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Laser threat defence

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Laser threat defence

Old 17th Feb 2016, 19:12
  #41 (permalink)  
 
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Quote:
"What are the regulators doing?"


Well, not knowing that pointers were the main problem, the FAA decided it had authority and banned commercial and most scientific outdoor [email protected] use in the US a decade or so ago until new rules were made. Then they found the problem was more than one or two rogue, automated, [email protected] shows at a hotel in Vegas, causing huge problems for McCarren a long time ago.


Until cheap Chinese pointers flooded the market, on average there were less then two reported [email protected] illuminations of aircraft per year. Which is why many of us who worked with outdoor [email protected] legally are STEAMING MAD.


[email protected] Safety in the US is regulated by the Food and Drug Administration, who co-operates with FAA and DOD on [email protected] in airspace.


FAA at first had the idea that it was not possible for a wimpy pointer to cause problems, and that it had to be professional or scientific [email protected] causing the problem. They had the Centers for Devices and Radiologic Health spent a lot of time looking for "rogue" commercial [email protected] gear. That was not the case, as we know now.


Then came some eye opening FAA simulator studies on just how little light was disruptive.


US Customs works hard to confiscate imports of [email protected] pointers at the border, So does the UK, Germany, and Oz. Most of those nations declare a legal pointer to be no more then one or five milliwatts... But stuff leaks thru like crazy.




In the US, FAA had the Society of Automotive Engineers form the G10 committee, which formulated a [email protected] safety standard that became FAA 7400.D (now 7400.G) which is safe use of [email protected] in Airspace, and requires qualified users to formulate a plan to integrate their [email protected] use with an airspace specialist at FAA, with review by DOD in the US. Those rules have been copied around the world with slight variations. I'll get to the effects of that when I get to SZED, CZED and airport runway centerline exclusion zones.


Of course pointer users generally don't even understand something like 7400.G exists, so the problem continued.


Many of the first prosecutions were for "Interfering with an Aircrew"


Over time its lead to a law...


In the US, You can now get five years in Federal Prison or a massive fine, plus there are state laws and local laws...


Here it is:


U.S.C. TITLE 18, CHAPTER 2

Sec. 39A. Aiming a [email protected] pointer at an aircraft
(a) OFFENSE -- Whoever knowingly aims the beam of a [email protected] pointer at an aircraft in the special aircraft jurisdiction of the United States, or at the flight path of such an aircraft, shall be fined under this title or imprisoned not more than 5 years, or both.
(b) [email protected] POINTER DEFINED -- As used in this section, the term `laser pointer' means any device designed or used to amplify electromagnetic radiation by stimulated emission that emits a beam designed to be used by the operator as a pointer or highlighter to indicate, mark, or identify a specific position, place, item, or object.
(c) EXCEPTIONS -- This section does not prohibit aiming a beam of a [email protected] pointer at an aircraft, or the flight path of such an aircraft, by--
(1) an authorized individual in the conduct of research and development or flight test operations conducted by an aircraft manufacturer, the Federal Aviation Administration, or any other person authorized by the Federal Aviation Administration to conduct such research and development or flight test operations;
(2) members or elements of the Department of Defense or Department of Homeland Security acting in an official capacity for the purpose of research, development, operations, testing or training; or
(3) by an individual using a [email protected] emergency signaling device to send an emergency distress signal.
(d) The Attorney General, in consultation with the Secretary of Transportation, may provide by regulation, after public notice and comment, such additional exceptions to this section, as may be necessary and appropriate. The Attorney General shall provide written notification of any proposed regulations under this section to the Committees on the Judiciary of the House and Senate, the Committee on Transportation and Infrastructure in the House, and the Committee on Commerce, Science and Transportation in the Senate not less than 90 days before such regulations become final."


END QUOTE


More to come, when I'm not at work... And yes there are window coatings, low visual impact goggles, various kind of shades, [email protected] countermeasures, specialized gear for helos, and prototypes and patents on tunable notch goggles...


