[Pseudoscience-is-malarkey (OP)]

As far as I know lasers are not yet at the point where they can replace bullets, but that doesn't mean they're not dangerous. There is a disturbing trend going on in the United States and UK, and other parts of the world, where people (mostly young adults) are shooting laser beams at aircraft with the expressed purpose of crashing them like wild game. Why is it that the police, military, private industry, et cetera, have not invented something that can protect aircraft from being blinded? Is it near impossible?

[alancalverd]

It's not the aircraft but the pilot that gets blinded. Since lasers have a very narrow bandwidth it might be possible to fit a filter to the windscreen but the only effective deterrent is to prosecute anyone caught doing this for attempted murder.

He might get 6 months' suspended sentence in a UK court, unless he has overfilled his dustbin, failed to pay his TV licence, or called a workmate "darling", in which case he will be lucky to get out alive. 

In many US states, endangering an aircraft carries a mandatory death sentence.

[Ethos_]

I've often wondered if the windshield on aircraft could be fitted with a one way mirror film which would reflect most of the laser beam giving the pilot some measure of effective safety?

[evan_au]

The main risk is for planes on final descent at night, when the pilot's pupils are wide open, the plane is low (short range), and the pilot needs to see the runway to land safely.

Frequently the main indication would be that the pilots would see a light shining on the roof of the cockpit. This is not so risky.

However, light shone from the area of the airport along the glide path towards the approaching aeroplane would be extremely dangerous.

Fortunately, most of the readily-available lasers are "Class 1", which means that they can't do any permanent damage even at very short range - but even a distraction could be disastrous on final approach. And people doing this for a joke are just as likely to shine their laser at the Police helicopter sent up to locate them.

People importing more powerful lasers into my country without good cause can be fined, and have their lasers confiscated.

In the cold war, when it was feared that a nuclear attack could occur at any time without warning, the US Air Force was concerned that many of its pilots could be blinded by an atomic bomb exploded in the sky. They experimented with windshields having electronically controlled portholes which could go opaque in microseconds to protect the pilots vision.

Another approach was to have pilots wear a pirate-style eyepatch, so if they were blinded by a flash, they could flip the eyepatch over, and continue flying the plane. But that is a bit extreme for commercial flying - two eyes are better than one.

Ultimately it comes down to people being aware of the dangers of laser beams, and taking responsibility for their own actions.

[RD]

I've often wondered if the windshield on aircraft could be fitted with a one way mirror film which would reflect most of the laser beam giving the pilot some measure of effective safety?

It would be very dark from the pilot's viewpoint : like looking through mirrored sunglasses.

[Pseudoscience-is-malarkey (OP)]

Herr Alancalverd,

I appreciate your response, but you might want to check your facts. In the U.S. a person cannot receive a death sentence for attempted murder.

[evan_au]

If it has been seen that someone is targeting planes with a laser beam, it is possible for commercial pilots to fly an instrument approach - at least until they pass the area where the laser beam was being used.

This also affects astronomers - adaptive optics can remove much of the atmospheric distortion by sending a powerful laser beam into the upper atmosphere. This can affect planes flying overhead, or even spy satellites. So they have to turn off their laser beam (stop observing) when planes approach, and astronomers have to get permission from the US government about what they are allowed to observe in space (and when).

[Don_1]

This is a disturbing escalation of this problem.

http://www.theguardian.com/world/2015/nov/23/ba-pilots-eye-damaged-by-military-laser-shone-into-cockpit-at-heathrow

[alancalverd]

Herr Alancalverd,

I appreciate your response, but you might want to check your facts. In the U.S. a person cannot receive a death sentence for attempted murder.

My suggestion was to prosecute for attempted murder in the UK - who knows, the criminal might even get sentenced to ten minutes' community service and having to say sorry, but the death sentence for endangering an aircraft was advertised on the security fences of several US airports I visited in the past.

A nice technical solution would be a beam-riding missile that simply flies down the laser beam and delivers a kilogram of Semtex to the source. Or a corner-cube reflector: there's nothing quite like getting your own back!

