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Laser Painting Could Lead to 25-Year Prison Term
lowy writes "According to this USA Today article, a New Jersey man was charged under federal anti-terrorism laws with shining a laser beam at a jet flying over his home. The Feds arrested him after he flashed a police helicopter searching for the source of the beam. He now faces up to 25 years in prison under Patriot Act charges." It seems to be happening around the country, as our earlier post makes clear.
Wired article http://www.wired.com/news/technology/0,1282,66173, 00.html?tw=wn_tophead_6
another site says:
Red laser pointers have grown cheap and ubiquitous, but unfortunately, they are not very effective as sky pointers. In contrast, green laser pointers are very effective because of the eye's greater sensitivity to the 532 nanometer green light. Under dark sky conditions, the beam from a 5 milliwatt green laser pointer creates a dramatic impression, and the beam apparently extends for more than a kilometer. Any bright light source, ranging from light pollution induced sky glow to a crescent moon, will reduce the apparent brightness of the SkyPointer(TM) although the beam will usually remain visible. The light pollution acts in such a way that people closer to you will still see the beam, whereas those further away may have difficulty.
Salon published a letter to the editor today regarding their prior story about the potential for lasers being used to blind pilots. In the letter the physicist argues that to use a laser properly for this task would require expensive and large equipment, at least two men, and good site selection. Basically, much cheaper and deadlier weapons are available to the motivated terrorist than lasers. The article and letter in reply are worth a read... --M
I know the /. article did not provide a link to the actual article, but you're making some rather strong incorrect statements. I did RTFA and (A) the laser light entered the cockpit and temporarily blinded both the pilot and the co-pilot. Apparently either the angle of laser relative to the cockpit was such that it went in, or else there was some unlucky refraction/reflection. (B) There was no concern that this represented someone pointing a gun at the plane, there was concern that terrorists were trying to blind pilots to cause them to crash. Although the investigators did state that they do not believe the actions of the suspect in this case to be terrorist.
-- I'm not a pessimist, I'm a realist. It's not my fault that life sucks so much. --
A typical laser will have a beam spread of 1.5 mRad.
As a rule of thumb this is about 1.5 millimeters spread to each meter
traveled. Hence at 100 meters the beam will be about 150mm wide which is
just under 6 inches in diameter. Using this formula you can calculate your
beam diameter at different distances.
Oh and semiconductor lasers have a much larger beam spread.
now, if at 100 meters if a laser can damage your eyesight 200 meters it will not. because the amount of laser light entering your eye is dropping extremely fast as the beam spreads further.
will you be "dazzled" by the bright light you see at the opening of the laser? yes, it will make it difficult for you to see who is standing behind that laser, epically if the contrast is high, I.E. completely dark room with little lighting on t he subject and a laser pointed at you. it will certainly not affect your vision at other angles.
I strongly suggest you learn about lasers, they are pretty darn fascinating, you seem to only know a very little about them but try to pass yourself off as an expert.
Do not look at laser with remaining good eye.
and this is not an abstract mildly interesting issue of civil rights to me.
First of all, let me say that all of the above posters who wonder "what the big deal is of a laser hitting the bottom of a plane when the cockpit window is on top" are uninformed. As a pilot on final approach, the only direction I cannot see is directly behind or directly under me, but I continuously scan every other segment of the sky. Especially at night I have to let my eyes pause for a moment on each section in order to discern relative motion, as a quick scan would not allow me to detect the characteristic red/green/white nav lights + strobe of a moving aircraft above the many lights (both stationary of all color, flashing, and more slowly moving ground vehicle) below the aircraft. So a fair amount of our time on final approach is spent gazing downward, since while descending that part of the sky represents the largest risk of collision hazard. This attentive watchfulness is of course an important part of what we do, and if while looking for aircraft below us both pilots are "temporarily blinded" or worse (depending on the type of laser used) we are obviously in a very scary situation.
Secondly, this idea that pilots fly the approach on autopilot is misinformed. Yes, cruise flight and the initial segment of the approach are usually (but by no means always) performed with the assistance of an autopilot. However, the autopilot is routinely and often given manual commands in a terminal environment to comply with air traffic control instructions all the way up to the very last final intercept of the glideslope. So pilot incapacitation during any descending maneuver before that final segment poses a very real threat to people on the ground below the aircraft's path (a much larger area than the airport proper). Also, with the exception of some large airliners and very few corporate aircraft, most jets do not have autopilots approved for autolandings, so at some point during the last 200 to 1000 feet the pilot will hand fly the plane, adjusting the pitch attitude and simultaneously reducing thrust to make a smooth landing flare. This is not something I want to feel my way through without sight.
There are many reasons to not use autopilot, some flights are also operational line checks where the pilot in command is being evaluated by a check airman who expects them to hand fly the plane to demonstrate proficiency. I often fly by hand both to keep my skills sharp as well as because it is enjoyable to have the responsiveness of a very powerful jet airplane at my fingers. There is satisfaction in rolling the plane onto a perfectly aligned final approach without the autopilot's assistance.
As a group, professional pilot's take the safety of our passengers very seriously. We attend recurrent training continuously throughout our careers, and simulate almost every conceivable emergency that it is possible to contend with. However, some emergencies elude constructing nice pat standard operating procedures to deal with. Obviously if an aircraft comes apart in flight then all you can do is follow the arc of the individual parts toward the ground below. Likewise, becoming blind is a situation that we just can't train for.
Finally, I've also noticed some posts recommending using some sort of film on the windshield that would protect the pilots. This is unlikely to happen soon for several reasons. I would love to hear that such a material exists that is effective over the many frequency ranges that could conceivably be used in a laser. But even if it did exist, each aircraft has a slightly different type of construction and would require a huge amount of research and development. The price would be astronomical. As an example, the windshield of a Learjet is nearly an inch thick, is comprised of multiple layers of various materials (including different types of plastic and acrylic and a layer of gold used to heat the windshield) which have been thoroughly tested for strength, compatibil