Fox: Commercial Pilots 'attacked' with laser

Fox News | Greta Van Susteren

[ableChair]

Greta Van Susteren reported that a Delta pilot enroute to Salt Lake City was lazed in the cockpit this last Wednesday. Only country I know that has that hardware (for lazing bomber pilots) was the Soviet Union. Pilot reportedly required medical treatment and this was not a minor injury (weak laser) wound. More will come out to tomorrow as this story hits the print press.

[ableChair]

Yea, but the difference with your credentials is that you're not a pompous a#$. I could care less about credentials, my point was that this guy was trying to insult me with his.

[ableChair]

I understand your point, but my recollection was that the energy levels delivered were also astronomical. Something on the order of 10 exp 21 Joules. That can't be required just to burn metal; it must be either for penetrating a media or for the radius of the beam (as one poster pointed out).

[Dan Evans]

Not to mention the fact that you'd have to hit a small target (a face) and hold it there for at least a few seconds, while the airplane was moving anywhere from 160 mph on takeoff or final approach,

It would require some kind of device to track the plane. The type of tracker they use on helicopter TV cameras could do it. They can hold the camera rock-steady while showing a X100 magnification of a scene about 5 miles away.

[Dan Evans]

I'm guessing that a lot of airline pilots are right now perusing catalogs of IR goggles.

[CyberAnt]

Yep, I remember the story .. can't remember the pilot's name though.

[Don W]

Just FYI, it hasn't been the RCAF for over 3 decades. Thanks to Trudeau and the rest of the pathetic morons who've run my nation for the ensuing 36 years (yes, I include JokeLark and Lyin'Brian) the Canadian Armed Forces (currently 14,000+ members below the nation's ARMY ALONE level in 1938) Air Arm is simply referred to as the "air force". No capitalization, and no funding.

Incidentally, it was ONE CAF pilot and ONE US serviceman who were "lazed" by a Russian FREIGHTER.

I was working in the Cdn naval base in Victoria when this happened.

[raygun]

Verbing nouns is cool. But cooler yet is nouning a verb. Meltage. Now that is cool. But even cooler still, adjectiving nouned verbs. Meltagness. Although, by far the coolest of all would be culturally stereotyped adjective nouned verbs. Meltagenessskiowitz.

[DB]

I'm not understanding what you mean by "heat energy dissipated by a laser".

A 50 watt laser takes far more in than 50 watts to generate the 50 watts of laser light output. So lots of heat energy dissipated there. I don't think that's what your talking about.

We're talking about 50 watts of laser light energy. In order for it to be "heat energy dissipated" it would have to be converted to heat somewhere on its travels.

In space for example the beam would go on practically forever virtually never being turned into heat energy unless it was absorbed by something. Its power density would slowly drop due the fact that the laser's light beam isn't perfectly coherent and would slowly spread over distance. As it spread the power level would be the same, just over a larger area.

In an atmosphere the laser light does a number of things. Some of it is absorbed and turned into heat. Approximately 19% of the sun's energy is absorbed by going through many miles of atmosphere. This is broad spectrum energy from the sun where some frequencies are readily absorbed and others aren't. That 19% is an average for all spectrums of the sun. Laser frequencies can be chosen for much less absorption over the same distance.

Scintillation is another problem in an atmosphere. That is why the stars twinkle. This is particularly hard on lasers because it disturbs the narrow beam width over distance causing it to shimmy around. Scintillation does not cause the light energy to be converted to heat, it just bends it slightly and disturbs the wave front making parts brighter and other parts dimmer momentarily.

The biggest loss factor for laser light through the atmosphere is scattering. This is caused by water vapor and small particles in the air. Fog is an extreme example. The fog doesn't absorb the light so much as it scatters it around. This scattering around is what makes the laser beam visible going through the air. This scattering doesn't cause the laser light energy to be converted into heat until the scattered light is absorbed by something.

Energy density is what it takes to damage the retina in the eye. As long as the laser beam isn't substantially spread, absorbed or scattered by the atmosphere it remains dangerous for long distances.

