Sukhoi's civil aircraft division has wrapped up flight-testing of its winglet-equipped version of the Superjet 100.
Two aircraft participated in the flight-test programme – airframes number 95032, built in 2013, and the later 95157 which was manufactured last year but retained by the company.
Number 95032 was originally the test airframe for the longer-range Superjet 100LR variant of the type.
Over 140 flights have been carried out for the certification campaign, which has included stability checks, controllability tests at a range of airspeeds and angles of attack, and verification of landing capability up to category IIIa.
One of the aircraft, 95157, was fitted with attachments to its wing, stabiliser and vertical fin leading edges to simulate ice accretion.
The campaign has particularly focused on fuel-burn calculations and the savings achievable using the composite 'sabrelet' winglets, manufactured by Voronezh-based VASO and available as an option on the type.
Sukhoi Civil Aircraft chief Ravil Khakimov claims the sabrelets will save up to Rb10 million ($156,000) annually for each equipped aircraft.
He says the modification is part of a broader enhancement programme intended to increase the Superjet's appeal to customers.
Russian trade and industry minister Denis Manturov says the Superjet is "constantly being improved" and that the sabrelets are designed to reduce fuel costs for operators by at least 4%.
Ulyanovsk-based firm Aviastar revealed earlier this year that it was carrying out a cabin fit on a winglet-equipped Superjet for Russian operator Severstal Aircompany.