Watchdogs baffled by 787 fault

Aviation authorities have admitted they still do not know what caused a fault that led to the emergency landing of a 787 Dreamliner plane earlier in the month. The US National Transportation Safety Board said it has found “no obvious anomalies” in the batteries thought to have been at the root of the problems that have grounded the entire Dreamliner fleet. Shares in Boeing, which makes the planes, opened one per cent lower.