[Boot Hill]

8	“I don't see a 50 watt (or less) laser fired through 5 miles of atmosphere not dissipating at least an equal amount of energy in heat.”

I can appreciate where you're coming from, at first blush what you suggest does seem logical, but here is the hole in that theory.

Just for the sake of argument, let's start out presuming that air will absorb that laser light at the same rate, irrespective of the initial power of the beam. For instance, we might find a particular wavelength laser light was absorbed 10% per kilometer. So, when would the beam be at zero power? Answer: never! It would always retain 90% of the power that entered which ever kilometer section you were measuring and would only lose 10% of that value as it transited through that kilometer.

For an eight kilometer path (~five miles) the final power factor would then be calculated like this:

.9 × .9 × .9 × .9 × .9 × .9 × .9 × .9 = ~.430

As you can see, no matter how many times we multiply by .9 (90%), the answer will always be greater than zero.

If your 50 watt laser beam could only travel 5 miles through the air before being entirely absorbed, then no beam, no matter how powerful or weak it was, could travel more than 5 miles through the air. In which case I'd ask you how it is possible for the dim light of stars to shine through 60 miles of air? Surely you don't mean to suggest that a weaker beam can travel farther through the atmosphere than a more powerful one?

Now let's look again at my original presumption that all beams of a given wavelength, no matter their power, will be absorbed at a constant rate as they travel through the atmosphere. Is it possible to employ such a high power beam that you literally "cook" the air and cause a change in its physical properties such that the rate of absorption is changed? The answer is yes, but at 50 watts (an a nominal beam diameter) you aren't even within 6 orders of magnitude of the power density necessary to do that.

I have a 100 watt, 5mm beam diameter, continuous wave, extremely well collimated, Nd-YAG laser in my basement lab and I flat guarantee you that if I ever pointed it at a plane flying 5 miles away, I'd blind the pilot, giving him permanent eye damage, IR absorbing cockpit windshield, notwithstanding.

Kind of hard to get these concepts across in a short post, but I hoped some of what I wrote cleared up the problems of atmospheric absorption of laser beams for you.

--Boot Hill

[Las Vegas Dave]

< snip > 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. The flight, which originated in Dallas, landed without further incident at about 9:30 p.m. local time.

< snip > the first officer felt a stinging sensation in one eye. ....A doctor who examined the pilot determined that he had suffered a burned retina from exposure to a laser device, the officials said.

< snip > She would not say whether TSA considers the incident a possible security threat to commercial aircraft. Other officials said the incident was serious enough that the pilot will be unable to fly for at least a week.

< snip > Officials were unsure of the source of the laser and could not determine whether the exposure was deliberate or accidental.

< snip > "The Air Line Pilots Association has received reports in the past of incidents where lasers penetrated cockpits and, in at least one case, caused injury," Mr. Mazor said.

< snip > Asked whether a laser aimed at pilots could cause a plane to crash, Mr. Mazor said: "I think that's highly improbable. In every case in the past, the flights landed safely."

< snip > "Numerous documented cases regarding the use of lasers against aircraft, civilians and military personnel exist, as well as does an all-too-lengthy list of the injuries that have resulted from the accidental and intentional misuse of these devices," Cmdr. Daly told a House Armed Services subcommittee.

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," he said.

[DB]

I should say a visible light laser beam is visible in the fog.

If the beam weren't being scattered you couldn't see it. Nothing for your eye to pick up. You'd only see what it hit on on the far end if anything. That is of course assuming the laser isn't aimed at your eye...

[Don W]

Baloney. Can't happen.

And you're nothing less than a complete idiot!

Read THIS with the correction that it was an INBOUND FREIGHTER (outbound ships are in CANADIAN waters in the Strait of Juan de Fuca).Baloney. Can't happen. BAH! I WORKED at the base, and knew many of the Cdn pilot's crewmates.

You're as ignorant as a Kerry voter.

[Eragon]

God I love that picture, and was myself looking for it.
Bunnies with stuff on their heads crack the heck outa me.
Thanks for the excellent post!

