Why do many "Airline" training organisations insist on flying such wide circuits? [Archive]

Awol57

14th Jan 2010, 09:58

Gee I guess none of you guys ever struggled early solo on downwind?

The airport I work at has a few schools that would fit this category and they generally aren't too bad. More often than not it depends on what level the student is at. From my days of instructing I recall most early circuit lessons the students struggled to get the pre landing checks done and the radio call on downwind completed (along with trying to fly the aeroplane). Whilst I like to keep it tight and would prompt along those lines, if I took over all the time how does the student learn? It was generally a non issue after a few lessons but still they can be busy early solo.

From an ATC perspective rarely will we tell you how to fly unless we specifically need it (ie Helicopter traffic inside the fixed wing circuit or about to leave the CTR).

Saying something can help, but a "can we tighten it up" has more effect than "am I following a 747 out there".

Checkboard

14th Jan 2010, 10:11

From my days of instructing I recall most early circuit lessons the students struggled to get the pre landing checks done and the radio call on downwind completed (along with trying to fly the aeroplane)From my days instructing, I would do the radio and checks for them, until they had the circuit OK - then increase the workload as gradually as they could handle it.

Awol57

14th Jan 2010, 10:15

As did I. The point I was trying to make is that early on they are busy doing all that stuff. Some of the closest circuits I see (and I see a lot every day) are the solo "airline" students. They aren't always the guilty ones, just the easiest target.

RENURPP

14th Jan 2010, 10:26

Well they aren't ready to go solo then are they?

Orion Delta

14th Jan 2010, 10:35

How wide are we talking? more than a mile?

ab33t

14th Jan 2010, 11:50

They sometimes fly seriously wide , I think I could do two circuits or close to that by the time they come in

kalavo

14th Jan 2010, 12:02

Because none of their instructors have had a real engine failure in a single yet..

toolowtoofast

14th Jan 2010, 16:44

Easy - just ask for a glide or short approach and drop inside them. You'll catch them back up in 2-3 circuits, but it's all good - it's about SA and managing your own positioning. Or ask ATC for an opposite circuit. Don't get frustrated - turn it into a lesson that's more than a takeoff, 4 left (or right) turns and a landing.

Lindstrim

14th Jan 2010, 22:52

I've seen some ome in on a 2-3 mile final from the circuit, I just ask for the opposite direction to what they're using at the time.

Jabawocky

15th Jan 2010, 00:09

Some of the a/c being used have a nice engine out quality and glide a long way further than a 172 does.......and I can imagine that they could be the cause of your stress.

They could introduce sideslip into every cct and help you out! :ok:

The Green Goblin

15th Jan 2010, 00:15

unfortunately most of the ones I have seen are in 172s or Grobs.

They don't glide to well.

Lodown

15th Jan 2010, 00:29

Large ccts because:

1. The instructor is too busy listening to his/her own voice and thinking the student needs to have some time to listen. Talk on the ground. Instruct in the air! Practice approach and landings when it's time to practice approach and landings. Practice straight and level away from the circuit. If you, as an instructor, have something important to say, make a full stop and talk on the taxi back to the threshold.

2. The student thinks he/she needs to have a long, stabilised approach for a good landing or he/she is just enjoying the view. What a waste of money!

Trojan1981

15th Jan 2010, 01:41

Pretty frustrating at CN, especially if you are flying a Pitts or something similar. Overtaking rarely allowed and LL cts no longer permitted :ugh: not a lot of fun to be stuck behind warriors, 172s and the odd Grob flying circuits big enough to warrant an alternate.

AYD

15th Jan 2010, 02:52

Lets get down to tin tacks on this, What does everyone think is a correct size circuit.

I'm a PPL with 90 hrs (wow) I was taught to have the wing tip running parallel with the runway on downwind left hand circuit, and halfway along the wing on a right hand circuit.

Base and final was always taught to be within gliding distance in case of engine failure.

But flying at a D-Class airfield with regular RPT operators this is not always possible.

Your Thoughts

The Green Goblin

15th Jan 2010, 03:18

As per the Jeps recommended circuit spacing is 1/2 to 3/4 of a NM on the downwind leg for most single engine piston types.

For high performance types a continual turn from upwind to downwind is adequate spacing.

GG

john_tullamarine

15th Jan 2010, 03:31

I guess attitudes and so forth are different these days ...

.. early circuit lessons the students struggled to get the pre landing checks done and the radio call on downwind completed ..

Then the student needs to be drilled before the first flight on the sequence of actions .. so that, by the second session in the circuit he/she is ahead of the aircraft throughout. The drilling takes a lot of time and effort on the part of both student and instructor .. but the result of such an approach and attitude is the student gets off solo in 4-6 hours and has the licence in minimum hours .. and ends up at a higher standard than the would be checklist reading airline student.

Some of the best fun I ever had in an aeroplane was half a dozen circuits in a 685 at Essendon years ago with the owner as payment for some engineering work I'd done on the aircraft. Didn't venture outside the aerodrome fenceline throughout (R17 as I recall). Tower thought it was great fun for a change and the owner (in the RHS) only saw the aerodrome on final ... he was an ex-airline driver in a past life and had raised eyebrows for the first one or two circuits (then again, I couldn't see too much myself on downwind) .... made the Shrike's performance look like a lawn mower's ... now, if only I could afford a 685 (or similar) for my weekend toy.

