Flag carrier Air China said late Tuesday that its net profit fell 16 percent in the third quarter compared to a year ago, hit by foreign exchange losses.

The airline said net profit was 3.17 billion yuan ($508 million) for the three months ending September 30, down from 3.8 billion yuan in the same period last year.

The company's profit was lower than a forecast of three analysts polled by Dow Jones Newswires, which predicted an average of 3.29 billion yuan for the reported time period.

Revenue rose by two percent to 28.75 billion yuan, from 28.14 billion yuan a year earlier.

Finance costs spiked almost 250 percent for the first nine months of the year to 2.08 billion yuan, because of "the depreciation of RMB against US dollars", the company said in a filing to the Hong Kong stock exchange.

Air China in August reported a 77 percent slump in net profit for the first half of the year and said the operating environment for the second half of this year remained "grim", citing fuel costs and exchange rate fluctuations.