[nw_arizona_granny]

Did you see this one?

[DB]

Just to be contrarian...

If there is finite light attenuation over a finite distance, when the last photon is absorbed it's over.

;-)

[Cindy]

Thank you Dave for that post.
We'll see how this story unfolds.
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FOX NEWS
http://www.foxnews.com

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NOTE: THE FOLLOWING TEXT IS AN EXACT QUOTE:

 Documents related to:


LCDR JOHN R. DALY, JR., U.S.N. v. FESCO AGENCIES, N.A., INC., and FESCO INTERMODAL, INC.This is an action for battery and/or negligence resulting from an April 4, 1997 laser attack on Plaintiff, a U.S. Navy intelligence officer on a surveillance mission in the Strait of Juan de Fuca, by the Kapitan Man, a purported Russian merchant vessel owned and operated by Defendants. In actuality, the Kapitan Man is a Russia spy ship gathering information on U.S. ballistic missile submarines.

Opening Statements - Presented by Larry Klayman
Trial Brief - See the document as filed
Complaint filed on behalf of LCDR Jack Daly - See the actual court document
http://www.judicialwatch.org/1280.shtml

[ableChair]

I'm not understanding what you mean by "heat energy dissipated by a laser".

All energy releasing devices produce entropy (2nd Law of Thermodynamics). Entropy often takes the form of heat. In the case of a laser, we're talking about heat generated within the unit itself (you're right, I'm not concerned about that) and heat energy generated as the laser excites air molecules or atoms of other elements within the air. That would be your "heat loss on it's travels" comment. Yes, you can play with wavelengths to avoid excitation, but some HAS to occur. But that energy has to come from somewhere. It is taken OUT of the laser beam itself. That's conservation of energy. You can't get something for nothing. Now, maybe lasers just ARE that efficient and the loss is too small to matter, but I suspected that they are not that efficient (namely because of the incredible hurdles faced by SDI). In other words, they will easily lose 50 watts * t2 of energy to the atmosphere in the form of heat over a 5-10 mile distance...or so it would SEEM, and possibly even lose an amount of energy equivalent to the thermal energy released by a space heater or a sufficiently brief time interval. The purpose of the space heater in the thought experiment was to intuitively illustrate how much energy we're talking about. A space heater just doesn't dump a lot of energy, even if run for a long time. Unfortunately, I think the thought experiment was too abstract for some of the posters here as they kept focusing on the mechanical differences between space heaters and lasers, which was not the point. The point was merely to give the reader an intuitive sense of the energies we're talking about, then use conservation of energy to compare the two ENERGIES, NOT devices.It's amazing what a little common sense and a background in basic physics can tell you regardless of your 'credentials'. These hyped claims about lasers just don't pass the sniff test. If it were as easy as some posters are claiming, we could protect the U.S. from ICBMs far, far more cheaply than the way we're doing it now and all these posters would be billionaires for their suggestion that we just go to Radio Shack and get the hardware. It can't be that simple. Yes, I realize that the energy required to burn out an eye is far less than the energy required to burn a missile, but if you can fire a 50 watt * t2 laser 10 miles and burn out an eye, why not a 10'000 watt * tn laser that can burn metal? It's not a big leap in power or energy. This is FAR less energetic than what SDI contemplated. Maybe the tech has changed in some dramatic ways, and maybe lasers ARE that efficient, but given that no one has developed a workable system as yet suggests that energy loss in the atmosphere is hugely significant, even for destroying a metallic missile.

[DB]

So planes that crash and burn on landing now need an eye autopsy... Special...

[Boot Hill]

“Just to be contrarian...If there is finite light attenuation over a finite distance, when the last photon is absorbed it's over.”

Twinkle twinkle, beam of light,
How I wonder what is right,
Are you particle or are you wave,
It's quantum knowledge that I crave!

--Boot Hill

[ableChair]

Ahhh, Boot, that's GOOD. But I'm not required to argue that the beam has zero energy on impact, only that it doesn't have enough to burn an eye out! Otherwise, I totally agree with you.