MOSCOW—A Russian prototype military transport plane crashed while performing a test flight outside Moscow on Tuesday, killing all three crew members on board, Russia’s United Aircraft Corporation said. The new light military transport plane, Il-112V, crashed in a forested area as it was coming in for a landing at the Kubinka airfield 45 kilometers (28 miles) west of Moscow, the corporation told the Tass news agency. Two test pilots and a flight engineer were aboard the plane, and none survived, the corporation said. The Baza online news outlet posted a video in the messaging app Telegram of an airplane crashing into the woods after one of its engines caught fire. Russian police have opened a criminal probe into the incident, as is usual in such cases. The plane flew to the Moscow region last week and was set to be unveiled at the Army-2021 forum later this month. It is …