The added complexity of the hyd system can be a problem. In the early days of the Puma in the RAF I lowered the gear at the end of a night sortie. The pressure in the nose jack blew the end off leaving me with only the two mains down. Raising the emergency gear lever stopped the remaining hyd fluid dumping, so at least I got the AP back. Oh, and I was low on fuel, so had to do a refuel in the hover while sandbags were obtained to build a mound for the nose area during landing.