Risk areas such as weight extremes, center-of-gravity positions, buffet boundaries and stall performance have all been addressed through the ongoing Mitsubishi Aircraft MRJ flight-test program.

Four MRJs are flying in the US, all at Moses Lake, Washington. They have been built to the design of the MRJ90 version, which is intended to seat 88 passengers in an all-economy configuration. A fifth MRJ90 is completed, but has so far been used only for ground tests at the program’s base at Nagoya, Japan.

The company plans to add two aircraft to the flight-test program to verify design changes prompted by a reassessment of certification requirements in late 2016. This will bring the flight-test fleet to seven aircraft, with the two additional units good candidates for later sales to customers, Mitsubishi general manager sales & marketing Yugo Fukuhara said.

In tests so far, no flutter has been encountered when reaching design speeds, Mitsubishi Aircraft said during a briefing at the Singapore Air Show this week.

Since mid-2017, the flight-test fleet has been used to verify performance with various weight loads and distributions, the points at which buffet is experienced and how the aircraft behaves in a stall. Other tests have evaluated the operation of the direct mode of the fly-by-wire system and specific fuel consumption of the Pratt & Whitney PW1200 engines, which has been as expected. No show-stoppers have been discovered, the company said. 

Mitsubishi Aircraft also is developing the MR70, with seats for 76 all-economy passengers.

Two redesign efforts were required after the company realized in 2016 that vulnerability to underfloor water ingress and to bomb damage could imperil the MRJ’s airworthiness certification. One change was a rearrangement of avionics in and between the forward and aft avionics bays, the design of which was completed in 2017. The other was changing wiring harnesses. For that, the architecture-level design is completed but detail design is not, the company said.

When launched in 2008, the MRJ was scheduled for delivery in late 2013. It has since been repeatedly delayed, usually because of some difficulty in complying with certification requirements.

Bradley Perrett/Aviation Week perrett@aviationweek.com