trust me; I know from personal experience.
The pilot is going to lose his medical and never fly again.
My guess is that they were screwing around with a laser pointer in the cockpit and the pilot got his eyeball fried.
Make the claim that you saw it come in while you were landing, and you've got a lifetime of disability payments.
A good friend will help you move. A really good friend will help you move a body.
Maybe you can't find the article because it was a RUSSIAN ship that the pilot was observing when he got hit.
Here's a quote from recent article that mentions the incident:
"In one case, Naval Lt. Cmdr. Jack Daly and Canadian helicopter pilot Capt. Pat Barnes suffered eye injuries hours after an aerial surveillance mission to photograph a Russian merchant ship that had been shadowing the ballistic-missile submarine USS Ohio in Washington state's Strait of Juan de Fuca."
You don't have any anti-American bias do you?
Insert witty sig here.
There's a link-collection about anti-personell lasers (including blinding ones) with similar stories. Seems old, but relevant.
Sig. under reconstruction.
I'm a regular visitor to Ibiza (it's an island near spain famed for it's nightlife) and a few years ago it was quite common for the nightclubs with laser shows to "point out" aircraft on approach (as they carried the next batch of party people). From the ground it just looks like you're shining the laser at the plane, but from inside it's crazy as the beam shines through the windows and lights up the cabin (which has it's lights off for nightime landing). Was quite fun at the time but looking back I can see the potential danger.
This was a few years ago, I believe the airlines complained and the clubs were banned from doing it any more.
---- Den ene knappen er powerknapp, den andre er Bender voice knapp "Bite My Shiny Metal Ass"
THis kind of thing was a problem for the US during the first Gulf War. Basically, a laser would be pread with a (parabolic?) mirror, an F117 would fly into the beam, the night-vision camera hooked into the pilot's helmet would be overloaded, and the pilot would be blinded for a second or two, enough to lose control and crash.
One countermeasure that was later looked into was to use a lens coating with a non-linear response - it remained clear for most light intensities, but went opaque almost instantaneously (in milliseconds) when the intensity went over a certain threshold.
The reason I know about this was that my nonlinear optics professor had an amusing story about being invited to give a lecture on his research in the US, only to find when he arrived that it was to a military lab with several times more people working on the field than the amount doing the same research, but publically.
No doubt some bright spark is thinking of trying to sell the same tech to commercial jet makers now, especially since the new invadee paradigm is to just let the Americans in, wait till they relax, then commence the guerilla warfare.
-- Proud descendant of semi-nomadic cattle-herders.
you can get a welding helmet that autodarkens when you arc. they are about $50 and change fast enough for you to not go blind, and run off a 9volt battery.
if you know nothing about welding, that is one issue when you are learning. knowing where the electrode is in relation to the work and getting it close enough to arc, but not to stick. normally you kinda peek then drop your helmet and go for it. the autoshade helmets let you see what you are about to weld and when it gets bright they tint fast enough to protect you..... the tinting is extreme, but under the plasma light youu can see your work.
it's possibly something like that can be used for lasers as well as any other type of super bright blinding light. maybe the lasers are too tricky to trip the sensors, but if they can make the helmets that cheap, and there is a market for it in planes... i bet someone can figure it out. it might help fighter/bomber pilots too. it has to throw their vision to see things explode in front of them... maybe?
You seem to be mistaken in one thing though. You assume that the goal is to actually take down an aircraft.
Terrorism is not necessarily synonymous with mass murder-- i.e. either one can exist without the other. It is entirely possible that terrorists could be trying to make people *think* that they are vulnerable in the sky, thus spreading terror and poisoning the economic climate for the airlines.
Hell, terrorism could include anything from leaving empty packages market "bomb" in airport restrooms and sending letters to various random people containing cornstarch and a note with the word "antrax" on it to incidents like September 11th where nearly 3000 people were killed. The important component is not murder, but terror, hence the word.
There are vast numbers of potential items, such as the corn starch and cardboard boxes mentioned above, which could be used as improvised terrorist weapons most of which have indispensible legitimate uses as well. Indeed no level of regulation can keep an imaginative indivitual from being able to concoct a scheme which will play on our fears and make the public or the government conclude that a threat to public safety or health or an attack against the people or government is either imminant or underway.
Back to the question of lasers. Schematics for building lasers are available with a minimum of research. Sufficiently powerful lasers may also be able to injure pilots even without directly hitting the eye (i.e. the scattering of the beam via imperfections in the window or reflections off other surfaces inside the cockpit).
