airplane watching questions

Date:         17 Mar 2001 08:33:39 
From:         "Jeff" <jcbowen.nospam@home.com>
Organization: @Home Network Canada
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Hello folks.

I indulged myself today in driving out to Pearson airport here in Toronto
Canada to watch planes land.

I had a fun time but came up with a few questions I hope someone (or
someone_s_) can answer.

1.  Most of the airliners seemed to follow an identical path down to the
runway but every so often one would tip its wings back and forth a little
bit on the approach.  Were the planes that were making these adjustments
making manual landings and the others making computerized landings?  What
proportion of airliner landings at an airport like Pearson International are
flown automatically by a computer locked onto a beam?

2.  It was a cool afternoon (temp had dropped to about 12 C) and very humid
(raining on and off and very low cloud cover).  Most of the planes landing
had a streamer of water vapor trailing from the wingtips like smoke
streamers and some had a cloud of vapor on the upper surface of the wings.
Someone once explained this to me and I forget what it is.  Something to do
with low pressure around the wing?

3.  I've always noted that the larger the airliner, the slower it appears to
be moving in the air.  Today, the big planes seemd to be slowly settling out
of the sky and the occasional executive-type jet appeared to be 'whistling'
down out of the sky.  Is this an optical illusion?  I am assuming it is and
may have to do with the fact that a long plane takes longer to travel its
own length than a shorter one?

Thanks in advance to anyone who can take a crack at any or all of these
questions!

Jeff