Boeing today completed two 787 test flights that were unrelated to the battery failures.

The first of two 2h12min flights started at Paine Field in Everett, Washington, and landed at Boeing's flight test centre in Moses Lake, Washington. That was followed by a short hop back to Paine Field.

Boeing did not reveal details about the flight test, but the 787 had endured technical problems other than battery failures.

Until the fleet-wide grounding caused by a pair of lithium-ion battery failures in early January, federal and public attention had focused on the 787's unique electrical system.

The P150 panel, which helps distributes electrical power around the aircraft, was linked to numerous malfunctions in December. Boeing had described the glitches as normal teething issues faced by any new aircraft that enters service.

Both United Airlines and Qatar Airways individually grounded 787s for several days in December to replace the electrical distribution panels. The malfunctions, which sent error messages to the cockpit and in one case prompted the pilot to make an emergency landing, were eventually traced to a batch of faulty circuit boards.

The test flight on the LN86 aircraft comes one week after Boeing conducted a functional check flight with a pair of redesigned lithium-ion battery enclosures.

A third test flight is still expected in the "coming days" to attempt to certificate the new battery design by the US Federal Aviation Administration.

The FAA's certification is necessary to allow the 787s to return to flight.

Source: Air Transport Intelligence news