This doesn't answer your question Robert, but you are right about the weather that can heavily distort the jet engine noise. My office is close enough to the airport to hear the "take-off max thrust" but yesterday these were barely recognizable during a time of particularly stormy weather.
Also, I suggest that a strong noise shows either:
a) A very old set of engines
b) An aircraft special enough that no one cares (or dares to comment
) about the noise.
And the reason is the revolutionary change in the jet engine design since the B747,which uses a jet of cold air surrounding the active part of the engine and mixing with the hot exhaust gases. This design reduced dramatically the engine noise.
It's funny to look through such an engine because it looks like it's 75% "empty", one can see the landscape behind it
I could hear this by myself some 10 years ago when I worked for several months quite under the glide slope at Orly, Paris. When aircraft were not landing but taking off above us, older B737 did signficantly more noise than B747s.
To put it shortly: old "thin" engines do much more noise than newer "fat" engines. And they're more fuel-effective too. So "your" aircraft is probably old. Very old. Older than me, I mean
Andrei
