Sukhoi has finally handed over the first Superjet 100, to Armenia's Armavia, while heated discussions surround the initial delivery to the next customer, Aeroflot.
An Armavia crew piloted aircraft 97007 - registered EK-95015 - from Komsomolsk-on-Amur, via Novosibirsk, for the 19 April ceremony.
"This event opens a new stage of the programme," says Sukhoi Holding general director Mikhail Pogosyan. "The beginning of commercial operation and full-scale serial production."
He promises "timely and high-quality after-sales support" for the PowerJet SaM146-equipped aircraft.
Armavia, which originally signed for the Superjet in September 2007, intends to use it for services to Moscow, St Petersburg, Sochi and cities in Ukraine.
"Most likely we'll deploy it on the premier Yerevan-Moscow route for an inaugural flight," says Armavia representative Gagik Sarkisyan, adding that the next delivery will probably be in May.
Sukhoi says the first delivery to Aeroflot, aircraft 97008, must also happen "sometime in May", while the carrier appears to have slipped first services at least to June, with sources pointing to 13 June to coincide with a St Petersburg economic forum.
"We're discussing terms of delivery with Aeroflot management in a friendly manner," says Sukhoi, adding that deliveries are still within a previously-agreed timeframe.
But Russian transport minister Igor Levitin, speaking days before the Armavia handover, said Aeroflot management was preparing to petition the government for "implementation of sanctions against [Sukhoi] for delays".
"We need to act according to how Aeroflot will be accepting these aircraft from the manufacturer, knowing that the promised delivery times have passed," he says, adding that Aeroflot has question over the aircraft's technical performance.
Sukhoi has yet to disclose operational performance data but a source close to the programme says the difference between actual and promised cruise fuel-burn is around 1-3%, while another source specifies the figure at 1,959kg per block-hour.