The maritime fitout, or at least parts of it (as far as I'm aware) can be taken out and seats fitted instead.
None of the actual mission equipment is removed. The saros and photographers seats are removed as well as the flare launcher to give room to standard (small) airline seats, more of which are fitted along the port side of the cabin. The larger 'Club' seats(x4) in the crew rest area can also be replaced by an extra row of smaller seats making 6 instead of the standard 4.
The rear panel of the aft cabin, the equipment cabinet and the raft launcher are also removed to allow unhindered access via the ramp.