Finally if pilots *think* they are at risk of permanent injury, it may also poison the economy for the airlines. This is another way in which we could be vulnerable as a country to this sort of attack.
The real issue is that if we live in a society where cornstarch can be used as a weapon of mass terror then we have to re-evaluate our very notion of the role of government in protecting us from the terrorists. Indeed perhaps we need a greater public discussion about all issues involving homeland security and face these as a people rather than delegating this responsibility to the Federal government. Perhaps issues such as airline security, airport security, etc. are best handled by public discourse rather than secret regulation. The public is best equipped to handle the threat of terrorism when they know what the risks are and are able to freely debate and discuss what to do about it.
Such an approach has been generally successful in the realm of computer security, in the sense that zero-day exploits are not nearly as common as they might be otherwise. An approach of full disclosure of security measures and problems would help us combat the issues much more effectively. The attacks on September 11th certainly seem to indicate that Al Qaeda has performed extensive recon of our airport security measures, so the argument that such disclosure would undermine security holds very little weight for me. Indeed such disclosure may allow us to close the holes before they are exploited (unlike computer software security attacks, successful large-scale terrorist attacks seem to take many months or even possibly several years to plan and execute).
I am posting anonymously out of fear that such a post could place me on a no-fly list.
"He noted that incidents of lasers being directed at commercial airliners during takeoff and landings have raised fears that "this in fact may be a new form of terrorism.
Lasers are easily obtainable and can be self-manufactured weapons in the terrorist arsenal, which essentially can effect a soft-kill solution and leave virtually no detectable evidence."
(Sounds a lot like file-trading.)
No problem.
Just pass another law.
This story appeared on Slashdot a while back. It mentions the use of near-infra red light to actually stimulate the healing of retinal cells. NASA has more information about it on their website as well. Here is a quote from the New Scientist article mentioned in the Slashdot story...
It seems to be very pertinent to the situations of the Delta pilot and Canadian Navy helicopter pilot in the current story. Some companies make devices using this technology for medical purposes.
About 8 years ago I was working on a broadcast transmitter that was in a room on the roof of a apartment tower near Keesler Air Force Base, Biloxi, Mississippi. It was shortly after dark when I emerged from the transmitter shack and I stopped to notice a C-130 on final approach to Keesler. A laser that was part of a display at one of the Casinos painted the bottom of the plane from the nose to tail. The plane wobbled as the pilot was temporarily blinded by the beam. Reading in the newspaper the next day confirmed that the pilot had been temporarily blinded by the laser and the co-pilot had finished the approach and landing.
At the time laser light shows were the rage at the newly built casinos. Several had them, and all used green lasers whose beams were panned around the sky by motorized mirrors. As these casinos were built surrounding an AirForce base, they were supposed to have safety shutoffs that, during operations, would disable the lasers upon request by the base. An investigation found that these safety devices had been bypassed by maintenance personnel, including a laser whose safety shutter had been defeated by wrapping wire around it.
Needless to say, the laser light shows were dismantled quickly and were never brought back.
Fortunately, in this case, the optics spread the beam out with distance, instead of keeping tight collumination, so the pilot did not suffer long term damage.
These lasers were in the range of 50W, not some little 5mW laser pointer. Their beams could be seen for miles orthogonally and would paint patterns on the underside of clouds over two miles up. Your 5mW laser does not have the collimation, nor the power after atmospheric absorbtion to do much after around 100 ft.
However, I must admit, lasers in the 50W range are available, would do grevious eye damage at distance, and could be used to down an airplane by blinding the pilots.
Uh, if you can see the ground, you can see the laser somebody on the ground is pointing at you.
Are you suggesting that the pilots can't see the ground?
-- Alastair
The threshold for damage to the eye from visible-wavelength laser exposure with a 0.1 second duration (about the time it takes you to blink) is a fluence of about 0.3 mJ/cm^2 (see D. Sliney and M. Wolbarsht, Safety with Lasers and Other Optical Sources, (Plenum, 1982), Fig. 8-2), which corresponds to an intensity of 3 mW/cm^2.
If you multiply 3 mW/cm^2 by 20 square feet you get about 90 watts. Not exactly a hand-held device!
My theory is that the pilot was really bored, and started playing with his laser pointer pen. His co-pilot and him made a bet about laser-pen tolerance, and he lost. Now he has to find a convenient excuse or risk losing his license.
Table-ized A.I.
