— Boeing sent a 787 up on a test flight Saturday afternoon, the first since the new airliner was grounded three weeks ago because of a battery fire.

The aircraft took off from Boeing Field in Seattle and spent two and a half hours flying back and forth over the inland Columbia Plateau. The flight-tracking website FlightAware reported the aircraft flew for 1,131 miles, slightly more than the 919 planned.

The 787 is the first commercial airliner to rely heavily on lithium-ion batteries, the same kind used in cellphones. Each plane has two of the 63-pound blue power bricks, one near the front to provide power to the cockpit if the engines stop, and one near the back to start up the auxiliary power unit, which is essentially a backup generator.

On Jan. 7, a battery on a plane that had recently landed in Boston short-circuited and caught fire. Nine days later, a battery on an All Nippon Airways plane started smoking, forcing an emergency landing in Japan. Boeing said Saturday’s flight was to assess the in-flight performance of the batteries. Data would be used to support continuing investigations of the recent incidents. Boeing Co. has billions of dollars tied up in research on the 787.