Home' Asian Aviation : AAV March 2016 Contents 30 AsianAviation | MARCH 2016
ast year, Mitsubishi Aircraft Corporation
(MITAC) headquarters personnel moved
into the terminal building at Nagoya Airport
(Tokyo), adjacent to the final assembly plant
where the company’s new – indeed, only — design
was being prepared for flight.
The second-floor office gave employees a
grandstand view as the Mitsubishi Regional Jet
(MRJ), Japan’s first airliner for more than 50 years,
flew for the first time on 11 November after more than
seven years of development that now has involved
four delays. The MRJ was to fly twice more before
MITAC withdrew it during December and January
for modifications to strengthen fuselage and wing
More than 30 years after being a partner in the
early 1960s’ NAMC YS-11 twin-turboprop airliner,
in 1996 Mitsubishi unsuccessfully proposed a
100-passenger airliner joint venture to Canadian
manufacturer Bombardier Aerospace. Only after a
further dozen years of consideration did the Japanese
company launch the MRJ as a go-it-alone design to
fulfil “a long-cherished wish of the Japanese aircraft
The MRJ has drawn on the aerospace experience
and expertise of MITAC parent company Mitsubishi
Heavy Industries (MHI), which gave it responsibility
for design, type certification, procurement, sales, and
customer support. Sibling MHI subsidiary Nagoya
Aerospace Systems Works manufactures the MRJ
and oversees flight-testing and entry into airline
service, first planned for as long ago as 2013.
MRJ testing recommenced with a 1hr 42min flight
on 10 February following modifications that had been
planned six months before November’s first flight.
After the static-strength test airframe failed to meet
formal airworthiness requirements last May, MITAC’s
decision to strengthen parts of the MRJ as soon as
it had flown vividly demonstrated its philosophy to
“proceed with caution.” Less-conservative (but more
experienced) manufacturers might have planned
modification work to coincide with incorporation of
other changes arising from more flight-testing.
Tests early last year on Mitsubishi’s static-
strength test specimen – one of two airframes that
will not fly – had shown that the MRJ’s structure
accommodated limit-loads, the maximum forces
expected to be experienced in normal flight-operating
conditions. But further wing “up-bending” tests later
indicated that the wing did not meet ultimate-load
requirements, which apply 50 percent-higher forces.
The manufacturer acknowledged this only on 24
December, when MITAC revealed the most recent
of four programme delays: “Analysis enabled us to
forecast that some components, such as those that
join the wing and the fuselage [and] those of the
fuselage frame, would have insufficient strength,”
according to MITAC strategic marketing head and
director, Hideyuki Kamiya.
In fact, Mitsubishi had provided a strong hint –
unnoticed by analysts and commentators alike –
three months earlier, when senior executive VP and
executive chief engineer Nuobo Kishi conceded that
modifications were planned following early flights
in order “to expand the flight envelope” – a tacit
acknowledgement of the MRJ’s marginal strength
reserves. Kamiya will not say by how much the aircraft
came short of meeting ultimate-load requirements.
(There is no suggestion that the MRJ failed to meet
other related tests, such as fuselage pressurisation.)
Long before the MRJ’s first flight, in 2011 MITAC
had developed a hydraulic and flight-control systems
test rig that had been “flying” experimentally in a
dedicated facility at MHI. The equipment (of a type
known universally as an “iron bird”) has been used
to establish MRJ hardware and software, and to
prove aircraft-manoeuvring functions – “one of the
most significant system-integration tests of the
development process,” says Mitsubishi.
Also developed for use in endurance testing, the
rig includes a flight deck, hydraulic and flight-control
equipment, on-board software to be uploaded
to the real aircraft, and simulation computers that
replicate the complete flight-operations environment.
Testing of the Mitsubishi Regional Jet has resumed after modification and systems upgrades following the maiden flight late last
year. Ian Goold reports on the first new Japanese airliner for more than 50 years and the manufacturer’s cautious approach to
development, which has included four programme delays.
Mitsubishi powers ahead with MRJ
The MRJ “iron bird” test rig.
3/03/2016 7:19:51 PM
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