Can laser pointers really blind pilots?

Since 1997, the Federal Aviation Administration in the US has documented more than 200 laser incidents involving aircraft in 16 states, according to an agency bulletin. And since the introduction of cheap, hand-held laser pointers in the mid-1990s, scores of incidents have been reported in the United States and United Kingdom in which police officers, firefighters, bus drivers, teachers and even soccer players have been ‘lasered’.

The hand-held laser pointers, powered by batteries, project a green beam that can be 50 times brighter than the more common red-beam pointers and can travel 8,000 to 10,000 feet into the sky. One company boasts it can increase the power of its green pointer so the beam of light can travel 25,000 feet into the sky.

Laser pointers shone directly into an eye at short distances can cause retinal damage if focused long enough. Experts say such damage is always averted because of the natural human reaction to blink and look away.

According to David Lytle, executive director of the International Laser Display Association, there's a big myth out there that lasers are powerful enough to do damage to pilot’s eyes. He further said that even the most powerful of their lasers, which are far, far more powerful than laser pointers, are not enough to do damage in flight because the distances are so great. He also said that they have done the math, and the FAA has also done the math. He further said that if green laser pointers are being directed at planes, pilots might see a ‘little twinkle of light’ or a wash of green light over the cockpit. But he said the light would not be nearly as strong as a camera flashbulb which can be seen at long distances away.

This is what makes me wonder just how authentic some claims of injuries from laser beams are.

Lt. Cmdr. Daly was a liaison officer with the Canadian Maritime Pacific Command in 1997. On April 4, 1997, Daly, then a lieutenant, and Canadian Coast Guard Capt. Pat Barnes were in a helicopter on a routine intelligence-gathering mission. Barnes was the pilot, Daly the observer as they photographed the Russian merchant ship Kapitan Man in the Strait of Juan de Fuca that separates Vancouver Island from the United States.

The freighter was suspected of gathering intelligence on U.S. nuclear submarines transiting through the strait to and from the Trident submarine base in Bangor, 20 miles west of Seattle. On that day, it was believed to be shadowing the USS Ohio.

Daly and Barnes recall seeing a bright flash of light from the ship and felt pain in their eyes.

A Pentagon spokesman later said that Daly received minor eye injuries as a result of being struck by a low-level laser beam, as did Barnes, but he added that there was no evidence to indicate the source of the laser. I should add that they were unsuccessful in claiming compensation from the government for their so-called injuries.

Lenny Tavarez, 19, was arrested in Hunting Park on October 1st, at night after he shined a Philadelphia police helicopter pilot in the eye with a laser. Police officials said Air Tac 2 was flying near Palmetto Street and Hunting Park Avenue at about 10:30 p.m. when Tavarez used a silver, pen-like green laser to briefly blind the pilot.

Incidents of pilots being blinded by lasers while attempting to land in the GTA are on the rise. Back in March, Transport Canada had got five complaints since 2005 from pilots attempting to land at Toronto area airports about someone shining a laser at their plane and trying to target their eyes from the ground. Since then, 15 pilots have filed local complaints about laser pointers aimed at incoming or outgoing aircraft. The most recent reports were from Oct. 10 and 13, 2008 by pilots flying into Toronto Island and Pearson International airports respectively. In total, Transport Canada has received 73 reports of lasers aimed into cockpits across the country, including 46 so far in 2008.

The aviation industry is labeling these incidents "security concerns," a category reserved for bomb threats, sabotage and hijackings in Transport Canada's civilian aviation reporting system.The types of high-powered lasers able to reach a cockpit from several kilometres away can be found in most boardrooms. Earlier in October, a WestJet first officer was hit in the eyes during takeoff from Calgary when someone shone a green light into the cockpit of the 130-seat aircraft. Upon landing in Kelowna, he was taken to hospital and released without injury.

The FBI and Department of Homeland Security are warning law-enforcement agencies to look out for laser-wielding terrorists. Lasers, a recent memo states, could be used to blind commercial airline pilots just prior to landing. Anyone who's ever used a laser pointer might be a bit skeptical of the alert, however, given how difficult it is to fix the beam on a stationary spot a few dozen meters away—to say nothing of a passenger jet zooming toward an airport runway.

How feasible is this laser attack? Quite feasible, assuming the terrorists can get their hands on some military-grade hardware designed for exactly this purpose. The Chinese-made ZM-87 is perhaps the best known of these blinding weapons, also known as laser dazzlers. It was designed to foil night-vision equipment and burn the retinas of enemy troops and has an effective range of up to 10 kilometers. The device is usually mounted on tanks, though there are reports that it's been added to the decks of naval vessels, too. China North Industries Corporation, better known as Norinco, has been manufacturing and selling the ZM-87 since roughly 1995.

