Bankstown RNP RWY 11 approach on Garmin G1000

[Dick Smith]

When carrying out the Bankstown RNP RWY 11C approach from the RAKSO IAF with a Garmin G1000 equipped aircraft while coupled to the autopilot, strange things happen. Fly over RAKSO at 3,700 feet and the Garmin unit doesn’t start descending to the 2,500’ SBKWI IF until there is a 3˚ approach angle. This would put the aircraft into the 2,500’ step.

In fact, if you look at the approach plate, it shows the descent should start at RAKSO from 3,700’, then go at a constant angle to WI at 2,500’. Once again, that means that the aircraft will clip the 2,500’ 20 DME Sydney Class C step. In effect, it means that the expensive and safer autopilot coupled system can not be used in this case.

Does anyone have an answer to this as to why the Garmin approach doesn't actually follow what is required in practice?

[alphacentauri]

Dick,

The approach coding for that procedure does not have any coded vertical guidance prior to SBKWI. Any vertical advisory provided before this point is Garmin system derived, and not from coded data. Therefore the only vertical advisory the system can generate is based on a known final altitude......the only coded 'known' final altitude is the 2500ft at SBKWI and so it generates a path to this point. In this particular instance, because there is a break in the descent, the vertical advisory provided will not ensure you reach 2500ft by 6.5nm to SBKWI.

Its a case of the navigation systems 'smarts' being smarter than the approach. It happens.

Alpha

[Dick Smith]

I am sure that the Collins Pro Line in my CJ3 flew the approach correctly.

So why the problem with Garmin?

[43Inches]

Sounds like that particular approach may be coded wrong for that particular units database, it happens.

[andmiz]

If it's any consolation Dick, a 'modern' 747-8 would have the same problem with its new 'Integrated Approach Navigation' mode. We won't arm this mode for RNP/RNP-AR descent until all altitude constraints are complied with and we're approaching the FAF.

[mustafagander]

That's why you have a pilot as the "master monitor" of the aircraft. It's why you're there mate.

[B2N2]

Have not flown G1000 in 9 years and unfamiliar with the approach, I’m just looking at the plate:

https://www.airservicesaustralia.com/aip/pending/dap/SBKGN01-170_24MAR2022.pdf

I’m not understanding why a 3 degree from Rakso to SBKWI would encroach the 2500’ shelf. That’s 20.3 miles and it should start descending approximately 3.7 miles out.

[Capn Bloggs]

My FMS would do the same. For obvious reasons, it tries to stay as high as it can. Since there is no limiting step on the chart at 6.5WI, the FMS will stay up until in needs to descend to reach 2500ft at WI. In fact, my FMS would probably go through RAKSO around 5000ft (and WB at around 3000ft, for that matter). Airspace steps are not in my database and the box knows nothing of them.

If this particular airspace config doesn't change, then an "at or below" step at 6.5WI would be in order. Whether that is an allowed design feature for an IAF>IF leg is another issue. And don't be naughty and edit the approach to put in a step. :oh:

Or, "request a clearance to leave and re-enter"... (note note 4).

In fact, if you look at the approach plate, it shows the descent should start at RAKSO from 3,700’, then go at a constant angle to WI at 2,500’.
I do not agree. A line on the profile chart doesn't mean you (or the box) have to fly exactly along it. It is merely depicting that a descent is necessary at some point between RAKSO and WI. You could actually pass RAKSO then whip it into VS, zip down to 2500ft and then wait for WI.

I’m not understanding why a 3 degree from Rakso to SBKWI would encroach the 2500’ shelf. That’s 20.3 miles and it should start descending approximately 3.7 miles out.
The box would only have to commence descent from 3700ft at 3.7nm from WI (assuming it will try to descend at around 3°), but the step is passed at 6.5WI. You'd be crossing 6.5WI still at 3700ft.

