Over flying at 500" AGL

[Guest davidh10]

Still no mention of those rotary winged types or are they now considered as just another aircraft as far as speed vs circuit hight.

I don't recall any mention in CAAPs, but in the new VFRG (V4) on page 249 it says:

 

Helicopters can arrive and depart aerodromes from various directions. Pilots of helicopters can choose to operate in the circuit and fly a circuit similar to a fixed wing aircraft but may be at a height not below 500' above the aerodrome elevation and closer to the runway. Check ERSA for any noise abatement procedures.

Helicopters can also operate contra-direction circuits on the opposite side of the runway at 500' above the aerodrome elevation. Check ERSA for circuit direction requirements. Pilots of helicopters approaching to land at a marked helipad or suitable clear area should avoid the flow of fixed wing aircraft.

 

Other pilots should be aware that for some helicopter operations, the only suitable landing area is the runway.

 

Helicopters and gyroplanes can fly slower than fixed wing aircraft and approach at steeper angles. Both helicopters and gyroplanes can be expected to practice power-off landings (autorotations) which involve a very steep approach and high rates of descent.

 

As helicopter and gyroplane operations can be varied and flexible pilots need to ensure they monitor and advise other aircraft of their position and intentions by radio where applicable.

I had also been wondering and looking for some reference:)

 

 

[Bill Hamilton]

crezzi,

 

Re. 500' "Recommended", it wasn't, that was the minimum height --- the height in the circuit was not regulated.

 

I regularly flew circuits in a B767 at 800"agl, although 1500' was the company standard ---- but we also had a "standard" low level circuit, thus 800'.

 

I saw at least one reference to "Boeing circuits", believe me our standard circuit was a lot tighter than many circuits I see at GA airfields. There is one chap (who shall remain nameless --- but you know who you are) whose students only manage 4 circuits an hour??? In C-152 ---- That's not a circuit, that's a x-country.

 

Please don't be unkind to the Twin-Pin, they can achieve 65kt in the circuit, they will wind up to almost 90kt in cruise, if you give them time --- and we have just one still flying regularly in AU, in very careful private hands.

 

Regards,

 

PS: I'm with you on overflying for a good look around and letting down to circuit height on the "dead side". We now have lots of flexibility, but that is still my preferred, with a straight in as second choice. And the latter only if I am thoroughly familiar with the aerodrome, and I have a Unicom or similar to tell me what wind is, and what is going on in the immediate area.

 

 

[Guest Crezzi]

John, I think you made a typo above. I am sure you meant descent on the "inactive side" is the safest way when you said "descent on the active side is the safest way" above.

A rather critical typo ! My bad & thanks for pointing it out ( I could have used "deadside" but dislike the term)

 

Cheers

 

John

 

 

[Guest Crezzi]

John, your suggestion is interesting and I would like to bounce this off you in this forum so we can all gain some insight into this issue. Are you suggesting that aircraft of different performance can be doing 1000' circuits at parallel positions on the circuit such that you could have three aircraft at 1000' on down wind separated horizontally by the required minimum of 600 metres for VFR? Would that be safe; I don't think so, would that be illegal; possibly not!

Sure.

 

Even disregarding (at least for now) your 50kt Drifter scenario, there is almost 100kts speed difference between aircraft recommended to use 1000' circuits. Does a 60-70kt aircraft really need to spend twice as much time in the circuit as a 140/150kt one ? I don't believe so (if anything, the faster aircraft probably needs more time in the circuit). But thats not how it works with one fixed circuit size for all.

 

I completely agree with you that a slow aircraft flying a large circuit pattern would indeed be very poor airmanship by forcing faster aircraft to adopt to its speed. But the slower aircraft doesn't need to do such a large circuit - it can have a similar circuit time by flying a smaller pattern. Faster aircraft can do the size of circuit which suits their requirements without being inconvenienced.