Oval circuits is the term, I believe ?

Aviast

15th Jan 2010, 03:50

As a student at one of these "airline training organisations" I've always flown what I consider to be a "standard" circuit (see below). We're taught to use "half wing strut" spacing in a C172R. On many occasions I've had to widen my circuit due to other traffic but I can't say I've ever noticed anyone flying a much tighter circuit than myself, which seems to be what some of the posters in this thread are suggesting should be "normal". (?)

I use a GPS flight recorder to record most of my flights; here is a composite of 9 circuit training flights. The white line is 1.02nm long.

http://lh3.ggpht.com/_N75r5-LFfE4/S0_vm5CUNTI/AAAAAAAAANI/X_JblQvWHX4/circuits.jpg

Awol57

15th Jan 2010, 06:30

The point I was trying to make is that in the first lesson, maybe 2, the student's work load is high. You can drill them for hours and hours, however actually flying the plane is different as I am sure everyone here is aware, otherwise everyone could get a license from playing MS Flight sim.

The camps we do with Air Force cadets we regularly send kids solo between 7-10hrs but meh. I am probably doing it wrong anyway.

Good luck with your wide circuits everyone.

One of the Night.

15th Jan 2010, 08:50

Perhaps I have been flying oval circuits in turbines too long (for my limited memory anyhow:confused:) to be qualified to comment, however.

What is wrong with simply turning downwind immediately upon reaching circuit altitude? (perhaps beforehand if you have poor performance).
Likewise base at a specified timing from abeam the landing threshold (varied for wind).

Why stray further than required?, safety aside, the exercise is about returning to ground!

Agreed John Tullamarine re: drills, students should have worn ruts into the living room floor walking the procedures and mentally flying the circuit, prior to even booking the lesson.

Scrapping long and hard for every dollar towards a lesson soon motivates one to make it all count.:ok:

the air up there

15th Jan 2010, 09:06

I agree with the comments about the student needing to fly bigger circuits because of the high workload on in ab-initio training. The purpose of the circuit is to position the aircraft, configure it and prepare for landing IMHO. If a pilot requires more room than someone else to do this initially then that is fine.

My beef with the whole big circuit thing is why aren't they later encouraged to see how tight they can make it. "Time is money" is what I was told even during PPL training (as I was then planning to jump straight to CPL). I see it daily, with commercial pilots (I use the term loosely) flying 2Nm circuits in aircraft rangine from 172's to 210's, meanwhile there are people in 402's, 404s, PA31's that are tighter.

Any ideas on that one guys, coz it has me stuffed.

MakeItHappenCaptain

15th Jan 2010, 10:43

Aviast, nice continuous spacings, (even if Qantas doesn't fly square circuits). Seriously though, the problem is that many students, and indeed, their instructors, don't notice the spacing on their downwinds. Myself and plenty of the other posters here do.

The correct spacings and attitudes should be the first thing demonstrated to any student starting circuits so that they can compare their spacing to what SHOULD be demonstrated correctly in the first place.
PRIMACY.

Maybe we should see more of the half a dozen students on pushbikes riding circuits and making their calls to the nominated "ATC" student/instructor standing in the middle so that they can handle the workload prior to flying?
Spot on, JT:ok:

NOSIGN

15th Jan 2010, 10:44

Aviast, good heading control with your ccts mate. Straight lines.

Only a few of us fly circuits the way they're meant to be flown... only a few.

Don't diss the beginners, they're learning but as the air up there said, teach them later to fly proper ccts... if they haven't worked it out for themselves.

Whoever flew the cct at ywgt the other day to make time for me... thanks :ok: It was such a relief to see others fly the way I do :}

Mark1234

15th Jan 2010, 12:12

As aviast was brave enough to stick his neck out.. I see nothing wrong with the lateral spacing, however, the crosswind / base legs on a few of those are a bit further out than I'd personally want to be.

As to why xc circuits - 2 reasons I can see;

1) some people suggest if you're training for the airlines, you should fly your PA28 like an airliner. Personally I disagree.. if you're going to be professional, you ought to be professional enough to fly appropriately for each type!

2) More common at YMMB, there's a slow a/c or two in the circuit - So the a/c behind goes a little wider, and the one behind follows/wider still. Eventually you're 5 miles out.. It never seems to occur that even the 'fast' a/c can usually drop a couple of notches of flap, throttle back, and happily fly the downwind leg at the same speed as the c150 in front. Bonus there is that if you should happen to have an inconvenient engine failure, you can holler out on the radio, dump the flap and make a swift turn onto the airfield somewhere - anywhere.

Then we have my personal pet hate.. people extend downwind for spacing all the time, rather than slowing on downwind.. but they still put some flap out on base, and the rest of it when they turn final - somewhere around the inbound reporting point. (sorry, that's turning into a rant...) think it's because people are taught by numbers, "turn final, 2000rpm, 2 stages flap" rather than to fly the aeroplane: "well, that looks a bit high, better put some flap out"

Sunfish

15th Jan 2010, 18:15

Most of us seem to agree that the first few circuit exercises as a new student are going to produce wide circuits. Mine certainly did and its a workload thing.

...Then at YMMB we work out the Springvale Road/Boundary road/Heatherton Road/golfclub or whatever landmarks and our circuit performance improves. Get real, after a few circuits at YMMB you are following roads and aiming at clubhouses and nurseries, not judging distances by wing struts, etc.

