The composite wing of the MC-21 became the subject of new questions after assumptions about its resistance to kerosene exposure emerged. In an interview with “Pervy Tekhnichesky” Honored Pilot of the USSR Oleg Smirnov did not confirm information about possible problems with the wing due to kerosene, but drew attention to the temperature fluctuations that the structure experiences during operation.
He drew attention to the significant temperature difference that the aircraft can experience during operation: from high positive temperatures on the ground (+40 °C) to significantly lower temperatures at cruising altitude (-60 °C).
Composite is a new thing. And under certain conditions, they begin to delaminate. I don't know about fuel exposure, but the temperature changes constantly.
According to Smirnov, it is composite material specialists who should identify possible risks and necessary preventive measures.
Earlier, the former head of the Ulyanovsk branch of “Tupolev” Stanislav Ryzhakov stated that “composites are afraid of kerosene”, and expressed doubts about the sufficiency of checks of the MC-21 composite wing for fuel exposure.