Standard Circuit?

[squeakmail]

I found the following comment on another thread.

<<That may mean turning downwind at 800 ft instead of climbing cross-wind to 1000ft. The fault lies primarily with the instructors concerned for not insisting on a standard circuit. >>

So, can anybody tell me their own opinion of "what is a standard circuit?".

There are numerous comments on these pages about "standardisation" and "CFI decisions" - but the guy who taught me to instruct (and numerous others I have met)say "finish the climb to circuit altitude if you need to", but the last decision maker (a 509 instructor standards man) clearly said "never turn downwind until at circuit altitude". A tailwind on the crosswind leg could make these circuits into cross country's (by CAA standards)...and gave you lots of time to enjoy the view on base leg.

So, whilst I personally prefer the former, I would be grateful to hear any suggestions as to a) what is a standard circuit and b) who says so - who is responsible for deciding?

------------------
LIVE in peace...or REST in it!

[Capt Homesick]

At the risk of a massive flaming, I would say there is no standard circuit.
The closest to a standard (in the UK at least) is:
Climb straight ahead to 500'
Turn crosswind
Climb crosswind to 1000'
Turn down wind. {In a C152 this should space you so that the runway appears about one third of the way DOWN the strut)
Abeam the threshold, look for a point on the extended centreline 45 degrees ahead of it, ie look at the threshold, turn your head 45 degrees towards the nose. When you get abeam that point, turn base, but DO NOT FLY TOWARDS IT.
On base, slow down, extend the first 10 or 20 flap, begin a powered descent.
As you approach the centreline, turn final, and you should be wings level over your (45 degree) point, ideally at 500'.
Note that I haven't even thought about drift, but you probably want to maintain the same ground track.
You'll probably have about 8 "standard" circuits described by the end of the week, just thought I'd be first! :)

[This message has been edited by Capt Homesick (edited 15 December 1999).]

[Teroc]

Hi Squeak,
Youre probably very familiar with this type of circuit but heres what we were instructed to do.
Climb upwind straight ahead to 500 feet
Turn crosswind
When runway in 8 O Clock position behind your shoulder (roughly 45°) turn downwind, this is regardless of the height as we had some planes which climbed like dogs while others shot up.
While on downwind in a cessna the runway should be cutting the strut about halfway down..
Abeam the numbers chop the power to 1700 rpm, Carb heat hot, when in the white arc 10° flaps (roughly 75 knots)
Again When runway is in 8 O Clock position behind you turn to base.
Drop another 10° flaps...you should be at about 700 feet at this stage and 65/70 knots.
Turn to Final and drop final 30° flaps..about 60 knots here..and basically chase her in from there.

Again this'll probably get shot down before the end of week but thats the way we were taught. :)

Teroc

[Squealing Pig]

My vote is with Capt Homesick’s circuit, I turn base when the threshold is in the 45° position behind, but I do like that idea of choosing a point 45° ahead when abeam the threshold, that would make better use of the visibility available to give the same turning point especially for a pilot is the left seat flying a right hand circuit in a C152, I’ll try it next time!

[Tinstaafl]

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.

+++++++++++++++

Anyway, all that lot is just one variation of who knows how many. I've certainly been required to teach a variety.


------------------
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?

[Capt Homesick]

Wow- seems like we are all teaching from thee same page, allowing for differences in type (eg, can you even see out the back?), etc.
Squealing pig, as I'm sure you spotted, picking your point to turn by looking ahead 45 deg when abeam the threshold means you turn base at the same point as turning when the threshold is 45 deg behind- I think the studes find it easier to assess angles in front, and more importantly I like to get them used to planning ahead as early as possible. Everybody have fun, and let's not do this: www.msnbc.com/local/WFLA/67894.asp (http://www.msnbc.com/local/WFLA/67894.asp)
:)

[squeakmail]

Well, if we are all on the same sheet...allow me to ruffle the page.

Teroc [nothing personal, my friend] says he was taught to drop (FAA for 'lower') first stage flap abeam numbers on downwind and chop the power to 1700 (FAA for 'reduce power').

This, of course, will give a rate of descent on the downwind leg....but it doesn't seem to happen in Uk - where the deal seems to be level turn to base then two stages flap.

Descending on downwind will require/allow for* (delete as applicable) a "tighter" circuit than staying level onto base.

Any thoughts, guys and galls?

(I'm also curious about the FAA phrase "Chase her all the way in" [just teasing, Teroc, just teasing])

------------------
LIVE in peace...or REST in it!

