An investment group completed the $1.1 billion acquisition of avionics test equipment manufacturer Aeroflex, based in Plainview, N.Y.bAeroflex shareholders in July approved the buyout by Veritas Capital Fund III L.P., Golden Gate Private Equity Inc. and Goldman, Sachs & Co. last month. Shareholders will receive $14.50 per share. The company, traded as ARXX on the Nasdaq exchange, designs, develops and manufactures ramp testers, bench testers and automatic test equipment for both civil and military aviation.