L@ser attacks on Aircraft
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Having been targeted inbound to LPL last week I thought how nice it would have been to open a hole in the aircraft and let out one of those fancy laser guided devices that would have really spoilt the tw@ts evening. I can but dream.
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CJ:
No, because it is not a simple answer.
For obvious reasons it is very difficult to do research into the flux levels required to permanently damage human retinas. The best we can do is to look at industrial accidents, and work backwards to try and figure out where the thresholds lie - however due to the low numbers of incidents this does not produce accurate data. Also most of the work has been into non-visible wavelengths, as they are far more common in industrial contexts.
The best efforts of the industry and regulators have led to the laser Safety Classes (Laser safety - Wikipedia, the free encyclopedia) which I wrote about on a previous post. The best models so far work on the assumption that permanent damage to the retina is thermal, so is a combination of flux level, wavelength and time.
Given the difficulty in aiming a laser at an aircraft (even for the military this has proved insurmaountable so far), it is almost impossible for the beam to be held on your eyeball for long enough to do thermal damage to your retina. You are talking milliseconds if not microseconds of exposure. Plenty of time to dazzle you, to leave afterimages, to disorient you. But not enough to cause permanent damage.
S.
Sorry about the wildly inaccurate moon numbers in the last post. The perils of trying to write this stuff from memory.
"Does anybody on this thread have any reliable figures?"
For obvious reasons it is very difficult to do research into the flux levels required to permanently damage human retinas. The best we can do is to look at industrial accidents, and work backwards to try and figure out where the thresholds lie - however due to the low numbers of incidents this does not produce accurate data. Also most of the work has been into non-visible wavelengths, as they are far more common in industrial contexts.
The best efforts of the industry and regulators have led to the laser Safety Classes (Laser safety - Wikipedia, the free encyclopedia) which I wrote about on a previous post. The best models so far work on the assumption that permanent damage to the retina is thermal, so is a combination of flux level, wavelength and time.
Given the difficulty in aiming a laser at an aircraft (even for the military this has proved insurmaountable so far), it is almost impossible for the beam to be held on your eyeball for long enough to do thermal damage to your retina. You are talking milliseconds if not microseconds of exposure. Plenty of time to dazzle you, to leave afterimages, to disorient you. But not enough to cause permanent damage.
S.
Sorry about the wildly inaccurate moon numbers in the last post. The perils of trying to write this stuff from memory.
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So let's do a calculation.
For a handheld laser pointed at an aircraft, let's work on the assumption that the eyeball is expose to the beam for 1/1000th of a second.
For visible light, for 1ms, the Maximum Permitted Exposure (MPE) flux is 0.01 W/cm2. (From IEC 60825)
For a laser with a beam angle of 1.5mrad (i.e. a very good narrow beam), the beam will spread by 3 feet for every 1000 feet travelled.
To make the maths easier, I'll round that to a 1m beam at 1000 feet.
Your pupil is defined at 0.39 cm2 = 0.000039 m2, so you will get 0.000012 (0.0012%) of the beam in your eye.
Working that backwards that means you will need 0.0256W of flux into your eyeball to cause damage, which will need a 2066W laser on the ground.
Now a 2kW laser is a bit beyond even ebay.
Or have I got the maths wrong again.
Simon.
For a handheld laser pointed at an aircraft, let's work on the assumption that the eyeball is expose to the beam for 1/1000th of a second.
For visible light, for 1ms, the Maximum Permitted Exposure (MPE) flux is 0.01 W/cm2. (From IEC 60825)
For a laser with a beam angle of 1.5mrad (i.e. a very good narrow beam), the beam will spread by 3 feet for every 1000 feet travelled.
To make the maths easier, I'll round that to a 1m beam at 1000 feet.
Your pupil is defined at 0.39 cm2 = 0.000039 m2, so you will get 0.000012 (0.0012%) of the beam in your eye.
Working that backwards that means you will need 0.0256W of flux into your eyeball to cause damage, which will need a 2066W laser on the ground.
Now a 2kW laser is a bit beyond even ebay.
Or have I got the maths wrong again.
Simon.
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the final result . . . . . . . .
Why are we discussing whether there is permanent retinal damage or not ?
If, as a result of dazzle, after-images or disorientation in a pilot, especially at the low levels often involved, an accident occurs . . . . . . well, who knows how many people would have permanent damage, to retinas and everything else as well !
Plenty of time to dazzle you, to leave after images, to disorient you
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If a 737 pilot experiences a laser incident on take-off what is the most prudent action to take? (1) Land immediately and have the pilot cleared by medical professionals before continuing? (2) Do a self-assessment and continue on to destination then be checked by a medical professional?