[apache]

Well...for what it's worth, here I go!!!

Climb out on upwind to 500' AGL...climbing turn at no more than 20deg AOB.
Crosswind should be perpendicular(90 deg) to the extended centreline, and flown until a/c is at 45deg from the upwind threshold.(regardless of altitude)
downwind should be at 1000'AGL and,in a c152, runway should be 2/3 up the strut.
maintain 2350rpm until turning base, then reduce power to 1500 rpm and take 1-2 stages of flap(normally 2, but if a strong headwind on base...stay at 1 stage).Carby heat should be applied IF the conditions dictate that it should be.
A mid base check should be made to check hi/low and adjust accordingly(mid base should be at 750'-800').
Turn onto final(no 's') begins at 600' at wings level should be at 500'(note: these heights are guidelines only and should not be used in place of turning onto extended centreline)
On final, maintain centreline all the way down, ensuring full flap(if using it) is selected by 300' AGL.Power should be used to adjust rate of descent...and attitude to adjust for airspeed.
Carby heat(when used) should be selected full cold on late final...and before touchdown, ensuring full power available for go-round.

NOTES:.....

1/ from downwind turn(in a single-engine a/c) the a/c should be able to glide back to rwy in case of eng failure.
2/ a/c should be climbed at best rate of climb speed.
3/ fly the a/c for the day!!!not by rote!!!
4/ have fun!

[Teroc]

Hi Squeak,
Ah that old squeakey humour.. keep it coming :)
Interesting you mention the fact that in the UK no flap is lowered till after the turn to Base... this is exactly the same way i was taught in Ireland...dont touch power or flaps till after the base turn... i was also taught in Ireland to turn with reference to ground features which i never liked for the obvious reasons....
Having experienced a wee bit of both worlds i'd personally prefer a hybrid of each circuit...use the 45° angle described above for judging turning points and dont touch power or flaps till after base turn as to be honest i found myself too low on lots of occasions while on base, having reduced power abeam the numbers....
As for the description of the phrase "Chase her all the way in" ...??
To me personally it means this...Once on final i leave the extremely well trimmed, runway centreline alligned plane to descend on a gentle glide along the textbook glideslope with the precision of a surgeons scalpel ...ahem..wink wink :)

Merry Christmas all...

Terry

[Capt Homesick]

In the Bulldog (admttedly, flying tight oval circuits, which I don't want to go into now) we lowered Inter flap (it only offered you Up, Inter or Full) as part of our downwind check.
But then again, you can get away with that when your flap limiting speed is greater than your maximum posssible cruise!

[ianh]

Most folks seem to be talking circuits in similar ways, but how about extending the climbout to 600 ft if conditions require it (crosswind from the dead side,heavy/low performing aircraft etc.), in order to achieve 1000ft for the downwind without going x-country? The extra climb gets in nobodys way.

[squeakmail]

Ahha!!

I've been waiting for somebody to come up with that suggestion as I seem to remember reading that the FAA way is "depart and climb to 300 feet below pattern altitude before turning onto crosswind"...this would have them climbing to a nominal 700' agl.

No doubt somebody will shoot me down for saying that...but it doesn't seem unreasonable...and for the purists who insist that that "in the event of an engine failure below 700' we will not turn back to the airfield" they have a 'cross check'.

Any more comments? Remember students read these threads as well as instructors. We can get some good arguments across here.

------------------
LIVE in peace...or REST in it!

[britavia]

We use that 700ft AGL turn to crosswind as stated in the FAA book. I find it works well and I prefer that to turning at 500ft AGL as by the time you get to the downwind, you will already be at traffic pattern altitude (assuming it's 1000ft AGL).

Another point is what happens when you fly a faster airplane into a busy training pattern? You cannot fly exactly the same pattern. The FAA state a turbojet has to be at least 1500 AGL against 1000 AGL for pistons. Even with our Apache dirty, we often have to fly a wider pattern to accomodate local C150s, else we "eat'em up!"

And how about pattern entries? The UK way of 2000ft overhead join seems odd to me. First, all aircraft join at the same point/altitude then it seems to be a free-for-all! (I've seen it first hand on a busy Sunday at Shoreham). The US way of 45 degree join to downwind is a bit more logical although this can get exciting too (we're talking uncontrolled fields here). Any thoughts, hybrids etc?

[Diesel8]

Wow, there must be something wrong since we all basiccally agree.

