Is there a regulation which specifies this?
In the UK, what they call a “low level circuit” can be down to about 700ft AAL, IIRC, in one place I know (EGKA) although in principle you should be able to do it down to 500ft, as this is the general rule for low flying near man-made objects. OTOH the low flying rule is exempted when taking off or landing, for obvious reasons!
If there is an IAP published, the circling minima may apply but I don’t see why since the pilot needs to have only a PPL, no IR, and thus would not have been trained on instrument approaches.
I don’t think there is a lower limit. My FI during PPL training demonstrated a “bad weather circuit” to me at about 200ft AMSL.
If there is an IAP published, the circling minima may apply
For instrument runways, the minima for CTL are specified in Part-NCO and printed at the bottom right of every Jepp plate.
Peter wrote:
In the UK, what they call a “low level circuit” can be down to about 700ft AAL, IIRC, in one place I know (EGKA) although in principle you should be able to do it down to 500ft, as this is the general rule for low flying near man-made objects. OTOH the low flying rule is exempted when taking off or landing, for obvious reasons!
The phrasing of the exemption is “except when necessary for take-off or landing”.
So I would say that 500 ft is the minimum height in the traffic circuit expect when you have to descend towards the runway (and when you are climbing out, obviously). When you have to descend will depend on things like the shape and size of the traffic circuit, aircraft performance etc. In any case it must surely always be ok to follow a 3° glidepath on final.
In any case it must surely always be ok to follow a 3° glidepath on final.
Not at all. There are plenty of examples where that is not ok.
This is not an IFR “circle to land” question, to which the answer is simple as per Timothy’s post above.
My “drift” in this question is how low can you fly around an airport.
Let’s say you want, or are somehow required to, fly a circuit to inspect the airport, for animals on the runway, etc.
Medewok has provided the minima for Germany, which seem to be, ahem, practically nothing just as long as you don’t hit the ground 
His posts suggests that was a VFR circle to land. Actually that is quite interesting in itself because what is the difference between
in terms of required obstacle clearance?
MedEwok wrote:
I don’t think there is a lower limit. My FI during PPL training demonstrated a “bad weather circuit” to me at about 200ft AMSL.
I was told to aim for 200-300ft with the “picture” the same as for a normal circuit. Told off if I drifted up to 400ft.
Regards, SD..
My understanding “VFR low level circuit” is done when you depart mis judging cloud-base for full circuit, that can be done at any height tough one has to take the following considerations:
- CB<500ft is no longer VFR or SVFR
- Straight flight until 394ft before first turn after takeoff (if no SID and not applicable to UK)
- Some max bank angle vs height I did read about but can’t recall (50ft wings should be level )
- In gliding, final turn not bellow 300ft agl
Most FI will do bad weather circuit at 600ft but I have got an FI who did it at 300ft, AIP AD CB is 600ft min
MedEwok wrote:
“bad weather circuit” to me at about 200ft AMSL.
Including when airport is at 400ft AMSL, you mean AGL 
As I understand it :
500’ AGL and 500’ MSD apply in the UK – the downwind leg of a low level circuit is not an ‘approach to land’. Circling minima is there to assure obstacle clearance so if go visual at that height you can safely start to perform the manoeuvre at that height, with an inherent assumption you may pop back into IMC and need some distance to perform a go around, 500’ still applies. A circle to land will not always be following a normal visual circuit pattern either.
Visual low level circuits may be performed lower than the circling minima because it is a visual exercise and you can see terrain / obstacles in theory.
The whole point is to get the aircraft onto a safe approach profile as expediently as possible, while maintaining visual reference with the intended landing area – it’s not heroic to mess around low level, slow, in potentially a draggy config IMHO!
Timothy wrote:
Not at all. There are plenty of examples where that is not ok.
I meant as far as the rules of the air are concerned. I am sure there are plenty of situations where, e.g. for noise abatement or terrain reasons you need a steeper glidepath. Or what?
