A hush kit is a device for reducing noise from an engine; most commonly the term refers to devices which reduce noise emissions from turbojets. An engine is something that produces some effect from a given input. ... A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ...

Jet aircraft generate a considerable amount of noise, contributing to noise pollution near airports. In modern turbofan engines, a fan is mounted before the actual jet engine, accelerating and cooling the airflow around the core engine, reducing its noise emissions. A hush kit produces a similar effect, mixing the exhaust gases of the old engine with the surrounding air and reducing its noise output. Jet aircraft are aircraft with jet engines. ... Noise is unwanted sound. ... Car stereo advertisement. ... CFM56-3 turbofan, lower half, side view. ...

Modern aircraft, equipped with high-bypass turbofan engines, are able to comply with contemporary aviation noise abatement laws and ICAO regulations. Hush kits are used on the many older freight and passenger aircraft stil in service, such as the B-727, DC-9 and DC-8. They are also deployed on smaller business and personal jets which are too small for turbofans. A high-bypass turbofan engine is a turbofan with a bypass ratio of at least 5. ... Aviation noise is a form of environmental noise. ... Abatement (derived through the French abattre, from the Late Latin battere, to beat), a beating down or diminishing or doing away with; a term used especially in various legal phrases. ... The International Civil Aviation Organization (ICAO), an agency of the United Nations, develops the principles and techniques of international air navigation and fosters the planning and development of international air transport to ensure safe and orderly growth. ... Sun Country 727 The Boeing 727 was, for a very long time, the most popular jet-liner in the world. ... The Douglas DC-9 is a twin-engined jet airliner, first manufactured in 1965 and, in much modified form and under a succession of different names, still in production today as the Boeing 717. ... The Douglas DC-8 is a four-engined jet airliner, manufactured between 1959 and 1972. ...

While hush kits effectively reduce noise emissions from older aircraft, noise cannot always be reduced to the level of modern planes at a reasonable cost. In 1999 this has led to a dispute between the United States and the European Union. The EU's proposed noise ordinances effectively prevented the use of hush kitted aircraft in Europe, reducing the value of the mostly American used airplanes so equipped and hurting the profits of American hush kit manufacturers. EU Regulation 925/99 passed over US threats to ban the Concorde, but was superseded and effectively repealed bu EU Directive No. 2002/30/EC issued March 26, 2002. 1999 is a common year starting on Friday of the Common Era, and was designated the International Year of Older Persons by the United Nations. ... World map showing location of Europe A satellite composite image of Europe Europe is geologically and geographically a peninsula, forming the westernmost part of Eurasia. ... The Aérospatiale-BAC Concorde supersonic transport (SST) was one of only two models of supersonic passenger airliners to have seen commercial service. ... March 26 is the 85th day of the year in the Gregorian Calendar (86th in leap years). ... 2002 is a common year starting on Tuesday of the Gregorian calendar. ...

External link

• BBC News, "Hell-bent on a trade war (http://news.bbc.co.uk/1/hi/business/the_economy/291304.stm)," March 5, 1999