Boeing completed a final certification demonstration flight on the 787 Dreamliner with an improved battery design today, and will present data from its tests to US authorities in the "coming days" as a final step in returning the type to commercial service.

The airframer conducted the 1h49min flight on a LOT-ordered 787, which departed Paine Field in Everett, Washington at 10:39 local time. Onboard were 11 crew members, including two representatives from the US Federal Aviation Administration (FAA).

"The crew reported that the certification demonstration plan was straightforward and the flight was uneventful," says Boeing. The aircraft, line number 86, landed at Paine Field at 12:28 local time.

Boeing will now gather and analyse data from the tests it had conducted with the improved 787 battery design and submit them to the FAA. "We expect to deliver all of the materials to the FAA in the coming days. Once we deliver the materials we stand ready to reply to additional requests and continue in dialogue with the FAA to ensure we have met all of their expectations," says Boeing. The airframer had completed a function flight test using the same aircraft on 25 March.

LOT 787 cert flight body

The FAA grounded the 787 on 16 January, following two incidents involving the lithium-ion batteries powering the aircraft's auxiliary power unit on two different 787s. The FAA's decision prompted a global grounding of the aircraft type across all operators.

Boeing's improved battery design involves three new layers of over-lapping protections to prevent short-circuits and fires.

The airframer improved the monitoring system for the batteries and strengthened the separation of flammable chemicals within and between each of the eight battery cells. Boeing also inserted the battery into an airtight steel box to prevent a short-circuit from causing a fire.

In addition, the box is vented directly to the outside of the aircraft in order to remove any fumes or smoke in the event that the battery malfunctions.

Source: Air Transport Intelligence news