Locate the Second Pilot | 10: Guilty Conscience Walkthrough Tomb Raider Guide

Move ahead along the linear path and after a while you'll reach a new location called the Mountain Pass. Start exploring the cave system, lighting the way with the torch (there are no "primary" collectibles here, only some crates). You can rest in the base camp on the way (Arid Canyon).

It shouldn't take long for you to reach the spot where the second pilot is. Approach him to trigger an interesting cut-scene and advance to the next stage of the game.