Bermuda Aviation Services fell 15 cents (4.28 percent) on the Bermuda Stock Exchange yesterday, trading 19,000 shares to close at $3.35.Butterfield Bank also dropped one cent (.80 percent), trading 280,411 shares to close at $1.23.BF&M and KeyTech traded shares to close at $16 and $6, respectively.The BSX closed at 1,069.32, down 5.39 points (.50 percent), trading 301,411 shares worth $425,555.53