In a very loud wake up call to Boeing, Mitsubishi Heavy Industries, which makes the carbon fibre wings for its troubled 787 Dreamliner project, has cancelled plans to use composites in major sections of its own MRJ regional jet project, including its wing.
The 787 project was plunged into disarray after a Mitsubishi built wing broke prematurely during a stress test involving a static assembly of the Dreamliner in May.
Mitsubishi is a design and risk sharing partner in the 787 program as well as a new contender in the regional airliner market currently dominated by Embraer of Brazil and Bombardier of Canada.
Its 70-90 seat sized MRJ was due to go into service by 2013, and feature carbon fibre wings and fuselage barrel, making it more than 50% composite by zero fuel weight in order to exploit the lighter weight promised by plastic laminates.
It was to be in a very material way, a mini-787.
However Mitsubishi’s shock announcement overnight says composites will now be restricted to a maximum of around 15% of the structure, mainly in the tail and other areas where composites have been used by jet makers for nearly 30 years.
It is excluding the material from those areas where complex load bearing stresses will occur, particularly in high cycle operations such as regional services where the jet may experience up to 12 landings or takeoffs and pressurisations a day.
A Mitsubishi spokesperson says, “ Structural changes are easier and require shorter lead times with aluminium wings. With an aluminium wing box, the wing structure can be more easily optimised for the family [and a newly announced stretch model with 100 seats or more].
“This enhances the overall competitiveness of the MRJ family.”
Mitsubishi said that cancelling composites on a large scale allows it to minimise the deterioration of range performance in the largest version of the range, yet render the smallest version lighter than it would have been.
The company is reported to have experienced serious over weight problems with the composite design, and in its contribution to the 787.
The 787 is supposed to fly before the end of the year and begin deliveries to airlines before the end of next year. The testing of a fix for the failed Mitsubishi wing is supposed to occur at Paine Field north of Seattle before the end of this month, and there are signs of work taking place in advance of that test.
Boeing concealed the failure of the 787 stress test in May until June, when its then head of commercial airplanes, Scott Carson, revealed that it had forced the postponement of the first flight of the 787 only days before it had been promised to take place.
This took the credibility of the 787 program to a new low.
Carson was subsequently relieved of his Dreamliner role, and the president and CEO of Boeing, Jim McNerney, recently told a technical conference that the 787 program ‘hurts like hell.’