Helicopters have several advantages over conventional fixed-wing aircraft, but so far as future operation on a wide scale is concerned, one of the most important may well be that they can be operated successfully in or near to city centres. Their acceptability to the general population depends principally on the effects of noise produced by them but no national or international standards exist at present which specify the maximum noise levels and /or the number of movements permissible for city-centre operation. There are many regulations pertaining to aircraft noise near to airports and to various noise sources in cities but none of these can be directly applied to helicopters.

The problem has been considered by the Committee on the Planning of Helicopter Stations in the London Area, which was set up by the Minister of Aviation in 1959, and whose report was published in 1961, the Wilson Committee on the Problem of Noise who reported in 1963 (Cmnd 2056), in the United States, particularly by Messrs Bolt, Beranek and Newman and also many others. It is not possible to review the literature in this short paper which gives some account of the practical work and considerations concerning the use of helicopters in London with which the author has been associated.