§ Mr. Mather
asked the Secretary of State for Trade and Industry what technical information is available to his Department on the limits to the reduction of aircraft noise.
§ Mr. Onslow
There may be physical limits to the reductions that can be achieved in aircraft noise from engine and aerodynamic sources. As engines become quieter, airframe noise becomes more significant. Limited information on some existing large jet transport aircraft indicates that on the landing approach the noise level of the airframe alone is about 8–10 EPNdB below the level measured with engines running. The full extent to which aerodynamic noise may be reduced in future designs is not yet known and my Department is supporting research directed towards better understanding of the problem.