I’m all for number 1…
I’m all for number 1…
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time is a good healer . . . . . .
If a 737 pilot experiences a laser incident on take-off
The aeroplane is still 100% sound, the other crew member is flying it safely, and the dazzle effects (or whatever) will subside in a relatively short time.
Report the incident to ATC: yes.
Emergency return to departure airfield (heavy with fuel, etc) : NO.
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AMC and PPL
I don’t think so as that’s not the safest response. (1) You have no idea exactly how much damage the crewmember has sustained if any. (2) Returning to land immediately in a 737 is no big deal (3) if any further incidents/accidents occur you and your company is on the legal hook big time
I don’t think so as that’s not the safest response. (1) You have no idea exactly how much damage the crewmember has sustained if any. (2) Returning to land immediately in a 737 is no big deal (3) if any further incidents/accidents occur you and your company is on the legal hook big time
Last edited by Tan; 23rd Oct 2008 at 22:14.
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fair point, but . . . . . . . .
You have no idea exactly how much damage the crewmember has sustained if any
Given the difficulty in aiming a laser at an aircraft (even for the military this has proved insurmaountable so far), it is almost impossible for the beam to be held on your eyeball for long enough to do thermal damage to your retina
Awaiting more views on this from others actually doing the job (I'm not ! ).
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Well, here's a first hand acount.
I got l@zered tonight going into LCY.
saw a green light moving about down on my left side. Suddenly it 'flashed' in a way that to me seemed to say that it had been pointed straight at me (us actually as the FO saw it too).
It did no harm but we reported it and the cops attended after pax got off.
I got l@zered tonight going into LCY.
saw a green light moving about down on my left side. Suddenly it 'flashed' in a way that to me seemed to say that it had been pointed straight at me (us actually as the FO saw it too).
It did no harm but we reported it and the cops attended after pax got off.
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Looks like Edinburgh is fast becoming 'laser alley'
23.10.08
"A police investigation has been launched after pilots landing two planes in Edinburgh Airport were dazzled by a green laser. Both planes landed safely. These latest incidents follows a similar incident last month.
The captain of a cargo plane from Aberdeen was targeted by the beam while he was landing, which caused the plane to drop 400ft on Tuesday. Half an hour later the laser was aimed at an easyjet Airbus landing at 22:00 from Stansted. It is the sixth incident in recent months.
A Police spokesman said: ‘Police are investigating an incident that happened at about 22:00 on Tuesday night, where a laser light was shone at two aircraft as they approached Edinburgh Airport. The light, which was thought to have emanated from the Leith area of Edinburgh, dazzled the pilot of one of the aircraft, which was a cargo plane"
23.10.08
"A police investigation has been launched after pilots landing two planes in Edinburgh Airport were dazzled by a green laser. Both planes landed safely. These latest incidents follows a similar incident last month.
The captain of a cargo plane from Aberdeen was targeted by the beam while he was landing, which caused the plane to drop 400ft on Tuesday. Half an hour later the laser was aimed at an easyjet Airbus landing at 22:00 from Stansted. It is the sixth incident in recent months.
A Police spokesman said: ‘Police are investigating an incident that happened at about 22:00 on Tuesday night, where a laser light was shone at two aircraft as they approached Edinburgh Airport. The light, which was thought to have emanated from the Leith area of Edinburgh, dazzled the pilot of one of the aircraft, which was a cargo plane"
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Sadly, it appears that the authorities in UK are still not taking these attacks seriously.
BBC NEWS | England | Suffolk | Pilot dazzler avoids being jailed
Pilot dazzler avoids being jailed
A man who shone a laser pen at a police helicopter, dazzling the pilot, has received a suspended sentence.
Glen Porter, 20, of St Augustine's Road, Ipswich, admitted using the laser pen from an Ipswich nightclub car park.
The town's crown court heard how the pilot, who was searching for a missing child, had to take a sharp turn because of a "green and blinding light".
Porter, who had admitted endangering an aircraft, received a 20-week jail term, suspended for 18 months.
Cannabis warning
The court heard Porter, who pleaded guilty at an earlier hearing, had smoked cannabis shortly before the offence on 27 April and had been in hospital four times for a mental health problem brought on by use of the drug.
Judge John Devaux said: "It's quite plain what the consequences of this could have been, both to the occupant or occupants of the helicopter and to those on the ground."
