All the ILS is supposed to do ( whether you chase the needles manually, or let the autopilot hold the approach ), is to get you to where you can see the runway, and then land the aircraft yourself.
Making a smooth landing by ILS, or any other method, is still up to you, the pilot. So, you're really asking, "How do I make a smooth landing?"
A smooth landing starts with a stabilized approach.. If you haven't mastered, textbook, by the numbers flight in a small, slow trainer (like a C172).. trying to land a big jet by ILS will be a frustrating, crash-filled "
trying to run before you can crawl" saga :)
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