500' Circuits

[Lurch]

Can someone please explain a logical reason to request 500' circuits at a controlled airport when you have no ceiling?

This is flight school aircraft, and they only seem to want to do one???

P.S they still fly the same huge 4nm circuits

Lurch

[200hr Wonder]

Cause they want to prove how good of pilots are that they can fly that close to the ground and still do a circuit!

[Hedley]

I fly tight, 500 AGL circuits all the time when I'm doing tailwheel training, because it allows the student to get more landings in, esp when the aircraft is not overly blessed with power. I doubt my downwind is even a quarter mile laterally from the runway.

Tailwheel aircraft fly pretty much the same as a nosewheel airplane, so large circuits - heck, why not climb to 10,000 AGL on downwind? - aren't terribly efficient.

I know of no CAR that is contravened by this practice.

[Old Dog Flying]

Possibly not Hedley but I was written up by a jerk at Langley for doing a 600' circuit after he pulled me up...no one else in the zone and my supposed trafic was already on the ramp when I crossed the threshold. Got a call from TCCA GA and we had a "meaningful" discussion.

[iflyforpie]

It's called a closed pattern. I was taught how to do this during my CPL training for low weather and confined areas.

We also did it in the Taylorcraft when doing continuous circuits, because the climb to 1000 AAE took too long.

I've only done it with no other traffic in the pattern. I think it is far better to learn how to do a 500 ft circuit during good weather than doing for the first time with a low ceiling. How about those circling minimums?

[AEROBAT]

People do them all the time at our airport, traffic permitting, especially if they are practicing touch and goes with anemic aircraft. Makes sense to me.

[Ollie]

Illusions created by drift?

PS. I've seen huge circuits from students at every school on the field. ie turning base north of the bvta for 07.

[KAG]

Not only do the students get more touch and goes, but it teaches them how to judge correct "hi VS low" corrections outside of the normal circuit.

[razorblade]

Not only do the students get more touch and goes, but it teaches them how to judge correct "hi VS low" corrections outside of the normal circuit.

I fly tight, 500 AGL circuits all the time when I'm doing tailwheel training, because it allows the student to get more landings in, esp when the aircraft is not overly blessed with power. I doubt my downwind is even a quarter mile laterally from the runway.

+1
Saves a LOT of time!

[ywgflyboy]

Through my CPL training my instructor would request various altitudes during the 180 practice. You are not always going to be 1000agl.

[Hedley]

I've only done it with no other traffic in the pattern

Good advice. Remember CAR 602.96(3)(b):

http://www.tc.gc.ca/civilaviation/regse ... htm#602_96

(b) conform to or avoid the pattern of traffic formed by other aircraft in operation

Now, I suppose you could argue at the Tribunal that by doing a 500 foot circuit, you were complying with CAR 602.96(b) and "avoiding the pattern of traffic formed by other aircraft" at 1000 AGL, but ...

It has been my experience that most student and private pilots are at 99% of their maximum allowable stress level when they are simply operating an aircraft straight and level in good wx - listen to their voices go up a couple octaves on the radio when another aircraft comes within literally a mile of them - so it's probably not always a good idea to ratchet that up a notch by flying an efficient pattern in an underpowered taildragger.

[2R]

Bad wx circuit training should be done at various altitudes.It is all about teaching the correct angles.As the angles do not change whether you are at 200 feet or two thousand.
Different aircraft types are often flown at different altitudes at different airports in some countries .It makes sense as why have turbine aircraft sharing a cicuit/pattern with an ultra-light or 150.
Check the AFD/CFS AIP supplement In the USA turbine aircraft are flown at 1500 agl in the pattern/circuit.Go to Savanah, Georgia and you may be sharing the with some interesting military aircraft pulling hard g's breaking midfield into a tight pattern.
It is all about learning the angles.The angles do not require altimeter settings

[Hedley]

In the USA turbine aircraft are flown at 1500 agl in the pattern

Not just in the USA.

military aircraft pulling hard g's breaking midfield into a tight pattern

Physics Interlude Follows. Mouth-breathers skip forward.

For the nervous nellies who get their panties in a bunch when they see aircraft exceededing 30 degrees of bank in the pattern, there is a very good reason for it. They aren't simply showing off, which is probably what you think they are doing.

You probably don't care about the basic physics which governs aviation, but first year university calculus tells us:

Radius equals Velocity Squared divided by Acceleration

Simply put, if you do a turn at 200 knots using the same G you use at 100 knots, the radius of the resulting turn will be:

(200/100) squared

or FOUR TIMES your normal 100K radius. A turn at 300 knots will be NINE TIMES your normal 100K radius.

In a fast aircraft, you must make every turn 60 degrees and 2 G's, otherwise you're going to be in a different zip code when you roll out.

