Don’t know pinochle, but how do you get 3 identical aces with only two decks in a double-deck game?
Pinochle deck has 48 cards...9 through Ace for two sets of each suit. Now double that for double deck of 96 cards.
Pinochle starts out as a weird game. Single deck pinochle is played with a deck of 48 cards consisting of two sets every card from the nine through the Ace in all four suits. Thus there would be two nines of spades, two tens of spades, two jacks of spades, two queens, two kings, and two Aces. Repeat for hearts, diamonds and clubs. Now, it gets gets a bit weirder. The order of priority of the cards from highest to lowest is Ace, Ten, King, Queen, Jack, Nine.
When you play double-deck Pinochle, you toss out the nines. That way when you deal them you will be able to handle the resulting cards in your hand without too many cards. When four people play, each player gets 20 card's dealt to them. If the nines were still in the deck, 24 would be more to handle and it get's awkward. The nines slow down the play, so most people toss them. Double-deck is played with 80 cards, instead of 96, with four Aces, Tens, Kings, Queens, Jacks in each suit.