@Stichhom
Thanks, I'm happy to hear that you find the thread interesting.
Regarding altitude or flight level:
SA is divided into airspace sectors, of which each has certain altitude limitations and restrictions. This will depend on where such an airspace is situated - i.e. how far from controlled airports, restricted and danger areas and so on.
Generally, airspace far away from controlled areas only start from 1,500 ft AGL (above ground level). If you fly at or below 1,500 ft, you broadcast on the general frequency, which is 124.8 mHz. This is also the frequency for most uncontrolled airfields in SA. You basically broadcast all your intentions: who you are, where you are and where you are heading.
When arriving at an unmanned field, you will announce from which direction you're inbound from, your estimate for the field, at what altitude you will join and and after doing the wind check, how you will be joining the circuit and which runway you'll be using.
The 1,500 ft limit is called transition altitude. This means that when you climb higher than 1,500 ft AGL, you are entering controlled airspace. The rules are that you then must contact the relevant control center on their designated frequency. They will then give you a transponder squawk code, which upon entering it into your transponder, will enable them to see you on radar.
You then also set your altimeter to standard 1013 hPa and then you are flying on flight levels, NOT altitude. This basically means that all aircraft, which are flying at or above the transition altitude, in the same airspace, will be on the same altimeter setting, which ensures correct altitude spacing between traffic flying on opposite directions. Obviously in order to avoid midair collisions.
So altitude basically refers to the local altimeter pressure setting and your altitude displayed will be the actual height AMSL (above mean sea level). Your height above ground will be whatever the the actual surface level will be in that area.
Flight levels will be displayed according to the standard 1013 hPa altimeter setting and will NOT be your actual height above either MSL or AGL.
Furthermore, flight levels are set out and are to be applied as follows:
If you fly VFR (visual flight rules):
For all compass headings from 0-179 degrees, you will fly at odd plus 500 levels: 1,500; 3,500; 5,500, 7,500 ft and so on.
For all compass headings from 180-359 degress, you will fly at evens plus 500 levels: 2,500; 4,500; 6,500; 8,500 ft and so on.
This results in a 1,000 ft separation between two aircraft flying opposite to each other.
If you fly IFR (instrument flight rules) the same as above applies, except that you will fly at odds or evens, without the plus 500 ft.
0 to 179 degress: 1,000; 3,000; 5,000; 7,000 ft and so on.
180 to 359 degress: 2,000; 4,000; 6,000; 8,000 ft and so on.
So separation between IFR and IFR will be 1,000 ft, VFR and VFR will be 1,000 ft and IFR and VFR will be separated by 500 ft.
This is helpful for them to follow your progress and to warn you of any other traffic which could inflict on your flight path. On reaching the point where you need to descend to the circuit altitude of your destination, or to avoid restricted or other airspace, you will ask the control center permission to descend.
They will comply and normally they ask you to report next when 10 nm inbound to your destination, or when you have the field in sight - this is for uncontrolled fields.
If you are going to enter another sector or controlled airspace enroute, ATC will hand you over to them, on their designated frequency and they will follow you further along your planned route.
The regulations further state:
When intending to land at a controlled field, or when your intended flight path will cross any controlled airspace, you have to file a flight plan.
I'll go into choosing my altitude or flight level and how Nampo is controlled in a next post.