 

Yes, this of course means that faster aircraft flying a larger pattern will overtake slower aircraft. Your scenario of 3 aircraft "line abreast" could logically occur (albeit only for an instant as they would be travelling at different speeds) but I'd suggest its unlikely to be a regular event. Even so, I don't see it as unsafe - the aircraft are at the same height on identical tracks - its exactly how you should overtake another aircraft. I don't believe its illegal either, its simply doing whats described in the CAAP - "Pilots may vary the size of the circuit depending on: the performance of the aircraft".

 

Cheers

 

John

 

 

[Guest Crezzi]

crezzi,Re. 500' "Recommended", it wasn't, that was the minimum height --- the height in the circuit was not regulated.

Thanks - thats what I thought. My point was that, post NAS2C, it was recommended to be 500ft for <55kt and this precluded doing higher circuits (as described earlier)

 

Cheers

 

John

 

PS it wasn't me that mentioned the Twin Pin - I'm actually fond of aircraft of that era & ilk. As a result of a guided tour as a youngster, one of my favourite aircraft is the AW660 Argosy

 

 

[Guest davidh10]

...Now lets go to a 500' circuit in a Drifter at 50 knots, there is little difference except there are short discernible cross wind and base legs because we are slow. But again you are well below 500' when leveling out on final; sure you can push the nose over and lose height rapidly if needed in a Drifter but you cannot do that in a slippery aircraft for obvious over speed reasons.So in both cases it is not practical to have completed the turn onto final at 500' agl; so the CAAP advice clearly lacks an exception for a 500' circuit does it not, or have I got it wrong?

 

Your comments please.

 

David

Not that I have any Drifter or even 3-axis experience, but let me posit an interpretation...

 

Following the CAAP procedures, the Drifter conducting a circuit at 500' would not commence descent until the turn to Final. The length of the Final just needs to be appropriate to the normal approach glide slope of the Drifter, just as the turn onto Final for any aircraft needs to accomplish the same. If the Drifter were conducting a 1000' circuit, it would, ergo, be at twice the distance from the threashold on Final than for a 500' circuit, albeit that the downwind track may be closer to the runway than the turn onto Final.

 

I certainly couldn't glide, even with engine idling, from my downwind track to land directly on the active runway without some maneuvering and a couple of steep "S" turns to lose height (except when nearing Base). Proved by simulated engine failures in the circuit.

 

The distance of the turn onto Final for any aircraft is determined by its normal approach glide slope, thus it will vary by make / model / type.

 

The only inconsistency that I see is that on a 500' circuit, you don't commence descent until the turn onto Final and need to judge the Final distance from the threshold accordingly.

 

 

[Mazda]

It's not rocket science guys. The new rules are all about commonsense and more freedom.

 

If you are flying a slow aircraft, join the circuit at 500' and stay there. The requirement to turn final no less than 500m from the aerodrome boundary has gone. The recommendation is to turn final by 500' AGL, but even that is a recommendation and you could turn final lower than that if required.

 

So stay nice and close!

 

 

[Tomo]

It's not rocket science guys. The new rules are all about commonsense and more freedom.If you are flying a slow aircraft, join the circuit at 500' and stay there. The requirement to turn final no less than 500m from the aerodrome boundary has gone. The recommendation is to turn final by 500' AGL, but even that is a recommendation and you could turn final lower than that if required.

 

So stay nice and close!

Exactly

 

:thumb_up: :thumb_up:

 

 

 

[Guest davidh10]

...1. what you say assumes you are always doing a glide approach in either type of aircraft and glide approaches are not typical approaches these days, at least not in GA.

...

David; I've seen the term "glide slope" used in relation to radar guided approach systems, so am assuming it has nothing to do with having the engine idling / stopped. Either way, it makes no difference except that the final will be shorter if the pilot is in fact doing a "glide approach". The convention I'm used to is that in such a case the pilot would announce "...on glide approach RWY nn..." so everyone knows and can act accordingly.

