Man killed by Frontier plane at Denver airport died by suicide, medical examiner says

DENVER — The pedestrian fatally struck by a Frontier Airlines plane at Denver International Airport on Friday died by suicide, according to the medical examiner.

Michael Mott, 41, died from multiple blunt and sharp force injuries caused by the plane engine, Denver Chief Medical Examiner Dr. Sterling McLaren said in a Tuesday morning news conference at the airport.

“As a scientific investigation, we can’t really know, really, what someone’s intent was,” McLaren said. “The best way to determine manner is to evaluate the totality of the investigation — scene findings, circumstances and history. Based on all of those findings together, we determined the manner of death to be suicide.”

The fatal crash happened just before 11:20 p.m. Friday, minutes after Mott jumped the Denver airport’s 8-foot security fence topped with barbed wire and walked onto a runway, airport officials said. The collision sparked an engine fire and created a 4,000-foot debris field, Denver International Airport CEO Phil Washington said during Tuesday’s news conference.

Mott’s breach of the airport’s security fence and trek onto a runway is an unusual airport disaster but it is leading the public to raise questions about security around the massive international airport, which is one of the busiest in the world.

“I cannot think of a time when this has occurred,” said Jeffrey Price, an aviation and aerospace science professor at the Metropolitan State University of Denver, who has worked in the industry for decades.

Price said he can’t remember another incident that rises to this level, calling it “extraordinarily rare.” The pedestrian strike has the potential to raise high-level questions about whether safety requirements should be updated at airports across the board, he said.

Los Angeles-bound Frontier 4345 was accelerating for takeoff when it struck and killed Mott. The crash started an engine fire, and the 231 passengers and flight crew on board evacuated the plane via slides.

Twelve people reported minor injuries from the evacuation, and paramedics took five to the hospital. As of Tuesday morning, four of the hospitalized passengers had been released.

The Federal Aviation Administration, Transportation Security Administration, Denver Police Department, Frontier Airlines and DIA are all participating in the crash investigation, airport officials said.

“Safety is paramount in everything that we do,” Washington said. “It is paramount in the aviation industry in general, and it is definitely paramount at DEN.”

A radar system on the fence detected ground movement and set off an alarm at 11:10 p.m. Friday, Washington said. When the operator on duty reviewed the alarm, they spotted a herd of deer outside the fence and did not see a trespasser, he said. The radar had detected the animals and the man.

Minutes after the alarm sounded, the airport was alerted that the pedestrian had been hit on a runway roughly 650 feet from the fence line, Washington said.

“Given the short time period, we were not able to intervene and prevent this person from reaching the runway,” he said.

A gulch between the fence line and the runway may have obscured Mott from the camera’s view, Washington said. The Denver airport’s security team will work to ensure cameras have a clear line of sight in those areas.

Washington said the airport has fielded questions in the days since the crash about why the security fence isn’t electrified, and why razor wire hasn’t replaced the barbed wire on top. The answer is simple — he doesn’t want the fence to be deadly.

Tom Foley, associate professor and program coordinator for Embry-Riddle Aeronautical University’s global security and intelligence studies department, said the preliminary reports on how Mott breached the airport fence do not indicate a security failure at the Denver airport.“It sounded like somebody managed to get past the gate and they got hit by a plane before anyone could get to them,” Foley said.

Even if the security personnel had seen Mott when the alarm sounded it still would have taken time to reach him because police officers cannot just start driving across taxiways and runways, Foley said. There is not a direct path from Point A to Point B at a large, busy airport.

“Two minutes is not a lot of time to react and stop this for an airport the size of DIA,” he said.

Trespassers have hopped the fence before, but most have been dealt with quickly and efficiently, Washington said. He did not specify how many such breaches the airport has recorded.

Federal investigators with the National Transportation Safety Board are still gathering information about the emergency evacuation to determine whether an investigation is warranted. As of Tuesday morning, they had not yet decided on the investigation, NTSB spokesperson Sarah Sulick said.

