Singapore Airlines on Thursday reported a quarterly net profit of 50 million Singapore dollars ( 39.4 million U.S. dollars) for the three months ended Dec. 31, 2013, which was down 65 percent year on year. However, its operating profit in the third quarter of its financial year grew by 15 percent year on year to 151 million Singapore dollars (118.9 million U.S. dollars). The group's revenue was flat at 3.9 billion Singapore dollars ( 3.1 billion U.S. dollars) as "higher passenger carriage was offset by weaker yields due to efforts to stimulate demand amid the competitive environment and unfavorable exchange rate movements on major revenue generating currencies," it said. The group's expenditure decreased marginally by 5 million Singapore dollars to 3.7 billion Singapore dollars, largely owing to lower net fuel cost despite appreciation of the U.S. dollar, as average jet fuel prices decreased 5.6 percent year on year. This was partially offset by higher staff and non-fuel variable costs which rose in line with the increase in capacity. The fall in the net profit was mainly due to higher non- operating expenses such as fines paid by SIA Cargo to foreign authorities for its alleged involvement in global price-fixing. Singapore Airlines, one of the world's leading carriers, said that the outlook for the air transportation industry continues to be challenging with airlines offering aggressive fares to fill up planes. (1 U.S. dollar = 1.27 Singapore dollars)