Tightening U.S. sanctions on Russia have interrupted the supply of foreign raw materials supply to United Aircraft Corp. (UAC), forcing the airframer to introduce yet another series of changes to the MC-21 program. Yet the company maintains that the next-generation narrowbody’s wing box and consoles will still consist of polymeric composites, even though that would require replacement of imported binding thread and resin by Russian substitutes.
The need to change suppliers arose as a result of Washington’s introduction of technology restrictions related to Aerocomposite and ONPP Technologiya, two key participants in the MC-21 program. The sanctions made it impossible for the companies to receive raw materials made in the U.S. or that use critical American technologies. Press reports in early January indicated Hexcel of the U.S. and Toray Industries of Japan have terminated shipments under earlier contracts, leaving the Russian buyers with just enough stock to build six airframes in addition to three aircraft already in flight test.
However, in a recent interview with Russian journalists, Aerocomposite boss Anatoly Gaidansky called the press reports misleading. “We never worked with Toray,” he said. “As for Hexcel, we cooperated with them at the initial phase, but then changed over to other suppliers. Instead, we were buying from Solvay, a company based in Belgium with production sites in the U.S.” That vendor terminated shipments in September 2018, shortly after Washington named Aerocomposite among other Russian companies to which technology restrictions apply.
Specializing in production of airframe parts, Aerocomposite has established production of wing boxes and consoles at its plant in Ulianovsk, using resin-transfer infusion technology that does not require big autoclaves. It has manufactured several sets of wings for the MC-21-300. Replacing foreign suppliers with local ones entails “no principal changes to the manufacturing process,” Gaidansky stressed. Yet, he admitted that shifting from imported to local raw materials “creates additional difficulties…but we have the experience that tells us how to overcome those.”
Even though Russia had amassed vast experience with composites, it did not produce the raw materials of required quality for resin-transfer infusion at the launch of the MC-21 project in 2008. Since then local makers’ expertise has progressed, Gaidansky claimed. In particular, they have already qualified for the manufacture of MC-21 control surfaces. “Right now some local vendors offer products that feature higher quality than their foreign competitors who we selected at the program launch,” he said. For the MC-21, the most difficult issue involves the wing box. To manufacture that part, Aerocomposite needs suitable resin and binding carbon thread. Gaidansky said that the latter will come from a plant in Alabuga built recently by the Rosatom corporation. “We look forward with cautious optimism,” he concluded.
Meanwhile, MC-21s continue to fly using airframes made with components from Solvay, with the prospect of type certification in early 2020. Airframes made completely of local materials will require a supplemental type certificate that would come no earlier than late 2020.
For more than five years, local scientists and industrialists have worked to perfect indigenous technologies to produce next-generation composite materials suitable for the MC-21, UAC president Yuri Slyusar noted. “Their solutions are close to serial production,” he said. “Specimens are being tested. They will be introduced into the MC-21 program step by step, as they pass through certification trials.” Another contingency plan involves the use of Chinese raw materials. In any case, any additional testing will be limited to comparison of parts made of older and newer construction materials, Slyusar said.
On January 14 the Central Aero Hydra Dynamics Institute (TsAGI) published a statement, signed by TsAGI CEO professor Cyril Sypalo and scientific advisor academician Sergei Chernyshov, to clarify the situation with the MC-21. “Raw materials and competencies created in Russia over the past few years allow for the creation of the wing and other parts in the MC-21 airframe using local materials only,” it said. At the same time, the institute acknowledged possible delays in certification that might occur as the result of “the vendor change.” TsAGI insists that the decision made ten years ago to employ the composite wings and empennage was the right one. “Therefore, the issue of a metal wing for the MC-21 is no longer on the agenda,” it concluded.