Hi All,

I'm back with another query. This time relating to circling.

Firstly I have had a look at a few approaches and it seems the circling viz is less than the straight in required viz for CAT A/B. An example would be Darwin NDB RWY27. Straight in 1000 and 5km and circling CAT A 700 2.4km. I would have thought that a straight in approach would be safer and therefore require a lesser met minima than circling. Ok so having had a read of AIP ENR 1.7.3 it says if daylight exists the pilot has the option to descend below MDA if he/she can maintain the required obstacle clearance. Can I then assume the circling minima apply? In effect I can descend from the staright in MDA to the circling MDA? But then it also says I can descend as long as I maintain obstacle cleearance!!

There is also no circling areas anotated on some approach plates. Again Darwin, however the AIP says if its daylight and VMC you can enter the circling area. Do I assume then as Darwin is Class C if the VMC are 5km viz 1000ft vertically and 1500ft horizontally clear of cloud and its daytime I can fly through the no circling area? The circling minima for Darwin is 700ft and 2.4km so if you were special VFR with a required VMC of 1.6km can you fly through the no circling area?

If the straight in MDA is higher then the circling MDA do you maintain the staight in MDA at night?

Any thoughts on this? It seems a bit confused to me!

Firstly, no approach plate shows the limits of the circling area. The circling area depends upon the category of aircraft only and applies to every approach. The visibility required for a straight-in approach allows heavier RPT type aircraft to stabilise the approach.

If you were flying a straight-in approach, and did not have the straight-in approach visibility at the minima, you could continue the approach as published to the missed approach point - that's got to be legal because you could do it even if you were still in cloud and it's what the chart indicates. However, once you arrived in the circling area [1.68nm for CAT A, 2.66nm for CAT B etc], you would need only the circling visibility to continue the approach and land.

Now, lets assume you get to that point and find the runway is occupied, or you are too high to land straight-in. Providing you remain in the circling area, and it is daylight, you can now leave the straight-in approach track and circle to land on another runway, or do a circuit and land on the original runway. You can do this even if you are below MDA as long as you remain in the circling area, with the runway threshold sighted, and visibility along your intended flight path not less than the published circling visibility. The only requirement for altitude is to remain at least 300 feet [for CAT A & B], above any obstacle you fly over. You do this visually by watching the ground pass beneath you. Obviously this option is not available at night!

No-circling areas apply only to IFR aircraft in IMC. An IFR aircraft doing an approach in VMC can ignore the no-circling areas, just as any VFR flight can - including special VFR. After all, a VFR pilot is not likely to have access to the approach plates so he/she could hardly be expected to avoid the no-circling areas.

Hi Bob,

Thanks again for the time. Can I just clarifyas may be I am being think!!

Flying the Darwin NDB RWY27 I am flying a straight in approach but I am planning to circle to land so I could assume I had a tail-wind or it was convenient. I fly to the MDA of 1000ft and once I reached the circling area I could descend further to 700ft? Not sure I am getting it as if it was daylight on reaching the circlng I could maintain 'visual reference' and clear obstacles by 300ft.

Any help would be great

Robbie

As you fly that approach by night, you would take note of the circling minima. If you were still in cloud at the circling minima, you could continue the approach to the straight in minima. If you became visual before the straight in minima you would have to land on that runway or do a missed approach [no circling at night below the published circling minima].

By day, if you were still in cloud at the circling minima, you could also continue to the straight in minima. If you became visual before the straight in minima, you could either land straight in or circle if necessary as long as you stayed 300 feet above obstacles and remained in the circling area with the circling visibility and kept the runway threshold in sight.

None of the published minima apply if you are visual in the circling area. All you need are the conditions described above.

Hi Bob,

Thanks for the reply. I think studying for the IREX is doing funny things to my bonce. Just went through the whole thing from scratch and it makes perfect sense!!

Ta