Lasers and aircraft.

[russ]

20km is 10nm

I would hope that the pilot has visibility of the ground within 10nm of the airport.

If the pilot can see the ground, then someone on the ground can shine a laser at the pilot.

No barrel rolls required.

 

[harvyk]

I don't think anyone is arguing the point of coming in to land such as the image in markis10 pic, however, a laser shining through the coughpit window of a 737 20km out from SYD would mean that:

1. Light suddenly bends - Albert's going to be quite upset about this
2. there are some very tall people / structures in Sydney
3. The aircraft is conducting barrel rolls on final approach*
4. Boeing has suddenly put windows in the floor for that "more accurate landing" ability

I don't believe that the hyperbole is overly factual for aircraft in established flight, also, holding a target of say 1m square (i.e. window) while the target is moving at 2 or 300 km per hour (let alone cruising speed) for even a few milliseconds from a distance of >1000m would need a pretty sophisticated tracking device. It would be easier to shine the laser on the fuselage, but even then, it would be more fluke than good management...

MHO....

*my fav reason!

A few years ago when I was still a kid we lived near the hills under the approach path for CBR. Given that CBR doesn't have a great deal of things for teenagers to do my friends and I used to go walk about's on those hills. Every so often we'd see a plane come into land (we're about 16km away according to google maps) and we could easily see the front of the plane \ into the coughpit with binoculars (This was in the pre-terrorists are coming to get you days, so no visits from men in dark suits afterwards \ and it was actually a camera with a very good telephoto lens) until the plane was pretty close to us (we're talking up to the point which you needed to consistently move you head to keep tracking the plane).

Keeping a laser, especially one which bounces off particles in the air tracked onto the front of an aircraft wouldn't be the easiest thing in the world but not impossible by and stretch of the imagination.

 

[markis10]

I don't think anyone is arguing the point of coming in to land such as the image in markis10 pic, however, a laser shining through the coughpit window of a 737 20km out from SYD would mean that:

1. Light suddenly bends - Albert's going to be quite upset about this
2. there are some very tall people / structures in Sydney
3. The aircraft is conducting barrel rolls on final approach*
4. Boeing has suddenly put windows in the floor for that "more accurate landing" ability

*my fav reason!

Who says light needs to bend, on descent an aircraft's nose is often below the horizon, otherwise it would never descend. QF521 in the scenario below who is more than 20Km out could easily be blinded by the a laser on the shores of Kurnell for instance, he is well below the horizon in terms of extended horizontal heading:



Dont forget one of the main aids for pilots is a PAPI (or old VASIS) which is a series of lights that can be seen a long way out (19km), and thats not a laser:
http://www.flightlight.com/airportlighting/4.0/4.0.html

 

[medhead]

the thing that makes laser "light" different is that being a coherent light source. All the light waves are inphase, parallel and polarised. This makes for a light source that can be used over very long distances.

Unfortunately due to the actions of fools the Victorian government has completely overreacted concerning the use of lasers so that even for completely legitimate uses such as astronomy you need to go through such a hassle with police checks and expensive yearly licences that it's not worthwhile anymore to use lasers at all.

These are actually national regulations so not just Victoria. The only thing that may vary is the need for licensing. In any case, you can have a laser that is less than 1 mW, in other states, without jumping through any hoops provided you have a legitimate use, which it sounds like you do. The controls are implemented at import by customs, bypassing Victorian government involvement.


Sent from my iPhone using Aust Freq Fly app so please excuse the lack of links.

 

[markis10]

These are actually national regulations so not just Victoria. The only thing that may vary is the need for licensing. In any case, you can have a laser that is less than 1 mW, in other states, without jumping through any hoops provided you have a legitimate use, which it sounds like you do. The controls are implemented at import by customs, bypassing Victorian government involvement.


.

Some light (sic) reading here from Customs

http://www.customs.gov.au/webdata/resources/files/LaserPointers.pdf

 

[harvyk]

Some light (sic) reading here from Customs

And the bad pun award goes to....

 

[medhead]

I don't think anyone is arguing the point of coming in to land such as the image in markis10 pic, however, a laser shining through the coughpit window of a 737 20km out from SYD would mean that:

1. Light suddenly bends - Albert's going to be quite upset about this

Not suddenly, light always bends especially when subject to large gravitational fields. Albert would be upset if it didn't bend.

Light also scattered and reflects, 2 properties that would be relevant to the importance of these events.

 

[medhead]

Some light (sic) reading here from Customs

http://www.customs.gov.au/webdata/resources/files/LaserPointers.pdf

An interesting outline about what your supposed to do.

 

[Archphoto]

We use green laser pointers in our photography work and picked some up in China - one is 30mW the other 50mW. Not sure what type they're using to shine at the aircraft, but I accidentally got an eyeful of the 30mW for only a split second and it hurt like hell!! Enough for me to be shaking my head and blinking rapidly for a few minutes. Distracting and painful - I wouldn't have wanted to be driving a car, let alone piloting an aircraft. . . . .

We were using red ones originally, but had a tough time seeing them during the day - the green ones however, seem to go on and on - visible day and night.

And yes, you can buy them here in BKK quite easily - currently have a 20mW that works just as well.

 

[medhead]

We use green laser pointers in our photography work and picked some up in China - one is 30mW the other 50mW. Not sure what type they're using to shine at the aircraft, but I accidentally got an eyeful of the 30mW for only a split second and it hurt like hell!! Enough for me to be shaking my head and blinking rapidly for a few minutes. Distracting and painful - I wouldn't have wanted to be driving a car, let alone piloting an aircraft. . . . .

