Boeing has advanced the service entry date to late 2019 for its developmental 777X widebody twin, according to two people familiar with the programme.
Although it is only potentially an acceleration of a matter of months – or even days – from its previous target of 2020 for the first customer delivery, it still represents a significant schedule shift.
One source, who asks not to be identified, says that Boeing has been working to "pull out the programme" to "look at a December 2019 entry into service".
The certification plan for the airframe and its General Electric GE9X engines "supports the December 2019 service entry", he adds.
And a source at a customer airline also confirms that it is planning for the arrival of its first 777-9 before the end of the decade.
Boeing, however, denies that it has altered the timing for the widebody. "Nothing has changed with the 777X schedule. The programme is still on track for first delivery in 2020," it says.
The Seattle airframer declines to offer greater precision on when in 2020 it expects to hand over the initial aircraft or reveal the name of the launch customer.
So far, Boeing has amassed 306 combined orders for the 777-8 and -9, with the largest customer, Emirates, having committed to take 150 aircraft.
Even if the programme has only been accelerated slightly, it is a sign of the pressure Boeing is under to bridge the gap between the end of production on the 777-300ER and 777 Freighter and the arrival of the 777X family.
Sales of both current-generation models have been slow, with Boeing recording a combined 38 bookings in 2015, according to its order and delivery data. The respective backlogs for the -300ER and Freighter stand at 172 and 41, the data shows.
In January, Boeing announced that from 2017 it would reduce the production rate on the 777 by 15% to seven aircraft per month, down from a little over eight at present.
It had calculated that it needed to pull in an additional 200 orders over the next five years in order to sustain that output level.
The 777X gains a longer composite wing with folding tips, a stretched and updated fuselage, and new 100,000lb-thrust (445kN) GE9X engines over the in-production model.
Boeing reached the firm-configuration milestone for the 400-425-passenger -9 in August last year and assembly of the initial aircraft will begin in 2017.
The smaller 350-375-seat -8 will follow around two years later.