"Without speaking about either the incident or investigation, I can tell you that we do supply pumps and valves to the program," a spokeswoman said.
The 787 program was already years behind schedule before last week's grounding, which means Boeing cannot deliver newly manufactured planes to customers. Boeing's chief 787 engineer, Mike Sinnett, told an aviation conference in Dublin he could not say when that would change.
"I can't really say anything about the timeframe of the investigation. The NTSB is really the only authorized authority in the US to talk about this investigation and they made some recent statements, but I can't speculate on timeframe," Sinnett said Wednesday in remarks made by phone from Seattle.
US Transportation Secretary Ray LaHood, the country's top transportation official, said Wednesday the goal was to return the 787 to service as soon as possible but that the government would not rush the plane back either.
"We are working diligently with Boeing to figure out the problem and find a solution. Our goal is to get this done as quickly as possible, but we must be confident that the problems are solved before we can move forward," LaHood told the Aero Club of Washington, an aviation advocacy group.
FAA Administrator Michael Huerta, appearing at the same event, said the review was looking at the 787's certification, manufacturing and assembly processes, and that he could not speculate on an end date.
For at least one Chinese customer, the uncertainty about the Dreamliner's production and delivery schedule has meant delays in launching new routes.
"Frankly, it's a little disappointing the aircraft has been delayed so many times," said Chen Feng, chairman of Hainan Airlines Co Ltd parent HNA Group, in an interview at the World Economic Forum in Davos. "We still think it's a good aircraft, but this has had some effect on our planning."
Hainan has 10 of the planes on order.
The grounding of the Dreamliner, an advanced carbon-composite plane with a list price of $207 million, has already forced Japan's ANA to cancel 151 domestic and 26 international flights scheduled for Jan. 23-28, affecting more than 21,000 passengers, the airline said on Monday.
ANA, which flies the most Dreamliners of any airline, is due to announce further flight cancellation plans on Thursday. The airline also said it may have to scale back its next two-year business plan because the 787 was to have been such a central part of that forecast.