According to UAC, NAZ "Sokol" is being involved in the production of MC-21 "due to the heavy workload of other aircraft enterprises", and a section for the production of the sub-keel compartment (SKC) and the necessary equipment is already being actively prepared there. The plant's specialists have studied and analyzed the equipment, materials used, assembly and riveting processes at other enterprises, after which they decided to divide the preparation for the production of the SKC into two stages.
The first stage involves стыковка гермоднища шпангоута 60 с ободом, the final assembly of the compartment from the upper and lower sections received from an adjacent enterprise, внестапельные works — installation of systems, final assembly, доклёпка of seams and subsequent transfer of the compartment along the cooperation chain. The second stage is the transition to a full cycle of sub-keel compartment assembly, which requires the availability of special equipment for automatic riveting at the enterprise, the need for which is laid down in the design documentation.
The complex for automatic riveting is the first complex for the aviation industry being created in Russia with the support of the Ministry of Industry and Trade of the Russian Federation. It is not yet available; it is being developed by the Central Aerohydrodynamic Institute named after prof. N. E. Zhukovsky.
Otherwise, the SKC assembly section for the MC-21 in the aggregate assembly shop is ready for operation and awaits the supply of SKC elements for assembly from cooperators as part of the first stage. For the second stage, equipment for assembling panels, upper and lower sections has already been designed and put into production. Duplicates of slipways are also already being produced to ensure a large volume of aircraft production in the near future.
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