Aviansies can be found in the God Wars Dungeon; The entrance can be found by pushing aside a boulder with your strength skill, or crawling through a crack with your agility skill - the entrance is near Trollheim, just walk around the outside ring with protect from range on and you'll find it - you'll need a rope if it's your first time too. For your inventory, you should take bones to peaches tablets, some food (and a rope, if it's your first time.) You'll also need to change up your armour a bit; I'm not sure on the recommended build - but you want to be a tank, so torag's legs and helm are a good idea. Remember, you can only attack Aviansies with ranged or magic attacks. One last thing, if you're going into the God Wars Dungeon, you may want to equip an item that represents the gods Bandos, Armadyl, Saradomin and Zamorak in order for the dungeon to be non-aggressive.