Circuits

[Pips]

Up till now I have spent almost all my time operating out of small grass strips in the country. Most often flying the Bleriot XI or Antoinette VII, varying it occassionally little gems like the AA-5B, P-12, the Waco and other small GA aeroplanes.

Lately though I've taken to flying in built-up area's with more structured airports. And was just wondering a couple of things:
* Why do folks fly a circuit before landing
* What is the correct format for a circuit
* What direction should the circuit be flown and how does one determine that.

Cheers :)

[stiz]

this should help explain it :wavey:

http://www.mpaviation.com/lessn11.htm

[mike_cyul]

When I was getting my ppl, a further detail in the circuit curriculum was to keep the runway at about 45 degrees (i.e. stick your arm out, and then point it 45 degrees down), so that if you had an engine failure in the circuit you could still make it back to the runway. I think that was good advice, one that I don't hear many schools doing.

As for circuit altitude, we has a special rule at my former airfield for ultralights that allowed them to do circuits at 500' agl - this was so they were not clogging the circuit with their slower speeds when there were other faster aircraft out practicing.

As for the specific questions, circuits allow aircraft to approach and land at the airport in an orderly manner. Radio calls identifying what leg you're on also help other aircaft (and the tower, if there is one) know where you are and avoid collisions, etc.. Circuit direction is a factor of wind direction and other concerns. For example, due to housing near the airport, we always keep our circuits to the side of the runway away from them.


Mike

[srgalahad]

The reference stiz quoted is good info. Bear in mind that:

a. not all circuits are left hand (more like left-hand unless otherwise stated) FS doesn't care as a rule so "when in doubt, go left." Right hand ( non-standard) circuits are normally set for tower view issues, crossing runways, noise abatement, terrain issues. Left-hand circuits keep the pilot of a side-by-side seating a/c with the best view of the runway.

b. the entry from outside--
*if entering from the downwind side, enter the downwind at a 45 deg. angle (think a highway merge). this allows you to adjust speed to fit with existing traffic
*If entering from the downwind 'side' but from off the departure end, just fly straight into the downwind leg but watch for traffic climbing out and on cross wind.
*If entering from 30 degrees of final it's generally accepted that you may fly 'straight in" but should establish yourself on final well back so you can see other traffic in the circuit AND they can see you and adjust their downwind to follow.
*30-90 deg. from Rwy heading, it's getting common ( and sometimes dangerous) for people to join to the base leg, but that means traffic in the circuit has to watch for a/c on both sides. better to move over and join downwind at the 45.
*if approaching from the opposite side of the airport the common practice is to cross at mid-field and join downwind while watching for traffic turning downwind from crosswind leg as well as current downwind traffic.

At a controlled airport, join where you are instructed as the controller is working to sequence traffic you may never see.

Want to have a personal conversation with a controller? Cut someone off in the circuit! -although it will likely be a very one-sided conversation:redf:

Other bits... the US has to be different.. they fly 'lights' at 800 ft, jets at 1500 ft for separation and a/c performance reasons. Works but makes it harder to spot traffic above/below you.

Why do you fly circuits to begin? To teach orientation and perception for climb, approach and landing, to get use to standard performance and power settings, to teach how to conform with other traffic. -- all while staying close enough to get down if needed AND because that way you get the most landings in a given time (it's the least distance needed to cover all the performance range.)

At a rough estimate, in 28 years in ATC I saw something like 1.2 MILLION circuits.:banghead:

Rob

[Tako_Kichi]

At a rough estimate, in 28 years in ATC I saw something like 1.2 MILLION circuits.:banghead:
And just how many of those were perfect? :costumes:

[Pips]

Thanks for the suggestions and comments guys, there are some real gems in there. :)

By the by how do you tell from which direction the wind is blowing in FSX?

[CBris]

Thanks for the suggestions and comments guys, there are some real gems in there. :)

By the by how do you tell from which direction the wind is blowing in FSX?

a. By cheating: press shift+z and read the display line on top
b. By flying to an airport with ATIS, tuning to that frequency and listening to them
c. By flying an aircraft with a wind direction indicator guage (the Wilco Tiltrotor has one)
d. By using active sky and turning on the weather radar in sim

Just a couple of ideas

[srgalahad]

a. By cheating: press shift+z and read the display line on top
b. By flying to an airport with ATIS, tuning to that frequency and listening to them
c. By flying an aircraft with a wind direction indicator guage (the Wilco Tiltrotor has one)
d. By using active sky and turning on the weather radar in sim

Just a couple of ideas

Or do it like real old pilots.. fly over the airport above circuit height, look down on the wind sock ... wind goes in the fat end and out the skinny end.. and of course at any airport you NEED to land at, the windsock points 90degrees to the best ( or any) runway. (Murphy's Law, Corr #34) :icon_lol:

Speed (IRL) can be estimated from the windsock too ... barely moving 0-3 knots; slightly extended 3-7kts ; extended about 45 degrees - 8-12 kts; stiff and horizontal 15-20 kts; flapping wildly >20 kts; windsock moving over ground - WAY to strong to land!!! (while the normal FS windsock is a solid orange colour, the striped ones (indicating a licensed airport normally) show speed ... count the rings that are 'filled' or rigid and each one is about 3 knots. But that's too much for FS to comprehend.