 

2. it potentially ignores the statement in the CAAP "The turn onto final approach should be completed by a distance and height that is common to the operations at the aerodrome and commensurate with the speed flown in the circuit for the aircraft type." (interesting that these two conditions may be mutually exclusive depending on the common operations at any given aerodrome). ...

...

 

Comments please.

 

David.

If the "common operations" at an AD differ from those generally expected, they should be in ERSA or NOTAMS, so you should know before you arrive. Never the less, you are correct that they may not always agree. An example is at Mount Beauty(YMBT) where due to the steep terrain at the south end of the AD, the turn to final on RWY 32 is below 500' and over houses even descending from a 1000' circuit. You then have to miss the wall of the hydro pondage as you overfly it and land long. It's a RH circuit for RWY 32 as well. There are a number of anomalies at this AD, since takeoffs are banned on RWY 14 so gliders takeoff on RWY32 and land in the opposite direction on RWY14. Anything with a really good glide ratio just isn't going to land on RWY32.Check it out on Google Earth and for a closer to the ground photo, here is one I took from a self launch glider. IMG_6328_DxO on Flickr - Photo Sharing!.

 

{It's a photo, not a video, but this site treats it like a video, just click on the window title}.

 

I don't feel that the changes cause any new potential conflict.

 

 

[flying dog]

Ok, I'm gonna jump in here.

 

I'm only down to post #4-ish and something of which I have been concerned has been mentioned.

 

Ok, the new system has three circuits.

 

500 feet for SLOW planes.

 

1000 feet for slightly faster planes.

 

1500 feet for turbo-prop planes - or FAST ones.

 

Couple of problems:

 

Flying over towns, you have to be 1000 AGL.

 

If the airport is on the "other side of town" to where you are, can you fly over at 500 feet? Ofcourse not. a: You have to be 500 feet above to "overfly", so you would be at the minimum legal height.

 

Now, other slightly faster planes should/would be flying over town at 1,500 feet. There is no conflict there - unless they are at 1,000 feet maybe happy snapping.

 

My "problem" is the overfly height.

 

We have THREE circuit heights, and (alas) three overfly heights.

 

What kind of height do trikes (or other SLOW planes) fly?

 

I know it would be painful to fly 4 miles from A to B and have to do what I am about to suggest, but hear me out.

 

Why not make ALL overfly heights 2,000 feet.

 

This moves the problem that exists.

 

Say a slightly faster plane is overflying while a FAST plane is in the circuit. Conflict.

 

What happens if a SLOW plane is overflying while a not so slow plane is in a circuit. Conflict.

 

There are too many points of conflict.

 

If everyone overflew at 2,000 feet, there would only be ONE place where there could be conflict. Well, ok: two.

 

As you approach, you look, get a feel for who is there and seperate yourself then and there.

 

Ofcourse the other place of conflict is constant: On final. That can't be avoided.

 

Now, if you are flying 5 miles from A to B, why bother going up to 2,000 feet.

 

Ok, this is where things get a bit "tricky".

 

Say you are doing circuits at "B". You don't need to go to 2,000 feet.

 

Unless you are in some weird place on earth, if the wind at A is 230, then 5 miles away it should be 230.

 

Yeah, yeah, I know.... There are exections.

 

I am only brain storming.

 

You live there. You know the "lay of the land". For those situations, you get in at circuit height.

 

Yeah, ok, I've shot myself in the foot. But I maintain: There is no golden answer.

 

We need to discuss things about the pro's and con's.

 

Bye for now.

 

 

[Guest davidh10]

...The CAAP clearly states that a LP aircraft intending to fly a 500' circuit can enter the circuit from 500' without overflying.

 

...

 

David

Actually it provides for LP aircraft to overfly at 500' AGL, but sensibly indicates that should be at a point where the track does not conflict with aircraft taking off and climbing rapidly... ie. probably mid-field, or if the runway is very long, even further back from the climb path. Again judgement comes into play.

 

 

[Guest davidh10]

...What kind of height do trikes (or other SLOW planes) fly?