I have a friend who is a noted Helo pilot and consultant, and this subject has came up often..


Just in the past, when the legit [email protected] user groups talked to the pilot groups, all [email protected] users got lumped together. There were a few pilots on the G10 committee who listened...


In my next post I'll get to exposure levels and selecting proper goggles, which is what most of you want to hear... I can't advise you to wear something in the cockpit, as pilots need to follow national rules and follow SOPs, but I can show you some links and the basics...


Sim,
SimVisualsEngineer is offline  
Old 17th Feb 2016, 19:13
  #42 (permalink)  
 
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Yes, and further you talk about aimlessly waggling at 60 degrees per second.
...and then went on to use a far more conservative value of 10degrees/sec for the actual calculations. That number came from standard data we use for human-induced jitter in ground [email protected] designators. Neither number means "move the [email protected] through 60/10 degrees" it's an angular velocity, not a movement distance.

Why don't you consider a more concerted waggle in the general direction of the aeroplane with the intention of actually hitting it.
I did - why don't you consider a more concerted reading of what was actually written rather than waggling your eyes in the general direction of the screen...



PDR

[sorry - couldn't resist that dig. I should be ashamed of myself]
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Old 17th Feb 2016, 19:15
  #43 (permalink)  
 
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He wouldn't need to "hold" it on the eyes.
No, but he'd need to hold it much more steadily and accurately to have *any part* of the beam passing into the eyes.

Which is kinda the point.

PDR
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Old 17th Feb 2016, 19:24
  #44 (permalink)  
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It is readily apparent, provable by real life examples, that people can do so. Often. Which is actually the point.

Why don't you go and have a look at images of [email protected] refraction through aircraft windows.
Chesty Morgan is offline  
Old 18th Feb 2016, 06:19
  #45 (permalink)  
 
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Chesty

Nobody is suggesting that a [email protected] at considerable distance can't flash across a cockpit and be distracting.

The discussion is about just how much power would be required to cause eye damage with a hand held [email protected] at any distance.
This is affected by many parameters
Wattage, beam spread, atmospheric attenuation, glass attenuation, tracking ability etc etc.

Pretty green lights in cockpits at height is not the same as proof that hand held [email protected] are a problem.
Fireworks are distracting to fly above, but nobody suggests we ban them.
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Old 18th Feb 2016, 06:41
  #46 (permalink)  
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The discussion is more than just about eye damage but also the effects of [email protected] exposure on pilots, and I don't mean only as a distraction.

The energy density (measure of energy per unit of area) of the [email protected] beam increases as the spot size decreases. This means that the energy of a [email protected] beam can be intensified up to 100,000 times by the focusing action of the eye for visible and near infrared wavelengths. If the irradiance entering the eye is 1 mW/cm2, the irradiance at the retina will be 100 W/cm2. Even a 4% reflection off an optic can be a serious eye hazard. Remember a low power [email protected] in the milliwatt range can cause a burn if focused directly onto the retina.

Last edited by Chesty Morgan; 18th Feb 2016 at 06:53.
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Old 18th Feb 2016, 07:54
  #47 (permalink)  
 
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Tourist

Pretty green lights in cockpits at height is not the same as proof that hand held [email protected] are a problem.
From captain Scrogg's post in the original thread:

As was reported in the news, the FO did receive retinal damage from what appeared to be a 'lucky' passing sweep, but it's not permanent and will heal fully. There was no visual impairment during the flight,
If you all want to check around numbers to prove or disprove they are a problem feel free, but the debate is starting to remind me of an old old story about dentistry......

https://www.lhup.edu/~dsimanek/horse.htm
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Old 18th Feb 2016, 08:16
  #48 (permalink)  
 
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Wiggy

You misunderstand me.