Physics Interlude Ended. My apologies if you are offended by my introduction of math and physics into your world of aviation.

[iflyforpie]

Physics Interlude Follows. Mouth-breathers skip forward.

I have a cold, give me a break...


If you want to quantify turn radius, you can use this formula...

Radius of Turn = V^2/11.26tan(bank angle)

[Hedley]

You left out the units.

I might guess the following:

Radius: furlongs
Velocity: furlongs per fortnight
Angle: radians

[iflyforpie]

Sorry, knots for airspeed, feet for radius. I could probably figure out one for smoots.

It doesn't matter what angle measurement you are using because the tan of the angle is the same regardless (though I would advise against using radians).

[Big Pistons Forever]

A non standard circuit altitude is a great way to break students of the habit of flying cookbook circuits (eg turn base over the white house, turn final over the bend in the road etc etc). To emphasize the view out the window provides all the cues you need I sometimes cover up the altimeter and in the later stages of training, the airspeed indicator.

[CaptnMurf]

A non standard circuit altitude is a great way to break students of the habit of flying cookbook circuits (eg turn base over the white house, turn final over the bend in the road etc etc). To emphasize the view out the window provides all the cues you need I sometimes cover up the altimeter and in the later stages of training, the airspeed indicator.

+ 1

Especially for those of us who operate out of a 'country' airport, uncontrolled with as many ultra-lights as GA planes flying off a turf strip with a parachuting operation thrown in for good measure.

Lots of times a 'non-standard' pattern is the safest choice, even in picture perfect WX.

[flyingdan]

Since low altitude turns are mentioned in the CYKZ Crash thread viewtopic.php?f=54&t=65064, does anyone think low circuits would help in engine failure after take off situations?

[AEROBAT]

Since low altitude turns are mentioned in the CYKZ Crash thread viewtopic.php?f=54&t=65064, does anyone think low circuits would help in engine failure after take off situations?

It sure wouldn't hurt to practice 500' circuits if for no other reason than the fact you will have to do them some day and you won't have a choice. As far as engine out on take off goes setting up for a landing straight ahead is probably your best choice. The problem with the standard circuit is a person gets into a bit of a rut and may have difficulty setting up a good approach the first time you deviate from the standard 1000' circuit alt.

[iflyforpie]

The problem with the standard circuit is a person gets into a bit of a rut and may have difficulty setting up a good approach the first time you deviate from the standard 1000' circuit alt.

All the time I see people struggling with approaches, and I just want to reiterate some of the lessons that I've learned over the few years I've been flying, pretty much none coming from the flight training environment.

A three or four degree slope looks the same from any distance as has been mentioned. Displace the runway the same angle from the aircraft (using a strut, fuel cap, or TLAR), don't extend out as far, and don't bother keeping a straight base leg. Somewhere along the line doing regular circuits, a pilot must see what a 1/2 or 1/4 mile final looks like... right? This will not only help you to do low circuits, but high ones as well (YYF, YLW, YVK are some examples around this neck of the woods), and weird ones (ZNL).

You don't have a ton of time to configure the aircraft doing a low circuit; but I remember this quote from an instructor of mine...

"This aircraft is a machine, it will do exactly what you tell it to."

If you set configuration for approach (power set, airspeed set, flaps set, trim set) and everything looks good, it won't be different the next time or the hundred or thousand times after. Small deviations in power to set glideslope will result in small deviations in airspeed, but that is it.

It appalls me that we make it so difficult on ourselves and students when we teach them to fly. I know there is the whole 'exercise' thing, but can't we at least give them the answers at the end of their training like we do for cross-countries (GPS Direct, block times, etc)?

The typical 172 short field circuit I see...

Abeam the numbers, pre-landing complete, carb heat, power to 1500, trim up for 70 (or 80), flaps 10, turn base at 45.

Extend flaps to 20 (really only about 15 in most 172s), trim for 70 (not much trim required at this point).

Turn final, extend flaps to 40. Trim forward to try and regain 60 (it is hovering just above 50). Power 2000 to arrest excessive descent rate. Fight to maintain airspeed. More forward trim. Drag it in at 60. More power, airspeed decays again, more forward trim, land at 60 or overshoot.


One secret I found out about Cessnas (I haven't had enough time on other aircraft to try it) is that they are specifically designed to go from cruise power level flight clean, to approach power with flaps, without moving the trim.

So I will reduce power to 1500 abeam the numbers and simply set the desired flaps and bingo, my approach speed is exactly where I want it, reducing itself incrementally as I add flaps. If I need to add power, I know that the trimmed speed of the aircraft will be reduced so I compensate for it before it decays. If I am too high and pull power, I know the airspeed will want to increase and I make sure I keep it in check first rather than trying to solve my height problem with attitude and come in too hot.

So really, you don't need a specific approach provided your visual cues are the same (angles) and your configuration is always the same...

