These are the known pieces of Flight 815 on The Island. Perhaps, with enough information, we can reconstruct Flight 815, and see if any pieces of the plane are unaccounted for.
Galley
Locke found parts of the plane's galley in Season 1. He raided it for any supplies left and later shared some of its coffee with Kate and Sawyer.
Seats
A pair of Flight 815 seats were found underwater at the pond Sawyer and Kate took a dip in Season 1. Along with them was various debris, a dead man and woman, and the Halliburton case.
Cargo Compartment
Part of the plane's cargo compartment was found in The Caves, along with some luggage and the coffin of Jack's father.
- Jack later attempted to use the Cargo Compartment's door to amputate Boone's leg.
Fuselage
The Front Section of the plane. Only The Pilot was found alive here. May possibly be located in or near the Dark Territory, due to the theory that the Security System can only attack those within the Dark Territory.
Midsection
The Middle Section is where the majority of the survivors crashed, and its surrounding area is where most of the story takes place. Unlike Tail Section, the Middle Section is probably not near the territory of The Others due to the low frequency of attacks. While some of it was burned, a good deal of it was used to build various shelters along the beach, as well as the Raft.
Tail Section
The Tail Section crashed on the far side of the island, in the territory of The Others. They didn't fare as well as the main group due to the lack of a doctor, combined with relentless attacks by the Others.