United Aircraft’s and COMAC’s eventful year

By Bjorn Fehrm

January 03, 2018, ©. Leeham Co: Both United Aircraft Corporation (UAC) and COMAC got their single-aisle airliner projects into flight test during 2017. The MC-21 and C919 had their first flights within less than a month of each other, with the Chinese C919 first at 5th of May, followed by the Irkut MC-21 on the 28th of May.

Superficially the aircraft and projects are similar. Both are 150-220 seat single aisle projects in the mold of Airbus’ A320neo and Boeing’s 737 MAX programs. Looking a bit closer, they are different. One is extending the state of the art in several areas; the other is playing safe.

Flight-testing starts for C919 and MC-21

The less experienced crew behind the C919 flew first, but then the MC-21 team took the lead with continued test flights in August.

The C919 stayed on the ground until September 28th and then after one flight had another hiatus until November 3rd. The long delays between first flight and following flights for both projects show the immaturity of the programs by first flights. Similar Western projects fly again within a couple of weeks.

One can conclude both first flights were “Monkey off your back” events, more so for the Chinese project than the Russian. Aircraft ground testing and instrumentation for the C919 and MC-21 were not at the level where continued flight-testing was safe or meaningful after a first cautious hop.

It’s possible to fly a test aircraft safely early in the design cycle, as long as speed and altitude are low. The critical danger for a flight test campaign is aerodynamic flutter, an aerodynamic/structural resonance that can break wings and stabilators in seconds. Such resonances only occur when the speed is raised.

The pace of the projects flight-testing shows the necessary ground vibration testing and aircraft instrumentation for these and other tests were not ready in May. Irkut continued the flight-testing in August and kicked it into high gear from October.  COMAC is still cautious with flying. Mid-November the C919 had completed five test flights. 

C919 and MC-21 technology

The C919 is developed by a country who’s only developed the regional ARJ21 airliner before. The state AVIC organization, from which COMAC was spun off, has developed a few indigenous fighter aircraft after license-producing Russian designs, but no operational airliners except for ARJ21.

The ARJ21 was modelled closely after the license produced McDonnell Douglas MD80. It was developed by a consortium of AVIC companies, called ACAC. After COMAC was created to handle civilian airliners, the ACAC and its ARJ21 were 2009 assimilated into COMAC.

The C919 is a prudent design. It’s closely modelled after Airbus A320 with similar technology. The avionics side has Ethernet-based IMA architecture instead of the older point-to-point design on the A320 and the Fly-By-Wire is all digital, but otherwise, the C919 is similar to the 30 years older base design of the A320neo.

The MC-21 is not a copy of a Western design. It advances the state of art in cabin standards and structures. The fuselage has a circular cross-section which is 0.11m wider than the A320/C919 and 0.27m wider than the 737. It allows a 24-inch-wide aisle where passengers can pass each other or a flight attendant with a serving trolley.

The MC-21 is also the only civil airliner with a Carbon Fiber Reinforced Polymer (CFRP) wing-box which has been produced with Resin infused dry fibre and then cured in an oven instead of an autoclave. The CFRP wing-box broke shortly before reaching Ultimate load (150% of the highest in-service load) in the spring but passed the test in November, after a 25kg reinforcement.

The MC-21 avionics and Fly-By-Wire use the same technology as the C919, now made by Russian vendors (the C919 technology has Western origin).

The projects use the same modern Western engines as the A320neo and 737 MAX. The C919 is standardized on the A320neo’s LEAP-1A engine, now called LEAP-1C. The MC-21 uses the Pratt & Whitney PW1100G engine from the A320neo, now called PW1400G.

Russia is developing an alternative for the PW1400G, the Aviadvidgatel PD14. We have analyzed this engine here.

New widebody

To avoid a dual development for a limited widebody market, UAC and COMAC have decided to jointly develop a 290 passenger widebody aircraft, competing with Airbus A330/A350 and Boeing’s 787. A separate company has been established for the project, China-Russia Commercial Aircraft International Corporation (CRAIC).

