NIZHNY NOVGOROD, January 29 (RIA Novosti) - A prototype Ilyushin Il-76MD-90A (also known as the Il-476) heavy-lift transport plane completed its first prolonged test flight on Tuesday, its manufacturer Aviastar said.

The flight, which lasted four hours and 25 minutes at altitudes of up to 10,000 meters (33,000 feet), was designed to assess the performance of its onboard avionics, engines, automated control system, and other characteristics, Ulyanovsk-based Aviastar said.

The prototype will soon be sent to the Zhukovsky flight test center near Moscow for further trials.

The Il-76MD-90A is an extensively modernized version of the forty-year-old Il-76 military transport aircraft, fitted with a new wing, fuel-efficient high-bypass Aviadvigatel PS-90A turbofans, and a modernized cockpit with so-called "glass cockpit" displays, allowing the flight crew to be reduced to three people.

Russia's Defense Ministry signed a contract last October for delivery of 39 Il-76MD-90As, to be built before 2018.

Aviastar hopes to build up to 100 such aircraft by 2020 for Russian state customers, the company has previously said.