Have seen & taught a variety of 'standard' circuits, depending on which school I was working for at the time.
Some advocated 'square' circuits (well, rectangular, really), others 'oval' circuits. Some had the standard height as 800', others 1000'. Some rounded up (or down) the 1000 to the nearest 100' on QNH.
But after all of that, I
suppose my preference is based on the following. All in nil wind, but HDG to be adjusted to make good the track if wind effect present:
upwind - x/wind Choose an x/wind aim point at 90 deg & as distant as possible. Turn onto X/wind at 500' AAL, stopping the turn when heading at the aim point. Check & adjust HDG to ensure lateral axis is parallel to RWY
x/wind - d/wind Choose an d/wind aim point at 90 deg & as distant as possible. Commence the turn onto d-wind at a point that would leave the a/c at the correct d-wind spacing. Easiest way I know is to just show the student & say "When the spacing looks like it does now, turn to point at the aimpoint".
Note: Don't like the 8 o'clock / aircraft reference method since this position changes with performance factors on the day & is not constant with reference to the aircraft. A hot day & heavy will give different perspective (relative to the a/c clock code) than a cold day & light, due to the different points where 500' is reached & x/wind commenced.
Also don't like using ground features to define the turning points since there won't be the same features at the next aerodrome.
Level at 1000' (to nearest 100') wherever that occurs. Could be on x/wind, turning d/wind or established on d/wind.
downwind - base Towards the end of d/wind, choose a base leg aim point as far distant as possible & at 90 deg to downwind.
Imagine a line emanating from the threshold & extending at 45 deg. towards the base turn point. Easy enough to do: it's half way between the RWY centerline & 90 deg to the centerline!
When the aircraft reaches this imaginary 45 deg. line turn to point at the base leg aim point. At the commencement of the turn, set approx. 1500 RPM or 15" MAP. Hold 1000'. As IAS reduces select 1st flap. When IAS is within about 5 kts of desired, lower the nose to maintain this IAS.
Check & adjust alignment. Assess approach profile & adjust power accordingly. Select 2nd stage flap about halfway through base. A bit earlier if high, later if low etc.
base - final Better to commence this turn
slightly early, than late. Particularly with close spaced parallel RWY's as opposite circuit traffic will now be 'merging' towards their respective final alignment (when they are near to each other) instead of high closure rates between themselves.
Should pass through 500' halfway through the turn but 500' established on final works well enough. Gives a target height as guidance during base and has a subsequent bonus if they go on to do a Night VFR rating and black hole approaches.
Established on final, commence IAS reduction to achieve final IAS. Select next flap. When to take last stage of flap varies with circumstance - bit high then earlier, bit low then delay etc.
Type characteristics make a difference too. In a C150 with 40 deg available, I delay the last 10 deg until mid/late(ish) final & use this drag to slow to Vat.
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Anyway, all that lot is just one variation of who knows how many. I've certainly been required to teach a variety.
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Fascinating how scientists & research engineers have managed to make aircraft that all use the same laws of aerodynamics all over the world.........Has anyone thought to tell the CAA?