Flight tests have started in Russia on the first production model of the Sukhoi Su-35S multi-role fighter, the company has confirmed.
Sukhoi chief test pilot Sergey Bogdan completed a 1.5h flight with the Su-35S from Komsomolsk-on-Amur airport in Siberia, checking the aircraft's two major advances - NPO Saturn 117S engines and the MNPK Avionika KSU-35 fly-by-wire control system.
The test programme is focused on obtaining the Russian air force's acceptance that the aircraft meets its requirements, said Sukhoi.
First flight of the production model comes two years after the programme's biggest setback. On 29 April 2009, the third Su-35S prototype was wrecked during high-speed ground tests, with test pilot Yevgeni Frolov ejecting unharmed.
The Russian air force has ordered 48 Su-35s for delivery up to 2015. Adding the first production model to the test programme has accelerated the flight-test schedule this year, Sukhoi said.
The Su-35 features several major changes from the Su-30MKI series. Besides the engines and fly-by-wire upgrades, the S-model dispenses with the distinctive canards and air brake of the Su-30-series. The aircraft's structure also includes more titanium to increase service life to 6,000 flight hours or 30 years of operation, with 1,500h or 10 years between overhauls.