He said Porter, who bought the pen on internet auction site eBay, had avoided being jailed immediately because the court did not want to "interfere" with his rehabilitation.
But the judge warned him the sentence would be enforced if he was caught in possession of a laser pen or cannabis within the next 18 months. Ebay has since stopped selling certain types of laser pen.
Story from BBC NEWS:
BBC NEWS | England | Suffolk | Pilot dazzler avoids being jailed
Published: 2008/10/27 12:35:30 GMT
© BBC MMVIII
BBC NEWS | England | Suffolk | Pilot dazzler avoids being jailed
Pilot dazzler avoids being jailed
A man who shone a laser pen at a police helicopter, dazzling the pilot, has received a suspended sentence.
Glen Porter, 20, of St Augustine's Road, Ipswich, admitted using the laser pen from an Ipswich nightclub car park.
The town's crown court heard how the pilot, who was searching for a missing child, had to take a sharp turn because of a "green and blinding light".
Porter, who had admitted endangering an aircraft, received a 20-week jail term, suspended for 18 months.
Cannabis warning
The court heard Porter, who pleaded guilty at an earlier hearing, had smoked cannabis shortly before the offence on 27 April and had been in hospital four times for a mental health problem brought on by use of the drug.
Judge John Devaux said: "It's quite plain what the consequences of this could have been, both to the occupant or occupants of the helicopter and to those on the ground."
He said Porter, who bought the pen on internet auction site eBay, had avoided being jailed immediately because the court did not want to "interfere" with his rehabilitation.
But the judge warned him the sentence would be enforced if he was caught in possession of a laser pen or cannabis within the next 18 months. Ebay has since stopped selling certain types of laser pen.
Story from BBC NEWS:
BBC NEWS | England | Suffolk | Pilot dazzler avoids being jailed
Published: 2008/10/27 12:35:30 GMT
© BBC MMVIII
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Cures for the l@zer epidemic
It sounds like arrivals over British urban areas are seeing this more and more often. Even if it is simply a larger reporting fraction, the consequences for safety are very significant. I am sure the constabulary are up to their ears, but I can think of several routes for them to get a result in finding the perpetrators. The kind of idiot that would do this must be up to all manner of other stuff that makes their neighbours' lives miserable, and getting them off the streets must be a good thing.
Location of a l@zer at night is difficult without images. Unless you see the beam and can collar the user on the spot.
1) Photos from the attacked aircraft would be useful, but I don't think it's realistic to expect a crew to grab a picture of the l@zer when they have plenty of normal work to do. Also, looking straight down the beam would not give as much position information as seeing it from the side. Nevertheless, a simple wide-angle infinite-focus camera with a multi-frame shooting mode (phone?) in the cockpit could probably give the police a good idea where to look.
2) CCTV cameras are aimed all over high streets. Maybe PC Big Brother could spare a few wide angle cameras to point up and around approach paths, to record the light show from different positions. If a l@ser's bright enough to dazzle, then it should be seen off-axis in scattered light. Comparing the images from a few cameras should get a 10-100-m accurate launch position.
Dedicated wide-angle video monitoring of the approach path to city airports from a few cameras spread out along 4-5 miles could give this kind of information too.
3) Or arm PCs with cameras and ask them to take pictures of beams they see, and note position and time. Even appeals to the public to snap beams with their phones, and record where and when, might help.
Like (2) this would give forensic evidence, not real time detection, but in some cases the police officer could get lucky and see or find the laser start point.
Of course, in all these cases, someone's got to do the geometry to extract the evidence.
4) As the Teeside case shows, a police helicopter, with excellent cameras is probably the best way to home in on the perpetrator. Given the potential danger of dazzling l@sers, along with a shared interest in flight safety, police helicopter crews would hopefully be willing to break off whatever they're doing to help, and be the fastest and most skilled way to gather prompt evidence and get convictions.
I presume operators groups and BALPA are lobbying to have this issue taken seriously nationwide, and to put a priority on police resources to respond to l@zer reports before the perpetrators get bored with the game.
In the cockpit: I'm not a doctor, but I'm pretty confident there would be no lasting damage. Consciously look away and you should be OK, and bear in mind the subconscious natural tendency to track your eyes to a bright light.
Location of a l@zer at night is difficult without images. Unless you see the beam and can collar the user on the spot.
1) Photos from the attacked aircraft would be useful, but I don't think it's realistic to expect a crew to grab a picture of the l@zer when they have plenty of normal work to do. Also, looking straight down the beam would not give as much position information as seeing it from the side. Nevertheless, a simple wide-angle infinite-focus camera with a multi-frame shooting mode (phone?) in the cockpit could probably give the police a good idea where to look.