[Atomic-S]

A nice technical solution would be a beam-riding missile that simply flies down the laser beam and delivers a kilogram of Semtex to the source. Or a corner-cube reflector: there's nothing quite like getting your own back!

These sound like ideas that might actually work.

[Atomic-S]

Because laser lights are of very narrow bandwidth, it would seem not inconcievable to devise goggles whose lenses were opaque right around those wavelengths. I am assuming, of course, that lasers are generally available in only a very few wavelengths.  These would dim general vision only slightly.

[Pseudoscience-is-malarkey (OP)]

My suggestion was to prosecute for attempted murder in the UK - who knows, the criminal might even get sentenced to ten minutes' community service and having to say sorry, but the death sentence for endangering an aircraft was advertised on the security fences of several US airports I visited in the past.

A nice technical solution would be a beam-riding missile that simply flies down the laser beam and delivers a kilogram of Semtex to the source. Or a corner-cube reflector: there's nothing quite like getting your own back!

Capital Punishment is abolished in Britain, and has been since 1964.

[alysdexia]

What's next?  Floodlamp beams, halogen lamp beams, LED beams, mirror beams, death ray beams?

http://google.com/search?num=100&q=photochromism+%22visible+light%22

[evan_au]

Tonight someone illuminated my plane with a green laser pointer as the plane approached Sydney airport.

Fortunately it was a bit off to the side of the glide path, but it was still quite bright. Not bright enough to make you blink, but it might degrade your night vision if it caught you by surprise.

I hope the pilots kept their eyes on the glide-path...

[syhprum]

If the problem was acute the pilots direct view could be replaced with a television system where only one of several redundant cameras each incorporating different filters would be the only things risking damage.
I would expect such a system to introduce additional dangers and only be used if the problem became acute.

[syhprum]

I think Alan underrates the severity of the English law in a recent case a defendant accidently killed a police officer trying to stop his car  in a case where the charge would normally have been one of causing death by dangerous driving was charged with murder and despite the disagreement of the jury the was convicted of manslaughter and sentenced to 21 years imprisonment.

[alancalverd]

Indeed. Killing a policeman is considered as heinous as laughing at a woman in high heels. I have at least one record of a motorist receiving a £50 fine for killing a cyclist (but not exceeding the speed limit whilst doing so), whilst on the same page the newspaper reported a motorcyclist being fined £500 and banned from driving for a year, because he was recorded as doing 150 mph on an empty road at 3 am, and thus inconveniencing the police who couldn't keep up with him.

Whatever statute law says, criminal justice changed in 1979 when the UK police force became an arm of political government.   

[Tim the Plumber]

I have a welding mask which becomes dark the instant I start arc welding. It was a cheap thing to buy.

The speed of it is good enough that there is no chance of damage to the eye from the extreme brightness of the arc welding process. Clever stuff. I don't know how it works exactly.

https://www.amazon.co.uk/Design-Darkening-Welding-Helmet-Grinding/dp/B01AOTJDRW/ref=sr_1_2?s=diy&ie=UTF8&qid=1461358346&sr=1-2&keywords=welding+mask

[alancalverd]

A nice thought, but probably in need of some further development.

Pilots were discouraged from wearing photochromic spectacles because whilst some can darken very quickly, they are slow to recover. Excellent as you climb through cloud into the blue bowl (where there's not a lot to see anyway), but descending to your destination can be something of a lottery.

Possibly a good idea for a 2-man crew, for one to wear photochromics on final approach, or even to make half the windscreen photochromic, since most two-pilot missions will use an instrument approach down to very low level, but those of us in sole command of an aircraft approaching a visual-only field are a bit vulnerable, and I'm sure the idiots who play this game would be just as delighted to kill a family in a Cessna as a hundred paying punters in a 737. That's certainly the proven case near here.

[wolfekeeper]

Personally I think that laser pointers should be made illegal in the UK; there's easier ways to entertain cats.