WASHINGTON -- U.S. regulators want to tighten oversight of aircraft-industry suppliers, such as the subcontractors that helped Boeing design and build the 787's batteries, to reflect lessons learned from the plane's grounding.
The Federal Aviation Administration also plans to seek the guidance of specialists outside the aviation industry to help with certification of new aircraft designs, Associate Administrator Margaret Gilligan said at a hearing Wednesday before a House transportation panel.
"We need to enhance communication between manufacturers and all the sub-tier providers that they buy parts from," Gilligan told the committee, without offering specifics. "FAA needs to be monitoring them more closely as well."
Boeing's Dreamliner, which uses carbon fiber to save weight and requires more electricity to gain efficiency, was grounded for more than three months this year after lithium-ion batteries on two of the planes overheated and spewed fumes.
The Chicago-based manufacturer used an unprecedented number of subcontractors to build parts of the Dreamliner to reduce financial risks on the new model. That arrangement led in part to 787 program delays as some contractors fell behind schedule.
While an FAA review of the plane's certification hasn't been completed yet, the agency is already considering changes to improve the process, Gilligan said.
"We and Boeing agree that there were opportunities for Boeing and FAA to understand better what was happening at the battery manufacturer, for example," Gilligan said in an interview after testifying.
GS Yuasa Corp. of Kyoto, Japan, makes the plane's battery packs. The battery charger is manufactured by Tucson, Ariz. based Securaplane Technologies Inc., a unit of Meggitt, based at Bournemouth airport in Christchurch, England. Both suppliers sell the products to Thales, based in Neuilly-sur- Seine, France, which provides them to Boeing.
Parts of the aircraft's electrical system, which interacts with the batteries, were built by United Technologies Corp.'s Hamilton Sundstrand division, now called UTC Aerospace Systems.
"There were some things that Boeing does at Boeing's facilities that they didn't see GS Yuasa doing that Boeing considers best practices," Gilligan said. "That was information that Boeing should have made sure it gave to its suppliers."
The FAA hasn't decided how to alter its oversight and is waiting for the review to be completed later in the summer, she said.
Boeing's chief engineer on the 787, Mike Sinnett, who also testified at the hearing, declined a request for an interview through Gayla Keller, a spokeswoman. Keller didn't immediately respond to a request for comment.
The FAA said April 19 it had approved battery improvements proposed by Boeing that would let the 50 Dreamliners in global fleets return to service. The changes limit the chances of batteries overheating, insulate individual cells from each other and encase the power pack in a fireproof enclosure.
The Dreamliner was grounded Jan. 16 after the second battery incident.
Firefighters in Boston took an hour and 40 minutes to control a battery spewing flames on a Japan Airlines 787 that had just landed Jan. 7. Nine days later, an All Nippon Airways Co. 787 made an emergency landing at Takamatsu Airport in Japan after one of its batteries overheated.
The two carriers, which have 27 of the planes, returned their Dreamliners to service May 31 after Japanese regulators signed off on the redesign and fixes were completed. Boeing has delivered seven more Dreamliners since the grounding was lifted for a total of 57, according to its website.
Another lesson the FAA has learned is that industries outside of aviation can be tapped for help on technical matters, Gilligan said. After the battery incidents, Boeing brought in a panel of battery specialists to assist with its redesign, she said.
Those outsiders can "make sure we haven't overlooked anything," she said.
Sinnett told the committee that the incidents prompted the company to alter the way it tests batteries.
Tests during the plane's certification didn't prompt the kind of violent overheating that took place in the two incidents, he said.
"Boeing advanced the state of the art" for battery testing, he said.
Gilligan and Sinnett defended the certification process while acknowledging flaws in the Dreamliner batteries.
"A great airplane has returned to the sky and I am confident it will serve our airline customers and the traveling public extremely well for decades to come," Sinnett said in his testimony.
Gilligan also defended her agency's use of Boeing employees to perform initial approvals of the company's aircraft designs. The use of those workers for some of the battery certification is under review by the National Transportation Safety Board, which is examining the Boston fire.
"Limiting the use of technical experts because of who they work for is the equivalent of imposing limitations on problem solving," Gilligan said. "That is not a limitation that FAA would ever support."
The 787 grounding, the first in the U.S. that wasn't a response to a fatal crash, was justified because the plane was still untested, Gilligan said.
"The accident rate for commercial aircraft operations is at an all-time low," she said. "Neither the public nor the FAA has the tolerance for that accident rate increasing."