[sa226]

Yea, its probably The NavCanada dudes testing the Navaids (ILS)

It is kinda fun to watch them because they don't fly the approaches like an airliner would, they do it clean and at high speed. Almost TOP GUN like.

They were probably circling around in a Hold, to allow other aircraft to land. I'm not sure how many times they will shoot the approaches, but at a busy airport like YYC they won't be able to get them in back to back. ATC will have to put them in a hold to fit the other guys in.

ILS stands for Instrument Landing System. It is a precision system independent of GPS (or WAAS, GNSS etc, etc) That depending on aircraft\airport equipment and certification can get you as low as 100ft.

There are basically 2 types of instrument approaches: Precision and Non Precision, and a few different ways to navigate those approaches. (GPS vs Traditional Navaid)

The two main differences between Precision and Non precision is:
1) Precision approaches typically allow you to land with lower minimums (crappier weather) than Non Precision
and
2) Precision approaches give you lateral and vertical guidance. Non-precision only gives you lateral guidance.

For example in on a precision approach you have a little bar to follow to make sure you stay on your lateral track , and also a little bar to follow to make sure you stay on your descent slope. On a non-precision, you only have a little bar to follow for your lateral tracking. For your descent profile, it is only guidelines of when to descend by what point. So slope vs step down.


Wow did I ever go off on a tangent....