Aviation Fleet Solutions (AFS) and Pratt & Whitney are unveiling at Paris a newly tested Chapter 4 noise-reduction system for the JT8D-200-powered Boeing MD-80 series, which the partners claim will cut overall noise by up to 6dB. The “Quiet MD-80” noise-reduction system has been developed in two configurations for high- and light-gross-weight applications, and for the former is priced at around $825,000 per aircraft, with an installation time of one day. “We’re making a big push at the Paris air show,” says AFS president Kevin Bartelson. The modification enables MD-80s to comply with Internatiional Civil Aviation Organisation Chapter 4 rules coming into effect in 2006.
The kit includes a modified fan case liner, developed by P&W several years ago to counter potential blade-out events, but which produced around a 1dB noise reduction from the high frequency fan sound.
“However the big issue is the noise at the back end where we have a new internal advanced technology mixer,” says Bartelson. The mixer has 16 primary lobes, in addition to a further 16 mini-sublobes, compared with the original 12 lobe design.
“We’re also adding a muffler [silencer] to the engine, by replacing the tail plug in the centre of the mixer with a muffler.” The only external evidence of the package is a “tabbed nozzle”, which is made up of chevron type shapes around the trailing edge. The kit adds 66.3kg (146lb) per engine.
Source: Flight International
