flufdriver,
I was at Aeronáutica Civil yesterday and concur with what
crack up says. They told me that there are two requirements:
1) You require approval from the Dirección General de Aeronáutica Civil for the flight to Bluefields. The required information and contact is in the
International Flight Information Manual (IFIM).
2) You need to coordinate with the Bluefields airport authorities. They will arrange for Immigration, Customs, and Police presence. Bluefields is managed by
EMPRESA ADMINISTRADORA DE AEROPUERTOS INTERNACIONALES (EAAI)
My well intentioned friend told me to advise you to make sure that you have these things in order prior to showing up, given that the Atlantic Coast is a sensitive region these days, due to the amount of international drug trafficking occuring out there these days. Hope this helps.