Equilibrium (neutral buoyancy) would be nice on nine out of ten occasions in an airship. However, an airship is ballasted to achieve a desired landing weight only. There are very few exceptions, such as filming sporting events etc.
There is presently no way of re-compressing helium on board, if it were, it would loose some purity in the transaction and therefore loose lift. Certainly, it would never be (commercially in a normal flight scenario) dumped. The only occasions one would dump helium would be to increase the pressure height attainable (for altitude gain) or in a non normal circumstance. Certainly, it would not be expelled in order to descend normally. Infact, we would sometimes perform a 'pump and dump' procedure to increase purity on a leaky airframe etc (refreshing the helium)
I do agree that some form of trained staff would be required on the ground.
Keo now
