The Schayne Plains Plains are seen in Ace Combat Zero: The Belkan War. The Schayne Plains are located in central North-Osea / South Belka and have many large hills; most of them are covered in dense pine trees. A river twists among the hills on its way to the ocean. A large, deserted base lies to the northwest. To the south there are massive scars in the earth caused by Excalibur, the superweapon that was fired for what was believed to be the second time, at Allied aircraft.
The Belkan War - Operation Dynamo
During the Allied Force's Operation Dynamo, Alpha, Beta and Theta teams were launched into combat against three key Belkan Postitions in the Schayne Plains. The plains acted as Belka's second defense line. Alpha Team was assigned to engage an enemy Anti-Aircraft base, backed by Belkan Armored Elements. Beta Team engaged a second large anti-air base, which also incorporated Aircraft and Theta Team engaged Belkan Air Force aircraft. Together each team cleared the Schayne Plains and allowed Allied Escorts to move north.
engaged and destroyed many Belkan forces
before Excalibur was fired at the Demon Lord's posistion. It missed him, and he destroyed the cannon four days later during Operation: Judgement.
Sources
Ace Combat Zero: The Belkan War (the game)
Official Ace Combat Zero Website by "Project Aces" - http://www.acecombat.jp/ace-zero/top.htm