Seattle-Tacoma International Airport’s number of perimeter intruders was among the lowest of major U.S. airports during the past decade, according to an Associated Press study.
Just five intruders made it past the external perimeter gates and tall security fences at the airport in the past 10 years, said Perry Cooper, Sea-Tac spokesman.
Those five intrusions rank Sea-Tac 20th of 29 major airports in the number of unauthorized perimeter penetrations according to an Associated Press study. Two major airports were not ranked because they did not have data for the full 10 years.
In most perimeter penetrations, said Cooper, the intruders were either drunk or disoriented.
“We had no intrusions where the intruder was armed or where the intruder intended to commit a terrorist act,” he said.
The latest intrusion occurred last year when a 22-year-old woman crashed her car through a gate near the airport’s D Concourse. The woman was inebriated, said the airport.
“She never got onto the taxiways or runways or near any aircraft,” said Cooper. “The cops were all over her.”
One reason the airport has had relatively few intrusions, speculated Cooper, is that the 1,500-acre property is surrounded by a 12-foot-high fence. That fence is 4 feet higher than federal security officials require.
That perimeter fence is designed not only to prevent human incursions but also penetrations by the coyotes that live in the nearby woodland.
The fence’s mesh is buried several feet deep slanting away from the airport boundary.
Studies have shown, said Cooper, that if the fencing were extended straight down from the surface of the ground, coyotes would dig under it. If the fencing is buried slanting away from the fence line, coyotes will encounter the mesh repeatedly as they attempt to burrow under it.
In the few cases in which coyotes crossed the airport boundaries, airport officials found the animals had crossed in areas where the fencing contractor had left small gaps in the buried fencing materials or had failed to link adjoining fencing sections underground.
Nationally, The Associated Press found at least 268 perimeter security breaches at 31 major U.S. airports between January 2004 and January 2015. Incidents ranged from fence jumpers taking shortcuts and intoxicated drivers crashing through barriers to mentally ill intruders looking to hop flights. None were terrorism-related.
The incidents at Sea-Tac, according to incident reports obtained under records act requests, were:
The Associated Press contributed to this report.