Two of Boeing's 787 flight-test aircraft were ferried home to Boeing Field after the fleet was grounded following the 9 November fire aboard ZA002 on approach to Laredo, Texas. The incident led to Boeing grounding its 787 test fleet.
Aircraft ZA001 and ZA005 returned to Seattle on 16 November, from Rapid City, South Dakota and Victorville, California.
Boeing is continuing its investigation, even as a replacement P100 power panel and structural repairs to ZA002's aft electronics equipment bay are being undertaken.
Boeing's preliminary findings suggest the duration of the incident was less than 90s, with the P100 and resulting insulation blanket fire lasting 30s before the fault was removed and the insulation self-extinguished.
Boeing says the aircraft "concluded the event in a configuration that could have been sustained for the time required to return to an airport suitable for landing from any point in a typical 787 mission profile".
However, while Boeing says "the incident demonstrated many aspect of the safety and redundancy in the 787 design", Morgan Stanley research analyst Heidi Wood cautions that Boeing's vagueness "alerts us, as it sidesteps claiming the systems all worked".
While Boeing says no timeline has been set for a return to test-flying, Wood anticipates it could resume in December or January and says first delivery to All Nippon Airways could slip from the mid-first quarter of 2011 into 2012 depending on the extent of any hardware and/or software changes as a result of the investigation's findings.