On Mon, 7 Nov 2011 11:31:17 +0000 (UTC), d
wrote:

On Mon, 7 Nov 2011 11:05:47 +0000
Roland Perry wrote:
In message , at 11:02:14 on Mon, 7 Nov
2011, d remarked:
That only goes back 12 years, go back to the mid 80's and the
improvement in the noise signature seen today is staggering.

Except there are probably 3 times as many plane movements now which rather
offsets any reduction in engine noise.

Heathrow was operating at 35% of capacity 12 years ago? Pull the other
one.

I was talking about compared to the 80s when air traffic control systems
were a lot more primitive. Probably 3 times is overstating it but its still a
lot more than back then.

It is quick and easy to go back to 1990 with verifiable sources

But this shows further back to 1986 (but their source is unknown)

http://en.wikipedia.org/wiki/File:Lo...Statistics.png

But ignoring that graphic the number of aircraft movements per day has
remained static at below 1300 for the past decade

Column 177W
http://www.publications.parliament.u...00323w0004.htm


2010 454,823 aircraft movements
http://www.caa.co.uk/docs/80/airport...ments_2010.pdf

2010 65,881,660 Passengers
http://www.caa.co.uk/docs/80/airport...to r_2010.pdf

1990 390,372 aircraft movements
http://www.caa.co.uk/docs/80/airport...ments_1990.pdf

1990 42,950,512 Passengers
http://www.caa.co.uk/docs/80/airport...to r_1990.pdf


So that is 53% more passengers over the past 20 years from 1990-2010,
with 16.5% more 'total' aircraft movements, (not all of which are
passenger aircraft) The vast majority being operated by more modern
aircraft, which like it or not, are significantly quieter than those
around in the mid 80's - 12dB is typical, sometimes it's more, and
that is a HUGE reduction.

Compare a screamer like a DC9 that British Midland used to use in the
early 90's into Heathrow to the Fokker 100 that replaced it in the
late 1990's. The 747-100/200 compared to a 747-400, or a
737-100/200 compared to 737-NG. How about a BAC 1-11, compared to a
A318, or a 727 compard to an A320.

The sooner they start building that thrid runway the better and in
parallel build Boris Island.


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