Victor 398
From Halopedia, the Halo wiki
Victor 398 was a UNSC Pelican dropship which crashed into the mountain gorge that is the Halo 3 multiplayer level, Valhalla.[1] The crash, which the crew barely survived, also scattered the Pelican's contents throughout the valley. V-398's rear hatch is sealed, presumably by the surviving crew, which denies access to the bird's interior. It was presumably on an ammunition run since the cargo it was containing was mainly ammunition.