But the immediate cause of the flooding was the failure of floodwalls and levees that were guaranteed to withstand a Katrina-sized storm surge, but failed thanks to faultydesign and construction by the Army Corps of Engineers.
Keith Hayward, head of research at the Royal Aeronautical Society, said that if the issue is no longer about replacing a faulty battery, it raised the prospect of Boeing having to do a major re-design.