The first flight of the Mitsubishi Aircraft MRJ regional jet is likely to be delayed, as the airframer acknowledged that there are "challenges" being faced in the programme.
The flight was originally scheduled for the second quarter of this year, but meeting this timeline will be "very difficult", said Hitoshi Iwasa, vice-president of sales and marketing at MRJ.
Mitsubishi expects to announce a new schedule for the programme in a few months.
The airframer had planned to make first delivery to launch customer All Nippon Airways in the first quarter of 2014, but it is not clear now if it will meet this timeframe.
Iwasa declined to specify the length of delay to the programme or the issues that will likely delay the first flight, saying that Mitsubishi is now studying the schedule carefully and that it is "confident" that it can overcome the challenges.
Pratt & Whitney's PW1200G geared turbofan engine, which will power the MRJ, will be mounted on a test bed in April. Ground tests of the engine were completed last year.
Mitsubishi has won orders for the MRJ from only three customers. New customers could come from the USA and Asia, said Iwasa.
He added that countries such as Indonesia, China and India are important markets for the company.