Boeing upped the ante Aug. 18, directing program suppliers to stop work on uncommitted C-17 aircraft.

The move will be the first step in an orderly shutdown of the production supply chain should no further orders be received from the U.S. government, the company said.

Boeing has been saying for weeks that it needs some type of a commitment from the U.S. Air Force, or a foreign air force, for another 10 C-17s, worth about $2 billion, in order to keep a whole production line going.

The Pentagon recently reaffirmed its position that it would make no such commitments. The Defense Departments says it has all the C-17s it needs in the fleet or on order, based on its own reports and analysis.

Boeing says the studies are dated and has pushed the Pentagon to wait until more recent data could be analyzed that would take into account the heavier use of C-17s and other transport planes after the United States began its global war on terrorism.

The Defense Department countered that no wait is necessary.

Most industry analysts say the Pentagon would like more C-17s, but can't afford them while paying for war costs and other expensive weapons programs. Instead, the Defense Department would rather wait for Congress to direct the military to buy the additional planes, and to legislate the money to do so.

Such a move could happen, even after the Boeing move to start shutting down production.

The action will ultimately affect 5,500 Boeing jobs in California, Missouri, Georgia, and Arizona that are directly tied to the C-17, and the program's nationwide supplier work force of more than 25,000. Nearly 700 companies in 42 states provide parts and services that go into each C-17, according to Boeing.

"The C-17 is one of the Defense Department's most successful acquisition programs ever," said Ron Marcotte, vice president and general manager of Boeing Global Mobility Systems. "No one questions its operational value. But we can't continue carrying the program without additional orders from the U.S. government."

The stop-work orders affect long-lead items from suppliers that, in many cases, are built 34 months before a C-17 is delivered. Boeing is re-evaluating the financial impact should the U.S. government not order additional C-17s, and may incur costs aside from any recovered from the U.S. government.

Congress has added funding for up to three more aircraft as part of its recent 2007 budget deliberations. But when the orders are totaled, there are not enough to sustain continued production beyond mid-2009, Boeing said.