SoylentNews is people
SoylentNews
from the promoting-laser-beams-on-sharks dept.
A Virgin Atlantic flight from London's Heathrow Airport destined for New York was forced to return following a "laser beam incident":
A flight heading to New York turned back to London Heathrow Airport after a "laser beam incident", Virgin Atlantic has confirmed. A crew member is recorded saying to Irish air traffic control that they had a "medical issue with one of the pilots after a laser incident after take-off". It happened at 20:13 GMT, shortly after take-off, the company said, before flight VS025 returned as a precaution. There were 252 passengers and 15 crew on board. Metropolitan Police tweeted: "Aircraft forced to return to Heathrow after being hit by a laser strike... #laserstrike CAD4."
[...] A new law introduced in 2010 means people could be charged with "shining a light at an aircraft in flight so as to dazzle the pilot".
Janet Alexander, a commercial airline pilot, said shining a laser beam into a cockpit was a very dangerous thing to do. "It's unfortunately becoming an increasingly problematic occurrence. It's very like a lightning strike in that it's very instantaneous, very, very bright light, which is dazzling basically," she said. "And of course if it's targeted in exactly the wrong way you could permanently damage someone's sight."
A total of 414 "laser incidents" in the UK were reported to the Civil Aviation Authority between January and June 2015. The highest number of them was at London Heathrow Airport - 48 were reported during this period. In 2014, there were 1,440 incidents in the UK, with 168 at Heathrow, according to the CAA.
The British Airline Pilots Association (Balpa) has called for lasers to be classified as "offensive weapons" and banned in the UK, following the Virgin Atlantic flight VS025 laser incident. Members cite the frequency of laser incidents and say the 2010 legislation on lasers isn't tough enough.
(Score: 2) by Foobar Bazbot on Friday February 19 2016, @02:59AM
For kicks, let's come up with actual beam intensity in candela; since automobile headlamps are regulated in candela, this will offer a useful point of comparison.
Let's assume a power of 5mW, wavelength of 555nm, which corresponds to the eye's peak sensitivity, and divergence of 1mrad. (I don't know of any 555nm lasers, but I can't be bothered to look up the lumens/W for the common 532nm green DPSSFD lasers.)
Since the beam is (roughly) circular in cross-section, its area is π/4 * (1 mrad)2, or 8*10-7 sr
At 555nm, the luminous flux is 683lm/W * 5mW = 3.4 lm
The average luminous intensity of the beam is then 3.4 lm / 8*10-7 sr = 4.3*106 cd, but since the beam is not of uniform intensity, the peak intensity will be higher -- let's call it 107 cd for easy figuring.
In comparison, the peak intensity of a single legal high-beam headlamp is generally about 106 cd, more or less. (IIRC 140 000 cd / side in Europe, 75 000 cd /side in the US, but I'm not certain that's current.) Since the inverse-square law applies, this factor of 1000 difference corresponds to a factor of about 30 (square root of 1000) in distance. Thus, an automotive high-beam headlamp viewed from 100m appears as bright as our 5mW green laser viewed from 3km. Of course, if we step up to a 50mW or 500mW laser, we're looking at a distance factor of 100 or 300, respectively.
Now I'm sure the rules for dipping your headlights to low-beam vary widely, but where I live, it's 300 feet (90m) behind a car traveling the same direction, or 500 feet (150m) from an oncoming car; thus at any distance over about 3 miles (5 km), the glare from the laser is less than half (because cars have two headlamps) the glare drivers are required to tolerate from oncoming traffic. Even for distances as close as 1km, it's comparable to getting hit with both high beams at a distance of 50m, and I'm sure inconsiderate or forgetful drivers impose this on other drivers much more than 1440 times per year in the UK, causing much annoyance but little apparent harm, and AFAIK no outcry for new laws.
Certainly, it seems incidents inside 1km (or involving more powerful lasers) could be a real problem -- after all, high beams rarely score a "direct hit" much closer than 50m, as the other car is rapidly exiting the brightest part of the beam, so that's about as high as our scale can meaningfully go. But I really wonder, out of these 1440 reported incidents per year, just how many actually are within this range, and how many are mere annoyances like drivers have to tolerate all the time?
Of course, human vision is very complicated, so I really don't know whether the sudden/flickering nature of a hand-held laser jittering on and off the cockpit windows makes a real difference in dazzling effect, but this comparison at least gives us an approximate way to relate the intensities to personal experience.
(Score: 3, Insightful) by legont on Friday February 19 2016, @05:43AM
While I think the issue with lasers is overblown, the danger to pilots is way higher than to drivers. First, a pilot can get disoriented at night even without interference. It's called vertigo. Suddenly brain interprets visual signals wrong, side, up and down mixes, and it takes significant will to believe instruments and if they already way off, to correct. Many people lost their lives this way cause it can hit a pilot of any experience and training. Second, the reason pilots are good at such a complicated task is that almost everything in the task is expected and drilled. A step away from the ordinary creates unreasonable burden. Don't get me wrong, many pilots are actually like to play, but not with a few hundreds people behind. I can continue on and on. Also, a crash never has a single cause. It is always a chain of relatively minor issues. It's in fact true everywhere - if you have your high beam and some hot coffee on your lap your chance of a car crash suddenly become way too high for a comfort. A pilot has a much higher load of events and he can't stop and get himself together on the side. The problem - any problem - is usually triggered by unexpected and no sane pilot would tolerate a laser beam in his eyes on regular flight. In fact even using taxi lights on the ground too much is considered "impolite".
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by hankwang on Friday February 19 2016, @07:05AM
"a single legal high-beam headlamp is generally about 10^6 cd, more or less. (IIRC 140 000 cd / side in Europe,"
Close enough. I think I read 225,000 cd as a maximum for both lights together (EU), the other day. But note that it's the maximum, not the typical value. Probably only achievable with high-end HID lamps.
"but where I live, it's 300 feet (90m) behind a car traveling the same direction, or 500 feet (150m) from an oncoming car."
I'm glad that I don't live there. Here (NL, EU) you are not allowed to use them at any visible distance. As a bicyclist with a 200 cd front lamp (pointing at the road surface) I highly appreciate that most drivers follow the rules, although the misadjusted 3000 cd LED lights of other cyclists are getting annoying these days.
Anyway, the assumption of 5 mW is debatable, given how cheap the 500 mW ones are.
http://www.aliexpress.com/popular/500mw-green-laser.html [aliexpress.com]
Avantslash: SoylentNews for mobile [avantslash.org]
(Score: 0) by Anonymous Coward on Friday February 19 2016, @09:53AM
Anyway, the assumption of 5 mW is debatable, given how cheap the 500 mW ones are.
And how many idiots are pointing wimpy 5mW or lower lasers at planes? Those idiots play with the higher powered ones.
(Score: 1, Insightful) by Anonymous Coward on Friday February 19 2016, @09:50AM
Many in the airline industry don't like pilots with impaired vision flying their planes, so better to land while the co-pilot is still OK (and doesn't have problems etc) - why risk bad PR if stuff happens (just look at the MH17 and MH370 incidents - people are boycotting MAS even though there's no clear proof yet that MAS or their pilots did anything more wrong than other average airlines/pilots were doing)
From what I gather it's more likely for your eye lenses to focus the light from the laser into a very small hot dot than for them to focus the headlamp light into a very small hot dot - it would be a bigger less hot dot at the back of your retina. So while you could probably get blinded by briefly staring at some headlamps very close, the danger distance drops off far more rapidly than for a laser. Even laser light from reflections might still stay collimated enough to do damage.