The Chinese are not the only military power curious about the offensive capabilities of lasers. The Russians are reputed to have developed a similar dazzler, which may have been involved in a 1997 incident in which the previously mentioned U.S. Naval intelligence officer claims his eyesight was permanently damaged during a helicopter mission in the Straits of Juan de Fuca. The United States has also tinkered with dazzlers of its own, though its focus is apparently more on short-range disruptors that can be attached to rifles.

Laser experts say even souped-up laser pointers put out power in the milliwatt range and don't pose much danger to flight crews because of the distances between ground and planes, and because of the difficulty of focusing a beam directly into the cockpit of a fast-moving plane.

Do any of my readers know anyone who can maintain aim for several seconds on something the size of your pupil at a range of greater than a thousand feet (at least) with the target moving at 150-200 mph and at an angle to boot? Most people can't keep them aimed at a word on a power-point laser at a range of ten feet more than a second.

The single conviction in Calgary aside, a more reasonable explanation is that pilots are catching sight of bright green reflections and reporting them as lasers, since they now expect to have lasers shone on them.

For a laser to cause blindness, it has to damage the macular region of the retina, and for it to damage the macular, it has to enter the eye directly along the visual axis at an angle of incidence that is perpendicular to the corneal plane - i.e. it has to be shone from the exact position that corresponds to where the pilot is looking. Assuming that the pilot is looking at the runway, someone with a laser has to be standing there for the laser to cause blindness.

Can you really imagine in your wildest dreams that someone with a laser pointer is actually able to stand at the edge of a runway without being apprehended by security personnel?

These laser stories have been reported before at many airports and not one instance has resulted in actual blindness. Seems to me the greater risk to the aircraft is the pilot's temporary distraction.

Pilots should be cautioned not to look directly at a laser if one is actually directed into the cockpit. As long as the laser beam does not enter directly into the eye along the line of sight, it will not cause functional vision loss.

Think about this for as minute. How do other pilots who can tell the authorities where the people using the laser actually are without first concentrating on the light source? And having done that, don’t you find it odd that they didn’t suffer from eye injuries? Evidence that supports this: (1) the Westjet pilot was released without injury from hospital after his laser incident in Calgary; (2) of the 73 cockpit-laser incidents reported, none of the pilots thus far have been diagnosed with laser damage to their eyes.

Even if for a split second, the beam hit their eyes, the distraction would be minimal because there are so many other distractions that their minds are focusing on when they are flying their aircraft.

Now with respect to the complaints of pilots complaining that laser beams are hitting them in their eyes when they are taking off, I find those claims incredulous. The pilot’s cockpit in a Boeing 747 is at least 19.3 metres (63.5 feet) above the ground. That is as high at least as a three story building. The average runway for such a plane is at least 3,962 metres (13,000 feet) in length. That is slightly more than three and a half miles away from the opposite end of the runway. When a 747 is fully loaded, it requires at least 10,137 feet of runway before it can lift off. Now all the time the plane is approaching the man with the laser at the end of the runway, the angle between the ground where the man is standing and the pilot in the cockpit is steadily increasing so by the moment the pilot is ready to take off, the angle is such, that the beam would only hit the ceiling of the cockpit.

Now we all know that the lift off is quite sudden so allowing for the possibility that the man would be aiming the beam at the pilot’s eyes a second or so before the plane suddenly rises, the pilot’s cockpit would be at least 900 feet further back which would mean that the man with the laser would have to aim his laser beam at the pilot’s eyes that are approximately 2,000 feet from him. Ask yourself this rhetorical question. Can anyone using a small laser pointer, even while holding it against a fence in order to steady his hand actually successfully hit a pilot’s eye at that distance? Most people using a rifle and lying down, can’t even hit a bull’s eye on a paper target at sixty feet in which the bull’s eye is the size of a silver dollar.

Now you could say that all the man would have to do is simply move the beam sideways back and forth and sooner or later, the beam would strike the pilot’s eye. To do that, he would need a gun sight; preferably a telescopic gun sight to do that and the laser pointer would have to be mounted accurately on the gun. But even that wouldn’t work because no gun sight is so strong that the man could actually see the red dot at the end of the laser beam striking the inside of the cockpit when it is 2,000 feet away.

What I have said in the previous paragraph would apply in landings other than the angle between the ground and the pilot since in landings the angle would decrease. However, by the time the pilot’s plane touched the ground, it would still be too far away for the man to accurately aim the laser beam at the pilot’s eyes.

Most of the laser incidents appear to be easily handled by air crews however; any kind of distraction during takeoff or landing is a concern. This is why anyone found pointing a laser pointer, especially one that emits a green beam, should be arrested and if convicted, dealt with severely.