New thermal-imaging surveillance footage has captured the moment a person walks onto a runway at Denver International Airport before being struck and killed by a Frontier Airlines jet.
The collision occurred at 11:19 p.m. Friday night as Flight 4345, bound for Los Angeles, was accelerating for takeoff.
“We’re stopping on the runway. Uh, we just hit somebody… we have an engine fire,” the pilot told air traffic control, in a recording released by ATC.com. In subsequent communications, the pilot added: “I think we hit someone. An individual was walking across the runway.”
The impact triggered an engine fire on the Airbus A321 and sent smoke into the cabin, prompting the flight crew to abort departure and evacuate 224 passengers and seven crew members via emergency slides. Photos from the scene appeared to show blood on the plane’s engine.
Shortly before the incident, an individual climbed a fence on to the runway, according to transportation officials. The person killed has not been identified, but airport officials confirmed that it was not a member of airport staff.

Twelve passengers suffered minor injuries during the evacuation, and five were taken to local hospitals, airport officials told The Independent.
One passenger, Jacob Anthens, shared a video on social media showing travelers sliding down emergency chutes while carrying backpacks. He also posted photos of what appeared to be a damaged engine, the Associated Press reported.
“As we were lifting off the engine of the plane exploded. There was so much smoke we couldn’t even see 1 ft in front of us,” Anthens wrote on his Facebook page, adding that passengers were left waiting on the tarmac for over an hour and had “still no transport or help with the cold.”
Most passengers were rebooked on a replacement flight to LA on Saturday.
Transportation Secretary Sean Duffy described the individual as a “trespasser” who had “deliberately scaled a perimeter fence” approximately two minutes before the collision.
“No one should EVER trespass on an airport,” Duffy wrote in a statement on X.

Airport radio traffic indicates that crews became aware of a person on the runway at 11:18 p.m., just one minute before the strike.
“We have a party on Runway 17L. We’re sending fire for that,” a dispatcher was heard saying.
Aviation experts suggest that even with immediate detection, stopping a plane already in its takeoff roll is exceptionally difficult.
“Their jet was already rolling,” Randy Klatt, a retired pilot and flight safety officer with the Foundation for Aviation Safety, told FOX31 Denver. “The timing just tells me that it was something that would be very difficult to stop within that short period of time.”
Federal regulations already mandate specific standards for airport fencing and patrols, but Klatt noted that breaches of this nature can prompt reviews of existing security protocols.
“Do we need to have more robust regulations that require more intense security?” Klatt said. “Because obviously security of the airport is very important.”

Airport officials said that an inspection of the 36 miles of perimeter fencing found the structure to be intact.
The Federal Aviation Administration and the Transportation Security Administration are investigating the security breach, as is the Denver Police Department.
“We are gathering information about the emergency evacuation to determine if it meets criteria for a safety investigation,” an NTSB spokesperson, Sarah Taylor Sulick, told the Associated Press Sunday.
Frontier Airlines said in a statement that the company was “deeply saddened by this event” and was cooperating with investigators.
The incident follows a separate safety concern for the airline last month, when a Frontier jet at Los Angeles International Airport narrowly avoided a collision with two trucks that had crossed onto a taxiway. No injuries were reported in that instance.


