Lan Chile is notorious for zeroing out the OWE fare classes (A/D/L) on some flights, even when there are lots of empty seats. The inventory is available "on request" ... this means your travel agent must send Lan Chile a message and they will then release an L seat for you on a specific flight. The AA RTW desk is quite good at doing this. Otherwise LA will release the seats close to the flight date, but not in advance. A really despicable practice, but one that is spreading (I ran into it on a flight that was 100% empty -- not a single seat had been sold yet but inventory was 0!!!!).