When the pilots of Frontier Flight 4345 aborted Friday night’s flight after a person walked onto the runway and into the plane’s path, the flight had not yet reached the point of no return speed, known as V1 Speed.
The flight from Denver to Los Angeles was aborted mid-takeoff after someone walked onto a Denver International Airport runway and into the plane’s path, causing an engine fire.
Based on publicly available data, the flight was traveling at 127 knots, which is about 146 miles an hour. According to Austin Hoelting, a flight instructor at AviaSim, that flight’s maximum abort speed was 140 knots or about 161 miles per hour. That speed is called V1 is determined based on many factors including the runway distance, weather and weight of the plane.
“If anything happens before then, we’re just going to bring the throttle back to zero and have the plane stop itself,” Hoelting said during a flight simulation.
Hoelting walked 9NEWS through simulated scenarios of stopping the plane at 127 knots and taking off with an engine failure after 140 knots.
“The speed at which the plane’s going to be traveling too quick to have enough runway to stop,” Hoelting said of what happens once that limit is crossed. “Once you get past that speed, you’re committed to doing the takeoff just because it’s more safe to get into the air with any issues you have than it is to stay on the ground, and more likely to start going off the end of the runway.”
He said pilots practice engine failure emergencies multiple times a year.
“Engine failure right before takeoff, and engine failure right after takeoff is one of the most practiced,” he said.
After takeoff was aborted, the 224 passengers and seven crew members eventually evacuated because of smoke in the cabin.
The airport reported 12 passengers had minor injuries, with five taken to the hospital. It was not clear if the injuries were from the aborted takeoff or from evacuating the plane.
“Probably one of the hardest decisions is commanding evac because, you know, someone is most likely to get hurt whenever you call for the plane to be evacuated, just because people are trampling on each other rushing out, all in a panic,” Hoelting said. “Pretty much a lot of common sense goes out the window in that situation.”
The National Transportation Safety Board said in a statement on Monday that Denver Police would be investigating the collision with the person on the runway. The NTSB was still determining if it would need to investigate the emergency evacuation.