I wanted to try out the A10 instruments in a zero vis environment, so I fired it up, headed out over FACT, then zoomed into the instruments. In order to have half a chance, I flew away from FACT 10 90deg from runway heading, then when I was 15mi from the ILS antenna as indicated on the compass, I turned 90 degrees. After that I turned as necessary to maintain about 15 mi from the ILS. When I was about 100deg from runway heading, I turned to my intercept heading. Intercepted the localizer, then the glideslope.
BTW, the reason it’s important to maintain that constant radius turn, is to get an accurate idea of when to make your intercept turn. If you just turn base, you’ll overshoot the localizer.
You can try different variations of this technique. For example you can fly a reasonable DW, say 8mi out, and when you’re 15mi from the ILS, start your turn to maintain 15mi. From there it’s the same. Nothing magic about 15mi either. Try some different things.
I suppose another technique would be to fly downwind a few miles out until you reach whatever distance you’re looking for to the ILS, then turn base. This time fly past the localizer, then turn 120 deg to intercept on the other side. A much simpler approach. But not as much fun. 😂
No map, it works by maintaining a constant radius turn. When your heading is 100deg from runway heading, you turn to the intercept heading.
The constant radius turn is important because your heading is a line tangent to the circle. If you stayed in the turn until your heading was 90deg from runway heading, you would be on the localizer, but by definition on a heading 90deg from it. You want to start the turn to intercept 10-15deg before that which is why I said turn when your heading is 100deg from runway heading.