[AEROBAT]

The problem with the standard circuit is a person gets into a bit of a rut and may have difficulty setting up a good approach the first time you deviate from the standard 1000' circuit alt.

All the time I see people struggling with approaches, and I just want to reiterate some of the lessons that I've learned over the few years I've been flying, pretty much none coming from the flight training environment.

A three or four degree slope looks the same from any distance as has been mentioned. Displace the runway the same angle from the aircraft (using a strut, fuel cap, or TLAR), don't extend out as far, and don't bother keeping a straight base leg. Somewhere along the line doing regular circuits, a pilot must see what a 1/2 or 1/4 mile final looks like... right? This will not only help you to do low circuits, but high ones as well (YYF, YLW, YVK are some examples around this neck of the woods), and weird ones (ZNL).

You don't have a ton of time to configure the aircraft doing a low circuit; but I remember this quote from an instructor of mine...

"This aircraft is a machine, it will do exactly what you tell it to."

If you set configuration for approach (power set, airspeed set, flaps set, trim set) and everything looks good, it won't be different the next time or the hundred or thousand times after. Small deviations in power to set glideslope will result in small deviations in airspeed, but that is it.

It appalls me that we make it so difficult on ourselves and students when we teach them to fly. I know there is the whole 'exercise' thing, but can't we at least give them the answers at the end of their training like we do for cross-countries (GPS Direct, block times, etc)?

The typical 172 short field circuit I see...

Abeam the numbers, pre-landing complete, carb heat, power to 1500, trim up for 70 (or 80), flaps 10, turn base at 45.

Extend flaps to 20 (really only about 15 in most 172s), trim for 70 (not much trim required at this point).

Turn final, extend flaps to 40. Trim forward to try and regain 60 (it is hovering just above 50). Power 2000 to arrest excessive descent rate. Fight to maintain airspeed. More forward trim. Drag it in at 60. More power, airspeed decays again, more forward trim, land at 60 or overshoot.


One secret I found out about Cessnas (I haven't had enough time on other aircraft to try it) is that they are specifically designed to go from cruise power level flight clean, to approach power with flaps, without moving the trim.

So I will reduce power to 1500 abeam the numbers and simply set the desired flaps and bingo, my approach speed is exactly where I want it, reducing itself incrementally as I add flaps. If I need to add power, I know that the trimmed speed of the aircraft will be reduced so I compensate for it before it decays. If I am too high and pull power, I know the airspeed will want to increase and I make sure I keep it in check first rather than trying to solve my height problem with attitude and come in too hot.

So really, you don't need a specific approach provided your visual cues are the same (angles) and your configuration is always the same...

You summed up the standard approach very well, however I believe the 1000' circuit was arrived at the fact at 1000' you have a good view of the airport you are arriving at miles before you get there which gives the low time pilot plenty of time to get all his ducks in order. This is great but jump forward a few years in time and you are doing a circling approach in crappy weather What happens? Very often you end up a little hot on final because you had NONE of the visual clues prior to final you have been doing for the last gazillion landings. Heck you don't have to even be IFR for that matter.

To top it off a guy, or gal, is already a little nervous due to the deteriorating weather and is worried about being acused of ".. running", or if IFR doing the death defying NDB app.

No, I think all the non standard approaches a guy can do is a bonus. If you are out on some farm strip or rural Alberta airport where nobody is around a good exercise is to take off, do a teardrop turn, and do a touch and go. Repeat untill proficient.

[tkdowell]

Illusions created by drift?

Our syllabus has it for this reason.

[chinglish]

If you do a 500ft circuit but stayed within gliding distance to the airport I don't see the problem. It was mentioned earlier, someday you might only be able to get your a/c up to 500 ft.

If I was stuck behind a Cessna doing 4 mi circuits I used to get my students to do a 500ft on the opposite downwind to pass the guy. Worked everytime.

[Shiny Side Up]

If I was stuck behind a Cessna doing 4 mi circuits I used to get my students to do a 500ft on the opposite downwind to pass the guy. Worked everytime.

This kind of thinking has lead to at least one mid-air collision I know of and at least half a dozen near misses I've seen.

No, I think all the non standard approaches a guy can do is a bonus. If you are out on some farm strip or rural Alberta airport where nobody is around a good exercise is to take off, do a teardrop turn, and do a touch and go. Repeat untill proficient.

And again the same here (this time I'm talking three more near misses in the safety file) good idea to practice, but make sure you're alone.

I know, I know. Everyone's a pro out there and should be able to just do as they feel. The thousand foot AGL circuit is like the legal drinking age in Quebec, just a suggestion. Clearly there's no real advantage to everyone adhereing to a circuit pattern, its just something abitrary that the powers that be just came up with. A thousand should be a nice round number everyone can remember, right?