Frequency tests for medium-range airliners, such as the MC-21, usually take from a few weeks to two months. However, the cycle may be extended, compared to Western aircraft, due to the integration of new domestic systems, according to the Gromov Flight Research Institute.
The duration of the tests depends on the number of units being tested and the scope of certification requirements. As part of the tests, engineers initiate structural vibrations at different frequencies, record vibration parameters, and evaluate the performance of the systems being tested.
After each stage, the collected data is analyzed and compared with the requirements established by aviation regulators. The tests should cover all major operating modes, including various landing gear and wing mechanization configurations.
The results of the frequency tests are documented in a report, which is submitted to the certification authority for subsequent admission to flight tests.
Earlier www1.ru reported that 14 SSJ-100 aircraft were found to have defects in the fuselage structure.
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