Helikopter-Streichquartett

thumb|upright=1.4|Dutch Grasshoppers aerobatics team, flying the Aérospatiale Alouette III|Alouette helicopters they used in the world premiere of the Helicopter String Quartet The Helikopter-Streichquartett () is one of Karlheinz Stockhausen's best-known pieces, and one of the most complex to perform. It involves a string quartet, four helicopters with pilots, as well as audio and video equipment and technicians. It was first performed and recorded in 1995. Although performable as a self-sufficient piece, it also forms the third scene of the opera Mittwoch aus Licht ("Wednesday from Light"), from the opera cycle Licht.

==History== thumb|Irvine Arditti, leader of the [[Arditti Quartet, who premiered and made the first recordings of the Helicopter Quartet]] The Helicopter Quartet was originally commissioned by Hans Landesmann of the Salzburger Festspiele in early 1991. Stockhausen's initial reaction was that he was not interested in writing a string quartet, but then one night he dreamed he was flying above four helicopters, each carrying a member of a string quartet; he could see into and through the transparent helicopters. He subsequently made some sketches and plans, but it was not until 1992–93 that he found the time to compose the quartet. By this time, he had had several more dreams concerning the piece, including one involving a swarm of bees and a violinist, about which Stockhausen said, "The buzzing made by lots of bees is a magic sound to me". The Arditti Quartet was to play the première. After Stockhausen finished his score, it was sent back to Landesmann for criticism. His reaction was positive, as was that of the Director of the Festspiele, Gerard Mortier. A long series of negotiations started with the Festspiele and the Austrian army, who were to lend the helicopters, as well as various TV channels who were airing the piece. In part because of protests by the Austrian Green Party, that it would be "absolutely impossible for Austrian air to be polluted by performing this Stockhausen", in the end the planned 1994 première had to be cancelled.