Originally Posted by pandaperth

On the RJ web site it states there is an airport tax of $20
http://rj.com/en/destinations_airports.html
So it looks the tax is genuine and not a rip-off

To cross-check I priced up a 1-way KRT-AMM flight on itasoftware, it shows only one tax
Sudan Passenger Service Charge (NY) 35.00SDG

There are a few countries that still collect an exit tax directly off the passenger - it is not included in the taxes you pay when you buy your ticket (Philippines and Bolivia come to mind)