How did Brian manage to recover the survival pack?

Brian managed to recover the survival pack by recalling the location where the plane had crashed. After days of survival in the wilderness, he used his resourcefulness to navigate back to the crash site, where he found the pack partially submerged in the lake. He swam out to retrieve it, overcoming his fear of the water and the challenges posed by the environment. The pack contained essential supplies that greatly aided in his survival efforts.