G'day,

Just a quick one re. the circling area. Why isn't the circling area pre-calculated and listed on the applicable approach chart? Is it due to the differences in each category? It just seems like a laborious task for a pilot to complete, especially given such obscure numbers.

Also, with regards to circling approaches and descending below MDA, mention is constantly made to 'visual reference'. This concept is defined by those values given on the chart, yeah? I.e. visual reference is defined as the value in brackets for visibility under "Circling" on the approach chart?

EDIT: Disregard the visual reference question, I've answered it myself, by turning the page. One other clarification, however. The instrument approach only gets you to MDA, is that correct? I.e. if you have not broken visual at the MDA, you must start the published missed approach? If you DO get visual at or before MDA, then you can circle to land if visual reference is maintained, terrain clearance is maintained visually and you maintain within the circling area?

Regards,

Dan

Yes, you have the right idea. However remember that by day, providing you have become visual and remain in the circling area, you can descend below the published MDA providing you maintain the appropriate terrain clearance [300 feet for Cat A and B] above any obstacle you fly over. The circling minimum altitude was determined by considering the highest obstacle in the circling area. As long as you can see the runway environment and the ground beneath you, it is quite safe to be lower than the published circling minimum altitude by day. By night of course, you must remain not below the published circling minimum altitude until you have intercepted the normal approach profile for your aircraft. This is because you don't know just where the highest obstacle is and you may not see it at night.

Bob