[B2N2]

Just another thought, the approach plate has a SYD CTR frequency, they’re the ones clearing you for the approach.
The hard altitude is 2500’ that one should be respected by the G1000.
Should be 4 ways to do this :

VNaV 3 degrees
VNaV release the altitude, descend early to intercept the path
Descend in Vertical Speed
Descend in FLCH

[swh]

When carrying out the Bankstown RNP RWY 11C approach from the RAKSO IAF with a Garmin G1000 equipped aircraft while coupled to the autopilot, strange things happen. Fly over RAKSO at 3,700 feet and the Garmin unit doesn’t start descending to the 2,500’ SBKWI IF until there is a 3˚ approach angle. This would put the aircraft into the 2,500’ step.

In fact, if you look at the approach plate, it shows the descent should start at RAKSO from 3,700’, then go at a constant angle to WI at 2,500’. Once again, that means that the aircraft will clip the 2,500’ 20 DME Sydney Class C step. In effect, it means that the expensive and safer autopilot coupled system can not be used in this case.

Does anyone have an answer to this as to why the Garmin approach doesn't actually follow what is required in practice?

The chart is a LNAV chart, i.e. 2D, there is no descent angle coded in database. What annunciation did you have on the HSI, LNAV or LNAV+V ?

The initial segment from RAKSO to WI is actually from the Westmead Hospital RNP 052 chart, that charts has crossing WI at 2700 (it’s steeper at 3.07 degree). To fly the BWU approach at near 3 degree all the way, cross RAKSO at 6700 ft (13.3 nmx318 ft/nm +2500), cross 6.5 WI at 4600 (6.5x318+2500), that is the 2500 ft SY step, cross WI at 2500.

[alphacentauri]

The chart is a LNAV chart, i.e. 2D, there is no descent angle coded in database. What annunciation did you have on the HSI, LNAV or LNAV+V ?

There is actually SWH....see attached extract of procedure coding (my red circle is the vertical path angle for the final segment)..........this only goes back to the FAF. There is no coded vertical path prior to the FAF. (Note this is source coding....not final coding for a specific navigation system)
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1157x226/ysbk_r11c_a5b08233ce3561d340179586a967654dcf77a7ed.png
So back to Dicks issue. Each navigation manufacturer can tweak the procedure coding to optimise performance for that particular navigation system. The final version of coding for each system will differ and its why the Collins Proline and Garmin system each fly the procedure differently.

You will also notice that the 2500ft altitude at SBKWI is an AT altitude, so this altitude will be honoured. How the aircraft gets there is up to each individual manufacturers navigation logic.

Alpha

[tossbag]

Alpha, why would each equipment manufacturer elect to code the descent differently?

[Dick Smith]

Both systems would put the aircraft into the 2500' class C controlled airspace step if the pilot relies on the automation.

[Chronic Snoozer]

I am sure that the Collins Pro Line in my CJ3 flew the approach correctly. What do you mean by that? What are you expecting the GARMIN to do?

[Chronic Snoozer]

Both systems would put the aircraft into the 2500' class C controlled airspace step if the pilot relies on the automation.
Which is why the plate Note 4 says approach approval required from SYD ATS.

[swh]

There is actually SWH....see attached extract of procedure coding (my red circle is the vertical path angle for the final segment)..........this only goes back to the FAF. There is no coded vertical path prior to the FAF. (Note this is source coding....not final coding for a specific navigation system)


I dont see 3 degrees in the Jepp database, just crossing altitudes, and no temperature limitations on the chart.

[mmm345]

I don't think its ever been automation's responsibility to keep an aircraft OCTA. Obviously, VNAV is capable of flying and meeting the level restrictions and forming/flying an approach path, but I believe it has always been the pilot's responsibility where if they haven't been cleared to enter and leave airspace ( or in this case via the RNP approach), to maintain separation from airspace.

I think in the case of this approach. Some aircraft ( potentially heavier, unfamiliar to the local environment aircraft such as private jets or potentially larger aircraft) it isn't efficient or safe to be descending early on that initial leg or the approach as whilst it does get you below the CTA step, it places you smack bang in the middle of the training area in particular with aircraft headed to the inbound reporting point TWRN. Therfore, it would be expected that in some scenarios, aircraft would be cleared to enter CTA via the RNP approach into BK and thus can fly the aircraft as depicted on the chart and negate CTA steps.

