SuperJet International has secured another key export order for the SSJ100 airliner, while acknowledging that certification of the type has stalled once again. Sukhoi now expects Russian approval for the 100-seater at the end of January–a month past the most recent slipped deadline of December 28.

At a press conference today in Venice, Italy, Mexican airline Interjet signed a $650 million contract covering firm orders for 15 SSJ100s and options for five more. Interjet currently operates 22 Airbus A320s and holds an order for a dozen more. According to Miguel Aleman Magnani, the operator’s executive president, Interjet chose the SSJ100 because it offers the performance to cope with high-altitude locations, such as Mexico City (8,057 feet msl) and Toluca (9,186 feet msl).

“We will receive our aircraft in a low-density configuration, with 93 seats and a 34-inch pitch, the same adopted on our A320s, to maintain our brand image as a comfortable low-cost airline,” Aleman Magnani told AIN. Interjet expects to receive its first SSJ100 in July 2012, following cabin outfitting by SuperJet International’s Venice, Italy factory in the spring of that year.

Mikhail Pogosyan, general director of SuperJet’s main shareholder, Sukhoi Civil Aircraft, said that the company has finished all SSJ100 flight testing. He predicted that authorities would issue certification by the end of January, followed by first deliveries to Russian carrier Aeroflot and Armavia of Armenia in March.