I guess it's equivalent to the A2 (maybe B1) Common European Framework level. You should be able to have a basic conversation:
-Can understand sentences and frequently used expressions related to areas of most immediate relevance (e.g. very basic personal and family information, shopping, local geography, employment).
-Can communicate in simple and routine tasks requiring a simple and direct exchange of information on familiar and routine matters.
-Can describe in simple terms aspects of their background, immediate environment and matters in areas of immediate need.
Imagine you're a Belgian Dutch speaking passenger and talk to the pilot of a Belgian airline who doesn't speak dutch at all, that wouldn't give a good impression of the airline...