Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

Virgin Atlantic flight from London to NY returns after pilot hurt in laser incident

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

Virgin Atlantic flight from London to NY returns after pilot hurt in laser incident

Old 16th Feb 2016, 17:23
  #161 (permalink)  
 
Join Date: Mar 2005
Location: UK
Posts: 17
I'm going to risk weighing in from the perspective of a background in physics (as well as avionics). Some of the physical observations here read to a physicist how aviation articles in the common press read to pilots. I think it's important for pilots to understand the mechanics behind this topic.

The power level of "high power" diodes purchased by consumers is typically in the tens to hundreds of milliwatts. Inexpensive visible light diodes which claim to be several watts are invariably mis-sold - I come across them now and again and measure them with a thermal effect [email protected] power meter. I think it's reasonable to generalise that a [email protected] pointer bought on eBay is unlikely to be more than a few hundred milliwatts of output power. It's worth noting that most (almost all) cheap visible light [email protected] are pumped by a much more powerful IR [email protected] and if an appropriate IR filter is not installed the output power will be much higher than that of the visible component alone. IR light will pass the cornea and heat up the retina as easily as most visible light. Only as the wavelength moves into UV does the effect switch from retinal to corneal damage.

That's not to say that somebody who genuinely wishes to incapacitate a pilot might not have purchased a high quality visible [email protected] with several watts of output power. It will have cost them several hundred pounds and I suspect the attackers under discussion here do not fall into this category.

At close range the output of even a low powered diode in the visible spectrum is very dangerous to sight. An 808nm (green) 50mW [email protected] shone at close range into the eye for more than a few milliseconds will could inflict permanent injury. [email protected] pointers around 200mW are widely available and these could easily cause loss of sight.

Exposure is considerably reduced by distance. For incoherent light (such as a bulb) the power of the light reduces by the inverse square of the radius, which is not true for a perfectly coherent [email protected] source. An ideal [email protected] will have the same power at any distance because the energy does not diverge. However there are no ideal [email protected], and the diodes one might purchase on eBay are very far removed from scientific grade. As the beam diverges a smaller area will contact the retina so the exposure is therefore a function of the radius of the beam at the distance of contact multiplied by duration.

At cruise altitude, or well into the climb, or early in descent, the distance of throw is substantial so the beam radius is large and the ratio of the beam area to the retina area is small. Furthermore the duration of exposure is likely to be short because it is difficult to manually track a moving target even with quite a shallow angle of incidence. As such this exposure is very unlikely to cause any damage to the retina - much higher exposures are experienced in night clubs when scanning the crowd with a moving [email protected] (and those exposures are also calculated to be safe). I would suspect that the greater risk to flight safety in these circumstances is the surprise of the momentary flash of light, and the distraction that could result from this.

I would be far more concerned about exposure closer to the source - shortly after takeoff or on final approach. Beam radius at these shorter distances could be as little as a few centimeters even with a low quality source. There is certainly some risk to eyesight in these circumstances, whether that's permanent scarring of the retina or temporary dazzling (which can last for quite some time and is extremely disturbing). The latter effect is possibly why pilots are reporting prolonged exposure in the cockpit, even though it's unlikely that such tracking could be achieved manually. A 10ms exposure at relatively high power could easily dazzle a victim for several seconds.

In the case of the Virgin incident, I feel the co-pilot would be extremely unlucky to have suffered any permanent injury. That doesn't reduce the impact of the distraction and the distress that uncertainty of the consequences must have caused. I feel that flight crews should receive better training on these matters (beyond the occasional bulletin) which might better equip them for decision making during such events. During critical phases of flight it seems entirely appropriate to handle a [email protected] strike as sudden incapacitation.

As for banning [email protected] - there's already categorisation and control for [email protected] products. It's a matter of enforcement not legislation.
egsc_h17 is offline  
Old 16th Feb 2016, 17:40
  #162 (permalink)  
 
Join Date: Jun 2001
Location: Rockytop, Tennessee, USA
Posts: 4,675
I'm going to risk weighing in from the perspective of a background in physics (as well as avionics).
An 808nm (green) 50mW [email protected] shone at close range into the eye for more than a few milliseconds will could inflict permanent injury.
808 nm is green?