....Then we go away from the familiar airport and mess it up all over again at a shorter, narrower, unfamiliar strip like I regularly do.

As for slowing down to get the spacing, I do that all the time, and occasionally I'm rewarded with an early Left turn by ATC.

Oktas8

15th Jan 2010, 21:29

There are two more common reasons for wide circuits at large flying schools.

If there are many aircraft (7? 8?) in the circuit all using the same runway, the circuit will increase in size simply to fit that number of aircraft in. Whilst in theory there is still no need to extend wide or long downwind, in practice someone does and then everyone else must follow suit.

With different types operating in a busy circuit, it is often difficult for students to judge the correct spacing behind preceding aircraft. Therefore students will extend "just a little bit" to get enough space on final. Whether necessary or not, this compounds very quickly in a busy circuit.

Rgds,
O8

Super Cecil

15th Jan 2010, 21:48

Maybe can understand at a busy Airfield but why big circuits when there's only one or two Aircraft at a regional or remote Airfield? Apart from lack of ability that is.

eocvictim

16th Jan 2010, 02:48

ahhh the old "GFS" circuit. I remember

"ABC you're number 2 to a 172 on wide downwind."

"Looking for the traffic ABC"

"Ahh ABC that traffic is now in your 3o'clock you're now number 1..." :}

The air up there:

The biggest difference between the bare CPL and the multi IFR driver is that the IFR guys are well aware how big their circling area is and they're always keeping the a/c within it (even when its CAVOK and above MDA). Plus time is money!

MCKES

16th Jan 2010, 05:22

Eocvictim, I think you have summed up this thread with saying. "Plus time is money!":ugh:

Ando1Bar

16th Jan 2010, 20:09

I have sat back and watched the usual dribble come out from the self-proclaimed experts, but I can't hold back any longer. I'm not defending large circuits, in fact the instructor shouldn't let this consistently happen.

The notion large circuits are flown to bleed money from the student is plain wrong. Many 'airline' training organisations have to stick damn close to the syllabus otherwise they leave themselves wide open when airline 'X' audits them. So it's not just a matter of turning a 1.0 lesson into a 1.2 or 1.3 hour flight so everyone can make more money. Flying a wide pattern benefits no one - only achieving six circuits in a lesson is not a beneficial as eight.

"Ahh, but you can charge extra remedial time when the student doesn't get to solo in the normal time" some bright spark will no doubt comment. That's true, but again it is nobody's interest for this to happen. The airline/client starts questionning why their students are overflying (and run the risk of losing their contract), or the student is scrubbed from the course. Not a good outcome for anyone.

So why the 'wide' circuit? Most clients have a requirement for their students to be taught good profile and speed control, in particular using a 3 degree profile. If you do the maths such a profile puts you 1.57 nm from the aim point at 500 feet.

Given the busy training environment we don't end up as far as 1.57 from the aim point turning final, more likely a bit over a mile. This still allows a good approach angle while maintaining a bit of power to control the speed. The aim of the game is to prevent a low power, fast, steep descent to land - if the student does this on their flight test they will fail.

Later in the student's training there may come a time when "Bloggs, I believe you won't be off to airline X in the short term and will have to cut your teeth up north. If might not always be appropriate to fly like we have been, how about we look at a closer circuit to save your boss some money". We attempt to teach them good habits if their headed for a single engine charter job in the near future, but hopefully by the time the student is at airline X they can fall back on the rule of primacy (flying the required profile they learnt back at the start).

So why the wide circuit? From my experience the crosswind/downwind leg (once mastered) isn't really much larger than what anyone else is flying. It's the positioning of the base turn which makes it challenging from those behind teaching steeper approaches.

Aviast, nice continuous spacings, (even if Qantas doesn't fly square circuits)

The Qantas circuit diagram shows a racecourse crosswind turn on to downwind, and a 'square base'. That's what we teach/fly, traffic permitting.

As aviast was brave enough to stick his neck out.. I see nothing wrong with the lateral spacing, however, the crosswind / base legs on a few of those are a bit further out than I'd personally want to be.

Probably further out than what he wanted as well. No doubt due to delaying the turn due to traffic ahead.

Now let me get my shield out as those who have never taught such students in such training environments take pot shots at my comments.

Checkboard

16th Jan 2010, 20:33

Cool, I'll start. :}

The Qantas circuit diagram shows a racecourse crosswind turn on to downwind, and a 'square base'. That's what we teach/fly, traffic permitting.

Why would you teach an airline procedure to a basic student not flying an airliner? :confused:

Trent 972

16th Jan 2010, 20:48

Qf jets aim for a 2 - 2.5nm spacing from the runway on downwind, therefore checkboards question of students flying the Qf circuit procedure isn't correct as it is modified for a light training aircraft type.
Looking at aviasts piccy, I would say he is being taught well. (Might just straighten up that downwind track to parallel the runway though).

Zoomy

16th Jan 2010, 21:03

Thats strange I have never seen or been on a QF flight that has flown a square base.

Flying training organisations, Airlines and all instructors, it takes sweet fu^kall training to convert your average CPL candidate from <5700kg ops to transport category ops. In other words, fly the bloody aircraft as per the POH and the DAY VFR syllabus not like the space shuttle.

