While the reports of the stealth fighters arriving in Syria are unconfirmed, it would be highly unusual to deploy a developmental asset into a combat zone before it is ready for war. Indeed, the Russian move—if confirmed—would be the equivalent of deploying the Lockheed Martin F-22 Raptor into combat during the late 1990s or early 2000s while the jet was still in the engineering manufacturing development (EMD) phase. However, deploying a developmental jet into combat to gather operational experience and data might not be unusual from the Soviet/Russian perspective.
“This is testing in actual war. The Soviets did that,” Vasily Kashin, a senior fellow at the Center for Comprehensive European and International Studies at Moscow’s Higher School of Economics, told The National Interest.
The main purpose of the deploying the Su-57 to Syria is to gather as much operational experience and performance data as possible on the jet’s avionics. Not only can Russia test the performance of the Su-57’s active electronically scanned array radar and electronic intelligence packages, there is an opportunity to perform some limited combat missions.