BOAC:
The 'CTL airspace' is not CTL airspace. It is the protected area (5.28nm) in which the CTL minimum will be at least 394' above the highest obstacle. It is not the area in which you PLAN to 'circle to land', just as 2.3nm (2 for 411A
) is
not the area in which you PLAN to circle to land in TERPS - it is the area that gives you vertical separation (300') at the minima. The circle you have drawn is not relevant to this accident. The a/c was outside it. That is why it hit the hill - simple.
Thanks for the flying and procedure design lessons.
The circle (oval actually) I have drawn is most pertinent. It shows the limits of protected airspace, which is an appropriate aid in the understanding of this accident.