Airbus believes that both the General Electric GEnx-1B and Rolls-Royce Trent 1000 engines are rumoured to have missed specific fuel consumption targets by 2-3% and 3-4%, respectively.
"We've continued to make tweaks to the engine and we will make fuel spec when we reach entry into service," GE says.
R-R has been unavailable to comment.
Airbus speculates that a rumoured design change to the Trent 1000 low-pressure turbine could require the first 787 to switch from the Trent 1000 to GEnx engines.
A 787 programme source confirms that R-R compatible pylons had been recently reinstalled on Dreamliner One.
Source: Flight International
