Circling approach
I remember at Busan (Pusan) sometimes a circling approach was required from an ILS due tailwind. On that chart there were various circling minima based on specified circling speeds. In that case the landing weight directly impacted on the minima. During marginal weather, it was therefore necessary to carefully consider how much extra fuel was carried if it resulted in an increased minima. At typical circling speed for an A321, the minima was 700 ft. At higher weights it went up to about 1100 ft. That increase could easy make the difference between getting in or not.
I also recall a poor understanding of this unusual chart presentation by most expat and local crew. Almost all chose a fixed 700 ft, thinking that the limitation was actually somehow related to aircraft category.
This approach is demanding. There are traps that caught Air China. An excellent description can be found by googling "circling accident case study air china 129".
13 days before that accident, I emailed the Korean Aviation Authority with a warning about the presentation of the circling part of the approach. Even if they planned to take notice, which I doubt, that is probably insufficient time to act.
There has to be a lesson here about pre-emptive action and aggressive interpretation of approach procedures. In this case it is not good enough to just rely on a ordinary study of the chart before descent.
Last edited by autoflight; 30th July 2013 at 13:35.