I think the safest option is to be at pattern/cct. altitude or very close theretoo before turning downwind, since if a high wing plane (ie Ce152)and low wing (ie PA 28)plane was at the same point in space but the high wing lower(arrgh) he could be climbing "blind" into a/c above. This becomes especially important in the states where a/c are supposed to join the pattern at a 45 degree angle on downwind at about midfield but alot of people seem to be joining closer to dept. end.

------------------
It's been real, it's been fun, but it has not been real fun


[This message has been edited by Diesel8 (edited 19 December 1999).]

[Night_Pilot]

Having read through this thread, there seems to be one fundamental thing missing from every single one of the postings so far.

What about LOOKOUT before turning!

Yes, we're talking about airmanship here. Flying a circuit by the numbers is OK for a basic teach in the classroom, but what about allowing for wind, talking to ATC or spacing with other aircraft? I appreciate that most of the posts have been describing the basic, classroom circuit, but come on guys (and girls), students read this BB as well!

Just for a bit of variety, how about this (Right hand) circuit for you all?

Trim forward slightly so that the aircraft begins to accelerate and continue trimming to prevent flapback. Once you reach translational lift, apply hover torque plus 15% and allow the aircraft to continue accelerating until 70kt. Adjust the attitude to maintain a 70kt/70% climb. At 2-300ft, check all T's and P's are in the green and then at 500ft look out left, through the nose and right before starting the turn at 600ft. Use about 20deg AOB maximum in the turn, rolling out 90 deg to runway heading but allowing 1 deg per knot of crosswind for drift. (eg If the wind is 10 kt, roll out 80 deg from runway heading) At 900ft, reselect 5-7 deg nose down and maintain 70% torque, allowing the aircraft to accelerate to 90 kt whilst leveling at 1000ft. Reselect a speed stable attitude with about 50% torque, and then look out from the left round to the right before starting a 20 deg AOB turn downwind.
Once established downwind, complete the checks and any applicable radio calls, waiting until the landing spot is back in your 4 o'clock. Select about 25% torque and wait for a rate of descent to begin before raising the nose to begin a flare, looking out and starting another 20 deg AOB turn in towards the airfield. Allow the speed to reduce to 70kt before reselecting a speed stable attitude, rolling out with an allowance for wind of 1 deg per kt of crosswind as before. Continue the descent down to 750 ft, when another 20 deg AOB turn should bring you out at 600 ft, lined up with your spot. Level from the descent at 500 ft and continue towards the spot until you reach the correct angle of approach, when you start a decelerating descent. Maintain a constant angle approach where the landing spot stays in the same point on the windshield, while rate of closure should be a 'fast walking pace' judged from the cockpit. At about 100 ft, allow the landing spot to slide under the nose of the aircraft, aiming to end up in a 10-15 ft hover as the final airspeed bleeds off.

OK, it's a helicopter circuit, but we all learnt to fly them as well!!

------------------
Illegitimati Non Carborundum

[squeakmail]

Well thanks for that, Night-Pilot. I knew if we talked long enough some prat would come along and try to be a smart a**e.

I was under the impression that we were discussing the potential of a "standard circuit pattern".

Reference was made by Capt. Homesick, Tinstaafl and Ianh to wind (therefore the potential for drift), reference was made by Tinstaafl, Diesel8 and Britavia to "other aircraft" - which suggests that they have considered the "lookout".

Granted, nobody else has been foolish enough to embarras themselves by mentioning R/T calls - as the R/T (apart from being the least worrying aspect of the circuit [you've haerd of "aviate, navigate, communicate"]) shouldn't have any real bearing on a STANDARD circuit..it may change one into a NON standard circuit - as may spotting another aircraft - but that isn't what we are talking about, is it?

[Night_Pilot]

OK Squeaks, consider the neck fully wound in...after all, I never expected that a little bit of constuctive criticism might actually offend someone!

Rather than trying to be a 'smart ****', the point I was TRYING to make was that studes read these threads too. If you're going to describe a STANDARD circuit then describe the things that you should do as standard. Yes, the mention of wind and other aircraft in the previous posts does indicate that everyone takes account of them, but reading the thread, I just got the impression that we were glossing over a couple of important little features. I pointed them out for completeness, NOT to show off, and so that any student reading this thread for some tips and hints about circuit flying might get a fuller picture than just the numbers. If that upset you, then I'm sorry but there's not a lot I can do!

