Bermuda Aviation Services Ltd shares fell 60 cents, or 15 percent, to close at $3.40 on the Bermuda Stock Exchange yesterday.Some 4,800 Bermuda Aviation Services shares traded.Butterfield Bank shares closed unchanged at $1.37 as 50,190 shares changed hands.BF&M Ltd shares closed unchanged at $17.05 as 2,545 shares changed hands.Argus Group Holdings Ltd shares ended unchanged at $3.60 as 1,735 shares changed hands.Overall the BSX fell 2.58, or 0.23 percent, to close at 1,144.11