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gramme-management office senior director Alex Bellamy (recruited
last year from Bombardier C Series flight-test team management).
Working with flight-test and airworthiness-approval type certification
(TC) partner Seattle-based Aerospace Testing Engineering & Certifi-
cation (AeroTEC), Mitsubishi earlier “found it necessary to make de-
sign changes” that may reflect the Japanese industry ’s lack of recent
certification experience. Changes that include relocating components
in avionics bays and re-routing electrical-wiring interconnect-system
cable harnesses “will not affect aircraft performance, fuel consump-
tion, or [systems] functionality”, according to the manufacturer.
Mitsubishi hopes later this year to define developments arising
from the MRJ’s latest (at least third) design review: “ We intend to
finalise the revisions and [new] specifications in the fall of 2017.” The
company told Asian Aviation in June that it would decide what addi-
tional flight-test time or aircraft would be required “in the near future,
based on the revisions of design, development, and flight planning”.
The manufacturer expects to invest in (at least) a sixth FTA and
to extend flight-test time from 2,500FH to 3,000FH. At Paris, it said
some 940FH had been logged by four flight-test aircraft that have
flown thus far.
Flighttesting at Moses Lake entered “a new phase” on 31 March
when — three months late — FTA-3 became the fourth MRJ to arrive,
says Mitsubishi. “ We conducted successfully initial natural-icing
tests at Chicago Rockford International Airport (Illinois) in February.
Cold and hot-soak tests were carried out in the McKinley Climatic
Laboratory at the Eglin Air Force Base in Florida [in early March].”
Arrival of FTA-3 enabled MRJ partners to conduct “multiple flight
tests on a daily basis...to accelerate development ” toward type
certification. Ironically, the programme suffered a hiccup when FTA-
3 returned to Honolulu (Hawaii) during its ferry flight from Japan.
“Right after taking off for San Jose (California) on 16 March, an
anomaly was detected in one of the three hydraulic systems,” says
the manufacturer. “F TA-3 returned safely to Honolulu where we
investigated and exchanged hydraulic parts (made by MHI). These
[circumstances] were specific to FTA-3.”
Mitsubishi explains that considerations, including “weather and
aircraft conditions”, dictated the routing of MRJ trans-Pacific fer-
ry flights to Moses Lake. When initial aircraft FTA-1 was ferried
last September — late in the northern summer — it would take
a more-northerly track via Kamchatka (Russia) and Anchorage
(Alaska). The remaining machines (which made the trip between
November and March) all flew a longer route through Guam, the
Marshall Islands, and Hawaii.
What have been the results of flutter, load surveys, and stall
tests? “We have gathered much valuable data from our flight tests,”
Mitsubishi tells Asian Aviation. “ We are progressing well towards
finalising our TC designs.”
Completion of flight-load survey and flutter tests “allow us to
operate throughout the full flight [altitude and speed] envelope and
confirm [that MRJ] aerodynamic performance is settled. We found
one or two areas that need improvement and are working on design
Flutter, an unstable aerodynamic oscillation that if unchecked
can be catastrophic, was Mitsubishi’s first TC test witnessed by
the Japanese Civil Aviation Bureau (JCAB). “ The initial natural-icing
‘campaign’ allowed us an early look at how [the] aircraft accretes
ice, and provided data for ice-protection system performance,” ac-
cording to the company.
Extreme temperature testing at Eglin provided valuable data,
specifically for the environmental control system (ECS), hydraulics,
engines, and auxiliary-power unit. Results allowed engineers to
validate thermal models and improve the design. When ECS design
improvements are implemented, MRJ FTA-4 will be deployed to
natural hot and cold locations to continue the testing and validation.
Mitsubishi is guarded about work required after early testing of
flight-control software (FCS) and cabin and cockpit-air manage-
ment. “Company policy doesn’t allow us to disclose these details.
We are continuously working with partners to optimise design of the
FCS, based on handling qualities and stability-and-control testing.”
The Eglin tests provided valuable data for analysis of the air-man-
agement system. “ We have a test-programme software delivery
schedule that allows our partners to incorporate changes and im-
provements to support upgrades,” says Mitsubishi.
Apart from flying four aircraft, the manufacturer also has conduct-
ed MRJ airframe static and fatigue tests. The former was completed
in November 2016, a few months after fatigue testing began in
“ We are gathering data from fatigue-strength tests,” says Mitsubishi.
◀ The regional jet undergoes heat soak testing.
MITSUBISHI REGIONAL JET FLIGHT-TEST LOG
Nov 11, 2015
Sept 28, 2016
May 31, 2016
Dec 19, 2016
Nov 22, 2016
Mar 31, 2017
Sept 25, 2016
Nov 18, 2016
Sources: Mitsubishi Aircraft and aircraft-production website http://www.abcdlist.nl/mrj/mrjf.html. *Manufacturer ’s serial number; **US arrival; ***FTA-1 was ferried from
Tokyo via New Chitose (Japan), Yelizovo (Russia), and Anchorage (Alaska). FTA-2 , -3, and -4 were ferried by a longer route via Guam, Majuro (Marshall Islands), Honolulu
(Hawaii), and San Jose International Airport (California).
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