(Reuters) - Safety regulators are poised to approve within days a plan to allow Boeing to begin flight tests of the 787 Dreamliner with a fix for its volatile batteries, a critical step towards returning the grounded aircraft to service, two sources familiar with the matter said on Wednesday.
The Federal Aviation Administration is expected to sign off on a "certification plan" allowing Boeing to carry out the flight tests to demonstrate whether authorities can lift a flight ban that sent shockwaves around the airline industry seven weeks ago.
"You could see the ‘cert plan' approved in the next few days," one of the sources said. Both spoke on the condition of anonymity because the discussions are confidential.
The FAA said it would announce the plan when approved. Boeing declined to comment.
Boeing proposed modifications to the design of the lithium-ion batteries and new physical protection systems to contain flammable materials after smoke or fire incidents on two aircraft in January. These measures include a stronger, stainless steel battery containment box and a tube to vent fumes and heat outside the airplane, should a fire occur in flight.
Investigators are due on Thursday to issue an interim report on a 787 battery fire at Boston airport, detailing facts uncovered so far. The report isn't expected to include analysis, recommendations for the FAA or the cause of the fire.
Despite uncertainty over the cause of the battery problems, the chief executive of 787 customer Qatar Airways said in Germany earlier that he expected Boeing to come up with a solution "imminently" and that this was awaiting approval from the FAA.
Reporting by Tim Hepher in Berlin and Alwyn Scott in New York; Editing by Cynthia Osterman