Trent 972

16th Jan 2010, 21:32

it takes sweet fu^kall training to convert your average CPL candidate from <5700kg ops to transport category ops.
I hope you get your shot soon Zoomy, but you might just have to rethink that statement. Multi crew ops are not any harder, just a lot different.
Also it is quite rare to fly a 'circuit' in an airliner, but it is a square base, just like the littlies. On the 380 it is a square base leg until .9nm xtrk deviation then turn final.

Ando1Bar

17th Jan 2010, 01:52

Trent, thanks for the backup based on your A380/QF experience.

To clarify what is being taught - turn crosswind 10-15 deg AoB depending on wind, wings level momentarily at 90 deg to check for traffic and runway alignment, then continue the turn. This gives the 'racecourse' crosswind turn. Of course given the speed we are flying we are going to be no where near as far away from the field as a jet on downwind.

On base a more square leg is used allowing more visual contact with the runway on approach. The circuit really isn't much different to what you would all be flying.

Why would you teach an airline procedure to a basic student not flying an airliner?

We're trying to teach skill sets from the beginning they will use throughout their career and introduce the concept of standard operating procedures. Of course this is adapted to the aeroplane and common sense applies. This allows us to, as Zoomy puts it:

...fly the bloody aircraft as per the POH and the DAY VFR syllabus not like the space shuttle.

As mentioned on a previous thread, if you have a real interest in wanting to know what is taught, don't post snide remarks - PM me. If the pilots in the white planes at YBAF are holding you up or doing silly things PM me - I'll speak to the pilots involved (it is part of my job to).

Slight thread drift, I read a post a couple of years ago by an instructor explaining how they teach landings. Every approach was basically a glide approach so the student would be able to land just in case he had an engine failure. Well, that's one way to tighten the circuit, but the student is in big trouble later in their career when it comes to flying a stablised approach with good aim point and speed control.

MCKES

17th Jan 2010, 02:56

Ando I know your position and I respect your comments. But Zoomy is 100% correct in saying that a Cessna 172 Is not a space shuttle. Sure there is a small - very small percentage of your students that will go straight into an aircraft above 5700 but the majority wont. Fly a 172 how it is meant to be flown. :ok:

Cap'n Arrr

17th Jan 2010, 03:18

My favourite was always:

"ABC request clearance to leave and re-enter the GAAP zone on downwind"

Tower: "Why do you need that?"

ABC: "Cause I'm going to need it if you want me to stay number 2 to XYZ ahead"

Tower: "Ahhh, XYZ tighten up your circuits mate":D

eocvictim

17th Jan 2010, 03:51

Ando1bar, I can understand teaching a stabilised approach but at 318ft/nm (3deg) in a 172 at 1.57nm at 500ft thats a ROD of 344/min. That seems very shallow, surely it would be better to do the norm and aim for 1 at 500 and go down at 542. That is the essence of a stabilised approach, teach 3deg profile when its required during instrument approach.

I dunno, that's just my thoughts, I dont know the training organisations over all goals but from the outside seems a little arse about.

I think answering the above, with an unquoted explanation from the ops manual, will finally put a rest to this argument. This is now essentially all it has come down to, your final position.

edit/might as well be accurate.

Trent 972

17th Jan 2010, 03:53

MCKES and eoc, I spoke a little while ago with the fellow who does a lot of the Qf interview sim checks and he said that he was disappointed with the majority of candidates inability to fly a 3 deg approach whilst maintaing an aim point, 'on' speed. He didn't care if they flew 172's or space shuttles.
Those 3 abilities are a must in Qf. Anyone who can't display that in the sim check has lessened their chances in a very competitive interview process. Ando has already pointed out the nm required to achieve a 3 degree path. There are a great many ways to fly a 172, but only one way will impress the interviewer. I think Ando is on the enlightened path, grasshopper.

eocvictim

17th Jan 2010, 04:11

I was basing my figures before on a 172 app speed of 65 kts, I guess you could fly it faster or drag it in on the prop, either way is undesirable but as you said possible. I guess with minimal hours picking what the strip should look like at 3deg is pretty important. Though a couple of hours in a Hi-Po piston or basic turbine would solve this too.

Trent out of curriosity what is the ROD for 3deg in the 380 I'd imagine it'd be close to 716ft/min? I'm assuming its about 135kts? Too slow?

3deg is easy once you work out the key number is 318ft/nm. Did my head in before then... idiot.:ugh:

Trent 972

17th Jan 2010, 04:28

Pretty spot on eoc. @ a normalish landing weight of 380 tonnes, ISA conditions = 141 knots. Which includes a 5 knot addition to Vls (velocity lowest selectable). RoD = 750fpm. I don't wish to tell anyone how to fly a 172 at all, just that if you want to get into Qantas, then you should probably consider this aspect. As Ando is obviously involved in an Airline Training School, he would be a fool to teach other than what the clients require.
As for the other CFI, cynical speaks of. He is obviously very good at what he does as well, but like I said earlier if you want to impress at a Qantas sim check..... Try diving at the runway in a Qf sim check and I'd bet that would be the last time you ever get to see inside a Qantas simulator.
The only other observation I've made is that the people who fly a stabilised approach (3 degree or whatever) make the transition to night circuits a lot better than those who are 'up and down like a brides nighty'.

