Dallas--American Airlines will outfit 52 of its fleet of 78 Boeing 727-200 airliners with the Raisbeck Engineering (Seattle) noise-reduction system, allowing the aircraft to comply with U.S. noise standards that go into effect on January 1, 2000 (DN 7/21/97, p.26). The system lowers drag and aerodynamic noise by reducing the degree to which the wing's leading- and trailing-edge flaps are extended during takeoff and landing. Thus engine thrust levels can also be trimmed, cutting engine noise as well.
The latest version of the Raisbeck system permits takeoff weight of 178,000 lb, up 11,000 lb from before, by optimizing (thus lessening) the leading-edge flap extension for the reduced trailing-edge values, not the original extensionswith their greater drag numbers. The airline needed the higher takeoff gross weight for greater payload, range, and operational flexibility. The modified aircraft will be delivered starting this September.
Richard Cherney, American's managing director for fleet acquisition, says the 727s are currently used on routes north and east from the Dallas hub; south and east from Chicago; and along the east coast and in the Caribbean from Miami. Use of the Raisbeck Engineering kits will allow the airplanes continued use along these airways.
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