1,500 or 2,000ft?

[Squawk7700]

Aviators,

What's the general consensus on this?

It seems clear that a 1,500 ft circuit exists for "fast" aircraft over 150knots etc, however in the real world is seems that nobody is approaching airfields at 2,000ft as would be required.

I have never heard anyone approaching your average CTAF at 2,000ft since this was introduced. Am I confused in that it's recommended and not mantatory?

If it is recommended, are pilots listening for the presence of "fast" traffic and simply sticking with a 1,500ft approach to the airfield? How do we know the they are fast, listen for a Qantas call sign or similar?

How does this all work out at places like Wagga where the turboprops fly in RPT?

[Styx75]

If the ersa says an aerodrome has rpt traffic, I use 2000ft, otherwise 1500ft (and listen out for fast movers).

[Squawk7700]

No more takers? Surely everyone does this on a daily basis when out flying...?

[Lead Balloon]

The lack of takers is probably because what you assert is clear and required is ... not: It seems clear that a 1,500 ft circuit exists for "fast" aircraft over 150knots etc, however in the real world is seems that nobody is approaching airfields at 2,000ft as would be required

[Old Akro]

The 150kt speed refers to speed in the circuit and the reality is that while many GA aircraft CRUISE over 150kt, very, very few would do 150kt or more in the circuit. Most fast aircraft would be at IAP procedure speed or gear extension speed in the circuit and 120 kts is a common speed for this.

I'm not really sure who this applies to, maybe a Citation or something, but no GA single or light twin that I know of.

[Squawk7700]

I'm not really sure who this applies to, maybe a Citation or something, but no GA single or light twin that I know of.

I guess that's my point... you don't really know who / what is there before you get there. You might hear "Citation ABC turning downwind for 18" or something and unless they say their circuit height, you are blissfully unaware as you approach at 1,500ft.

I've asked this because it came up recently at a regional airfield where someone was "abused" for attempting to fly over an airfield at 1,500ft as 1,500ft circuits were in use by a high speed aircraft and I was wondering how frequent that is.... seemingly not very, based on the responses.

[Lead Balloon]

I think the standard phraseology in that circumstance is: "Forgive me oh fast skygod. I shall continue downwind until thou condescend to my returning to thine vicinity."

I've never encountered a 'fast' aircraft joining and carrying out a 1,500' circuit. If I heard calls from an aircraft doing that at an aerodrome to which I was inbound, I would do what I do everywhere else: have a chat and decide how best to ensure separation on arrival.

Faced with abuse (never happened to me and I don't expect it ever to happen) I would use the standard ICAO phraseology: "Piss off, stupid."

[AerocatS2A]

I've never encountered a 'fast' aircraft joining and carrying out a 1,500' circuit. If I heard calls from an aircraft doing that at an aerodrome to which I was inbound, I would do what I do everywhere else: have a chat and decide how best to ensure separation on arrival.


You've never been to a CTAF aerodrome that has RPT jet traffic?

Agreed that abuse is uncalled for.

[Lead Balloon]

I'm yet to encounter RPT regionals or RFDS 'doing a circuit'. Always straight in or via base.

Not to say it doesn't happen.

But I'm yet to mix it with RPT or RFDS in circumstances in which they care whether I'm proposing to overfly at 1,500', 2,000' or 250'.

[kaz3g]

the ambos into Shepp usually do straight in approaches but I pricked my ears up the other day because I heard him ask someone in the circuit what the sock was doing.

He decided to join downwind instead which I thought was a good call because it was straight out and it could have been interesting had he persisted with his original call.

Kaz

[AerocatS2A]

I'm yet to encounter RPT regionals or RFDS 'doing a circuit'. Always straight in or via base.

Not to say it doesn't happen.

But I'm yet to mix it with RPT or RFDS in circumstances in which they care whether I'm proposing to overfly at 1,500', 2,000' or 250'.Ah I see. We used to regularly join overhead at Moomba in the BAe146, but it just worked out efficiently that way. If the runway was aligned differently we'd have been joining straight in or downwind. And indeed we wouldn't care what height you were at as long as you weren't there when we were there.

[Old Akro]

I guess that's my point... you don't really know who / what is there before you get there. You might hear "Citation ABC turning downwind for 18" or something and unless they say their circuit height, you are blissfully unaware as you approach at 1,500ft.


With modern circuit discipline - especially RAA - you never know anyway.

[R755]

RPTs and others conduct 1,500 foot circuits at Wagga on a daily basis, along with straight ins, against or with the traffic.
None of it is a problem.
Also no need to "have a chat" about it.
In a SAAB last week, we had 240kt GS at 5NM and 200kt into downwind with a 15kt tail component. Captain confirmed 180 indicated as typical onto downwind.

