CNN  — 

A woman who punched a flight attendant on a May Southwest Airlines flight from Sacramento to San Diego pleaded guilty to interfering with a flight attendant, according to the U.S. Department of Justice.

A flight attendant asked Vyvianna Quinonez, 28, to buckle her seatbelt, stow her tray table, and wear her mask properly, as the May 23, 2021 flight was on its final descent, according to a plea agreement reached last month.

After requesting that Quinonez comply, she returned to her own seat for landing.

Quinonez started filming the flight attendant with her cell phone, according to the agreement, and the flight attendant approached her again. Quinonez pushed the flight attendant and the incident then became more violent.

Quinonez admitted to intentionally punching the attendant in the face and head with a closed fist and grabbing her hair, according to the DOJ, a scuffle seen on another passenger’s video that went viral after the incident.

A male passenger jumped between Quinonez, according to the plea agreement, and the flight attendant, who was visibly shaken, and instructed Quinonez to sit down.

The flight attendant was left with three chipped teeth, she needed stitches on her face, and according to the plea agreement, she also “had a bruise in the shape of fingers on her right forearm.”

The flight attendant who was assaulted was simply doing her job to ensure the safety of all passengers aboard the plane,” said Acting United States Attorney Randy Grossman. “It’s inexcusable for anyone to use violence on an airplane for any reason, particularly toward a flight attendant who is there to keep all the passengers safe. We are not going to tolerate violence or interference with the flight crew, and we will pursue criminal charges against those who break the law.”

Quinonez’s lawyer declined to comment when contacted by CNN.

The day after the incident, the union representing Southwest flight attendants said passenger misconduct has reached an “intolerable level.” The in-flight incidents and other working conditions, the union said, left its ranks “weary, exhausted, frustrated and forgotten.”

This incident was one of 5,779 incidents reported to the Federal Aviation Administration so far this year regarding disruptive and sometimes violent passengers onboard aircraft. More than 4,000 of the incidents were related to mask-wearing.

Quinonez will be sentenced on March 11, 2022. She could face up to 20 years in prison and a $250,000 fine.

CNN’s Gregory Wallace contributed to this report.