BTW, I didn't realise that talking about something as basic as radio calls would 'embarras'(sic) me! Personally, I don't think referring to anything that I do in the air should be regarded as embarrassing! (Well... apart from THAT, but that's a thread for JB!!) Other people don't seem to have embarrassed themselves by talking about checks, which is similarly fundamental, so why me?

(Maybe it's because I'm not a regular contributor to this forum...after all, one little post seems to have upset someone!!!)

Basically mate, I wasn't trying to upset anyone and if I did then I'm sorry but it's more your snag than mine. I was only trying to close the loop on a couple of things.

------------------
Illegitimati Non Carborundum

[ianh]

actually folks, the radio call is another part of the circuit drill that people need to sort out - how often have you heard someone calling downwind either to early or at the end of the downwind leg (it should of course be abeam the upwind end of the runway), this then leads to mix ups in who is ahead of who. Don't call early, and if you call late for any reason, call "late downwind".

[squeakmail]

Night Pilot...OK, call atruce?

Ianh, ahhh..the "late downwind" call.

Much as I agree with you, I have written verse from the Ministry of Aeroplanes (CAA) stating that there is no such thing as a "late downwind" call and that they should not be made.

It would appear that if you haven't called "downwind" at the point abeam the upwind end of the runway, there is no legitimate call that you can make.

I wrote to the CAA about this very point and was told that if the "call" is not in CAP413 it should not be made at all - and to remind everyone that "final" is singular, do say say "finals". Does it really matter, CAA?

I say again, I agree with you - IMHO you are talking to everyone on the frequency...not just ATC.

As for the downwind point....a lot of USA airfields take it to be midfield downwind, not abeam the upwind end. Another one for the students to note.

[Sensible]

In Florida, with the Temperature and humidity in the 90s, a clapped out 150 and two fat gits on board, the aircraft will only reach 1000ft at the end of the downwind leg, given that the turn to crosswind is made at 500ft, the airport would be pretty well out of site if the turn to downwind was made only at 1000ft agl. Cessna 150s become hedge trimmers in high temperature and humidity conditions.

[ianh]

smail- "late downwind" may not be in the book, but surely we can put this under the heading of airmanship? common sense shouldn't go out of the window just because of what is written down, and if I hav not managed to get my call in, either someone is waffling to much, or the traffic is so busy that we need to have as good an idea as possible where everyone is!
I also know about the join in the states,but i'm not teaching there, and I always point out to my students that if they fly in any other country they need to know the rules for where they are flying.

[This message has been edited by ianh (edited 19 December 1999).]

[squeakmail]

Yep, that's exactly what I said in my letter to the Ministry of Planes.

Their response was CAP413 only...no such call as "late downwind"...don't do it.

My thoughts for a response would be only suitable for JetBlast.

[Oz_Pilot]

Any thoughts on the use of an oval pattern for part of the circuit? I was taught (and it looks like I will teach)

- climb ahead to 500'
- 15 AoB
- Climbing turn to downwind at 1000'

These are the main points, we do use features to check progress through the turn and change AoB as required for spacing. The downwind, base and final are a square pattern. Spacing is most definitely gliding range (in PA28's)

[squeakmail]

OK guys (and gals)the differences are starting to show themselves at last.

Question for the Americans and the Oz's.

If a student came to you and said "I want a CAA licence, it's cheaper to do the training here rather than in the UK - but I'll do most of my flying in South London [for example]"..would you teach the CAA method, or your own national method?

[Checkboard]

My national method - that is what you know how to teach, satisfies the local expectations, and when they go home they will have plenty of time to assimilate any changes. Even gives them a different expierience.

[ianh]

OP If oval is standard for where you fly, then teach that ( though there are many a/c that i would be very surprised to see reach 1000ft from 500, even if you are not turning at the same time), the main thing is you teach the same as those around you teach, or you will really confuse the hell out of the studes.

[Sensible]

Oval circuits huh !!
Is that what its called to justify making a complete mess of turning downwind/base/final ?

And to think that Ive been calling them eagle swoops until now!

so now can I call complete pattern indiscipline "oval circuits" Thanks for that!

[apache]

I was taught "oval circuits" for low-level circuits.
Basically I would teach what I know, or not at all.
If someone came to me and wanted a CAA syllabus, I would refer them to someone else as I am not familiar with the requirements.
I could not ever take their money if they are not going to get what they pay for!!! and I wouldn't expect any other instructor to either!!!

[squeakmail]

Sensible...now we have an excuse for them eh?

When you find yourself on what I call "Binal Approach" (45° to runway heading) we can say that they were taught oval circuits.