[maverick22]

In the large turboprop I fly, most of the time we will do a straight in approach if we can. This can be in the form of an RNAV approach, a 5 mile final or a base join, which will put us on a 3 mile final. Bear in mind, as per CAR 166, we need to know what the wind is doing before we can do this. Some places we fly to don't have any TAFS/METARS/AWIS available, so guess what? I overfly the airfield at 2000 AGL and look at the wind sock then join the circuit. We join at about 170 -190kt, so I fly a 1500' circuit. Sometimes I join the circuit for traffic separation. The main thing is, I COMMUNICATE what I am doing.

[no_one]

I have made a similar post to this elsewhere before but have repeated it again here as I think that it is relevant in the discussion about mixing air traffic of different levels of performance.

The image below is extracted from CAP166-1(3). I have marked up the images below with some of the potential conflicts where aircraft of different performances operate.

http://i64.tinypic.com/122etkn.png

The methods of joining the have different levels of conflict if there are aircraft of varying performance in the circuit.

Joining at 45
This option also gives you a good view of the field and time to set up but has the advantage of allowing you to adjust the position you join the circuit to slot in with others. In my opinion at most fields this is my preferred entry and is the preferred entry in the USA(refer AIM FIG 4−3−2) If you have descended to your circuit height prior to joining it is difficult to have a conflict with an aircraft of different performance.

Joining a circuit on Downwind
This option give you a good view of the airstrip and a good change to see that it is clear check the wind etc but If there are existing aircraft in the circuit it can be hard to slot in well as your only option is to speed up or slow down. This can be made more difficult if the other aircraft is operating at the same height as you but is substantially faster or slower.

Arriving above Circuit height and descending on the "dead" side
It gives you plenty of time to slot into the circuit and a very good opportunity to look for traffic and the field however there are several potential conflicts with this option. Aircraft that are departing overhead are likely to be conflicting traffic when you turn and begin descending to get to circuit height. They will potentially be in you blind spot being behind you just before you turn. The other potential conflict is with a high performance aircraft taking off from a good length runway. As you cross over the airstrip at circuit height they may only be a few hundred feet below you.

Additionally you have to lose 1000 feet fairly quickly, in slick aircraft that can be hard. The other issue with this arrival is that often there is either a noise sensitive area (town) or high terrain on the dead side of the circuit and you are doing maneuvering in this area. For some reason this seems to be the preferred entry in Australia, at least by the instructors I have had.

Joining on Base Leg
In my mind this is only preferred when the strip is well known and this is the direction you are approaching from. It docent give you time to look at the field or slot in though adjusting base leg in or out to fit with other traffic is possible. With aircraft of differing performance you have to be aware of the higher performance aircraft on a longer final as they may be under the nose. This can be made safer if the pilot decides to do a low approach to have a look at the runway and windsock and then a full stop landing on the next one. (ie a go around but premeditated)

Straight In
Similar to joining on base only worse for being able to slot in with other traffic.

[Lead Balloon]

Run me through the logic of your "requires 1,000' descent" box. Why?

And why are aircraft departing overhead at circuit height on the dead side? :confused:

[Squawk7700]

It's a 1,000 ft descent because you are in theory required to be at 2,000 ft on approach and you need to get down to 1,000 ft standard <150 knots circuit height.

[mcgrath50]

It's a 1,000 ft descent because you are in theory required to be at 2,000 ft on approach and you need to get down to 1,000 ft standard <150 knots circuit height

Only if there is an aircraft operating in the 1,500ft circuit no? Which brings us back to the original question, you hear Citation ABC and Cessna 210 XYZ in the circuit ahead, how do you know what altitude everyone is at? (Ask them, is the obvious answer)

[no_one]

Run me through the logic of your "requires 1,000' descent" box. Why?


You are supposed to arrive 500ft above the circuit height which could be as high as 1500 ft AGL if there is a high performance AC in the circuit as per the question in the first post of this thread. See section 6.6 of CAAP 166-1(3) (https://www.casa.gov.au/sites/g/files/net351/f/_assets/main/download/caaps/ops/166-1.pdf)


And why are aircraft departing overhead at circuit height on the dead side?

They might be 500 feet above their circuit height but so is the inbound aircraft....

[Lead Balloon]

Not trying to be offensive, no one, but how much time have you actually spent flying in and out of non-controlled aerodromes?

My experience may be atypical, but I have:

- never joined crosswind when a high performance aircraft happened to be taking off at the same time

- never *arrived* at a height greater than 1,500' above the aerodrome (unless my TOPD and descent calculations and management have been inaccurate and poor ... :uhoh:)

- never joined downwind or dead side when an aircraft happened to be departing overhead.

There's lots and lots of nothing going on out there at non-controlled aerodromes, punctuated by the occasional flurry of entirely mundane and easily manageable activity. That includes places like Mildura, Wagga, Broken Hill, Kalgoorlie ....

