Astrojet From Germany, joined Aug 2000, 565 posts, RR: 2 Reply 1, posted (12 years 7 months 4 days 4 hours ago) and read 603 times:
This are noise regulations.
Stage I are the loudest planes like the DC 8-30 or the Trident and I believe they had to quit operations on January 1st 1986.
Stage II are planes like DC 9-30 or B 737-200 and they have to quit on January 1st 2002.
Stage III are the silent planes like the B737-300 and up or A 320.
I still remember in the seventies, when I was a kid and went close to the runway to see those stage I planes take off, that was noisy! even the ground was shaking like a small earthquake! and then the black smoke. Things we never gonna see again.
Astrojet From Germany, joined Aug 2000, 565 posts, RR: 2 Reply 3, posted (12 years 7 months 4 days 4 hours ago) and read 601 times:
Well , the regulation only cares about the noise in db. (I don´t know if in english you write decibels), but it may fit pretty good to that categories of engines.
Trintocan From United Kingdom, joined Apr 2000, 3191 posts, RR: 4 Reply 5, posted (12 years 7 months 4 days 3 hours ago) and read 596 times:
Lahaina you are generally correct about the noise levels of the different categories of jet engines fitted to airliners. Older planes such as Stage I or II types are only able to continue in service by being modified to reduce noise levels. This can be done by fitting hushkits to the engines or putting on new engines altogether. For instance, many 727s are hushkitted while others have had JT8D-217A/C engines (as on MD80s) fitted on the outboard pylons. Hushkits reduce the power of the engines, though, so that in the case of some 727s winglets have been added to improve performance.
As Astrojets said, though, even hushkitted planes will eventually have to be retired. Concorde is (was) the only exception - it has an ICAO waiver which permits its continued service despite its extremely high noise levels. That is because it cannot not fly at supersonic speeds if hushkitted and, in any case, kitting it is not practical. The small numbers of them in service may also have been considered.
OO-VEG From Netherlands, joined Oct 2000, 1081 posts, RR: 1 Reply 6, posted (12 years 7 months 3 days 23 hours ago) and read 588 times:
Nowadays every new (civil) aircraft is stage III, so will there be a stage IV sometime (or is there already a stage 4)??? That would be very handy for lots of airports who struggle with noise regulations.
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