The news media are reporting that a Delta Airlines first officer yesterday suffered minor retinal injury after a ground-based laser illuminated the plane’s cabin. No other details at this time, other than the plane landed without incident and the first officer won’t fly for a week or so.
Not that it would be realistic, but would wearing the standard-issue laser goggles provided to researchers in laser laboratories have protected him, or are they effective only in cases of indirect exposure–that is, when looking indirectly at the beam? Obviously, they have some type of limit.
It seems evident that the laser in use wasn’t one of those convenience store .1 milliwatt-type lasers (whatever). Just how powerful would this laser have to be to be visually sighted inside an airliner at, say, 30,000 feet–and who would have access to one? What about the issue of beam diffusion? I thought the lasers used at concerts would be difficult to procure, given the possibility of abuse.
Commercial laser safety goggles typically have optical densities of 3 or 4. It lets in, in other words, 0.01% to 0.1% of the incident light. Whether or not that’s safe for a direct hit depends on the intensity of the laser. I wouldn’t want to look into a 20 Watt argon laser with it, but you can laugh at a milliwatt HeNe laser.
But airline pilots typically wouldn’t want to wear such goggles – why would they? And no one fixed wavelength goggle can protect against all possible lasers.
I wouldn’t worry about even a 20 watt laser at 20,000 feet. Beyond a certain distance even a laser beam begins to spread out approximately as the inverse square of the distance.
You’d think so, but no. You can routinely find multiwatt lasers for sale on eBay and other similar places, though the prices are generally too high for the casual prankster.
I can’t speak to most of your post, but the lasers used in concerts are not difficult to procure at all. They are very expensive, however - maybe a terrorist with a big bankroll could afford one, but Joe Sixpack certainly couldn’t.
For example: (just a random Google search)
I would think it’d be really, really hard to aim a laser beam through the window of a plane flying 550mph at 30,000 feet much less get it in a pilot’s eye. Not to mention keeping the laser on target (pilot’s eye) for more than an instant. Seems like a one-in-a-million chance to me even if someone was trying so I doubt pilots need to start wearing protective goggles. Heck…you’d think the ibiquitous aviator sunglasses pilots wear would be sufficient protection from most things less than a concerted attack on the plane.
The lasers best suited for an intentional attack on a pilot aren’t the concert/dance club type. Weapons lasers are generally going to be in invisible parts of the spectrum for three reasons:
Powerful Infrared lasers are even more plentiful and CHEAP than entertainment type devices. These are the type used for metal working and industrial cutting. That 20W argon might struggle to light a candle while a big, similar-costing CO2 cutter with kilowatts at the aperture could, literally, cut up the airliner’s hull skin.
Infrared lasers are invisible and would be easier to keep on a fast moving and blinking target like an eye. One’s best natural eye defence is the ‘blink reflex’. If something, like a 5W emerald green YAG laser comes close to the eye, its owner detects the discomfort and threat and blinks, rendering the weapon ineffective. The only symptoom of a 5W IR laser would be a crashing jet…ok, maybe just an injured pilot. Point is that the first indication of a problem is serious damage.
Finally, the attacker’s location is given up as soon as the laser is turned on and aimed towards the sky. Neighbors, the copilot and pilots in other planes are likely to see the beam and can easily trace it back to its source.
The only reason to keep the attack laser visible is for some psychological motivation.
There’s a fourth reason. Lasers operating in the IR have better haze penetrating power than visible-light lasers. Dust, clouds and fog all strongly attenuate visible light but IR, especially the longer wavelengths, passes through quite well.