And don't confuse the CAAP for requirements.

[Squawk7700]

how do you know what altitude everyone is at? (Ask them, is the obvious answer)

So you're gonna ask every aircraft for their altitude? I've never heard that before.

[maverick22]

I think you will find that most aircraft will delay the takeoff roll until aircraft joining the circuit on crosswind have crossed the runway centreline. Im not going to knowingly blast off towards traffic that I can see coming. Same goes for an aircraft joining downwind.

[Lead Balloon]

Exactly. And sometimes inbound traffic will, on hearing a taxi broadcast, decide to remain a few miles clear until the departing traffic has done so.

[Godot64]

I still generally overfly at 2000' and let down dead side if I'm not familiar with the aerodrome. I got trained that way, it often still works for me, and a lot of pilots still seem to do it as a matter of course. Easy enough to fly a different approach if the circumstances and traffic require, though.

[andrewr]

Not trying to be offensive, no one, but how much time have you actually spent flying in and out of non-controlled aerodromes?

My experience may be atypical, but I have:

Typical or atypical, your experience isn't universal. If there is no other traffic it doesn't matter what you do but there are uncontrolled airfields with significant traffic i.e. less than 3 aircraft in the circuit is a quiet time.


- never joined crosswind when a high performance aircraft happened to be taking off at the same time

Not taking off, but I have had a close encounter with a twin practising an asymmetric go around when I was joining crosswind. They were too busy with the go around to do a radio call after turning base.

- never *arrived* at a height greater than 1,500' above the aerodrome (unless my TOPD and descent calculations and management have been inaccurate and poor ... )

I now routinely arrive at 2000 AGL if overflying, because:
1) I don't trust the students (or others) in the circuit to always maintain 1000 AGL and,
2) We will apparently now have high performance aircraft doing 1500' circuits because they were having trouble fitting in with the 1000' traffic


- never joined downwind or dead side when an aircraft happened to be departing overhead.

On one occasion as I was approaching the airport there were 2 aircraft on downwind, one on base, one climbing overhead for departure and 2 descending on the dead side. It is routine here to have multiple aircraft inbound/descending on the dead side and/or climbing for an overhead departure.

There's lots and lots of nothing going on out there at non-controlled aerodromes, punctuated by the occasional flurry of entirely mundane and easily manageable activity.

At many or most non controlled airfields, yes. But not all.

[Lead Balloon]

So how often have you (Godot64) encountered aircraft doing a circuit at 1,500'?

How do you manage to descend 1,000' between the point overhead and joining mid field crosswind or downwind, and remain within cooee of the runway? Speedbrakes?

[andrewr]

And sometimes inbound traffic will, on hearing a taxi broadcast, decide to remain a few miles clear until the departing traffic has done so.

That seems pretty extreme. It's not too hard to separate yourself from someone taking off - if nothing else, you know exactly where they are when they make the broadcast.

[andrewr]

So how often have you encountered aircraft doing a circuit at 1,500'?

How do you manage to descend 1,000' between the point overhead and joining mid field crosswind or downwind, and remain within cooee of the runway? Speedbrakes?

Only once or twice in the past, but we have been warned that it will be happening more often now.

The aircraft I fly has plenty of drag so descending is not an issue. I guess for more slippery aircraft they need to plan a wider turn. Although you can probably start descending below 2000' AGL safely once you are inside the normal circuit area rather than waiting until directly overhead - 1500' circuits are presumably also wider.

Or maybe a 45 degree join really is better.

[Lead Balloon]

3 or more aircraft in the circuit, Andrew? Sounds scary.

The busiest non-controlled aerodrome I've been to in Australia is Temora on Warbirds Downunda days - the slot for arrivals before the Romeo gets a bit busy, and the stampede of departures when the Romeo ends is very entertaining.

The Bicentennial Air Race was also fun, with departures every 30 seconds and lots of aircraft with approximately the same performance converging on the same spot at the other end.

Not enough enough fingers to count the aircraft on finals, base, downwind and reported inbound. Nobody's doing 2,000' overflies or fretting about high performance aircraft or overhead departures.

When you mix it in higher traffic densities in the circuit, seeing other aircraft in close proximity is not such a big deal. It's just Bankstown or Jandakot in their heyday, without ATC.

What's "extreme" seems to be something in the eye of the beholder. If someone chooses to stay away from the circuit while someone else departs, I'd call that "their decision" with no greater safety risk than going through the joining procedure while the other aircraft is lining up and departing.

[Godot64]

So how often have you (Godot64) encountered aircraft doing a circuit at 1,500'?

How do you manage to descend 1,000' between the point overhead and joining mid field crosswind or downwind, and remain within cooee of the runway? Speedbrakes?

I've not often encountered aircraft at 1500' in the circuit, but often enough for proof of concept. And descent dead side before the turn onto crosswind has rarely proven to be a challenge in the distinctly unslippery aircraft I mostly fly!