Good luck to all (if that's what you want)

Veruka Salt

17th Jan 2010, 04:35

Guys,

Not sure about the A380 as I haven't flown it, but have flown the 744 and 767 with QF, and A330/340 with another carrier and in all cases downwind is flown with approx 2.5nm spacing and a curved base leg. Doubt whether the A380 is any different.

Cheers,
VS.

Keg

17th Jan 2010, 04:50

Veruka, 767 oval base? Really? The diagram I'm looking at, whilst not particularly clear, implies a 'square' base. Given the speeds on crosswind and the turn to downwind (as opposed to the speed coming across base and then F30 prior to the turn onto final, I'm not sure how you can fly an oval base unless using a very small angle of bank all the way around. Remember the old trick with the trend vector being a 1/3 of the way the final approach? You can't do that on an oval base.

I'll leave the discussion as to whether a C172 should be flown the same way to other people.

Veruka Salt

17th Jan 2010, 04:56

Keg,

I know the 'base training' circuit diagram you refer to, however I never flew square base either on the line or in the sim.

20 deg AoB xwind turn (nil wind), adjust tracking on downwind, 15 deg AoB on base (initially), adjusted as necessary for headwind/tailwind. Airbus similar except more like 15 deg AoB xwind, 10 deg on base.

Definitely not a square base unless I'd stuffed it! :{

VS.

Trent 972

17th Jan 2010, 04:59

Greetings Veruka, I haven't flown the 76, so I'll leave that to Keg, but I also have flown 330 and 744 and quoting from the 744 FCTM...
......Turning base leg, adjust thrust as required while descending at approximately 600-700fpm. Extend landing flaps prior to turning final.....
I guess I must be intepreting it differently.
*No probs Veruka. I only quoted that part of the text because it talks of a base turn and a turn to final, inferring a base leg, if you wish.
**Airbus A380 FCTM/Normal Operations/Visual Approach/Intermediate-Final Approach = Square Base Leg (diagram) Also A330 FCTM 02.140 square base...That pretty much covers 380/330/744 (in theory).

Veruka Salt

17th Jan 2010, 05:05

Trent,

Not disagreeing with rates of descent or selecting landing flap etc .... rather, the only times I've ever flown a square base are when I'd used too large an AoB turning base, or had a strong headwind, or been too wide on downwind and not corrected it prior to turning base ....

Current teaching where I work now is to use constant bank all around base, particularly in poor vis (common in our part of the world).

VS.

MCKES

17th Jan 2010, 05:35

If they want to see what the runway looks like when on slope just teach them to use the PAPI's or T-VASIS when they go into YBCG, YBMC, and all the other places. There they can see it, not when practicing circuits in busy airspace with varying performance aircraft in the same circuit including twins and high performance pistons.

Keg

17th Jan 2010, 06:37

Veruka, fair enough. I've always used 20 degrees AoB and flown a square base leg. No one has ever chipped me for it.

Ando1Bar

17th Jan 2010, 07:13

Ando1bar, I can understand teaching a stabilised approach but at 318ft/nm (3deg) in a 172 at 1.57nm at 500ft thats a ROD of 344/min. That seems very shallow, surely it would be better to do the norm and aim for 1 at 500 and go down at 542.

Agreed

Ando I know your position and I respect your comments. But Zoomy is 100% correct in saying that a Cessna 172 Is not a space shuttle. Sure there is a small - very small percentage of your students that will go straight into an aircraft above 5700 but the majority wont. Fly a 172 how it is meant to be flown.

Agreed also.

Which I why I have said in previous posts in this thread:

We're trying to teach skill sets from the beginning they will use throughout their career and introduce the concept of standard operating procedures. Of course this is adapted to the aeroplane and common sense applies.

We're not doing anything ground breaking in a C172. In fact someone flying our planes a page or two back posted an image of what is flown. I also mentioned:

Given the busy training environment we don't end up as far as 1.57 from the aim point turning final, more likely a bit over a mile. This still allows a good approach angle while maintaining a bit of power to control the speed. The aim of the game is to prevent a low power, fast, steep descent to land - if the student does this on their flight test they will fail.

Ecovictim, you asked:
I think answering the above, with an unquoted explanation from the ops manual, will finally put a rest to this argument. This is now essentially all it has come down to, your final position.

Here you go:

An approach is stabilized when the aircraft is:
a lined up with the landing runway
b established on 3° glidepath
c in the landing configuration at Vref +5 / - 0kts
d descending at less than 500fpm

eocvictim

17th Jan 2010, 08:09

Thanks Ando1bar, clears it all up and should put a stop to it all. The ops manual wants it, then thats how you fly it.

Checkboard

17th Jan 2010, 09:40

Also it is quite rare to fly a 'circuit' in an airliner, but it is a square base, just like the littlies. On the 380 it is a square base leg until .9nm xtrk deviation then turn final.

I would imagine it is quite rare to fly a circuit in a 380! ;)

In Ansett, based in Perth, we flew to 60 odd destinations throughout the north and west of Australia, and only three or four of them were ILS's. All of the rest were circuits. Three jet types, a lot of circuits, and not one of them had a square base (at least, not a planned one!). In Europe, on the odd occasion I fly a circuit, it is an oval base.