CRAIC, which is based in Shanghai, was formed on 22 May 2017. Development will predominately be done in Russia and assembly in China. Entry into service is projected for 2027.

The aircraft, called CR929, has its closest Western equivalent in the Boeing 787 project, with the base variant modeled closely after the 787-9.

Like for the C919 and MC-21 projects, the aircraft will have Western base engines in the 75klbf class. Russian and China are discussing the joint development of an alternative engine. It could be based on a scaled-up version of the PD14 engine, called PD35. 

Organizational developments

The MC-21 program is managed by Irkut, a company in Russia’s United Aircraft Corporation. Similar to its Chinese equivalents, the Russian civil aircraft industry developed a regional airliner, the Sukhoi SSJ100, as first modern airliner after the fall of the Soviet Union.

With the sale of the SSJ100 on the world market in cooperation with Italy’s Leonardo, Sukhoi learned how to work with Western airlines and the requirements for Sales and Support of a Worldwide airliner project. Irkut has no such experience.

UAC has therefore decided to create a group-wide Commercial aircraft division where Sukhoi’s sales, service and support structure will be used for all the group’s civil airliners. The Irkut organization will focus on development and production for the MC-21.

For COMAC, which was formed 2008, Sales and Support of civil airliners is new territory. The ARJ21 project gives the organization some experience, but only the for captive customers in the domestic market. It will use the C919 to learn the trade of civil aircraft development, sales, production and support.


19 Comments on “United Aircraft’s and COMAC’s eventful year

  1. LNC: “The avionics side has Ethernet-based IMA architecture instead of the older point-to-point design on the A320 and the Fly-By-Wire is digital, but otherwise, the C919 is similar to the 30 years older base design of the A320neo.”

    Bjorn, does that mean the Fly-By-Wire on the A320 is not digital, but analogue like on Concorde? I always thought that FBY was digital on the A320.

      • Hi Kevin,
        well, actually we are both correct. The flight laws are calculated digitally but the actual Fly-By-Wire, i.e. the transmission of the commands from the Sidestick and Pedals to the computers and then from the computers to the different actuators and therefore the movables is analog. This means the base design is a mixture of analog and digital technology. Concorde and the original F16 FBW were all analog, A320 a mixture and modern FBW are all digital, including the transmission of all signals from inputs and to actuators.

  2. Safe does not get you anywhere but further behind.

    Still I don’t believe that Russia or China with their current systems will ever be taken as reliable supplier.

    Politics enters into it, when people are building empires others are nervous to deal with them and then there is the backlash and sanctions that follow.

    Russia has used natural gas as a weapon and Europe has learned that lesson.

    China is claiming huge areas of the world that at one time a Junk Fleet sailed by.

    Not a recipe for confidence.

  3. The MC-21 is on a different level to the c919. To me it looks a considered approach to the A320 conundrum with application of advanced materials in the places of most advantage. It is living a sort of charmed life at present but the issue with all Russian aircraft has been ramping to commercial levels of production.

    If I were in the market for a new state of the art large narrow body this programme fits the bill, it would comfortably fit in the Boeing stable as a competitor to the A321 or at least the basis of development. If Comac are truly interested in getting a toehold in the market they would write off the c919 with a run of 400-500 frames and back the MC-21 by extending the JV. Any c929 will need all of Russia’s skills, china’s Money and western engines it can get to be in the slightest competitive.

    What are the odds on Boeing snaffling this one, they would need economic turmoil in Russia for it to happen but that is not beyond the realms of possibility. It would put the wind up Airbus in a manner nothing else could, a ‘cheap’ NMA/NSA product and a vastly strengthened narrow body offering above the MAX 8

    • Something close to the MC-21 is what B should have done instead of MAX, but they didn’t because they were still in the chaos phase of the 787 mess or because the Max would be more profitable in the short to mid term.