This question is the reason CASA dropped using the term "Trikes" and left it at "Aircraft with a cruise <= 55kn".

 

It depends on the trike. Here's three examples:-

 

• An X (two stroke) with a Wizard Wing: about 40-45kn. (500' cct)
   
   
  
• An XT912 (four stroke) with a Streak-3 Wing: about 60-70kn. (1000' cct)
   
   
  
• An XT-912 (four stroke) with an SST Wing: about 70-90kn. (1000' cct)
   
   
  
• and there's others in between.
   
   
  

 

 

The term "Trike" is a description of the overall design concept and is just about as useful as "3-Axis" in determining performance.

 

 

[Guest davidh10]

...We have THREE circuit heights, and (alas) three overfly heights....

No. Actually just two overfly heights:-

 

• Aircraft with cruse <= 55kn overfly at 500' AGL.
   
   
  
• All others should be overflying at >=2,000' AGL. ie. 500' above the highest circuit.
   
   
  

 

 

 

 

[Bill Hamilton]

---one of my favourite aircraft is the AW660 Argosy

Crezzi,

Absolutely nothing to do with the thread, but an Argosy is the only Aircraft I have heard of to crash backward, and the crew survived.

 

It was a British European Airways aircraft, in a holding pattern outside Milan. The prevailing winds were so strong, plus turbulence, that it has "negative groundspeed", it went into a forest, more or less attitude and wings level, tail first.

 

Early 1960's, from memory.

 

Regards,

 

 

[Bill Hamilton]

Folks,

 

Re. this thread as a whole, there is a CULTURAL SHIFT everybody has to make.

 

Some of you, with all due respect, haven't yet made that shift --- and it will take time.

 

The basic regulation that applies (suitably paraphrased from the Act) is: Thou shalt fly safely otherwise known as S.20A(1)&(2) of the Civil Aviation Act 1988.

 

Then there is CAR 166 complete.

 

And a few others, minimum heights for cruise, not forgetting the requirements that when it is 500', there is how AGL is measured, it is not just directly under the aeroplane.

 

1000' ( but look at the whole rule, gliding distance etc ---) over a built up area (if you can figure out what that is ---there are three definitions in various regulations) ---- but only if you are flying an aeroplane that can fly over a built up area.

 

The CAAP is an "acceptable means of compliance", generally "good gen", but with all due respect, too many of you are looking for prescriptive rules, that you have been used to, even thought the "rule" might never have existed existed ---

 

ie; fly circuits at 1000'. In fact, there have always been a variety of circuit heights, from 500' up --- to suit the occasion.

 

You are now expected to use your noggin, and vary your operation to suit your aircraft, the time and place, other traffic, not causing a noise nuisance etc.

 

For our purposes here, rote compliance is OUT, using your brains is the name of the game.

 

There is no "one size fits all".

 

It is great pity that the CASR 91, General Operating and Flight Rules, never went into place, it was a very simple document, hardly needed an AC ( Advisory Circular, legally the same as a CAAP) to understand it.

 

Regards,

 

 

[JayKay]

Cultural Shift from what to what?

 

You can't just talk about safety and interpret the rules your own way to suit.

 

I note that the law does not allow us to define our own 'safety standards' in a car. Why then should it allow us to define our own individual safety standards when in the air?

 

My feeling is that we should fly safely WITHIN the rules. That's why we have to understand what they are in the first place.

 

If we all 'fly safely' within our INDIVIDUAL interpretation of the rules there will be chaos in the air, as there would be chaos on the streets if we applied the same principle to driving.

 

I'm by no means advocating the fact that 'the rules' are perfect. They clearly are not. But we should do our best to understand them and interpret them the same way so our actions in the air become more predictable to others and therefore safer.

 

 

[Guest davidh10]

Folks,Re. this thread as a whole, there is a CULTURAL SHIFT everybody has to make.

Some of you, with all due respect, haven't yet made that shift --- and it will take time.