Good one.

[britavia]

Squeakmail: I have taught CAA Private syllabus in the USA and used the recommended procedures ie. poor weather @ 500ft, "baulked" landings etc. It can be useful, especially if you are up in the Northeast as I was for a while. Adaptability is the name of the game.

As for oval patterns..why not? Suppose you fly a slow airplane like a Citabria. Better flying them at 500ft than at 1000ft!

[Capt Homesick]

Most of the places I've flown light a/c at used square circuits, as we've discussed above. When I joined the UAS, though, we flew tight oval circuits, either at 800' (at military airfields) or at 1000' (at our home airfield, GLA/EGPF).
I once asked the ATC Manager if he liked having us doing oval circuits, three flying clubs on the airfield doing square circuits, lots of turboprop traffic doing bigger square circuits (arriving from all directions), all fitting in with jet traffic.
He replied yes- then explained. GLA was used for training new ATCers, and that sort of workload made excellent training!
Sometimes they would even invite the light traffic (including the Loganair Twotters, which I flew later) to use 28, while keeping the airline traffic on 23. CROSSED circuits must have made ATC's life very interesting!
Sorry, a little off-topic there. What I was meaning to say is that a properly flown oval circuit is no more untidy than a properly flown square one; it just has to be approved by ATC. I think oval circuits date back to Spitfires or earlier- when you can't see the runway over the nose on a straight in approach, you want to delay the moment when you point at the runway as late as possible.

[britavia]

It's quite common here in the USA to have traffic using more than one runway at a time. Lakeland (home of Sun n' Fun) often do this and having talked to the Tower guys, they often prefer it as slower training traffic can be accomodated on one whilst bizjets etc. are on another one.

[Oz_Pilot]

I might not have been 100% clear - the only part of the circuit we do oval is the upwind/crosswind/downwind. An oval (or circling) approach is IF "break visual" territory, another topic altogether...

What I've described is the promulgated standard for our school, the PA28's seem to comfortably get to 1000', it just seemed odd compared to the rest of the posts.

Sensible, if this is flown properly you roll out on downwind at height about 9 times out of 10 without further positioning - it's very neat.

The circuit we fly is aimed *primarily* at achieving the base turn point, from which (with the correct RoD) you'll always get a good landing.

[This message has been edited by Oz_Pilot (edited 23 December 1999).]

[vetflyer]

Any comments on the speed to use for approach? Recently trained on PA28 using an approach speed of 85kts which was also the Best glide speed. Prevoiusly been told better to use a speed lower than best glide. Does it make any difference?

[Charlie Foxtrot India]

A PA28 Warrior and Archer glides and approaches best at 75 knots.

------------------

[squeakmail]

Vetflyer... what model of PA28 would that be, sir?

I was under the impression it was 73knots for best glide speed....although, having just looked it up in the flight manual for the PA28-151 it says 72knots....though to be fair to CFI..I've always heard it "rounded off" (CAA) to 75knots [although often heard 73kts by FAA].



[This message has been edited by squeakmail (edited 24 December 1999).]

[foxmoth]

excuse me, but has anyone heard of aircraft manuals? :rolleyes:

[foxmoth]

Yes, I was going to ask - have most of you not heard of aircraft manuals :rolleyes:

[Tinstaafl]

Do you mean I can't just rely on the little labels peeling off the instrument panel? http://www.pprune.org/ubb/NonCGI/frown.gif

Damn...always suspected those manual thingy's must be good for something other than ballast. :) :)

[vetflyer]

thanks for your replies ,my quoted figures were mph ,sorry. However my question was in essence :
should the approach speed used, be less than the best glide thereby encouraging the use of power and minimising the gliding during the approach.

Yes foxmoth i have heard of manuals and even look at the pictures occasinally .

ps it was a PA 28 -140

[Hudson]

En-Route Supplement Australia (ERSA). Instructions therein for GAAP airports (ie busy GA training airports). "Call downwind with intentions. If unable to call at beginning of downwind leg, call Late Downwind as required." Pragmatic and clear cut. No bureaucratic CAA nonsense.

[Hudson]

En-Route Supplement Australia (ERSA). Instructions therein for GAAP airports (ie busy GA training airports). "Call downwind with intentions. If unable to call at beginning of downwind leg, call Late Downwind as required." Pragmatic and clear cut. No bureaucratic CAA nonsense.

[foxmoth]

So if we are calling 'late downwind' in the uk we just need to roll inverted? :) ;)