A former senior executive of Qantas Airways pleaded guilty to charges in a conspiracy to fix freight prices, the U.S. Department of Justice said Thursday.

Bruce McCaffrey, once the carrier's vice president of freight for the Americas, agreed to pay a $20,000 criminal fine, to serve eight months in jail and to cooperate with the continuing investigation. Charges filed in U.S. District Court in Washington, D.C., allege that McCaffrey and co-conspirators plotted to fix rates on air cargo shipments charged to U.S. and international customers from January 2000 until February 2006.

McCaffrey was Qantas' highest ranking U.S. executive, but the company refused to offer him any legal support. Faced with a possible fine of $1 million and a maximum prison sentence of 10 years, the 65-year-old McCaffrey accepted the plea bargain offered by the Justice Department.

He is the first person involved in the investigation to be jailed. Four airlines, including Qantas, have pleaded guilty and paid fines. The latest was Japan Airlines, which pleaded guilty in April and was sentenced Wednesday to pay $110 million. Qantas pleaded guilty in January and was sentenced to pay $61 million. British Airways and Korean Air pleaded guilty in August. They received the harshest sentences so far. Each must pay $300 million.

Virgin Atlantic, which blew the whistle on British Airways in 2006, and Lufthansa are cooperating with the investigation.