Changing from straight in to circling approach
Guys,
As far as I have always been told, if you are circling, the circling MDA is the minimum altitude for circling until in a position in the circuit to carry out a normal descent using normal rates of descent for the aircraft type to the landing threshold.
The circling MDA is designed to give you the required Obstacle clearance of 300' Cat A & B or 400' Cat C&D anywhere within the prescribed circling area.
You cannot circle at an altitude of your choosing that you think will keep you 300 or 400' above all obstacles based on where you think the critical obstacle(s) are.
If you cannot remain clear of cloud with the required visibility as per the chart and keep the runway environment in sight whilst at the circling MDA then the weather is below the circling minimums, and you shouldn't be there, ie you should have executed the MAProc.
Also I was told, by examiners both here in Aust and in the US that if because of the aircraft's design you cannot see the runway and keep it in sight ,for eg when trying to circle to the right, because of the wing, engine nacelle, viewing angles thru cockpit windows or whatever then you should not be doing that either.
As far as I have always been told, if you are circling, the circling MDA is the minimum altitude for circling until in a position in the circuit to carry out a normal descent using normal rates of descent for the aircraft type to the landing threshold.
The circling MDA is designed to give you the required Obstacle clearance of 300' Cat A & B or 400' Cat C&D anywhere within the prescribed circling area.
You cannot circle at an altitude of your choosing that you think will keep you 300 or 400' above all obstacles based on where you think the critical obstacle(s) are.
If you cannot remain clear of cloud with the required visibility as per the chart and keep the runway environment in sight whilst at the circling MDA then the weather is below the circling minimums, and you shouldn't be there, ie you should have executed the MAProc.
Also I was told, by examiners both here in Aust and in the US that if because of the aircraft's design you cannot see the runway and keep it in sight ,for eg when trying to circle to the right, because of the wing, engine nacelle, viewing angles thru cockpit windows or whatever then you should not be doing that either.
Aussie
What you say about not descending below the circling minima until a normal descent at normal rates can be made is right - but only at night. By day, you can descend if you maintain the required obstacle clearance depending on aircraft category - see the quotes from AIP above. But - yes - you must remain clear of cloud, with the required visibility and keep the threshold in sight.
What you say about conducting a missed approach if an engine nacelle (or something else) prevents you from keeping the threshold in site is also correct - technically. That would rule out a circling approach in just about everything I can think of though, so I guess most people are applying a little bit of "commonsense" to the rule. Legitimate question though: how much "commonsense" before you wind up in trouble.
The important point about circling approaches, though, is that they are higher risk than just about anything else we do. And controlling the aircraft by reference to instruments and [some] visual reference is gonna be challenging ...
Ted
What you say about not descending below the circling minima until a normal descent at normal rates can be made is right - but only at night. By day, you can descend if you maintain the required obstacle clearance depending on aircraft category - see the quotes from AIP above. But - yes - you must remain clear of cloud, with the required visibility and keep the threshold in sight.
What you say about conducting a missed approach if an engine nacelle (or something else) prevents you from keeping the threshold in site is also correct - technically. That would rule out a circling approach in just about everything I can think of though, so I guess most people are applying a little bit of "commonsense" to the rule. Legitimate question though: how much "commonsense" before you wind up in trouble.
The important point about circling approaches, though, is that they are higher risk than just about anything else we do. And controlling the aircraft by reference to instruments and [some] visual reference is gonna be challenging ...
Ted
Join Date: Sep 2007
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J3piper and Ted D, have nailed it.
This is one that always seems to draw a wide variety of opinions. But the rules as J3 described and found in ENR 1.7.3 are quite clear.
Important to read note 1, the 'concept' section in ENR 1.7.3 where it describes further how the rules should be applied.
Also note that this concept section says pilots should maintain maximum practical obstacle clearance.
So, you can descend below MDA by day ifvisual with required circling visibility, but you should attempt to maintain maximum terrain clearance while doing so.
This is one that always seems to draw a wide variety of opinions. But the rules as J3 described and found in ENR 1.7.3 are quite clear.
Important to read note 1, the 'concept' section in ENR 1.7.3 where it describes further how the rules should be applied.
Also note that this concept section says pilots should maintain maximum practical obstacle clearance.
So, you can descend below MDA by day ifvisual with required circling visibility, but you should attempt to maintain maximum terrain clearance while doing so.