"I call bullshit. If the frequency is doubled, the wavelength is halved, and ~400 nm is around the boundary between violet and UV, not green."
If you had any idea WTF you were talking about, idiot, you would know that a ~800nm diode laser is used to optically pump a small crystal of Nd:YVO which then lases at 1064nm and whose output is then freq. doubled to 532nm (green) by a piece of potassium titanate phosphate KTP.
- "Hear that?! The percolations are imminent! Cease your ingress!"
Having worked with Class IIIb Lasers for 25+ years I can attest to the fact that it is nearly impossible to incur eye damage from 5-15 mW. You reflexively look away and blink. In order to incur damage from such a laser it would require:
1.Anesthetizing your eyelid muscles
2.Anesthetizing your eye muscles
3.Mounting your head in a clamp
4.Firing the laser point blank into your eye for 10 min.
This would cause temporary damage.
In addition, while the laser beam is nominally collimated over distances of tens of meters the beam spreads, reducing the energy entering the eye by an inverse square relation.
This is not to say that lasers are not hazardous, something in the 1 Watt range can be seriously dangerous to your retina. But the inverse square law still applies over long distances. Pointing and tracking with an accuracy of 1cm over several kilometers is spectacularly difficult as well.
Eye-popper lasers have been evaluated by both the US and the Russians but they have had little effectiveness. They have been banned from the military as inhumane. Usually banned weapons tend to be both inhumane and ineffective.
With a big enough laser (>>10W)you could injure a pilot, in the same fashion you can bring down a plane with a sniper rifle, it's possible, but highly unlikely, and not a particularly good terrorist tactic.
A kamikaze falcon or the sudden release of a crate full of pigeons would be more effective by orders of magnitude.
You have the right to remain silent.
42,000 people die in car crashes every year. 0 people die in laser induced headaches.
Lasers represent a threat matrix position of 0.00000% relative to the highest threat.
In fact by all accounts Lasers are less deadly than peanut butter.
AIK
Comment removed based on user account deletion
I'm a grad student in utah working on a large lidar system used to make measurements in the middle atmosphere. We use a q-switched nd:yag laser that generates about 18 watts of green light in a 7ns pulse at 30 hz. So there are high powered lasers pointed into the night sky.
I'm colour-blind. Not massively so, just the most common red-green deficiency (deuteranopia, I think?) that affects around 5 in 100 males, maybe more (http://webexhibits.org/causesofcolor/2.html)
;) But you're going to have trouble with vessel identification from their lighting (is that a ship or a rig?), and you're going to have some trouble coming into ports; not something I'd want to have to deal with single-handed.
I'm not a pilot, but I've done a fair bit of sailing; my last trip was a ~1500 nautical mile blue-water passage from the Azores back home to the Isle of Man. That's 12 days at sea, and even with four crew you spend a couple of hours on nightwatch per day. You're bound to encounter various situations where coloured light recognition is *very* useful, nearing on essential. For instance: you see a very large tanker directly ahead; the very fact that she's already over the horizon means that she's going to have a hard time stopping within those 5km, and probably hasn't seen you. You may need to get out of her way, and fast. While you can try hailing someone on the VHF or SSB, even with DSC some ships don't pay attention, and a surprisingly large amount of don't have their radar on all the time (due to the limited life magnetrons, I guess?). So, can you tell if he's actually coming towards you, or going away? Can you tell the configuration of the lights? Is that red or green on their port side? (Yes, you should be able to see their white aft light, but bulbs die.)
Personally, I wouldn't be 100% sure. My general daytime vision is pretty good, and I can usually tell what colour an object is, but low-intensity lights at night? Not with confidence. (Even with bino's.) On a ship it's not too bad: you have time to play with, so you can take a bearing, wait a minute and take another one, then calculate if she's on a collision; you can check the radar if you have it (we do); or you can piss off one of your crewmates by waking them up
Personally, I wouldn't be confident enough to pilot a plane at night. I'd imagine that things happen much faster compared to sailing (we travel an average of 6 knots an hour, and most motor vessels do 30kts tops) and that extra dimension of movement must make a lot of difference! Sailing's got plenty of procedures, knowledge requirements & useful instrumentation; I'd imagine that piloting has many more, so I guess what I'm interested in is whether you feel these would cover absolutely any situation that happened? I know that if it came down to it, if I was stuck on a boat by myself I'd be able to manage in spite of being colour-blind; can you say the same of yourself as a pilot?
(This isn't meant in a confrontational manner, I'm genuinely interested.)