I read a post a couple of years ago by an instructor explaining how they teach landings. Every approach was basically a glide approach so the student would be able to land just in case he had an engine failure.
Silly idea, I agree. the aircraft eventually has to leave the circuit - that's why we teach PFL and Prec Search - the tiny amount of time in the circuit makes no difference. The only glide approaches I taught were to complete the PFL exercise (the bit below 500', where you introduce the skills for a glide touch-down)

Remember the old trick with the trend vector being a 1/3 of the way the final approach? You can't do that on an oval base.
Trend vector? Oh yeah - got one of those now. :}

......Turning base leg, adjust thrust as required while descending at approximately 600-700fpm. Extend landing flaps prior to turning final.....
Doesn't say or even imply that the base leg is square. A curved base occurs before final, just as a square base does.

An approach is stabilized when the aircraft is:
a lined up with the landing runway
b established on 3° glidepath
c in the landing configuration at Vref +5 / - 0kts
d descending at less than 500fpm
I don't know where that's from, but it isn't a very good definition. There are many approaches around the world which require greater than a 3º approach to the runway. :cool:

Back Seat Driver

17th Jan 2010, 10:11

Checkboard said In Ansett, based in Perth, we flew to 60 odd destinations throughout the north and west of Australia
60 I bet you couldn't name more than 40 of them. Unless we're talking the 1960's but then that wouldn't have been AN.
ps
All you blowhards who carry on about curved bases and other crap, are full of it.
Easiest picture I could find of a standard circuit is here (http://www.auf.asn.au/groundschool/umodule12.html#circuit_pattern)
God help the poor newbies who listen to all this sooking about curved this and curved that. There are 5 legs to a standard circuit pattern and they are all straight and perpendicular to the previous leg. How you fly it is your business.

Ando1Bar

17th Jan 2010, 11:01

Quote:
An approach is stabilized when the aircraft is:
a lined up with the landing runway
b established on 3° glidepath
c in the landing configuration at Vref +5 / - 0kts
d descending at less than 500fpm

I don't know where that's from, but it isn't a very good definition. There are many approaches around the world which require greater than a 3º approach to the runway.

It was from our ops manual, the question was raised where it said such an approach had to be flown.

Checkboard

17th Jan 2010, 11:16

It was a guess, I admit. Hmmm ...

Perth, Kalgoorlie, Newman, Geraldton, Meekatharra, Cocos Is, Christmas Is, Bali, Barrow Is, Port Hedland, Argyle Mine, Karratha, Broome, Derby, Kununurra, Darwin, Gove, Groote Is, Weipa, Cairns, Hamilton Is, Townsville, Mt. Isa, Alice Springs, Ayers Rock, Sydney, Melbourne, Adelaide.

... Ok - not 60 :O

Still a lot of circuits, though. ;)

Back Seat Driver

20th Jan 2010, 03:44

Ok thanks for that Checkboard
It's not 60, but 25 (Sydney, Melbourne and Adelaide have not ever, nor are likely to be, (barring global warming) in the "north and west of Australia" (and 6 of those have ILS's), but still a very respectable list.
Your claim of "still a lot of circuits" does not hold much water when what you were probably doing was maneuvering in the circling area after carrying out some form of instrument/dme arrival.
Not really what this thread on training school circuits was about, though.

ForkTailedDrKiller

20th Jan 2010, 04:12

Easiest picture I could find of a standard circuit is here (http://www.auf.asn.au/groundschool/umodule12.html#circuit_pattern)
God help the poor newbies who listen to all this sooking about curved this and curved that. There are 5 legs to a standard circuit pattern and they are all straight and perpendicular to the previous leg. How you fly it is your business.

BSD

Not necessarily so!

Part of the problem, I think, is that the rules keep changing! For the first 15 years or so of my flying things were pretty much stable and most of us knew what we were doing. Then the inmates were put in charge of the nut house and most of us struggle to keep up with the changes.

Two things came out of my last "workover" with a very, very, very experienced senior instructor and ATO.

1) My nice square turn onto cross wind after TO is out and "a continuous rate one climbing turn onto downwind" is in, and

2) When joining overhead, flying crosswind over the downwind threshold is out, and crossing mid-runway to join mid-downwind is in.

My answer to all this? Keep my eyes peeled out the window and make it up as I go along. Seems to work OK as I flew into YCAB about five times before I figured out that it was RH circuits onto Rwy 30.

Dr :8

Back Seat Driver

20th Jan 2010, 04:58

Hello Dr,
The 'racetrack' turn to downwind you described, is as taught by Ando and his cohorts and described earlier in this thread. I've also noticed the very military terms 'High Key and Low Key' appearing in CASA's Visual Pilot Guides as well. Maybe the oval circuit as taught at BFTS is the future.

What the law says about the circuit pattern (http://www.austlii.edu.au/au/legis/cth/num_reg_es/caar20053n243o2005453.txt/cgi-bin/download.cgi/download/au/legis/cth/num_reg_es/caar20053n243o2005453.txt)
The circuit pattern consists of five flight legs, each of which involves a series of standard procedures and manoeuvres used to allow the safe and orderly flow of aircraft traffic into, around and from an aerodrome. The circuit procedures also safely expedite a number of take offs and landings to be practised in a short period of time. The circuit is a series of events beginning with the preparation for take-off and culminating in a stable approach and landing.

The operational practices that are covered by the regulation are those general requirements with which the pilot-in-command of an aircraft will be required to conform when approaching a non-controlled aerodrome for a landing and when joining or departing the air traffic circuit.

