Shares of Bermuda Aviation Services Ltd made a rapid descent in Bermuda Stock Exchange trading.BAS dived 49 cents, or 32.7 per cent, to close on a 52-week low of $1.01, as 200 shares changed hands.Butterfield Bank, the only other stock to trade, gained 18 cents, or 0.5 per cent, to close on $34.97 as 288 shares were traded.Butterfield’s US-listed shares also gained ground, climbing 48 cents, or 1.36 per cent, to close on $35.83 on the New York Stock Exchange.The Royal Gazette/BSX Index gained 5.82 points, or 0.25 per cent, to close the day on 2,294.4.The BSX Insurance Index fell 5.81 points, or 0.34 per cent, to close on 1,695.81.