BTW, real-world winds are rarely constant. speed rises and falls and except in rare cases in the short-term, direction can vary by quite a bit so all winds are reported as the "mean wind". Variance of less than ten knots is normally reported as wind 260 @ 5-10, but if the variance is 10 kts or more it becomes "gusting" as in wind 260 15G25. Again, more info than you get from FS however it makes a difference on approach. Rule of thumb is to take (half?) the amount of the gust and add it to the approach speed - that allows a margin in case the wind drops suddenly on short final.

There's lots more to the wind issue, but that's for another post.

[CBris]

...and of course at any airport you NEED to land at, the windsock points 90degrees to the best ( or any) runway. (Murphy's Law, Corr #34) :icon_lol:

Ah yes... good old Murphy!

Don't forget Corr #34a: "...the wind will change to a tailwind on short finals..."

[Lionheart]

Man, SirGalahad,

Some good learning there...

I never knew that most turns were left turns (left pattern).

Good to know on the gusts and wind-sock angles also for real world training.



I love to fly patterns in FS. Dont know why. I find it to be pretty intense at times to keep patterns exact, finding land marks to make turns at, etc. In FS, I like to go 'off radio' and fly 'in' the traffic. If I use radio ATC (in FS) they keep flagging me off (go arounds) when timing isnt just right. (I hate that, arrgh.. ).


Some good airfields for Touch and Goes; (addon scenery)
* Pattonville EDTQ
* LFBK
* LFCE (These last two come together in one package, good for flying to the other one and doing touch and goes, then a return flight).
* Plum Island by Bill Womack. (This one is brilliant for land marks and the short (very short) runway is good practice for lowering your speed and calculating a good approach as there are trees and runway elements that require some good piloting to put down just right).


Bill

[Pips]

Windsocks eh?? Can't say I've noticed them. Are they present at all airports (standard scenery) in FSX, or just certain ones?

[guzler]

Having flown microlights from a farm without a windsock, there are other tell tale clues - smoke from chimneys, better one is the ripples on ponds and lakes, the upwind end is usually unrippled. The reason I say better, is because you fly directly over them, chimneys from a distance can be deceptive as to the wind direction as I found out a few times :isadizzy: Not that these would be any use in FS though

[mike_cyul]

One thing we used to do at my former airfield (which was small, no tower), and which can be fun in FS, is to see who could do the fastest "circuit". You don't follow circuit procedures, you just see how fast you can go from stationary to stationary, or wheels off to wheels on, going around. I think the record we had was something like 22 seconds. I do remember he was an Air Canada pilot, and I think he was in a Citabria.

My own personal record there was't speed, it was number of circuits - one day when the weather wasn't really good enough for cross-country, I just got in and flew circuits of one kind or another, one after the other, for an hour or so. I didn't realise the airport manager was there that day, and he counted them, as I found out in the airport newsletter - it's a while ago, but it was over twenty. He said I must have been really desperate to fly that day.:d

Mike

[srgalahad]

A standard circuit teaches the 'standards' so a new pilot understands the parameters.

Then you wander off on a cross country and the published circuit says something like: "Right hand circuits, base leg must be kept inside the hospital marked on the chart for noise abatement" so you struggle to find a big X on the ground that marks the hospital.. finally find a Y-shaped building, turn your base and find you are still at 1000ft agl as you turn a 1 mile final... flaps, power back, nose down, get it down and yes, the wind shifts or dies on short final and the far end of the runway looks AWFUL close!...
and that's the day you learn to anticipate and be flexible.

Non-standard circuits like Mike described are fun and good training but at uncontrolled airports do have risks.. anyone joining will not expect to have someone downwind at 200 ft or turning base abeam the threshold... but these are things to learn! Running under the scud trying to find an airport, out it pops from the goo and you want to keep it in close to avoid losing sight of the runway... but low level turns come with visual illusions and it's easy to lose altitude and BANG! or you fail to slow soon enough and overshoot a short runway.

You can never have enough practice with the hardest part of flying... getting down, kissing the earth and watching your hands shake.:redf:

Rob

[srgalahad]

If I use radio ATC (in FS) they keep flagging me off (go arounds) when timing isnt just right. (I hate that, arrgh.. ).

Bill

I agree Bill, but... balked approaches are important to learn and deal with.. critical to watch speed, establish a climb, re-configure the a/c (flaps, gear up etc.) all the while maintaining control and dealing with traffic or a puking passenger and not losing sight of the airport.

A good example is the P-51.. go around on short final, shove the power up to the firewall and watch yourself die as the torque rolls you and you dig a furrow... you have to learn to e a s e the power on and start cleaning up the a/c before firewalling it.

Or, in other aircraft, keeping stable until the power is up enough to defeat the sink rate and you can get climbing ( that's the reason turbojets carry 75% power til the landing is assured.. takes time to spool up otherwise and you'll sink onto the guy who just pulled on to the runway in front of you.:isadizzy:

[Cazzie]

Ah yes... good old Murphy!

Don't forget Corr #34a: "...the wind will change to a tailwind on short finals..."

It's :censored: funny how much Murph's law plays into bicycling too, only in an opposite method. One rides out in a headwind expecting a tailwind on the way back, but it rarely happens. :icon_lol: And the wind is "always" blowing this day and time in my area.

Caz

[CBris]

It's :censored: funny how much Murph's law plays into bicycling too, only in an opposite method. One rides out in a headwind expecting a tailwind on the way back, but it rarely happens. :icon_lol: And the wind is "always" blowing this day and time in my area.

Caz

Actually all the MLs on wind can be summed up in one...

"The wind always blows from the wrong direction"

Oh, and even if it's from the seat of your pants...

[harleyman]

Wow...Some very intresting things here to learn.....:ernae: