During the early hours of a late spring day, a crew member of a Boston MedFlight helicopter with a patient aboard reported the flash of a green laser aimed at its cockpit as it descended toward Beth Israel Deaconess Medical Center.
State Police scoured the Storrow Drive area near the Esplanade on that May 27 morning, searching for the laser’s source, but found nothing. While no one was injured, the company denounced the incident as a “terrible thing” that had put its crew and the patient at risk.
The tiny laser pointers, easily available in office supply stores, can cause big problems for pilots, who are increasingly encountering their disorienting light in Massachusetts and across the country — through mischief, malice, or accident.
Between 2008 and 2014, the number of laser incidents reported in Massachusetts climbed 175 percent, according to a Globe analysis of thousands of Federal Aviation Administration records. Nationwide, the number grew by 327 percent.
In Boston this year, pilots have reported 17 laser events, including the May incident, through June 19, said FAA spokesman Jim Peters, already surpassing last year’s total of 15.
The FAA attributed the rise in reports to the increased availability of inexpensive laser devices and greater awareness among pilots of their danger.
A laser can be as distracting as a camera flash or the high-beam headlights of an oncoming car, the FAA said on its website. While pilots are unlikely to suffer permanent eye damage, it may take them a few minutes to adjust their vision back to normal, which is particularly dangerous during a flight’s takeoff and landing.
“At 35,000 feet, you have time to react,” said Patrick Murphy, who tracks laser incidents on the website LaserPointerSafety.com. “At takeoff or landing, you may not have time to recover.”
No aircraft accidents have been attributed to lasers, but “given the sizeable number of reports and debilitating effects that can accompany such events, the potential does exist,” a FAA report said.
The FAA began formally tracking laser events in 2005. The number of annual reports climbed steeply during the next six years, then held steady. In 2012, George Johnson, a supervisory federal air marshal, said the number of attacks had almost reached an “epidemic level.”
Across the country, pilots reported 3,894 laser-related incidents last year, according to the FAA records. Through June 19 of this year, 2,524 laser events in the United States were recorded, said Peters.
Almost 70 percent of these laser events occurred at altitudes between 2,000 and 10,000 feet, according to the FAA. Most took place between 7 and 11 p.m. and involved a green laser. Green lasers are more visible than other colors, the administration found.
Laser incidents were more densely located on the West Coast, particularly in California, which had 888 reports in 2014. The highest number of reports last year came from the Los Angeles area, which had 107.
Officials warn that thousands of incidents each year still go unreported. Murphy said pilots may have tired of reporting them, particularly when they occur at times when no significant danger is posed, such as when their airplanes were at cruising altitudes.
The light from laser pointers can radiate for miles, growing in size and scope at longer distances.
Murphy said there are generally two types of people who shine lasers at aircraft: those who do so inadvertently, not realizing how far their laser extends and others he called the “criminal and antisocial element,” who flash lasers at aircraft cockpits deliberately to distract pilots.
A Medford man was sentenced to 36 months in a federal prison in 2011 for shining a powerful green laser beam into a State Police helicopter that was escorting a tanker through Boston Harbor and then lying about the incident. His conviction on the charge that he pointed the laser at the helicopter on purpose was vacated upon appeal, however.
According to federal law, anyone who knowingly aims the beam of a laser at an aircraft can be fined or face up to five years in prison. But prosecutions are rare and convictions even more so. The technology publication Ars Technica tallied 134 arrests made in the incidents nationwide from 2005 to 2013. Eighty of those arrests led to convictions.
“It’s difficult to locate the person doing it,” said State Police spokesman David Procopio, noting that there is often a lag between the time of the incident and when it is reported.
Even so, each Massachusetts report is forwarded to the Boston’s joint terrorism task force and investigated, said Procopio. The vast majority of the local incidents were considered “nuisance activities,” however, where terrorism was not the aim, he said.