At Charlotte’s airport, 2 security fence jumpers in 2015

Two people jumped fences that protect the runways and planes at Charlotte Douglas International Airport in 2015.

Airport officials revealed the incidents during an Associated Press investigation which documented at least 345 perimeter security breaches at 31 of the nation’s busiest airports between 2004 and mid-February. In that span, Charlotte had eight.

Despite some investments nationally to fortify the nation’s airfields, breaches remain as frequent as ever. In recent years, they’re happening about every 10 days at one of the airports AP studied.

Airport officials say outer defenses are strong and note no breach involved a known terrorist plot.

In Charlotte, a pilot saw a man walking on a taxiway in July – he had scaled a fence topped with razor wire. The other intruder jumped a fence in December.

A year after an Associated Press investigation first revealed persistent problems with airports’ outer defenses, breaches remain as frequent as ever despite some investments to fortify the nation’s airfields. As Americans focus on the wait in ever-longer security screening lines inside terminals, new documents show dozens more incidents happening outside perimeters than airports have disclosed.

At the same time, leaders at some airports and the U.S. Transportation Security Administration are saying some of the 345 incidents AP found shouldn’t count as security breaches, even when intruders got deep into secure areas.

Was it a perimeter security breach in March 2015 when a woman walked past a vehicle exit gate at San Francisco International Airport and onto the tarmac, where she tried to flag down a jet for a trip home to Guatemala? No it was not, said the airport and TSA officials, who also tried to suppress information about the case. Nor did they label it a breach when a man, following voices only he could hear, drove through a San Francisco security gate and asked a worker fueling a plane when the next flight was.

After discussing intrusions openly at first, officials at several airports and the TSA started withholding details, arguing the release could expose vulnerabilities. Following a two-year legal struggle with the TSA, AP has now used newly released information to create the most comprehensive public tally of breaches.

The count shows that an intruder broke through the security surrounding one of 31 major U.S. airports on average every 13 days from the beginning of 2004 through mid-February; since 2012, the average has been every 9.5 days. Many intruders scaled barbed wire-topped fences or walked past vehicle checkpoints. Others crashed cars into chain link and concrete barriers. AP’s tally is of breaches at airports that handle three-quarters of U.S. passengers; it’s an undercount, because several airports refused to provide complete information.

While several intruders had guns or knives, the TSA and airports have been more focused on stopping weapons that passengers or baggage handlers try to sneak onto planes.

“It doesn’t surprise me that people sometimes try to jump over fences to see what they can get away with,” TSA Administrator Peter Neffenger said in a brief interview. It’s impossible for airports and local law enforcement to keep everyone out, he said, so “the question is: What’s your ability to detect it and ... what might you do to mitigate that happening in the future?”

The AP began its investigation in 2014 after a 15-year-old climbed a fence at Mineta San Jose International Airport and scrambled into a jet’s wheel well. No one knew it happened until he emerged after the plane landed in Hawaii.

Last spring, AP reported there had been at least 268 breaches from the start of 2004 through early 2015 at San Jose and the nation’s 30 busiest passenger airports. This update identified 77 more breaches through mid-February, including 41 incidents that airports told TSA about, but not AP.

Airport officials stress that the miles of fences, gates and guardhouses protecting their properties are secure and say many intruders who get through are quickly caught. They point out that no case involved a known terrorist plot.

Perimeters are not “a gaping vulnerability,” said Christopher Bidwell, vice president of security at the advocacy group Airports Council International-North America. And the problem is not even as bad as airport and TSA records suggest, he said, because some intruders were detected immediately.

“Their ability to do anything nefarious isn’t really there,” Bidwell said. “It’s being neutralized because they are actively being surveilled.”

But video cameras and guards don’t always spot intruders.

After eluding security and reaching parked planes at New York City’s John F. Kennedy International Airport, one intruder warned an airport worker in December that he “better not say” anything. Authorities never found the man, though they did arrest three others at different times in 2015, including one man who managed to drive his vehicle in with a convoy entering the airfield during a visit by Pope Francis.

The four intrusions were the most at JFK in any year.

Aviation security consultant Jeff Price said the TSA and airports have not done enough to address gaps in perimeter security.

“The straight-up honest answer as to why it’s not being vigorously addressed? Nothing bad’s happened. Yet,” Price said.

U.S. Rep. William Keating began demanding improvements to airport perimeter security after the body of a stowaway fell into a Massachusetts neighborhood in 2010. The teenager had hopped a fence hours earlier at Charlotte Douglas International Airport. That could have been a terrorist, Keating warned at the time.

The Massachusetts Democrat reacted to AP’s findings by saying the TSA must extend its focus beyond screening passengers and help airports protect their perimeters.

“It’s like saying your door is locked but your window’s wide open,” Keating said.

Altogether, there were at least 39 breaches nationwide in 2015, which also was the annual average from 2012 through 2015. The low was 34 in 2013 and the high 42 in 2012, when incidents spiked after several years hovering around 20 breaches.

Through mid-February, the large airports with the most known incidents were in San Francisco (41), Las Vegas (30), Philadelphia (30) and Los Angeles (26). New York’s JFK ranked 10th, with 12 breaches.

Police reports suggest many of the trespassers were disoriented, intoxicated or delusional. Some came on skateboards and bikes, while others commandeered vehicles on the tarmac. One man got into a helicopter cockpit and was preparing to take off.

Some were caught immediately, others not for hours. Five intruders brought knives and one a loaded gun.

This story was originally published May 26, 2016 at 1:30 PM with the headline "At Charlotte’s airport, 2 security fence jumpers in 2015."