The Downside of Just-in-Time Inventory

In a control center above a wide-body jet plant in Everett, Wash., a group of Boeing (BA) staffers is poring over data from suppliers in Japan—making sure the company has enough parts to build its 787 Dreamliner in the U.S.

It's a long list. Japanese manufacturers helped design and now produce 35 percent of the 787, 20 percent of the 777, and 15 percent of the 767. What they build can't be duplicated anywhere else, and Boeing can't call in a new supplier to make one piece if it runs short. So far, the jetmaker says it has enough inventory to keep running for a few weeks.