If Garmin put an altitude restriction to get the aircraft OCTA by the step, aircraft that had been cleared to enter CTA would now descend OCTA if following that VNAV profile.
I think at the end of the day, id imagine it wouldn't be feasible for there to be an option to select if the pilot had been cleared to enter CTA or remain OCTA, so therfore build the approach and code it as any other approach, and make the pilot responsible for remaining OCTA as they should .

Practically, you would brief that you must descend from at or above 3700 to 2500 by 6.5nm WI. This essentially makes the RAKSO- WI leg 6.8nm ( as you need to be at 2500ft by 6.5nm WI) rather than the 13.3nm unrestricted leg.

6.8nm x 318ft ( 318ft per nm for a 3 degree descent path) = 2162ft. This means that to fly a 3 degree descent and be established at 2500ft by the step, you can cross RAKSO at 4662ft ( 2500ft+2162ft), rather than the published 3700ft. This enables you to stay higher longer and delay your initial top of descent from cruise by a few miles.

If you indeed crossed RAKSO at 3700ft, you could level off and maintain 3700ft. 3700ft-2500ft= 1200ft to lose. 1200/318ft= 3.77nm. Therfore, your descent should begin at 10.27nm WI to fly a 3 degree descent from 3700ft to 2500ft and not clip the step at 6.5nm WI

Obviously, you could also cross RAKSO at 3700ft and descent straight away to 2500ft. Whilst this is less complicated, you are flying longer at low altitude which is less efficient and also having more conflict with training area traffic.

[alphacentauri]

Tossbag, different manufacturers modify the coding in order for their specific navigation system to perform in a certain way for certain aircraft. For example its widely known that Boeing and Airbus navigation systems perform vertical path generation differently depending on the aircraft being flown. All whilst utilising the original coded data from Jeppesen. Even Garmin post process the Jeppesen data for different navigation systems.

SWH, that screenshot is from the Jeppesen database, granted its an older cycle so unless it have been taken off, which I am not aware it has been, then it is accurate. How are you viewing the coded data? The procedure doesn't have to be a VNAV procedure to have the vertical path angle in the coding, hence the lack of temperature limitations.

Alpha

[tossbag]

Thankyou Alpha.

Boeing & Airbus "in order for their specific navigation system to perform in a certain way for certain aircraft" as in, due to the different aerodynamic properties of individual airframes?

[alphacentauri]

Tossbag, yes pretty much.

From my own experience it seems that Boeing aircraft systems seem to favour a 2.5-3 degree profile, whereas the Airbus logic is not quite as straight forward and in some cases goes towards a more dive and drive profile. This can vary based on weight, wind, and temperature. Its just the different logic used in the navigation systems.

Garmin systems being more GA focused seem to also favour a 3 degree profile. The key thing to remember here is that the system is only as smart as the information it hold. In the Bankstown case for the RAKSO-SBKWI leg there are only 2 known points that being RAKSO or SBKWI (the 6.5nm fix and the airspace boundary are unknown to the system). So starting at 3700ft at RAKSO and wanting to be 2500ft at SBKWI presents some options..
a) I can give you a 3 degree descent from 3700ft @ RAKSO to 2500ft, or
b) I can give you a 3 degree descent to 2500ft @ SBKWI from 3700ft, or
c) I can plot a constant descent from 3700ft @ RAKSO to 2500ft SBKWI which would be 1.5deg (approx)

These are pretty much the only coding options available......each nav system manufacturer may choose a different option....and each of them are valid for a specific system/aircraft. For example option a) may be suited Cessna 400 series piston aircraft allowing for deceleration. Option b) may be more suited to turboprop aircraft and option c) may be suited to jet aircraft. In all cases the start, end and minimum altitudes are honoured.
I hope this helps explain it.
Alpha

[Lead Balloon]

"... and the airspace boundary are unknown to the system"

Wow. As usual, I've learned something new from you, Alpha. It's counterintuitive, as I've seen airspace boundaries on (TSO'd) GPS displays.