A penalty of 25 penalty units applies for non-compliance with the subregulation. The offence is an offence of strict liability. One penalty unit is currently set at $110 under the Crimes Act 1914.
The answer to what should be a simple question is?????

Aviast

1st Apr 2010, 07:11

A fun report :)

Exclusive Video: A Humorous But-Not-That-Gentle Look at Flying Traffic Patterns (http://www.avweb.com/avwebflash/exclusivevids/ExclusiveVideo_PatterFlying_CFIs_SarcasmHumor_202261-1.html)

Tee Emm

1st Apr 2010, 13:02

If the controller then feels they are a bit wide, they will ask them to tighten it up.

By then it's too bloody late.

Tee Emm

1st Apr 2010, 13:19

and "a continuous rate one climbing turn onto downwind" is in,

Why only a rate one turn? The rate of climb in a 30 degree banked turn is almost identical to that of a rate one. You would never pick the difference in the short time it takes to turn through 90 degrees. In a Cessna high wing type the blind spot during the turn means you spend more time blind at Rate One than if the turn is steeper for a shorter period.

The Rate One climbing turn harks from the old days in Tiger Moths where a circling climb to height prior setting course for a cross-country from over the field, was best done at Rate One in order to get to height more quickly that a continuous steep turn over the field over a smaller radius. Nothing wrong at all with a 30-35 degree angle of bank turn for the first crosswind leg -straighten up for a few seconds for spacing and a good look around, then same bank angle on to downwind. Same on base and final.

OZBUSDRIVER

2nd Apr 2010, 01:42

Aviast, Paul Bertorelli is pure gold....like his instructor shirt with multiplying gold bars...looks like the US runs into the same problems as we do here.

......Often wonderd about circs at PC...should you have to wear a life jacket?

j3pipercub

2nd Apr 2010, 02:51

That video was legendary!

rmcdonal

2nd Apr 2010, 02:54

That was a funny clip, but I'm not too sure about his advise on slipping to get down, sure it is a useful skill to have but side slipping near the ground for most students should be a big no no (unless of course they are flying an aircraft that uses sideslips to control descent) If we teach students to side slip down final all the time then when they start taking paying pax up they will be plastered to the side window.
Yes I think students are flying larger circuits then needed but there is also a point where the circuits can get a little too close, (if you fly AG ignore all of this, it is in no way aimed at you). Turning final at less than 500ft is unnecessary at most airports (there are always exceptions) it invites error and leaves little room for inexperienced pilots. On the other hand turning final at 1000ft is also unnecessary (unless you're trying to demonstrate something to a student) and shows poor airmanship. In a standard light single your final and base speed will be appx. 60-70kts, so to be at 500ft as you roll wings level on final should have you about 1.5nm from touchdown (standard 3deg profile).

jimmygill

2nd Apr 2010, 04:06

Thanks for the picture you posted

In a downwind you are at a horizontal distance of approximately 6000 feet from the runway, and vertically about 1000 ft above runway. An observer at the runway will see your aircraft at an elevation of 10 degrees. ( 100 feet height over one NM subtends 1 degree arc)

Which means that the observer on runway should raise his eyesight 10 degrees above horizon to sight you. In the same manner you should see the observer 10 degrees below horizon from your left window.

In order that this 10 degree line of sight to pass through "half wing strut" and pilots eye, the pilot's eye must be at the same level as the glare shield. You can do this small exercise using a protractor and 3 plane view in the manual.

As you maintained that you did these circuits with "Half-wing-strut", the only way to accommodate a comfortable eye hight and the 1.02 NM wide downwind leg is by flying at 1500 AGL instead of normal 1000 AGL.

Usually the half wing strut method gives a width of 3/4 statute miles or 4000 feet approx. While in your case it gave a width of 1 NM, i.e. 6000 ft. Which led me to think there must be something wrong, but still you have managed fairly consistent widths, Is it possible that you were using any landmark other than the runway itself? My primary instructor emphasized that I should be able to do the pattern with reference to the runway, the aircraft and nothing else.

In my opinion safe distance from runway for single engine piston aircrafts is no more than 4 times the pattern height above ground. Then instead of 10 degrees it ought to be 15 degrees elevation.

One of the foremost consideration in designating such relation is the scenario of power loss in pattern. Just from how far can a trainee pilot safely land at airport in case of an emergency? We must take into account, representative glide ratio, adverse winds and low time pilot.

Any one trying to maintain wider than 3/4 sm in SE Piston is a safety hazard. There are several schools especially outside USA which recommend patterns as wide as 1nm to 1.5nm for SE Piston. I have never understood why they do so?

Aerlik

2nd Apr 2010, 10:26

A few years ago, an instructor commenting on this issue at Jandakot, reckoned a certain foreign school used circuits as nav. exercises, such was the distance from the field.

jimmygill

2nd Apr 2010, 12:55

so to be at 500ft as you roll wings level on final should have you about 1.5nm from touchdown (standard 3deg profile)

And for this reason the standard three degree profile is not the best for SEP aircrafts, they ought to be more on 6-8 degrees.

Capt W E Johns

2nd Apr 2010, 13:20

Two points from me.

First, it is unlikely you'll safely make the runway in the case of power loss mid-downwind, no matter what your spacing. You might physically reach the runway you've just departed from, but you're pretty sure of running off the end (unless you happen to be training at Edwards AFB). Much more achievable is a turnback from ~500+ feet AGL after takeoff, or through crosswind, or early downwind. From mid-downwind onwards, on a regular training circuit you just won't make the runway. (There's a narrow window just before base turn, but that's discounted in this discussion as it's a highly unlikely scenario).

