European authorities have certificated the higher-thrust Package C version of the Rolls-Royce Trent 1000 powerplant, which is designed to power the Boeing 787-9 twinjet.
The 74,000lb engine will be fitted to the initial 787-9s which will enter service with Air New Zealand next year.
Boeing has rolled out the 787-9 prototype but has yet to set a first flight date.
Rolls-Royce Trent 1000 programme director John Griffiths says the European Aviation Safety Agency certification is "another milestone" for the powerplant.
The manufacturer claims a dispatch reliability figure exceeding 99.9% for the engines in service on the 787-8 fleet.
Package C powerplants will be available for the -8 as well as the -9.
Rolls-Royce is also developing a 78,000lb variant, the Trent 1000-TEN, intended for the 787-10. This engine, which will enter service in 2016, will also be able to power the two smaller 787 family members.