Cathay Pacific Airways Ltd may review the fleet at a cargo venture with Air China Ltd after losses at the operations contributed to the Hong Kong carrier's first unprofitable half year since 2008.

Air China Cargo will have to assess what will be the right aircraft to make it profitable in the long term, Cathay Pacific Chief Executive Officer John Slosar said on Thursday.

The venture is taking four Boeing Co 747-400 freighters from Cathay, which the Hong Kong-based airline is replacing with newer models.

"Old, fuel-inefficient airplanes is a tough business model," Slosar said in an interview in the city on Thursday. "We'll have to look at that to see what is the right way forward in terms of the fleet."

The carrier agreed to buy a 49 percent stake in Air China's cargo unit in 2010. It's using the four 747-400 freighters, which were converted from passenger planes, to help pay for the investment. The new joint company began offering flights in March 2011.

China Daily-Agencies