2) CCTV cameras are aimed all over high streets. Maybe PC Big Brother could spare a few wide angle cameras to point up and around approach paths, to record the light show from different positions. If a l@ser's bright enough to dazzle, then it should be seen off-axis in scattered light. Comparing the images from a few cameras should get a 10-100-m accurate launch position.
Dedicated wide-angle video monitoring of the approach path to city airports from a few cameras spread out along 4-5 miles could give this kind of information too.
3) Or arm PCs with cameras and ask them to take pictures of beams they see, and note position and time. Even appeals to the public to snap beams with their phones, and record where and when, might help.
Like (2) this would give forensic evidence, not real time detection, but in some cases the police officer could get lucky and see or find the laser start point.
Of course, in all these cases, someone's got to do the geometry to extract the evidence.
4) As the Teeside case shows, a police helicopter, with excellent cameras is probably the best way to home in on the perpetrator. Given the potential danger of dazzling l@sers, along with a shared interest in flight safety, police helicopter crews would hopefully be willing to break off whatever they're doing to help, and be the fastest and most skilled way to gather prompt evidence and get convictions.
I presume operators groups and BALPA are lobbying to have this issue taken seriously nationwide, and to put a priority on police resources to respond to l@zer reports before the perpetrators get bored with the game.
In the cockpit: I'm not a doctor, but I'm pretty confident there would be no lasting damage. Consciously look away and you should be OK, and bear in mind the subconscious natural tendency to track your eyes to a bright light.
Last edited by awblain; 28th Oct 2008 at 03:51.
Eight Gun Fighter
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A man who shone a laser pen at a police helicopter, dazzling the pilot, has received a suspended sentence.
"Glen Porter, 20, of St Augustine's Road, Ipswich, admitted using the laser pen from an Ipswich nightclub car park.
The town's crown court heard how the pilot, who was searching for a missing child, had to take a sharp turn because of a "green and blinding light".
Porter, who had admitted endangering an aircraft, received a 20-week jail term, suspended for 18 months.
Cannabis warning
The court heard Porter, who pleaded guilty at an earlier hearing, had smoked cannabis shortly before the offence on 27 April and had been in hospital four times for a mental health problem brought on by use of the drug."
bbc
I would hazard the mental health problems were present before use of the cannabis. Sentence not long or servere enough.
"Glen Porter, 20, of St Augustine's Road, Ipswich, admitted using the laser pen from an Ipswich nightclub car park.
The town's crown court heard how the pilot, who was searching for a missing child, had to take a sharp turn because of a "green and blinding light".
Porter, who had admitted endangering an aircraft, received a 20-week jail term, suspended for 18 months.
Cannabis warning
The court heard Porter, who pleaded guilty at an earlier hearing, had smoked cannabis shortly before the offence on 27 April and had been in hospital four times for a mental health problem brought on by use of the drug."
bbc
I would hazard the mental health problems were present before use of the cannabis. Sentence not long or servere enough.
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hear, hear . . . . . . ! !
I would hazard the mental health problems were present before use of the cannabis. Sentence not long or severe enough.
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as a green l@zer "user"
I use a green 5mW laser to educate my kids about astronomy - I make damned sure there are no airplanes in the field of vision at the time.
My kids (twins aged 5) love to see the e.g. "there is Orion" (pointing with laser pointer).
Should I be banned from doing this?
I'm sure this post will be followed by a load of "how did you know there were no airplanes in the area" posts, but I'm open to suggestions. I do try hard to make sure I'm not shining a light into the sky when there may be a pilot up there. We're well off any flightpaths here in the sticks. I'd appreciate your thoughts.
My kids (twins aged 5) love to see the e.g. "there is Orion" (pointing with laser pointer).
Should I be banned from doing this?
I'm sure this post will be followed by a load of "how did you know there were no airplanes in the area" posts, but I'm open to suggestions. I do try hard to make sure I'm not shining a light into the sky when there may be a pilot up there. We're well off any flightpaths here in the sticks. I'd appreciate your thoughts.
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Legitimate use of l@zers in the sky
adamnaylor #120,
You're far from alone in using 5mW class pointers - #41 does, and my #63 also describes uses of potentially dangerous 10-100W yellow lasers by professional astronomers to measure and correct their images for atmospheric turbulence (certified and regulated by the FAA in the US).