So we can discount trying to make the runway as a factor in circuit design. This brings me to my...

Second point. The primary reason for flying circuits is to give a student pilot the opportunity to practice takeoff, approach, and landing. Therefore, the circuit should maximize the student's training value, by being as efficient as possible while coonsidering the aircraft's performance characteristics. As student ability changes, so should the manner in which the circuit is taught/flown. In my opinion, the oval circuit is better, as it challenges judgment and assessment in ways the square pattern cannot, and it copes better with changing wind conditions.

jimmygill

3rd Apr 2010, 03:07

First, it is unlikely you'll safely make the runway in the case of power loss mid-downwind, no matter what your spacing.

Isn't power of 180 landing a part of FAA commercial pilot practical test standards for ASEL, which all CPL applicant have to demonstrate.

The applicant must land the aircraft within 200 feet of a point on runway abeam the point in downwind where the engine failed.

If one can do it at the end of the runway, you can do it at the middle of the runway.

Millions of pilots have demonstrated and passed the Power of 180 accuracy landing from traffic pattern.

ForkTailedDrKiller

3rd Apr 2010, 05:41

it is unlikely you'll safely make the runway in the case of power loss mid-downwind

?? Surely you jest!

You might physically reach the runway you've just departed from, but you're pretty sure of running off the end

Isn't that why the retractable undercarriage was invented?

Dr :8

Gligg

8th Apr 2010, 11:26

I'm actually a fan of both the square AND the round circuit (depending on terrain) and staying within gliding distance - but maybe thats just a Papua thing :}

Tee Emm

8th Apr 2010, 12:50

so to be at 500ft as you roll wings level on final should have you about 1.5nm from touchdown (standard 3deg profile).

A typical single engine trainer with full flap, 60-70 knots and a trickle of power is not a "standard 3 degree profile" by any stretch of the imagination. The three degree profile was put in place for jet transport aircraft where a combination of thrust amount, approach speed and aircraft weight (inertia) meant a rate of descent not exceeding 1000 ft per minute to allow for inertia in the flare.

Of course you can drag a Cessna 150 in with full flap on a estimated three degree glide slope but you will need considerable power to keep the speed up. The normal approach angle for a light single with landing flap, 60-70 knots and 1200 to 1500 rpm is more like five or six degrees and perfectly comfortable. Try flying a PAPI or ILS in a Cessna 150 or Warrior and you will soon discover that significant power is needed to make such a relatively shallow approach if flap is full down.

A three degree approach at 65 knots ground speed gives a rate of descent of 325 feet per minute. Try a 15 knot headwind component and the rate of descent reduces further to 250 fpm. 250 fpm in a Warrior with full flap means an awful lot of power. That means from 500 ft on final it takes you two minutes to the flare. For 140 knots airspeed the rate of descent is around 700 fpm which is omfortable for a 737/A320 allowing for inertia in the flare.

Aiming for a "standard" three degree glide path profile in light aircraft is impractical and unnecessary.

Aerohooligan

9th Apr 2010, 23:44

Tee Emm,

that's why I keep the 210 at 140 knots til just under a mile... :}

(in all seriousness though, I agree - no one could argue that the half-screen attitude taught for final approach in baby cessnas results in three degrees...)

Go down hard, or go fast! :ok:

d.shaw15

28th Apr 2010, 04:23

Because when you fly at places like Point Cook where the clowns from the school down there have 6-7 planes in the circuit at a time you need to space yourself out. But for some reason this is beyond their comprehension and they continue to do short finals and go arounds without getting any actual useful practice in. Use your common sense......

Barberspole-5

28th Apr 2010, 05:15

there are few flying colleges that flies light aircraft down a 3 degree profile, not the usual 4, for most light aircraft. This means that downwind (and base) is extended slightly, so as to prevent an excessive ROD on base/final. The result is a bigger circuit.

Ted D Bear

30th Apr 2010, 06:10

On a check flight recently, I had a [senior] instructor tell me to turn final at 400' and fly the PAPI (3 degree approach path) and do this all at night in a low performance single :ugh:

FokkerInYour12

3rd May 2010, 06:30

I know a few ATCs hang out here.

What sort of radio call would you like to hear us say when we have been told to following a C150 on downwind to find he is on far far far far downwind and we've already got to the base turn point?

"Request #1 to the preceding aircraft so I can actually remain in the circuit"?

Request callsign and operator of preceding aircraft to notify them of their non standard circuit?

conflict alert

3rd May 2010, 10:20

when I used to watch my traffic in the circuit, you soon learnt who was doing the huge circuits and if a suttle hint of "can we try and keep final approach inside the control zone" didn't work when the aircraft was back logging the 5 or 7 behind them then I would tell them on their next downwind call to "extend downwind until advise number (6) following the (5th) lighty behind you" and then get about 5 behind, ahead of them. Only used to take about 2 circuits to get everything nice and tight again after giving them the base turn clearance about 6 miles from the runway!!!! At a busy airport - regardless of the size of aircraft - you need to run a tight ship. One aircraft doing one wide circuit can cause a huge backlog which results in a longer and longer and longer final for every subsequent aircraft.