Crashed Phantom on Metropolis

While fooling around on Metropolis at Heroic difficulty, I noticed this crashed Phantom. Normally this Phantom drops off the second Wraith tank when you advance far enough along the bridge. However, in this case, when it appeared, I was with two marines in a Warthog. When the Phantom and its Banshee escorts arrived, I returned to the beginning of the bridge to retrieve the Scorpion tank. When I advanced 3/4 along the bridge, I found the Phantom embedded in the bridge surface, with the Wraith still attached below.