As a consequence Boeing will undertake a minor redesign of the power panel to reduce the chance of FOD creating and electrical arc or short circuit. Boeing will also implement software changes to make sure that power distribution is improved. This appears to be an acknowledgement that the electrical power redundancies failed as well.
Boeing did not present a revised schedule as they have yet to work that out but they are saying it should be ready in a few weeks. They are developing a plan to present to the FAA for the resumption of flight tests as well asto ferry ZA002 back from Laredo.
Also Flightblogger reports that the foreign object was small and not something the size of a tool as had been earlier reported. KING 5, a Seattle TV station says that it was a washer that caused the short circuit.
Again there is no word on how long it will take the implement the redesign or the software changes. Additionally, the FAA will have to approve all these changes so the schedule will remain in flux.
Boeing will be closed tomorrow and Friday for the Thanksgiving holidays.
Here is Boeing's press release:
Boeing Initiates Changes to 787 Power Panel, Updates to Software
EVERETT, Wash., Nov. 24, 2010 /PRNewswire/ -- Boeing (NYSE: BA) is developing minor design changes to power distribution panels on the 787 and updates to the systems software that manages and protects power distribution on the airplane. These changes come as the result of what has been learned from the investigation of an onboard electrical fire on a test airplane, ZA002, earlier this month in Laredo, Texas.
"We have successfully simulated key aspects of the onboard event in our laboratory and are moving forward with developing design fixes," said Scott Fancher, vice president and general manager of the 787 program. "Boeing is developing a plan to enable a return to 787 flight test activities and will present it to the U.S. Federal Aviation Administration (FAA) as soon as it is complete."
Engineers have determined that the fault began as either a short circuit or an electrical arc in the P100 power distribution panel, most likely caused by the presence of foreign debris. The design changes will improve the protection within the panel. Software changes also will be implemented to further improve fault protection.
The P100 panel is one of five major power distribution panels on the 787. It receives power from the left engine and distributes it to an array of systems.
The 787 team is now assessing the time required to complete the design changes and software updates that are being developed. A revised 787 program schedule is expected to be finalized in the next few weeks.
"Our team is focused on developing these changes and moving forward with the flight test program," said Fancher. "The team in Laredo is also well along in preparing to return ZA002 to Seattle.
Flightblogger: Breaking: Electrical redesign to push 787 delivery
Guy Norris: 787 fire - arc or short
Scott Hamilton: 78 fire caused by FOD, design changes coming, no word on delay
Randy Tinseth: Likely cause of ZA002 incident determined
Aubrey Cohen: Boeing: 787 will need minor changes; schedule impact unknown
At the end of the day everyone wants to know what is the schedule impact of the fire and the resulting redesign of software and hardware. A source told me that he believes that it would set back the 787 no more than three months. Given the information that has come out thus far and my discussions with sources, I do feel that mid to late May delivery time frame is probably about right given the redesign efforts as well as the rework that has to be done on the production aircraft.