UPDATE 1-Boeing says more India C-17 orders possible

* Military aircraft sales seen growing over 5-10 years

* India decision on fighters seen in early 2011

(Adds details, additional quotes)

FARNBOROUGH, England, July 19 (Reuters) - India could buy 10 to 12 more C-17 transport planes from Boeing Co BA.N beyond the 10 planes already planned, Christopher Chadwick, president of Boeing military aircraft told Reuters on Monday.

Boeing, the No. 2 U.S. defense contractor, is forecasting strong demand for the C-17 planes, which have been used heavily during the Iraq and Afghanistan wars, Chadwick said at the Farnborough Airshow outside London.

Boeing had seen interest from multiple buyers in the Middle East and the Asian-Pacific region, and NATO countries could also buy more of the cargo planes in coming years, Chadwick said in an interview.

On Sunday, Boeing officials said the company could sell 20 more C-17 transport planes to foreign buyers over the next five to ten years, in addition to the 10 already planned for India.

Chadwick said the number could rise even higher, given expectations that India could eventually more than double its planned purchase of 10 C-17s.

The Pentagon’s Defense Security Cooperation Agency in April announced approval of the sale of the 10 transport planes and related equipment, putting its value at up to $5.8 billion.

Chadwick said Boeing expected a slight increase in military aircraft revenues internationally over the next five to 10 years, bolstered by sales of transport planes and fighter aircraft.

Chadwick said delays in international fighter competitions should not jeopardize Boeing’s forecast for moderate growth in defense revenues in 2011, given strong domestic sales.

Boeing is negotiating a third multi-year procurement deal for its F/A-18 fighters with the U.S. government, which would make that production line “rock solid out through the middle of the decade,” he said.

India was also expected to pick a winner in its competition for 126 new fighter jets early next year, he said, while Japan is due to issue a request for proposals later this year.

Brazil’s fighter competition was also nearing an end, and a final decision could come next year, he said.

Boeing had a good track record in winning international competitions, Chadwick said, but the company’s revenue forecast factored in possible wins by other contractors as well.

“There are so many competitions in play right now,” he said. “We never count on all of it.” (Reporting by Andrea Shalal-Esa; Editing by Sharon Lindores)