Denver airport officials said workers failed to catch a runway intrusion late Friday night after a man climbed a perimeter fence and walked into an active runway, where he was fatally struck by a Frontier Airlines jet taking off for Los Angeles.
Airport CEO Phillip Washington said the man, 41, triggered an alarm as he crossed into the airport in a remote area about 2 miles (3.2 kilometers) from the terminal, but security personnel mistakenly attributed that alarm to a nearby herd of deer. He said the airport did not realize the intruder was on the grounds until after the fact, when the pilot notified the control tower that the plane had struck someone.
Washington said a ground-based radar system activated in the area shortly before the man scaled the fence, and a worker checked a surveillance camera but initially saw wildlife rather than the person. He said the camera view was “alternating between the wildlife and the individual,” and that there were also “some ditches in the area,” which kept the person out of view at times.
Investigators said the intruder crossed about 650 feet (200 meters) from the fence to the runway and was inside the perimeter for about two minutes before being hit. Emergency personnel were dispatched after air traffic controllers were notified by the pilot, airport representatives said, responding to questions from The Associated Press. The airport declined to provide details on its trespasser-handling procedures or how often such intrusions occur.
Sterling McLaren, the chief medical examiner for the City and County of Denver, said the man died by suicide. She said no note from the victim was immediately recovered and that the manner of death was determined based on the investigation at the scene, a records review and a postmortem examination. McLaren also said the collision was “a purposeful act with a foreseeable fatal outcome.”
In a description of the crash sequence, McLaren said the man’s death was caused by the plane’s engine. An airport video released in black-and-white showed a figure walking toward the runway with arms swaying, crossing onto the runway at a slight angle seconds before the aircraft sped past; officials said the plane struck the person with its right engine, which burst into flame.
Washington said the Frontier Airlines collision, which occurred as the plane was taking off, caused an engine fire that forced passengers to evacuate via slides. He said twelve people suffered minor injuries and five were taken to hospitals, with four later released.
Police Chief Ron Thomas said investigators were contacting the man’s family and people who knew him to seek more information about his motivations. The airport is also within the scope of broader aviation-safety scrutiny because perimeter breaches and runway intrusions remain a recurring challenge at major airports, even when intruders are typically not viewed as a serious threat.
Security expert Jeff Price, who led airport security in the 1990s, said it is “really not that difficult to jump an airport perimeter fence,” and he said standards can be insufficient. Price said fences at major airports are typically 6 to 8 feet (1.8 to 2.4 meters) tall with barbed wire at the top, and he said they are approved by federal inspectors but that there are no set rules on their construction. He also said Denver typically has intrusion detection systems that include cameras and motion sensors.
Price said intruders nationwide are often intoxicated or “messing around just to see if they could do it,” adding that most do not pose a real threat, while Denver sometimes sees rare cases such as people seeking to test conspiracy claims. He said the Transportation Security Administration oversees airport security programs, including perimeter-security requirements.
Beyond the airport perimeter, the National Transportation Safety Board said it was gathering information about the plane’s evacuation. An agency spokesperson said an investigation would be launched if it determined the injuries met the agency’s definition for “serious,” which it said can include hospitalization for more than 48 hours, broken bones, or burns affecting more than 5% of the body.
Denver International Airport spans about 53 square miles (138 square kilometers), twice the size of Manhattan, and lies on open prairie northeast of the city center, officials said. Authorities said the man was killed on the airport’s easternmost north-south runway and at least 1.25 miles (2 kilometers) from any airport buildings, where empty fields and croplands surround the facility in most directions.