(Updates with prosecutors' request for sentence, paragraph 3)
By Ju-min Park
SEOUL, Feb 2 (Reuters) - The daughter of the boss of Korean Air Lines, on trial in what has popularly become known as the "nut rage" case, treated flight crew like "feudal slaves", a chief steward said in court on Monday.
Heather Cho, daughter of Korean Air chairman Cho Yang-ho and the former head of in-flight service, is on trial for breaking aviation laws and conspiring with other company executives to force crew members lie about the Dec. 5 incident.
Prosecutors are seeking a three-year prison term if she is convicted.
Cho had demanded the chief steward, Park Chang-jin, be removed from a flight at New York's John F. Kennedy airport after a first class flight attendant served her macadamia nuts in a bag, not on a dish.
The plane, already taxiing, had to return to the gate.
Park said Cho "was like a beast that found its prey gritting its teeth as she became abusive, not listening to what I had to say at all".
"I don't think Cho showed an ounce of conscience, treating powerless people like myself like feudal slaves, forcing us to sacrifice and treating it as if it was the natural thing to do," Park said, fighting back tears.
Cho resigned from her posts at the airline, including vice-president, in the face of public anger and ridicule over her behaviour, which raised questions about the power of the country's "chaebol" conglomerates.
Park appeared in court in his uniform after returning to work over the weekend after a leave of absence.
Cho's father apologized in court on Friday to Park and promised he would not face any reprimand.
Cho's lawyers previously told the court that she was sorry for her actions, but that they did not merit punishment. They also denied that she used violence.
Park and prosecutors had said he was forced to kneel down and Cho poked his palm several times with a folder.
Heather is the oldest of Cho Yang-ho's three children. Her siblings are also executives with the airline. (Editing by Jack Kim and Nick Macfie)