All this time I thought it was infrared...

Are you maybe thinking of the very common green 532 nm DPSS [email protected] with an 808 nm GaAlAs pumping diode?

Exposure is considerably reduced by distance. For incoherent light (such as a bulb) the power of the light reduces by the inverse square of the radius, which is not true for a perfectly coherent [email protected] source. An ideal [email protected] will have the same power at any distance because the energy does not diverge.
Aren't you confusing coherence with collimation? It's the collimation that keeps the power from dropping much with distance, not the coherence, right? In fact, don't [email protected] diodes (with a short coherence distance) often use a collimating lens?

Last edited by Airbubba; 16th Feb 2016 at 17:59.
Airbubba is online now  
Old 16th Feb 2016, 17:40
  #163 (permalink)  
 
Join Date: Jan 2016
Location: UK
Posts: 967
LlamaFarmer is offline  
Old 16th Feb 2016, 17:56
  #164 (permalink)  
 
Join Date: Mar 2005
Location: UK
Posts: 17
Ha, fingers faster than brain!

Originally Posted by Airbubba View Post
808 nm is green?

All this time I thought it was infrared...

Are you maybe thinking of the very common green 532 nm DPSS [email protected] with an 808 nm GaAlAs pumping diode?
egsc_h17 is offline  
Old 16th Feb 2016, 18:03
  #165 (permalink)  
 
Join Date: Aug 2001
Location: se england
Posts: 1,100
Knowing the area where this incident reportedly occured quite well iwas curious to try and locate the area where the [email protected] may have been shone from.

The track at the beginning of this thread shows a easterly departure from LHR 9R and assuming a standard Compton departure the captains estimate of about 8 miles from Heathrow puts the plane just south of Lego land themepark situated in the middle of the crown estate at Windsor. That would fit perfectly with estimates that the [email protected] was 1-2 miles off to one side- ie to the north of track.

So I wonder if this was either an errant [email protected] from a show or an employee testing/fooling around with one. They have a lot of [email protected] shows there and it does seem a bit of a coincidence that this occured not just close to lego land but just the right distance to the south-so maybe just an error on an operaotrs or technicians part.

Not an ideal location for [email protected] shows though being under SID tracks from both easterlyand westerly departures from LHR-presumelably they normally operate restricted power versions
pax britanica is offline  
Old 16th Feb 2016, 18:25
  #166 (permalink)  
 
Join Date: Nov 2003
Location: Amsterdam
Age: 65
Posts: 159
There are problems with [email protected] protection glasses/goggles, they are not perfect
Far from perfect, as in Boeings like the B737 and B777 with lcd or led displays you will be unable to read them.
Capt. Inop is offline  
Old 16th Feb 2016, 18:27
  #167 (permalink)  
 
Join Date: Dec 2013
Location: Aberdeen
Posts: 49
Pax Britanica

At last a rational explanation, thank you for researching that.

Would you mind sending that explanation to the BBC who are drooling at the idea of high powered [email protected] in the hands of Windsor toffs bringing down aircraft.
enola-gay is offline  
Old 16th Feb 2016, 18:48
  #168 (permalink)  
 
Join Date: Mar 2010
Location: UK
Age: 71
Posts: 601
They have a lot of [email protected] shows there
Legoland is closed until March.
Airclues is offline  
Old 16th Feb 2016, 18:56
  #169 (permalink)  
 
Join Date: Jan 2016
Location: UK
Posts: 967
Originally Posted by Airclues View Post
Legoland is closed until March.
To the public I presume?

Any chance they might be undergoing any testing/training/other there currently before reopening in March?



Not at all suggesting this is the likely source of the [email protected], merely open to considering all possibilities at this stage
LlamaFarmer is offline  
Old 16th Feb 2016, 19:30
  #170 (permalink)  
 
Join Date: Dec 2013
Location: Aberdeen
Posts: 49
Legoland opening

Sorry Airclues. the place is open:

February half term Junior Builder Week at the LEGOLAND Resort Hotel will take place from 12th — 20th February from just 140 per family!
enola-gay is offline  
Old 16th Feb 2016, 20:30
  #171 (permalink)  
 
Join Date: Aug 2001
Location: se england
Posts: 1,100
I actually did wonder if the place was open this early not realsiing it was indeed half term hence my comments about 'testing'. What does interest me is what sort of [email protected] they use because the pics on the web look pretty spectacular but as I pointed out tis just to the north of the Compton SIDs for easterlies and ty much over it at the point where the 27R SID is in a right turn to pick up the track to Compton.

