Boeing expects to achieve US Federal Aviation Administration type certification of the 787 with Rolls-Royce Trent 1000 engines by the end of August.
"Barring any issues that can't be resolved", said Boeing chief executive Jim McNerney during the company's quarterly earnings call, the 787 is in the final phases of certification and will be delivered "later in the third quarter".
The 787's launch customer, All Nippon Airways, plans to take deliery of its first 787 in September for initial deployment on charter routes between Tokyo and Hong Kong.
Initial certification will cover the Rolls-Royce Package A engine, which will only account for four 787s before transitioning to upgraded Package B engines. Neither Boeing nor Rolls-Royce has indicated when Package B certification will be completed, though the engines are currently in flight test aboard test aircraft ZA002 and ZA004.