Boeing has announced the signing of a previously announced order for 10 C-17s for the Indian air force that will extend production of the tactical airlifter by one year.

The signing of the $4.1 billion order means that Boeing now has 28 C-17s in an order backlog stretching to mid-2014, with India now the largest of six international operators.

The future of C-17 production now depends on whether Boeing can scrape at least 30 additional aircraft orders within the next five years. At that point, the US Air Force may consider alternatives to inducting about 30 more Lockheed Martin C-5As into a reliability enhancement and re-engining programme.

Unrest in the Middle East has shifted priorities in some key countries. This has prolonged discussions on potential deals with Qatar to purchase two more C-17s and with Kuwait to buy its first C-17, said Bob Ciesla, Boeing's C-17 programme manager.

"It's not number one on that priority list to work through," Ciesla said.

Meanwhile, local reports in India suggest that the nation's air force may sign orders for more than six additional C-17s within a few years.

Boeing is now in the process of reducing its yearly production rate from 15 to 10, which should be complete by the end of the third quarter, Ciesla said. The company also has studied options to drop yearly rates to as low as six aircraft, but decided this number makes the C-17 "unaffordable", he added.

"Ten is that knee in the curve," he said. "That's where we need to be."

Source: Flight International