Thanks.

[tossbag]

Tossbag, yes pretty much.

From my own experience it seems that Boeing aircraft systems seem to favour a 2.5-3 degree profile, whereas the Airbus logic is not quite as straight forward and in some cases goes towards a more dive and drive profile. This can vary based on weight, wind, and temperature. Its just the different logic used in the navigation systems.

Garmin systems being more GA focused seem to also favour a 3 degree profile. The key thing to remember here is that the system is only as smart as the information it hold. In the Bankstown case for the RAKSO-SBKWI leg there are only 2 known points that being RAKSO or SBKWI (the 6.5nm fix and the airspace boundary are unknown to the system). So starting at 3700ft at RAKSO and wanting to be 2500ft at SBKWI presents some options..
a) I can give you a 3 degree descent from 3700ft @ RAKSO to 2500ft, or
b) I can give you a 3 degree descent to 2500ft @ SBKWI from 3700ft, or
c) I can plot a constant descent from 3700ft @ RAKSO to 2500ft SBKWI which would be 1.5deg (approx)

These are pretty much the only coding options available......each nav system manufacturer may choose a different option....and each of them are valid for a specific system/aircraft. For example option a) may be suited Cessna 400 series piston aircraft allowing for deceleration. Option b) may be more suited to turboprop aircraft and option c) may be suited to jet aircraft. In all cases the start, end and minimum altitudes are honoured. I hope this helps explain it.

Yes, perfectly, thanks very much :ok:

[Dick Smith]

So if you are given the BK 11 LNAV approach by Sydney Terminal when you are OCTA approaching RAKSO does that allow you to enter and leave the class C airspace on descent to WI?

[swh]

SWH, that screenshot is from the Jeppesen database, granted its an older cycle so unless it have been taken off, which I am not aware it has been, then it is accurate. How are you viewing the coded data? The procedure doesn't have to be a VNAV procedure to have the vertical path angle in the coding, hence the lack of temperature limitations.


Current cycle in ARINC 424 format.

[UnderneathTheRadar]

So if you are given the BK 11 LNAV approach by Sydney Terminal when you are OCTA approaching RAKSO does that allow you to enter and leave the class C airspace on descent to WI?

one wouldn’t think so - you have ATS approval to conduct the approach but no clearance to enter controlled airspace. For an LNAV only approach it’s pilots choice to get permission to re-enter and leave or dive’n’drive. If it were +VNAV and the profile was going to fly you through CTA then the chart would(should?) be very clear that a clearance was required.

I’m a little confused by this thread - I would never expect a G1000 or other system to keep me clear of controlled airspace - only to fly the approach appropriately (I.e to the manufacturers specs as alfacentauri explained). How can your FMC know what clearances you have or don’t have?

UTR

[Dick Smith]

Only in Australia from my experience would an IFR aircraft on an IFR approach go in and out then in again of controlled airspace.

Once I flew the approach with a US trained pilot coming in from overhead Richmond. It was beyond comprehension to him that he was not cleared for the approach. I explained that we would actually be in uncontrolled airspace when the approach started and he was on his own. No descent clearance would be given.

[tossbag]

Only in Australia from my experience would an IFR aircraft on an IFR approach go in and out then in again to controlled airspace.

Agreed, it's very poor form in a supposed first world country and for all the boasting about how much airspace is 'controlled' by this mob.

So if you are given the BK 11 LNAV approach by Sydney Terminal when you are OCTA approaching RAKSO does that allow you to enter and leave the class C airspace on descent to WI?

Given or cleared? ATC can't 'clear' you for an approach that is outside controlled airspace, that is your choice and decision. They shouldn't really be 'giving' it to you either, that implies a clearance.

