No. Consider the case of an ellipsoid with three distinct axes, and remove the four umbilic points. Then you cannot find such vector fields on a (punctured) neighborhood of the deleted umbilics. Have a look at [this reference on umbilics][1] and try drawing the vector field on such a punctured neighborhood, and you'll see why. [1]: https://en.wikipedia.org/wiki/Umbilical_point "this"