Bermuda Aviation Services Ltd dropped 10 percent (40 cents) on The Bermuda Stock Exchange (BSX) yesterday.The transportation company traded 2,500 shares to close at $3.60.KeyTech Ltd also fell 0.16 percent (one cent) to $6.05 with 1,900 shares changing hands.But West Hamilton Holdings Ltd rose 3.2 percent (20 cents) to $6.45 as 7,000 shares were transacted.Overall the Index slipped 1.62 points (0.14 percent) to 1,200.22 with 40,400 shares worth $106,535 traded.The BSX Insurance Index climbed 12 points (1.23 percent) to 987.