We were using red ones originally, but had a tough time seeing them during the day - the green ones however, seem to go on and on - visible day and night.

And yes, you can buy them here in BKK quite easily - currently have a 20mW that works just as well.

That is really, really bad. I'm going to pass on your story for laser safety training.

 

[munitalP]

Not suddenly, light always bends especially when subject to large gravitational fields. Albert would be upset if it didn't bend.

Light also scattered and reflects, 2 properties that would be relevant to the importance of these events.

Physics 101

I was meaning at right angles!

:shock::shock::shock::shock:

 

[medhead]

Physics 101

I was meaning at right angles!

:shock::shock::shock::shock:

Yeah I know, still nice to stir.

BTW right angles is called reflection from a plane (different type of plane, no pun here) surface, with an angle of incidence =45 degrees.

 

[Archphoto]

That is really, really bad. I'm going to pass on your story for laser safety training.

When I'm shooting, I always start with the laser pointed at the floor and work my way up - it never starts anywhere near my assistant's head. I ask her to watch the "green dot" and move it upwards *slowly*.

The presentation ones are fine for presentations - but really useless in our situation as they aren't powerful enough, and red is really difficult to see as well. The green ones though - perfect (and dangerous if not used correctly).

The photographer who originally got me, hasn't forgotten and is now *very, very* careful when he's using his with his new assistants; think my yelling and dancing around like a crazy person, has scarred him for life.

 

[Stephen65]

These are actually national regulations so not just Victoria. The only thing that may vary is the need for licensing. In any case, you can have a laser that is less than 1 mW, in other states, without jumping through any hoops provided you have a legitimate use, which it sounds like you do. The controls are implemented at import by customs, bypassing Victorian government involvement.

The problem is that a <1mW laser pointer is far too weak to be useful for astronomy. Typically the ones used in astronomy range from at least 5 to around 30mW.

In Victoria it is possible to get an annually renewed prohibited weapons permit to use a laser for astronomical purposes but to me it wasn't worth the hassle and expense (e.g. I am not going to buy a safe and have it permanently attached to the wall of my house just to store one laser pointer).

Yet another example of the nanny state overreaction.

 

[medhead]

In Victoria it is possible to get an annually renewed prohibited weapons permit to use a laser for astronomical purposes but to me it wasn't worth the hassle and expense (e.g. I am not going to buy a safe and have it permanently attached to the wall of my house just to store one laser pointer).

I am restraining myself from my whinges about OTT security requirements in my work. 911!

Yet another example of the nanny state overreaction.

With the earlier comment about from someone experiencing pain, the know damage these can do to people's eyesight and the excessive number of complete ****wits[SUP]1[/SUP] out there trying to copy Seinfeld; I just cannot agree this is a nanny state overreaction. These things can do serious, permanent damage to people and there are ****ing[SUP]1[/SUP] idiots everywhere.



1 Yes I feel very strongly about this

 

[Stephen65]

Unless you have a very powerful laser it's not possible to do permanent damage to eyesight because the blink reflex means people will close their eyes long before damage can occur. This is why laser pointers are typically either not banned or allowed at considerably stronger powers than in Australia throughout almost all of the rest of the world. I am not aware of any rash of reports of people suffering eyesight damage from laser pointers.

There are plenty of dangerous tools readily available to people that are not banned despite being regularly used to inflict harm, for example, kitchen knives and baseball/cricket bats.

 

[munitalP]

I am restraining myself from my whinges about OTT security requirements in my work. 911!



With the earlier comment about from someone experiencing pain, the know damage these can do to people's eyesight and the excessive number of complete ****wits[SUP]1[/SUP] out there trying to copy Seinfeld; I just cannot agree this is a nanny state overreaction. These things can do serious, permanent damage to people and there are ****ing[SUP]1[/SUP] idiots everywhere.



1 Yes I feel very strongly about this

im not sure you are really saying what you mean medhead - can you show a bit more emotion from now on?
























*ducks*


BTW.... http://www.australianfrequentflyer....iscussion/munitalp-has-run-afp-per-21444.html

 

[medhead]

Unless you have a very powerful laser it's not possible to do permanent damage to eyesight because the blink reflex means people will close their eyes long before damage can occur. This is why laser pointers are typically either not banned or allowed at considerably stronger powers than in Australia throughout almost all of the rest of the world. I am not aware of any rash of reports of people suffering eyesight damage from laser pointers.

Sorry but that is wrong. You were talking about 5 to 30 mW lasers. These are all class 3B lasers. The blink reflex is only good for class 2 or lower lasers.

Further laser pointers are limited to 5mW, 3A in the US and Canada and 1mW class 2 in UK and Oz. So maybe 5mW is acceptable by world wide standards depending on the emission mode and characteristics. But 30 mW is just not on.

Sent from my iPhone using Aust Freq Fly app so please excuse the lack of links.

 

[jb747]

A laser hit on the coughpit may well be more or less a fluke. But, I think an old rifle stock and a scope would pretty readily allow me to make up something that would be much more 'aimable' than the laser itself. If the turkey needs a hundred attempts to hit the coughpit, it doesn't make it any less dangerous.

The most dangerous time for lasing comes quite late in the approach. The target is big, close, and relatively slow.

Even a momentary hit on the coughpit is extremely dazzling....and as soon as we gain the means to shoot back, I'm all for it.

 

[Noob]

I don't really understand why they do it, how would they feel if something bad did happen? Is there some kind of thrill involved in possibly endangering the lives of a couple of hundred or more people? :shock: