SEATTLE - Boeing Co. on Monday resumed the flight tests of its long-delayed 787 jetliner aimed at achieving Federal Aviation Administration certification for the aircraft.

Boeing halted all flight testing of the two-engine widebody jet following a Nov. 9 in-flight electrical fire in a power distribution system that forced a 787 to make an emergency landing in Laredo, Texas. The flight tests resumed in late December after Boeing came up with an interim software fix, but not the tests for FAA certification.

The federal agency must certify aircraft before they can enter service, an all-important milestone Boeing must achieve before deliveries can begin on the aircraft, already three years late getting to customers.

The plane involved in the FAA tests made two flights Monday from Yuma, Arizona, the second lasting about three hours as it made a series of back-and-forth loops over the southern Arizona desert.

Boeing spokeswoman Lori Gunter said two other 787s also were in the air elsewhere in the country, including the aircraft that had the fire, which made its first flight since returning from Laredo to the Seattle area.

Gunter told The Associated Press she could not provide details about the testing. "We just don't do that on a day-to-day basis," she said.

Gunter said Boeing has four 787s in active flight tests, with the remaining two in the testing program expected to be flying again in the next week or so.

She declined to say when Boeing might announce a revised delivery schedule for the plane. Japan's All Nippon Airways had been scheduled to receive the first 787 early this year before the latest setback.

Last Wednesday, Jim Albaugh, president and CEO of Boeing Commercial Airplanes, told reporters that the company hoped to announce a delivery schedule within two weeks, but the FAA first had "to agree to the fixes we're going to put in place" and give its permission to restart certification flights.

Even before last fall's fire, production problems, including those from outsourcing much of the aircraft's construction, had forced repeated delays for jet, which made its first flight in December 2009.