Denver airport security missed trespasser who was killed by plane on runway

Frontier Airlines jetliner number n646fr sits outside the airlines technical operations center with other jetliners in for service north of Denver International Airport Saturday, May 9, 2026, in Denver. (AP Photo/David Zalubowski)

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FORT COLLINS, Colo. — Workers at Denver airport missed a security breach by a man who scaled a perimeter fence and crossed a runway where he was hit and killed in a fiery collision by a plane with 231 people on board, authorities said Tuesday.

The runway fatality underscores the longstanding challenge of keeping intruders out of major airports. Denver International Airport sprawls across 53 square miles (138 square kilometres) — twice the size of Manhattan — on open prairie northeast of the city center.

The 41-year-old trespasser triggered an alarm as he crossed into the airport in a remote area about 2 miles (3.2 kilometres) from the terminal late Friday night. But security personnel mistakenly attributed that alarm to a herd of deer that was nearby and the airport did not find out about the intruder until after the fact, when the pilot notified the control tower that the plane had hit somebody.

Authorities said the man died by suicide. However, no note from the victim was immediately recovered. The manner of death was determined based on the investigation at the scene, a records review and a postmortem examination, said Sterling McLaren, chief medical examiner for the city and county of Denver.

The collision involving the Frontier Airlines plane as it was taking off for Los Angeles sparked an engine fire that forced passengers to evacuate via slides. Twelve people sustained minor injuries and five were taken to hospitals. Four have since been released, said airport Chief Executive Officer Phillip Washington.

A black-and-white video released by the airport shows, from a distance, a figure walking toward the runway with arms swaying. The person crosses onto the runway at a slight angle and seconds later the plane is seen speeding past. It strikes the person with its right engine, which bursts into flame.

Federal officials notified the airport

A few minutes before the man scaled the 8-foot (2.4-meter) fence, a ground-based radar system activated in the area, triggering an alarm. A worker at the city-owned airport checked a surveillance camera and saw a herd of deer in the same area but did not initially see the trespasser, Washington said.

“The camera view was alternating between the wildlife and the individual. There are some ditches in the area, so the person was out of view for a bit as well,” Washington said.

The man crossed about 650 feet (200 meters) from the fence to the runway and was inside the perimeter for only two minutes before being struck by the Frontier Airlines plane that was traveling at 150 mph (240 kph), he said.

Emergency personnel were dispatched to the scene after air traffic controllers were notified by the pilot about the collision, airport representatives said in response to questions from The Associated Press.

The airport declined to provide details on their procedures for dealing with trespassers or how often they enter its grounds.

The plane’s engine caused the man’s death, McLaren said. She described it as “a purposeful act with a foreseeable fatal outcome.”

Denver police Chief Ron Thomas said investigators were contacting the man’s family and those who knew him to seek more information about his motivations.

Trespassers breaching airport perimeters is a regular problem, with perhaps dozens annually nationwide, said security expert Jeff Price, who was assistant director of security at the Denver airport in the 1990s. The airport is surrounded by about 36 miles (58 kilometers) of perimeter fence, which airport officials say is continuously inspected.

The vast majority of airport trespassers are intoxicated or simply “messing around just to see if they could do it,” said Price, adding that they typically don’t pose a real threat. Denver also gets the rare individual who will jump the fence seeking to prove a long-running conspiracy theory about there being a UFO base at the airport, he said.

The Transportation Security Administration oversees airport security programs, including perimeter security requirements.

“It’s really not that difficult to jump an airport perimeter fence,” Price said. “They meet the standards for TSA, but the standards are not that robust.”

The fences are typically 6 to 8 feet (1.8 to 2.4 meters) tall with barbed wire at the top, he said. They must be approved by federal inspectors, but there are no set rules on their construction. Major airports such as Denver typically also have intrusion detection systems that include cameras and motion sensors, he said. Some systems detect the seismic impact of people dropping to the ground, Price said.

Evacuation under scrutiny

The person was killed on the airport’s easternmost north-south runway and at least 1.25 miles (2 kilometers) from any airport buildings. Empty fields and croplands surround Denver International Airport in most directions. Distant trees and structures in the video showed that the person was headed toward the airport when they crossed the runway.

The National Transportation Safety Board on Sunday said it is gathering information about the plane’s evacuation.

An agency spokesperson said an investigation would be launched if it’s determined the injuries meet the agency’s definition for “serious.” That can include a person requiring hospitalization for more than 48 hours, suffering a broken bone, or second- or third-degree burns affecting more than 5% of their body.

Mead Gruver and Matthew Brown, The Associated Press

Brown reported from Billings, Montana.

If you or someone you know is in crisis, here are some resources that are available:

Canada Suicide Crisis Helpline (Call or text 988)

Crisis Services Canada (1-833-456-4566 or text 45645)

Kids Help Phone [phone])

If you need immediate assistance call 911 or go to the nearest hospital.