If you can see an aircraft's strobes, then the crew could see your laser. I think we should leave it to you to use your judgement and turn the laser off or away if and when you see an aircraft. Pointers are used to point for a crowd. That means witnesses, and so while you should keep a lookout for aircraft, you're not going to be in trouble for legitimate use.
Human spotters with dead-man's handle kill switches are the safety system for telescopes' 10-100W sounding lasers: if strobes are seen within 25 degrees of the beam, then the light is shuttered immediately: see http://www2.keck.hawaii.edu/optics/l...cs/kaon361.pdf for one set of protocols.
Added thread link, Oct 30th: best discussion of the appearance and risks I've seen so far in
http://www.pprune.org/rotorheads/320314-l-ser-searchlight-attacks-aircraft-incl-prison-sentences-offenders.html#post3704281.
Credit to the site for tying it in at the bottom of this thread.
I assume the blinding effect of scattering from scratches on the windows is less of an issue for airliners with glass cockpit windows than for the police helicopters described on the linked thread.
You're far from alone in using 5mW class pointers - #41 does, and my #63 also describes uses of potentially dangerous 10-100W yellow lasers by professional astronomers to measure and correct their images for atmospheric turbulence (certified and regulated by the FAA in the US).
If you can see an aircraft's strobes, then the crew could see your laser. I think we should leave it to you to use your judgement and turn the laser off or away if and when you see an aircraft. Pointers are used to point for a crowd. That means witnesses, and so while you should keep a lookout for aircraft, you're not going to be in trouble for legitimate use.
Human spotters with dead-man's handle kill switches are the safety system for telescopes' 10-100W sounding lasers: if strobes are seen within 25 degrees of the beam, then the light is shuttered immediately: see http://www2.keck.hawaii.edu/optics/l...cs/kaon361.pdf for one set of protocols.
Added thread link, Oct 30th: best discussion of the appearance and risks I've seen so far in
http://www.pprune.org/rotorheads/320314-l-ser-searchlight-attacks-aircraft-incl-prison-sentences-offenders.html#post3704281.
Credit to the site for tying it in at the bottom of this thread.
I assume the blinding effect of scattering from scratches on the windows is less of an issue for airliners with glass cockpit windows than for the police helicopters described on the linked thread.
Last edited by awblain; 31st Oct 2008 at 04:05.
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Seem to remember posting two to three years ago on this subject,unfortunately being shot down in flames by someone with a little knowledge of lasers.
Like TheotherSimon as my avatar suggests I work on lasers. 30 years experience of which 18 years purely on medical lasers. At the moment on lasers for the treatment of diabetics. So in contact with most of the top guys in the field.
Pan retinal photocoagulation uses on standard lasers a power of around 120 -220mW at an exposure of 0.10S(edited wrong exposure time,not 0.01S,sorry) to achieve a blanching effect(dependent on pigmentation) inside the eye for diabetic retinopathy.This is a focussed beam at about 300-400 microns.
As TheotherSimon says and his maths is not wrong beam divergence at that distance comes into play,plus the 'blink reflex' of the eye is also a factor.
Not in any way condoning these idiots as it must be a distraction. Studies done at Dundee university after the spate of attacks on bus drivers concluded no permanent damge was done to the eye, and the distance between laser,drivers mirror and driver is a lot less than most of the 'air attacks'.
Like TheotherSimon as my avatar suggests I work on lasers. 30 years experience of which 18 years purely on medical lasers. At the moment on lasers for the treatment of diabetics. So in contact with most of the top guys in the field.
Pan retinal photocoagulation uses on standard lasers a power of around 120 -220mW at an exposure of 0.10S(edited wrong exposure time,not 0.01S,sorry) to achieve a blanching effect(dependent on pigmentation) inside the eye for diabetic retinopathy.This is a focussed beam at about 300-400 microns.
As TheotherSimon says and his maths is not wrong beam divergence at that distance comes into play,plus the 'blink reflex' of the eye is also a factor.
Not in any way condoning these idiots as it must be a distraction. Studies done at Dundee university after the spate of attacks on bus drivers concluded no permanent damge was done to the eye, and the distance between laser,drivers mirror and driver is a lot less than most of the 'air attacks'.
Last edited by lasernigel; 28th Oct 2008 at 10:27.
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any more views . . . . . . . ?
Still no more responses to the question / answer posed in posts # 109 and # 110 . . . . . . . .
lasernigel seems to be concurring that serious or permanent damage is very unlikely. Do others agree that report to ATC, but continue flight once airborne is prudent ?
If a 737 pilot experiences a laser incident on take-off what is the most prudent action to take?