This letter is based on an order issued in late 2012 that was to take effect 01Aug13 effectively banning commercial operations from Aeroparque by any Argentine airline other than Aerolineas Argentinas / Austral.
This is the latest chapter in a long-running conflict between the Argentine government and LAN Argentina where the government has repeatedly enforced measures that have been disadvantageous to the carrier's operations in the country. See blog entry from 20Dec12:
The seriousness of the situation is underscored by the fact that LAN's CEO, Ignacio Cueto, interrupted a trip to Colombia to inaugurate the country's first biofuel flight to fly to Argentina to negotiate with airport authorities.
It will be interesting to see if the police show up at Aeroparque in ten days to forcibly remove LAN from the hangar.