 

...

 

You are now expected to use your noggin, and vary your operation to suit your aircraft, the time and place, other traffic, not causing a noise nuisance etc.

 

For our purposes here, rote compliance is OUT, using your brains is the name of the game.

 

...

Bill;

 

I think you are correct and this thread is an expression of the fact that people are discussing the differences and attempting to come to grips with the less prescriptive rules and guidelines.

 

The change requires everyone to recognise which are rules and which are guidelines / expectations. The former can only be infringed for imminent safety reasons, whereas the latter are open to a greater degree of lattitude, provided that does not infringe / impinge safety.

 

At the CASR presentation I attended, the presenter said [paraphrased] "this new approach to being less prescriptive is an experiment to see if pilots can make sensible decisions within the guidelines and thus enable simplifying the rules. If this approach fails, then the regime will be changed back to being veryprescriptive."

 

The greatest lattitude has been given with radio calls, with a very simple one sentence stipulation. All the other documentation is aimed at helping everyone to come to terms with this lack of specificity and to encourage sensible and appropriate decision making.

 

That said, there are reasonably clear expectations of the behavior under the new rules and JayKay is correct in that Rafferty cannot be allowed to rule;). I think much of what has been discussed is the level and circumstances of compliance with the expectations in specific situations. As such it is a good exchange and promotes a common understanding.

 

These changes all go to support Alerted See & Avoid, for which the fundamental premise is that all pilots in the vicinity of an AD will know of the existence, identity, location and intentions of all other aircraft in the vicinity. Being in possession of this knowledge permits airmanship to complement expected behaviors (be they through convention, ERSA notification or radio announcement).

 

Thanks to all for their contribution to this thread. It has made me think through the changes in more detail in an applied versus a theoretical context. For me, writing reinforces learning, so it's all good. When I get told I'm wrong, that's good too because it causes me to re-read the authoritative material and re-think the subject.

 

 

[Bill Hamilton]

Jaykay and Davidh10,

 

Jaykay,

 

Please try and understand what I have written, nobody has suggested Rafferty's rules.

 

Indeed, there has been only a marginal change in "the rule" in the CARs 166.

 

The cultural shift you have to make is in understanding that the old Australian tradition of laying down blanket "rules" usually written in the negative, then followed by a long list of where "the rule" doesn't apply, is changing.

 

Many of the "circuit rules" never were rules, (example: circuit heights) but the Australian mindset seems to want to stick with the "pingya" protocol ----- if you do (quote a long list of rules, shibboleths, and "The CFI said") so and so, "they" (whoever they is) can't pingya.

 

Far too much of Australian aviation is about "compliance", even when there is nothing to comply with, and certainly, all to often, imagined or otherwise "compliance" is at the expense of air safety.

 

If you are flying in the UK, up to PPL level, you will probably never have heard of, let alone seen the "UK AIR Pilot" or the Air Navigation Order ---- the rules --- but leaned what to do from some excellent CAPs, our equivalent of CAAPs and ACs. In the US, almost as true, holders of a Sports Pilot, RPL or PPL will not be obsessing about Acts, Regulations and Orders.

 

And guess what, the GA accident rate in the US is about half Australia ---- so education and using your educated brain produces far better air safety outcomes than "blind compliance:, which has been the Australian way (and almost unique in aviation significant countries) for far too long.

 

One well known commentator say it is because we are descendants of convicts, we only know how to obey the orders of the guards and the trusties --- I hope he is wrong, but I think there is a measure of truth.

 

In summary, go read S.20A(1) & (2) of the Act, to learn what you have to comply with, that's your answer ---- read in conjunction with the regulations and recommendations for operations at airfields in Class G..

 

David,

 

You are headed in the right directions.

 

It's all called "outcome" or "performance" based rules for a best outcome ----- not complex, convoluted and contradictory prescriptive rules where, hopefully, "compliance" will cause "air safety" to eventuate, but all to often doesn't

 

Regards,