The Australian model Adau Mornyang has wept in a US court as she avoided a prison sentence despite assaulting a flight attendant on a drunken, raucous Melbourne-to-Los Angeles flight.

Mornyang, 24, was facing up to 21 years behind bars for assaulting a United Airlines flight attendant, but a US district court judge, Cormac Carney in Los Angeles, sentenced her to 100 hours of community service and three years of probation.

“I am a human being who made a terrible mistake,” Mornyang told the judge on Monday.

The judge cited what he described as her “tragic history” of sexual and physical abuse and alcoholism. “It’s quite sad and tragic,” Carney said.

In March an LA jury found Mornyang guilty of a felony charge of interference with a flight crew member and a misdemeanour count of assault.

The court heard the former Miss World Australia finalist ordered “several glasses of wine” on the 21 January flight. When she was denied more drinks, she yelled obscenities and racial slurs, and struck a flight attendant. She was then handcuffed by an air marshal, refused to leave a toilet and had to be held at the rear of the plane.

Prosecutors recommended she serve a month behind bars. Probation officers recommended three years of probation and a US$2,000 (A$2,850) fine.