      An Mc-21 size fuselage with two wing options could cover everything from max 8 to 757- 300 capacity and range from 2500 to 5000 NM. An NSA and NMA in one.

      Even now, with max mostly developed it is still a way forward for B, they would just need to start with the bigger ones and work down

  4. “The MC-21 is not a copy of a Western design. It advances the state of art in cabin standards and structures. The fuselage has a circular cross-section which is 0.11m wider than the A320/C919 and 0.27m wider than the 737. It allows a 24-inch-wide aisle where passengers can pass each other or a flight attendant with a serving trolley.” And a corresponding increase in drag yes? (Assuming I’ve absorbed past posts correctly)

    • Modern take on the Single aisle market.

      Sort of a C Series on Steroids for the upper and of that.

      It looks good, the issue is why should anyone trust Russians?

      And the support is crucial and neither the Russians nor the Chinese are noted for getting that and then executing it.

      India’s experience with US Equipment is a case in point.

      Gee golly whiz, it works and if there is a problem, its fixed.

      Contrast that to, its only been sitting on the ground for a month, whats the problem.

    • Hi Rick,

      the drag due to the increased frontal area is minute (see last weeks Corner). The wetted area is the important parameter as it decides Friction drag (this weeks Corner and next). The wetted area per meter of fuselage is decided by the fuselage circumference. Due to the A320’s double bubble, the difference in circumference is less than 1%. The MC-21 cross section is a clever one.

  5. I understand the ARJ21, was a development of the MD90 with a new wing design which was done by Antonov from the Ukraine, who of course are capable at this scale, while China are not.

  6. To me the MC-21 appears just what the doctor ordered for Boeing, a plane to go up against the A321/322. So pushing forward a few years

    Boeing/Irkut/Embraer vs Airbus/Bombardier in a straight fight for dominance with winners and place fillers of equal proportions and allows Boeing to soldier on with the MAX 8 until well after I am pushing up daisies.

    This leaves Comac and Mitsubishi out in the cold. Re Comac I feel that the C919 is looking more and more like an A320 copy that is too late and too conventional to be of interest outside the China influence countries. If Russia and China decided to join forces and effectively ditch the C919 (small run of 400 to gain manufacturing expertise and put their collective forces behind the MC-21 then things could become very interesting in 5-10 years time.

    All that is needed to get the players to find a dance partner is bit of healthy recession and it looks like one is coming along in

    • You will not see UA (ala Irkut ala United Aircraft of Russia) and Boeing in the same organization.

      Russia is not going to let Boeing have that aircraft.

      Boeing is not setup to produce it.

      • I was under the impression that they have collaborated in the past, trading aerodynamic of the padded engine for knowledge in working titanium.

        I don’t see the setting up of new FAL as a major difficulty, Russia brings their skill and knowledge of the frame, Boeing brings their skills and knowledge of getting frames out of the door.

        Accepted that UAC would have to be seriously in trouble to sell but these things happen.

  7. From my little experience with Leehamnews I got the impression that it refrains covering the SSJ 100 although it passed some interesting milestones in recent years – Western Operators And operations from LCA. I don’t think one should also ignore it’s operations in Russia and elsewhere . 30 of the type were delivered in 2017 , more then C100/300 which is covered a lot. I would very much like to understand why this aircraft did manage not penetrate the American market ( where some customers are awaiting the similar much delayed MRJ ). Is it because of it’s technical merit or does it have to do something with politics.

    • Hi David,

      we have no problem covering the SSJ100. I want to wait until I can talk to a Western operator first hand, which will happen pretty soon. Then I’ll do a write-up on the aircraft.

  8. Irkut installed approximatly 500 sensors on the first prototype. What type of information these sensors provided and what are the results of the analysis of the first 33 flights?

    Also how the sensors provided info fits into the flutter situation as described in this article?

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