Visual Cues in the Circuit

[fireflybob]

Just wondered what fellow instructors were teaching in the circuit with respect to when to turn from crosswind to downwind and when to turn from downwind to base leg etc.

Referring only to "square" circuits and types such as PA38, normal powered approach.

Thanks for any replies.

[NorthSouth]

ffb:

Crosswind to downwind: tailplane crossing the runway (imaginary low tailplane if you're in a PA38!)

Downwind to base: when downwind end of runway is 45 degrees back from wing.

Pity about those runways obscured by trees from 1000ft/1nm away.

[Tinstaafl]

X-wind to d-wind: At the correct spacing. Not angle to the runway or angle from the runway. That angle changes depending on WAT & a/c type. Not at circuit altitude either. That altitude's position also changes with WAT & type.

D-wind to base: at 45 deg from the approach threshold. Not angle relative to the a/c since that changes with drift correction.

[FormationFlyer]

Tinstaafl

Yeah thats what I do too. I do however use ground references as well to help orientate students - but emphasis is placed on knowing the position in realation to the runway rather than vrps.

[FlyingForFun]

I'm curious about how you instructors would go about teaching a circuit at an airfield with very strict noise-abatement procedures?

I think my instructor did a pretty good job of teaching me. Groundschool covered the theory which Tinstaafl has explained perfectly a couple of posts higher up. Then we looked at the published circuit for the runway in use on that day. Once we were flying, we compared the two: "We need to make sure we turn downwind inside the motorway because we don't want complaints from that village. But see how that puts the wingtip on the runway - right where we want it to be?" Or "We have to make sure that the base leg takes us outside the church - but see how the runway is more than 45 degrees behind us? So we're further out than we want to be in the ideal world - that means we'll need to be a little higher than normal when we turn final."

Any comments?

FFF
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[Keygrip]

I waited for some answers before responding - I would like to see the arument discussed as to whether it is OK to continue the climb to circuit height on the downwind leg - or should/must you be there before turning??

Both have merits, both have flaws.

[HighandTight]

Well, I've always taught, and was when learning myself, that you should always be at circuit height BEFORE turning downwind.

The reason for this becomes very apparent particularly after having flown at some rather 'uncontrolled' airfields where joining procedure seems to be anything at any height.

Climbing into the downwind, particularly in a highwing Cessna creates a blindspot with regard to aircraft, especially low wing, joining the circuit higher.

ie: You climb and turn in a 152 and meet a Cherokee joining who can't see you either.

I'm sure though someone will have a reason why you should climb in the downwind, but personally I'm against it!

[Charlie Foxtrot India]

Out here if you are in a PA38 and it's 38 deg C and you have a tailwind on crosswind leg, you could have to do a pretty wide circuit if you had to be at 1000 feet before turning onto downwind...

[Tinstaafl]

Climbing on downwind minimises the variability of position compared to only turning once at circuit altitude. It's a lot easier to find an a/c that is constrained within a small area laterally ( ~ 'standard' circuit width) and maybe several hundred feet vertically up to ciruit height, than it is to find an a/c that could be anywhere within several nm. spacing.

To borrow H&T's paragraph : the reason for this becomes very apparent particularly after having flown at some rather 'uncontrolled' airfields where joining procedure seems to be anything at any height.

For those who advocate variable width/constant height d-wind as a separation issue, how do you cope with low-level circuit traffic, or other types eg turbine, that may use 1500'?