All that said I am sure legoland would have had to pass some kind of check on [email protected] shows as it is so close to LHR
pax britanica is offline  
Old 17th Feb 2016, 00:51
  #172 (permalink)  
 
Join Date: Dec 1997
Location: Southwest Suffolk UK
Posts: 4,923
Some of you will know who I am. Most probably don't. However, I am the Captain in this event. I haven't been involved in PPRuNe for many years, but I used to be very involved, for which I offer apologies if appropriate!

It's been fascinating to read the speculation, and very interesting to read some of the factual postings in this thread. I don't take offence at those who question my decisions - all captains' decisions should be challenged and tested to see if they are indeed appropriate and proportionate, and this forum is as reasonable a place for that to happen as any.

For now, I won't be offering any significant justification or explanation. There's likely to be more investigations to be carried out, and I don't want to pre-empt, prejudge or influence any of those, or compromise my ability to speak freely to those who need to hear what I have to say. I'd just like to thank those who have some faith that I had some idea of what I was doing and why, and those who helped me get the job done both on the ground and in the air.

For those who have any relevant expertise, it was a red beam, not a green one. It was indeed reported as and when it happened. The pictures we got show its ground position (which wasn't Legoland as far as I can see), and will hopefully help those in the know to estimate its power and provenance.

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, but there was no way of knowing (for me) that that would continue to be the case.. The symptoms were slow in making themselves apparent. That's about all I'm prepared to say for now.

For the terminally pedantic, yes, I admit my Pan call was incorrectly phrased!

Last edited by scroggs; 17th Feb 2016 at 01:42.
scroggs is offline  
Old 17th Feb 2016, 01:03
  #173 (permalink)  
 
Join Date: Jun 2001
Location: Rockytop, Tennessee, USA
Posts: 4,675
For those who have any relevant expertise, it was a red beam, not a green one. It was indeed reported as and when it happened. The pictures we got show its ground position (which wasn't Legoland as far as I can see), and will hopefully help those in the know to estimate its power and provenance.

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, but there was no way of knowing (for me) that that would continue to be the case.. The symptoms were slow in making themselves apparent. That's about all I'm prepared to say for now.
Thanks for the update, we really appreciate it! Great news about the FO's healing prospects.

For the terminally pedantic, yes, I admit my Pan call was incorrectly phrased!
As you know, endless debates about proper R/T procedures and how to do practice PAN's are classic PPRuNe topics from the 'old' days. It's a cultural thing I would say.
Airbubba is online now  
Old 17th Feb 2016, 01:15
  #174 (permalink)  
 
Join Date: Aug 2013
Location: PA
Age: 54
Posts: 36
Good Form scroggs!

i am wondering why the ac cockpit windows cannot be coated with the same material as military ac and equipment against [email protected]
In the military, many of the weapons systems use [email protected] for rangefinding and guidance, and I know the gunsights and windows/ports on tanks are coated to reflect the [email protected] from direct and return, with no optical reduction.
They also use this coating on building windows so that a [email protected] cannot be used to listen to conversations inside.

Edit: Found this on a lab website..

A [email protected] is a light source that can be dangerous to people exposed to it. Even low power [email protected] can be hazardous to a person's eyesight. The coherence and low divergence of [email protected] light means that it can be focused by the eye into an extremely small spot on the retina, resulting in localised burning and permanent damage in seconds. Certain wavelengths of [email protected] light can cause cataracts or even boiling of the vitreous humor, the fluid in the eyeball. Infrared and ultraviolet [email protected] are particularly dangerous, since the body's "blink reflex", which can protect an eye from excessively bright light, works only if the light is visible.

egsc_h17....people pull them out of color [email protected] printers..very powerful uncontained.
underfire is offline  
Old 17th Feb 2016, 01:35
  #175 (permalink)  
 
Join Date: Jan 2006
Location: Ijatta
Posts: 435
Great job Captain!