NTSB teams investigate civil aviation accidents with “substantial damage to an aircraft” or “serious injuries,” Sulick said.

Airport workers examined the perimeter fence after the incident and “found it to be intact,” Washington said.

DIA’s perimeter fence spans roughly 36 miles, an unidentified spokesperson for the airport said. It appears that most of the property is surrounded by a chain-link fence with barbed wire laced across the top and slanted toward the outside borders, according to a Denver Post reporter’s drive around the perimeter. Security officers monitor who is coming and going at traffic entry points, which are blocked by gates.

Denver’s airport has six runways, with the longest covering three miles. The pedestrian strike happened on runway 17L, one of the farthest from the terminal.

“There’s nothing out there,” Cary Grant, a retired United Airlines crew member and assistant professor at Embry-Riddle Aeronautical University, said of the remote runway. Grant flew out of Denver for 23 years.

Grant could not recall another incident where a pedestrian had wandered onto a remote runway and been killed. Typically, people who are killed on runways are airport workers who mistakenly get in the way of a plane on a busy ramp, he said.

Crashes and injuries are more common — though not routine — on taxiways and near the gate area, Price said. There are people towing planes, directing traffic and transporting luggage, a lot more moving parts, he said.

“The runways are such a protected environment at airports,” Price said. “Everyone knows you don’t go out there without proper clearance.”

FAA requirements only specify that the airport must provide “safeguards to prevent inadvertent entry to the movement area by unauthorized persons or vehicles” and “reasonable protection of persons and property from aircraft blast,” according to the Code of Federal Regulations. TSA requirements are more extensive and are airport-specific.

On average, perimeter fences are required to reach minimum heights of 6 to 8 feet with barbed wire at the top, Price said.

“It’s basically whatever TSA says it should be for that airport,” Price said. “DIA’s required height is in their Airport Security Program, which is a protected document. I do know they meet the standard, though, or else TSA wouldn’t allow it.”

Climbing the fence is not that difficult, Price said. It is designed as a deterrent and a delaying measure to stop people from accessing planes before airport officials can respond.

Grant said he once was on board a United flight that hit a coyote on a DIA runway. Security fences are designed to prevent deer and other wildlife from accessing the airport grounds just as much as people, he said.

Some airports exceed TSA’s standards, but most simply meet the minimum requirements, Price said. Installing taller fencing around airports’ miles-long perimeters is “extraordinarily expensive” compared to how infrequently incidents occur, he said.

“It simply does not happen often enough to justify the expense, at least not yet,” Price said.

As for solutions, Foley, the global security expert, said he did not have an immediate, easy fix that could prevent people from wandering onto DIA’s runways. Security personnel will need to evaluate the risk, the likelihood of it happening again, and the expense of higher fencing.

Denver airport’s team could decide to move the perimeter fence further away from the runways, giving security more time to respond. But that would depend on how much land the airport owns and what the expense would be, he said.

“It might just be a risk you have to live with,” Foley said. “I wish I had a quick and dirty answer to say, ‘Oh, you can do this and it will never happen again,’ but it’s not that simple.”

Some people on board expressed concern about the evacuation, including being stuck in the plane for several minutes as smoke filled the cabin and being left on the tarmac in the cold once they were out. Videos posted to social media also showed passengers coming down the emergency slide with what looked to be their carry-on bags and backpacks.

Pre-flight instructions from airplane crews always include a reminder to leave personal belongings behind during an evacuation, Grant said.

“What do people do? They grab their carry-on and head to the slides,” he said. “That’s where they get hurt. It slows the evacuation, and there’s an increase in the likelihood of getting injured.”

Deciding to evacuate is always a tough call, he said. Experience and research show that keeping people on an airplane often is the safest option.

“The crew has to use their best judgment,” he said.

Washington called the actions of the Frontier pilot and crew “exceptional.”

“This could have been far worse,” he said. “We are indebted to their professionalism.”