The MRJ regional jet programme's FTA 1 has completed structural reinforcements and is scheduled to resume flight tests in February.
The prototype has been on the ground since its third test flight on 27 November 2015, undergoing structural reinforcements and system software upgrades, Mitsubishi Aircraft's head of strategic marketing Hideyuki Kamiya tells Flightglobal in a phone interview.
The Japanese manufacturer identified the need to strengthen the aircraft's wing roots and the fuselage frame above the centre wing, after it conducted structural tests before the aircraft's first flight in on 11 November 2015. It has since applied a "temporary treatment", strengthening the sections with "additional plates".
"For the flight test aircraft, we added additional plates on the original parts for reinforcement... for the production aircraft, we will redesign these parts to increase the thickness a little bit and the weight influence is within a few kilograms," says Kamiya.
Mitsubishi also clarified that its delay of first delivery to mid-2018 from the second quarter of 2017, announced last December, was not related to wing and fuselage strengthening work. Rather, the company wants additional time for simulation ground tests before the first flight of each FTA. It also wants more time to analyse data gleaned during test flights.
“After talking to aviation experts [at out] Seattle engineering centre… we reviewed with them our entire flight test programme,” says Kamiya. These informed the decision to extend testing.
Enhanced simulation ground tests and analysis work in Japan, as well as the addition of more time between flight tests in the US, where most of the programme's test flights will occur, combine to add about one year to the testing campaign.
Kamiya says the MRJ’s first flight was “pretty successful” and that the aircraft could take its second and third flights all within a month, because of the ground tests that were done before the aircraft flew. Mitsubishi had conducted a simulation system check on the aircraft, getting rid of "false errors", and made sure that the aircraft's systems work properly together.
The airframer is using five test aircraft for the flight campaign, which is expected to cover 2,500 hours of testing.