Regional aircraft manufacturer ATR has tentatively scheduled the first flight of its new -600 variant for early September.
The company had indicated in May that the flight-testing of the ATR 72-600 could start in June.
But during the Paris Air Show last month the airframer confined itself to saying that the first flight would take place in summer.
A source familiar with the programme says that ATR has fixed a provisional date at the tail-end of the summer season, and that the turboprop will fly within the first two weeks of September.
Ground testing of the 72-600 started last year, with power-on taking place in December. The manufacturer is also developing a -600 variant of its smaller ATR 42 aircraft.