Thus far there has been a lot of speculation but we do know that there was smoke throughout the cabin and heat damage in the rear crown area. The Ethiopian Dreamliner was not equipped with a crew rest area nor where there air conditioning pack in the area of the fire. There has been speculation that this fire may have been intentionally set and even though the chances are highly remote it has not been discounted.
I do think that the AAIB along with the NTSB and FAA should be able to get to the how and why within a few weeks. In the meantime, 787 customers including Ethiopian continue to operate the 787 and Boeing continues production and flight testing.
Here is the text of the AAIB's July 13th press release:
Date: 13 July 2013
Serious Incident to Boeing 787-8, ET-AOP,
at London Heathrow Airport on 12 July 2013
Location: London Heathrow Airport
Aircraft Type: Boeing 787-8
Operator: Ethiopian Airlines
At approximately 1550 hrs UTC on 12 July 2013 a Boeing 787-8 of Ethiopian Airlines, registration ET-AOP, suffered an event at London Heathrow whilst the aircraft was parked on stand, with no persons on board. The initial witness and physical evidence shows that this event resulted in smoke throughout the fuselage and extensive heat damage in the upper portion of the rear fuselage.
In exercise of his powers the Chief Inspector of the Air Accidents Investigation Branch (AAIB) has ordered that an investigation into this serious incident be carried out, in accordance with the Civil Aviation (Investigation of Air Accidents and Incidents) Regulations 1996 and the Standards and Recommended Practices of Annex 13 of the International Civil Aviation Organisation (ICAO). The sole objective of the investigation is to determine the causal and contributory factors of this serious incident, with the intention of preventing a recurrence. It is not the purpose to apportion blame or liability.
In accordance with these international standards and recommended practices, the National Transportation Safety Board (NTSB), USA, representing the State of Design and Manufacture, and the Civil Aviation Authority of Ethiopia, representing the State of Registry and Operator, have been invited to appoint Accredited Representatives to participate in the investigation, along with advisors from the Federal Aviation Administration, Boeing Commercial Airplanes and Ethiopian Airlines. The AAIB has also invited the participation of the EASA (European Aviation Safety Agency) and the UK CAA (Civil Aviation Authority) as advisors to the investigation.
This team, under the direction of the AAIB, has initiated the technical investigation into the event. The aircraft is currently located in a hangar at London Heathrow. There has been extensive heat damage in the upper portion of the rear fuselage, a complex part of the aircraft, and the initial investigation is likely to take several days. However, it is clear that this heat damage is remote from the area in which the aircraft main and APU (Auxiliary Power Unit) batteries are located, and, at this stage, there is no evidence of a direct causal relationship.