Airbus has tentatively fixed a 19 October date for the maiden A330neo flight.
The date falls within an interval it had previously identified as a possible window for the A330-900's initial sortie.
Airbus says the first flight of the Rolls-Royce Trent 7000-powered aircraft remains weather-dependent.
It had originally intended to achieve entry into service with the re-engined twinjet by the end of this year.
But the schedule has slipped by several months, partly as a result of delays in the engine development.
Airbus has yet to indicate a likely date for delivery of the first aircraft. TAP Portugal is set to be the first customer to receive the A330neo.