SEATTLE – Boeing’s 787 Dreamliner has suffered numerous electrical system flaws beyond the battery problems that led to its current grounding, according to engineers with knowledge of the situation.
Company engineers blame the 787’s outsourced supply chain, saying that poor-quality components are coming from subcontractors that have operated largely out of Boeing’s view.
“The risk to the company is not this battery, even though this is really bad right now,” said one 787 electrical engineer, who asked not to be identified. “The real problem is the power panels.”
Unlike earlier Boeing jets, he said, the innards of the 787 power distribution panels – which control the flow of electricity to the plane’s many systems – are “like Radio Shack,” with parts that are “cheap, plastic and prone to failure.”
Any malfunction in a major system, such as the power panel fault that caused a United 787 flight to divert to New Orleans in December, must be reported to the Federal Aviation Administration, though the data is not public.
Another engineer said the number of such faults reported for the Dreamliner is roughly on par with those on Boeing’s previous new jet, the 777, but “on the 787, one big difference is, there’s a preponderance of electrical faults.”
A senior Boeing engineer not directly involved with the 787 said he believes the company’s early delegation of control on 787 outsourcing to multiple tiers of suppliers is now coming back to bite the jet program, though it made belated efforts to tighten up oversight of suppliers.
“The supplier management organization (at Boeing) didn’t have diddly-squat in terms of engineering capability when they sourced all that work,” he said.
Boeing spokesman Marc Birtel declined to answer specific questions for this story, citing the shortage of time, but denied that Boeing’s oversight of its 787 suppliers was insufficient.
“Our standards and expectations for design, production, quality and performance have always been, and remain today, as high on the 787 as they are on any other commercial program,” Birtel said.
Boeing faces an indefinite grounding of the Dreamliner because of a battery fire on a 787 in Boston and the smoldering of another battery on a flight in Japan a week later.
A National Transportation Safety Board update on Friday said an investigator will travel to a manufacturer in France to examine a battery contactor, which connects a wiring bundle from the airplane to the battery.
Since the battery and its monitoring system were made in Japan, and all the connected pieces were integrated by French company Thales, blaming outsourcing for that and other electrical system faults is a reflexive response among Washington state employees and observers.
Yet Boeing has never made batteries, and the electrical systems on all its jets have always been sourced from outside suppliers, just like the engines and the landing gear. In that respect, the 787 is not different from Boeing jets like the 777 and the 737, both renowned for their reliability.
But what is very different on the 787 is the structure of the outsourcing.
On the Dreamliner, Boeing contracted with a top tier of about 50 suppliers, handing them complete control of the design of their piece of the plane.
Those major partners had to make the upfront investment, share the risk and own their design. Each was responsible for managing its own subcontractors.
“For the 787, they changed the structure” of the supply chain, said Christopher Tang, professor of business administration at the University of California-Los Angeles Anderson School of Management and lead author of a much-cited 2009 case study of outsourcing on the 787. “You only know what’s going on with your Tier 1 supplier. You have no visibility, no coordination, no real understanding of how all the pieces fit together.
“With a brand-new design and so many parts and so many players, it’s a major challenge,” Tang said. “Can the management team trace all the way down the tree to every single supplier and unit? That’s really difficult.”
On the United flight in December, a short circuit and electrical arcing were caused by a fault in a module that controls a generator and plugs into the power panel motherboard.
That sparking inside the circuit boards was tiny – Boeing Vice President Mike Sinnett described it in an interview last month as “a low-energy arc that lasted milliseconds, very small” –and produced no real risk to passenger safety.
But it caused the cockpit instruments to indicate that one of the plane’s six generators was down. And though the plane’s multiple alternate power systems easily handled that, the pilot diverted out of caution.
Following that in-flight problem, United in late December reported continuing “sporadic issues with our 787 generators and power distribution panels.”
Sinnett said last month, “While we don’t have the specific exact root cause, the issues have all been traced back to a single lot of (circuit) boards manufactured at one time by a subtier supplier.”