Laser Strikes On Aircraft Increasing In Frequency (usatoday.com)

puddingebola writes: The FAA is reporting a record number of laser strikes on aircraft for 2015. From the article: "The Federal Aviation Administration recorded 5,352 laser strikes through Oct. 16, up from 2,837 for all of 2010. ... Some airports have reported more than 100 laser strikes this year: Los Angeles had 197; Phoenix had 183; Houston had 151; Las Vegas had 132, and Dallas-Fort Worth had 115. On July 15, during a 90-minute period, 11 airliners and one military aircraft reported laser strikes near New York City-area airports. Those incidents remain under investigation by the FAA, FBI and New Jersey state police."

Comments

Re:Always had a problem with laser pointers

[mpoulton]

Most laser pointers are class IIIb laser devices.

IIIa, not IIIb. The CDRH requires that handheld pointing lasers meet the IIIa classification, which means less than 5mW output power among other things. Red laser pointers virtually all comply with this. Green pointers are hit-or-miss, since the cheap DPSS laser inside has highly variable power output depending on unpredictable factors. In my experience measuring the power output of green pointers (and I've measured a lot of 'em), they are generally 3-5mW but sometimes you get a hot one that pushes 5-10mW. They can all be cranked up with tinkering though, sometimes to 100mW or more! It's the tweaked green pointers and black-market IIIb and IV devices that cause some concern. 5mW in the eyeball is extremely unpleasant, but does not cause retinal damage - especially with the poor beam quality (and thus large focal spot size) of handheld lasers. A tweaked-out DPSS pointer running tens of milliwatts can definitely cause instant permanent damage at short range though, and the 500mW to 1.5W blue diodes are quite dangerous (but totally awesome).

Here's the thing, though: None of these lasers are really dangerous at long range. The beam quality is universally terrible, which results in high divergence and therefore large beam diameter at long range. The total amount of light produced by even the most powerful handheld lasers is not very much, and quickly loses its brilliance when spread over a circle a few meters in diameter. At one mile, a 2mrad beam will be approximately 10 feet in diameter. A 1W laser would then have an intensity of 0.138W/m^2, or 0.0138mW/cm^2. That's nothing. The sun is over 100 times brighter than that.