I'm suggesting this might be something other than a little handheld toy. The numbers just don't add up.
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Old 18th Feb 2016, 13:49
  #49 (permalink)  
 
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Originally Posted by Chesty
The energy density (measure of energy per unit of area) of the [email protected] beam increases as the spot size decreases. This means that the energy of a [email protected] beam can be intensified up to 100,000 times by the focusing action of the eye for visible and near infrared wavelengths. If the irradiance entering the eye is 1 mW/cm2, the irradiance at the retina will be 100 W/cm2. Even a 4% reflection off an optic can be a serious eye hazard. Remember a low power [email protected] in the milliwatt range can cause a burn if focused directly onto the retina.
Which is very interesting, but if you read BS-EN60825 and the definition of MPE you'll find that the numbers on the graph relate to energy levels that can cause damage at the retina (amongst other things) so this is already taken into account, because the people writing these standards aren't complete idiots*.

PDR

*I gather a few of the parts are still on back-order
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Old 18th Feb 2016, 13:53
  #50 (permalink)  
 
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From captain Scrogg's post in the original thread
I'd love to read these comments, but of course I can't because I'm not even allowed to read that thread.

Are all pilots book-burners by nature, or is it just a few who give the rest a bad name? The test pilots I know are not like this. They have integrity...

PDR
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Old 18th Feb 2016, 14:30
  #51 (permalink)  
 
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Just seen this, and my credulity is (I will admit) struggling [to recap - we were talking of a claimed hand-held [email protected] attack on an aeroplane at FL360]

I'm sure you're clever enough to work out the difference between a hand held [email protected] and a stabilised [email protected]
Maybe so, but how did YOU determine that the brief flashes you saw at FL360, at night, were a handheld device?

And 14 miles? No.
Well you were over 7 miles up, and I'm assuming your aeroplane didn't have wind-up windows in the cockpit and that you didn't have your head hanging out of the window looking vertically downwards, so we know it must have been at least 7 miles*. The convention we've been working with to date is that from you can see downwards by about 30 degrees with your head and eyes in the normal positions in the driver's seat - that says that the source must have been 14 miles away (sin30 being 0.5). No one has questioned this convention so far - what angle do suggest we can use?

PDR

* Unless you happened to be passing Mount Olympus at the time, in which case you can reduce that to 5 miles height and 11 miles slant-range @30 degrees
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Old 18th Feb 2016, 17:30
  #52 (permalink)  
 
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Some of you may be wondering why I don’t just specify off the shelf [email protected] safety goggles.
The issue with that is that if Captain Bloggs buys low cost, off the shelf gear, he runs three risks.
Risk One, There are low cost, uncertified, “fake” googles out there, made by the same folks who sell the pointers. While many of the pointer engineers have Masters and PhDs in [email protected] engineering, one does not expect them to be well versed in the design and test of a critical safety device. Please believe me that it is fairly difficult to expect the colored dyes in a 50$ pair of injected molded glasses can withstand high amounts of [email protected] energy without the plastic bleaching or work at the correct [email protected] wavelength, without lab certification to national standards. I find it sad that there are 15$ fakes on auction sites that do not pass even simple home lab tests…
Risk Two, The glasses may be incompatible with the cockpit displays. If the cockpit is Blue-Green ANVIS compatible, for example, most “orange”laser safety glasses for the common 532 green wavelength may adsorb most of the instrument lighting.One would not want a unprepared “Child of the Magenta” to be unable to see a critical display during critical flight. Typically, Aviation [email protected] Safety Devices must be evaluated for human factors and cockpit compatibility.I’ve hit my head and tripped several times in the lab, because my glasses which protect against all the [email protected] wavelenths present, are too dense to allow me to see obstacles in a darkened lab. Thus “Secondary” hazards must be evaluated.
Risk Three, as we shall see in the following examples, the “Optical Density” of the glasses must be designed to match the level of annoyance provided by the [email protected] There is no reason to lose sixty five percent of visible light transmission when the “threat” is not great. You may need what is called an “alignment” or “Aiming” goggle vs a full out hazard protection device. You may also need a more expensive custom device which counters the threat(s) but allows the pilot to function with little impairment. Full wrap around [email protected] safety glasses are annoying to wear, and reduce the visual field. They can impair peripheral vision. And what happens when you dim the lights and displays? What happens if both the PF and PNF are wearing protection?
Thus in a flight situation, risk management review by professionals, and safety cases are important when selecting [email protected] protection. Is Captain Bloggs, 1500 Hour CPL, qualified to decide he needs OD6 or OD3, or something custom? In most cases No…One also needs to set in the actual cockpit, light up the instruments, press “self test” on the warning lights, dim everything, and see if one is personally comfortable with the risks. Training is a huge factor.
FAA responded to the initial crisis with the 7400.G rule for professional and scientific users of [email protected] in airspace. This is based on the ANSI Z136.1 standard for [email protected] safety. In the UK, it is adopted as CAP 736 by the CAA. I can work backwards from this to make a good example of the actual power levels often involved.
First of all the rules define the “Airport No [email protected] Zone” for two nautical miles either side of the runway centerline and three miles from the runway ends. There is no purpose for a [email protected] to be in this area other than cloud height finders, and in some rare cases “approved [email protected] glideslopes”.


