Sukhoi and Siberian carrier Yakutia have moved back the delivery date for two Superjet 100 regional jets to 2012.
The airline placed a firm order for both aircraft through Finance Leasing Company in 2009 with a view to receiving them in 2011.
During the MAKS air show in Moscow last week, the two sides renegotiated the supply terms, based on a confirmation letter from Sukhoi.
Yakutia managing director Ivan Prostit said: "Delivery is now tentatively to take place next year after the manufacturer completes cold weather trials to operate the Superjet 100 in temperatures below -40C.
"Our pilots are to take training at Sukhoi Superjet International for several weeks ahead of the first delivery. We'll put the aircraft into commercial service after they make familiarisation flights from Yakutsk."
In 2010, Yakutia saw its traffic increase by 37% to more than 900,000 passengers.