Wishing your F/O a speedy recovery!!
wanabee777 is offline  
Old 17th Feb 2016, 01:40
  #176 (permalink)  
 
Join Date: Dec 1997
Location: Southwest Suffolk UK
Posts: 4,923
Those are - to me at least - good points, and, as I'm the star player in today's teacup tornado, hopefully I'll get a chance to ask some pertinent and hopefully difficult questions which can be tossed into the melting pot as 'the authorities' temporarily agonise over what to do about this before something else moves their attention elsewhere.

If anyone with authoritative knowledge of mitigation measures which can relatively easily be applied to aircraft would like to PM me, I'm happy to include their contributions to the conversation. Please, I don't want - indeed I will actively reject - casual speculation, 'what-ifs', or otherwise non-expert inputs. I have a temporary but hopefully powerful opportunity to have a say, and I want to make sure that what I say has some weight. I'm well aware that terminal obliteration of the scrotes may be the ideal solution, as well as introducing the sellers of these devices to a man-eating monster of my choice, but it's unlikely I'll persuade anyone to legislate for that. Indeed, it's unlikely I'll persuade the legislators to do anything, and I'll leave that argument to the unions and other interested parties. Right now, I'm interested in what we as operators can do.
scroggs is offline  
Old 17th Feb 2016, 04:04
  #177 (permalink)  
 
Join Date: Sep 2014
Location: Canada
Posts: 1,257
i am wondering why the ac cockpit windows cannot be coated with the same material as military ac and equipment against [email protected]
There have been tests:

Lamda Guard partners with Airbus to test [email protected] interference solution

Halifax N.S. (June 4, 2014) Lamda Guard, a company based in Atlantic Canada, has signed an agreement with leading aircraft manufacturer Airbus to test a breakthrough innovation designed to deflect unwanted bright light or [email protected] sources from impacting jetliner flight paths, and causing pilot disorientation or injury.

Lamda Guard’s innovative thin films utilize metamaterial technology on cockpit windscreens to selectively block and control light coming from any angle even at the highest power levels.
peekay4 is offline  
Old 17th Feb 2016, 07:14
  #178 (permalink)  
 
Join Date: Jan 2001
Location: Home
Posts: 3,400
Originally Posted by underfire View Post
Good Form scroggs!

I am wondering why the ac cockpit windows cannot be coated with the same material as military ac and equipment against [email protected]
Erm, not sure what you are talking about. No aircraft I have ever heard of had [email protected] protective coatings on the windows.
[email protected] are very effective against military aircraft which is one reason they are banned I believe. We certainly would never blind an enemy pilot of course. That would be unsportsmanlike.


Originally Posted by underfire View Post
In the military, many of the weapons systems use [email protected] for rangefinding and guidance, and I know the gunsights and windows/ports on tanks are coated to reflect the [email protected] from direct and return, with no optical reduction.
They also use this coating on building windows so that a [email protected] cannot be used to listen to conversations inside.
I'm afraid you have been reading bad fiction.
You cannot stop an optical [email protected] without affecting vision through a port.

[email protected] used to listen to conversations are bouncing off the window and the vibration of the window causes doppler shift which is detected. Coatings won't change that one iota.
Tourist is offline  
Old 17th Feb 2016, 07:16
  #179 (permalink)  
 
Join Date: Sep 2009
Location: 64N, 020E
Age: 51
Posts: 32
"Safe" [email protected] energies

Regarding the "safe" energy levels, does anyone know how what the assumptions of the pupil size are? If the "safe" estimates are based on a normal (day adaptation) pupil, wouldn't the resulting figure be an overestimate for a dilated (night adaptation) pupil?

According to wikipedia, a normal diameter of the entrance pupil is about 4mm, ranging from 2mm (bright) to 8mm (dark), so the underestimate might be with a factor between 4-16.

Just my SEK .10.
NiclasB is offline  
Old 17th Feb 2016, 07:41
  #180 (permalink)  
 
Join Date: Jul 2004
Location: Netherlands
Posts: 575
Maybe we need to retrofit all aircraft with nuclear blast shades, as installed on the B52:

B-52 Cockpit for Sale, Boeing Stratofortress and other military aviation Memorabilia

That will surely keep our eyes protected?
fox niner is online now  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.