Pechanec Marek, 44, was ordered to pay $140 (about R1 600) for accidentally activating hijacking code 7500 instead of the emergency code 7700, Nguyen Trong Thang, chief inspector of the country's civil aviation body, said.
Activating the code indicates that someone has forced their way into the cockpit.
The incident occurred last month as the plane was travelling from Ho Chi Minh City to Vinh. Low cabin pressure forced the plane to reduce altitude from 11 000 metres to 4 000 metres.
The crew then requested an emergency landing at Noi Bai airport, outside Hanoi.
