Chicago-based Boeing Co. conducted another test flight of its 787 passenger jet over the West Coast.
The company said Monday's flight was designed to test system upgrades and not to check operation of the plane's batteries.
Airlines have 50 of the planes, which Boeing calls the Dreamliner. But they're still grounded after two of them overheated in January. Boeing is trying to assure regulators that after some design changes, the batteries are safe. Boeing expects to make at least one battery-test flight.
On Monday one of the 787s made a 2-hour flight from the Seattle area to Moses Lake, Wash., then returned to Boeing Field. Boeing conducted one test flight of the 787 last week and two in February.
Boeing shares fell 60 cents to close at $85.25. The stock is up 13 percent so far this year.