Sukhoi's Superjet underperforms due to engine problems, customers complain. SSJ100s have been delivered to airlines since 2011, but so far they fly very little. The average flight time of the aircraft in Russia became 3.3 hours per day in 2017. The reason is the shortage and long delivery time of spare parts in case of breakdowns. The Embraer E170, which began to fly exclusively on short regional routes of S7 Airlines, flew last year around six hours per day. Airbus 320 and Boeing 737 family jetliners flew at an average of ten hours a day in the same period with the Russian carriers.