I don't slavishly follow the 2000' overfly, but was responding to the OP who said he'd never heard of anyone doing it. I do, and quite often, because it works for me. YMMV.

[andrewr]

3 or more aircraft in the circuit, Andrew? Sounds scary.

Mock if you like, I was just pointing out that your comments:

how much time have you actually spent flying in and out of non-controlled aerodromes?

lots and lots of nothing going on out there at non-controlled aerodromes, punctuated by the occasional flurry of entirely mundane and easily manageable activity.

doesn't apply to all locations.

I did say 3 was quiet - that's a number that is pretty easily manageable. 5+ starts to get difficult. 3 or 4 inbound from different directions with ETAs within a minute or 2 also gets interesting - not least because the radio starts to get congested when they all to work out where the other aircraft are.

It wasn't me that decided that the high performance aircraft would do 1500' circuits. I just try to keep clear. If you want to arrive at 1500' don't let me stop you - it's your decision.

[Lead Balloon]

Understood. And my apologies if I came across as mocking.

I'd only make one last point: Nobody's decided that high performance aircraft will do 1,500' circuits. It's just a CAAP....

[R755]

As for overflying and then killing 1,000 feet on the dead side...
I prefer a tight spiral with a high angle of attack to control speed and a high rate of direction change per second. This means that I get to scan 360 degrees in only a few seconds. No traffic can sneek up, unseen!

[Lead Balloon]

I'd probably go for the initial and pitch, with a loop if necessary to confirm the location of other traffic. Between my loop and your tight spiral, R755, we should have all circuit risks covered. :}

[maverick22]

I'd only make one last point: Nobody's decided that high performance aircraft will do 1,500' circuits. It's just a CAAP....

I'm not sure why you are so sceptical about this. Every high performance aircraft I come across will fly the circuit at 1500' AGL. I'm not sure what part of the country you fly in, but in my neck of the woods you get anything from kingairs to 737s in the circuit, and they are at 1500 AGL.

On a side note, if there is a high performance aircraft in the circuit, you probably wouldn't being over flying the field anyway, because: a) they wouldn't want an aircraft overflying them only 500' above as this may cause a TCAS advisory and b) there's no need to overfly as you will know what the duty runway is based on the aircraft already in the circuit so you can just join behind the other aircraft :ok:

[Lead Balloon]

I'm not sure why you are so sceptical about this. I'm not being sceptical about anything.

I'm merely pointing out: (a) that the CAAP is not the rule and (b) I've never joined above 1,500' AGL unless I've stuffed up and (c) it's never caused a problem for a 'high performance aircraft'. Every high performance aircraft I come across will fly the circuit at 1500' AGL. I'm not sure what part of the country you fly in, but in my neck of the woods you get anything from kingairs to 737s in the circuit, and they are at 1500 AGL.We do, indeed, fly in different necks of the woods.

In my neck the pilots of 'high performance aircraft' usually do straight ins or base joins. Continuous descents. Professionals being professionals.On a side note, if there is a high performance aircraft in the circuit, you probably wouldn't being over flying the field anyway, because: a) they wouldn't want an aircraft overflying them only 500' above as this may cause a TCAS advisory ...Whattha? :confused:

So now the 2,000' in the CAAP isn't enough? Should it be 3,000'?

And what "they wouldn't want" determines my overfly altitude? Are "they" in charge?

We are clearly in different necks of the woods, if not different planes of consciousness. ... and b) there's no need to overfly as you will know what the duty runway is based on the aircraft already in the circuit so you can just join behind the other aircraft. That depends on my judgment. The pilot of the 'high performance aircraft' may be able to land on a runway in wind conditions that may not be suitable for the aircraft I'm flying, or with which I may not be comfortable.

But rest assured: Choosing a different runway hasn't resulted in my being head to head with a 'high performance aircraft' on approach.

[maverick22]

So now the 2,000' in the CAAP isn't enough? Should it be 3,000'?


All I'm trying to do is provide some insight into what happens in the real world. Not trying to come across as some form of sky God. We fly the circuit at 1500'. It's in our ops manual. All I'm trying to say that if you were overflying us only 500' above, you would potentially cause a resolution advisory on our TCAS, meaning we would need to take evasive action, and fill out paper work afterwards. We don't own the sky, but this is a scenario we would avoid. Basically what I'm trying to say is good communication and airmanship in the CTAF is a good thing. Fly the circuit however you like, as long as it's legal and safe:ok::ok:

[Lead Balloon]

Basically what I'm trying to say is good communication and airmanship in the CTAF is a good thing. Fly the circuit however you like, as long as it's legal and safe.Basically what I'm trying to say is good communication and airmanship in the CTAF is a good thing. Fly the circuit however you like, as long as it's legal and safe. :ok: