As ’s 787 enters the second month of its fleet-wide grounding, the U.S. airframer is poring over data collected on a series of flight and ground tests and says it is making “good progress” toward a solution.
The fix, at least in the short term, continues to be focused on improving containment of the aircraft’s two existing lithium-ion batteries and adding more temperature monitors to provide earlier warning of abnormal battery performance via the engine indicating and crew alerting system.
Program insiders say that initial data from the tests have reinforced the company’s confidence in its baseline redesign package and that it “feels good” about the revised configuration.
Boeing test captains Mike Bryan and Randy Neville, together with a crew of 11 flight test personnel, completed a second battery monitoring test flight on Feb. 11 on board 787 test aircraft ZA005.
The uneventful 1 hr. 29 min. flight followed an initial flight on Feb. 9, which lasted 2 hr. 19 min. The flights assessed the performance of the main and APU batteries over a matrix of altitudes and speeds. Further ground tests of batteries were conducted on ZA005 on Feb. 13 and the previous day on units in an aircraft destined for.
However, in addition to the technical challenge is whether the short term, containment-based option being studied by Boeing will be approved by the.
Specifically, Boeing must comply with the agency’s Jan. 16 edict that “operators of U.S.-registered,aircraft must demonstrate to the Federal Aviation Administration that these batteries are safe.” With the spotlight firmly on the FAA and Administrator Michael Huerta’s promise to “restore the highest level of safety and create the best methods and best procedures,” Boeing is preparing for a dialogue that could be as much political as technical.
Adding to the intensity are questions concerning the FAA’s original certification of the battery publicly posed Feb. 7 byChairman Deborah Hersman. Together with its ongoing investigation into the cause of the first battery fire Jan. 7 on a aircraft at International Airport, the NTSB is evaluating the validation methods originally used for certification of the battery, as well as testing of field replacement batteries.
The board found that a short circuit in a single cell can propagate to adjacent cells, resulting in smoke and fire. “The assumptions used in the certification of the battery must be reconsidered,” said Hersman.
As the investigation continues to narrow down the apparent cause to the internal workings of the battery, rather than the associated charging or control systems, it is still unclear whether the FAA will accept an interim configuration designed to mitigate and contain a failure condition that may well recur in service.
Confirmation that the focus is shifting to internal failures came this week when the NTSB acknowledged it is investigating possible links to the formation of small build-ups known as dendrites. Late in January, battery experts told Aviation Week that NTSB testing at the Carderock Division of the Naval Surface Warfare Center laboratories included examination for signs of dendrite-caused short circuiting.
Boeing’s decision not to slow down 787 production or development of the stretched 787-9 also is seen by suppliers as “a bullish indication” that the company remains confident of working through the issues. Parker Hannifin and Eaton, two major suppliers on the 787, say they have had no sign from Boeing that the aircraft’s supply flow would be cut back.
“We have weekly interactions at all the right levels, and right now it’s full steam ahead in terms of production,” Parker Aerospace President Roger Sherrard tells Aviation Week. “We don’t see any near-term impact at this point.”
Business As Usual
Craig Arnold, chief operating officer for Eaton’s Industrial Sector, which includes Eaton Aerospace, also notes, “They have a very long backlog of 787s, and to the extent that they take their foot off the accelerator it’s tough to catch up.
“Right now, it’s business as usual. They’re building airplanes, and we’re shipping to their lines and they’re confident they’re going to work through this.”
As 787s roll off the Everett and Charleston, S.C., lines at a combined rate of about one per week, Boeing is considering contingency plans for freeing up extra storage space at its Washington manufacturing site. By mid-February, 22 completed new aircraft are expected to be awaiting delivery, of which 16 will be at Everett. A further 20 aircraft are waiting for or undergoing change incorporation, of which about nine were originally expected to be completed in 2013.