FAA defines the Critical Flight Zone as an area that is 10,000 feet in height and extends for 10 nautical miles from the airport center. In the critical zone, a [email protected] or searchlight shall not exceed 50 nano Watts per Square Centimeter.This level is considered visible but will not constitute a distraction or annoyance to a pilot. For calculations, this is known as the “LFED distance.
The Critical Zone Exposure Distance (CZED) is the distance from the [email protected] source to where it reaches an irradiance of 5 microwatts per square centimeter. This level is considered the lower level for creating annoying glare or attracting attention.
FAA defines the Sensitive Flight Zone as the area where the beam Exceeds 100 microwatts per square centimeter. This level is task disruptive and where significant flashblindness and afterimages occur.This is the “SZED” distance for legitimate users of [email protected], when siting their equipment.
Reference for the following data, which is not Slant Range Corrected per FAA rules, from Skyzan [email protected] Safety Software and the ILDA [email protected] Safety Officer Coursework:
For a 5 milliwatt, 1 milli-Radian [email protected] Pointer:
NOHD 52 Feet
SZED 262 Feet
CZED 1,171 Feet (The beam can cause task disruption to this distance)
lFED 11,170 feet, (The beam is considered annoying to this distance)
For a 1 Watt, 1 milli-Radian Visible [email protected]:
NOHD 726 Feet,
SZED 3,700 Feet
CZED 18,600 Feet
LFED, 186,000 Feet (Not practical in many cases, due to horizon and atmosphere, included as example)
The whole point is that the night adapted eye is amazingly sensitive. The second point is the number of damaging cases is so far miniscule compared to the personal injury cases. However I am concerned that those will rise, given time.
The NOHD is the distance for a 50/50 chance of a large damage spot on the retina.
So do you really need protection "in flight" against a legal device, probably not. But you do have to weight the issues caused by the protective device against the actual [email protected] threat.
For the record, I’ve been “lased” by pointers while in a car, and while working at a concert in the past. At the concert I was able to secure the device involved, and get some data. I was not happy. My [email protected] show friends now have a “No Pointer in Audience” clause on their show riders and contracts, for a couple of reasons, not the least of which is liability for the audience’s safety. ..
There simply is no need for more than 5 milliwatts of [email protected] light to be in the hands of the general public in hand held form. FAA/USCG/US Law makes an exception for [email protected] rescue beacons, which are highly effective.But other than that, the existing world wide 1 and 5 mW limits are enough. This is now a societal addiction problem.The real issue is lack of enforcement with the makers and vendors.The existing laws on the books need to be enforced.
Unless there are questions, my last post will be links to current aviation oriented [email protected] safety devices.


Steve
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Old 16th Sep 2016, 04:31
  #53 (permalink)  
 
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Thanks for great Info!

Just a word of thanks to Sim Steve, your remarks are very informative and helpful!

It would also be nice to hear from the helo guys in the UK, who seem to get lased
100 times a month now, about the measures they take and procedures for dealing with this...
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