[mmm345]

You can only ever have one IFR aircraft ( that hasnt reported visual) in the BK CTR at one time. My understanding is the APPCH permission from SY CEN is for sequencing into BK even though you are OCTA from SY airspace for the majority apart from the aformentioned segment of the IAF-IF leg, which without a clearance to enter ( different to approach permission), you must avoid.

[alphacentauri]

Lead Balloon,

To clarify, the airspace data and approach data are in separate parts of the database. They are unknown to each other, and so there are no smarts to compare approach path and airspace data…..

Thats kind of the point of the prediction arc in large fms systems. It allows the pilot to know if an altitude is going to be reached by a certain point and adjust if required.

[tossbag]

You can only ever have one IFR aircraft ( that hasnt reported visual) in the BK CTR at one time. My understanding is the APPCH permission from SY CEN is for sequencing into BK even though you are OCTA from SY airspace for the majority apart from the aformentioned segment of the IAF-IF leg, which without a clearance to enter ( different to approach permission), you must avoid.

Just out of interest, is this 'procedure' published anywhere? ERSA, DAP's/Jepps?

[mmm345]

Just out of interest, is this 'procedure' published anywhere? ERSA, DAP's/Jepps?

Not to my knowledge but have tried to find a reference. I am aware of it via local knowledge of flying there. Whenever it's less than VMC and Special VFR and IFR aircraft are operating, they can only ever have one aircraft operating under those rules.

I believe it is to do with ATC are required to seperate IFR from IFR in Class D. Under normal circumstances, most IFR aircraft when VMC prevails operate inbound via the VFR reporting points, and report visual with their inbound call, which enables ATC to employ visual separation to IFR aircraft as they are visual, which obviously cant be done in conditions less than VMC with aircraft on IAP's. Radar/ ADSB is only available for situational awareness to controllers in BK tower to my knowledge.

The only quote that somewhat references it is in the ERSA " IFR Operations in VMC", " Pilots electing to terminate an IFR flight under the VFR should communicate itention to ensure their arrival is processed efficently "

[tossbag]

So what it looks like is a 'local procedure.' Unpublished, but IFR pilots are expected to understand and comply. Contributing to confusion and misunderstanding (as in Dick's question).

Great airspace system (sarcasm).

[le Pingouin]

tossbag, it's pretty simple really. You're IFR operating in Class D airspace so subject to a clearance to conduct the approach in D, and as you're required to be separated from other IFR aircraft in D you have exclusive use of the airspace until you've either landed or conducted a missed approach.

[Capn Bloggs]

Tossbag, Dick's question had nothing to do with your "local procedure". He asked about why his FMS didn't stop him clipping a CTA step in when in full auto. He was given the answer.

I see nothing "local" about being cleared for an approach. The fact that you start out OCTA and, because of the way you operate your aeroplane/FMS, you then clip a CTA step, sound like a personal problem.

There is much nashing of teeth about hypotheses here. To go anywhere with this, we need to know exactly what ATC says. Obviously they won't "give" you the approach (your post #27).

As for
Just out of interest, is this 'procedure' published anywhere? ERSA, DAP's/Jepps?
Read note 4. And observe the 20nm range ring from SY.

Perhaps a more-specific caution on the chart re the Sydney step might be in order. AVSEF it.

[43Inches]

I'm just wondering if a note is missing from the RNP chart, there is a star next to the @2500 limit at WI, which resembles the same star on the NDB RWY 11C chart which states you have to be 2500 by 17 DME SY. Although this procedure is horribly non aligned with rules concerning CTA as some of them seem to pass in and out of CTA steps. The marked descent line seems to infer all is ok as long as you are 2500 at WI. It would be interesting what a controller familiar with the area would expect an aircraft to do, ie remain clear of the 20 DME step or as long as you are 2500 by 17 DME SY no probs...

[tossbag]

tossbag, it's pretty simple really. You're IFR operating in Class D airspace so subject to a clearance to conduct the approach in D, and as you're required to be separated from other IFR aircraft in D you have exclusive use of the airspace until you've either landed or conducted a missed approach.

That there is some confusion about being 'cleared' for an approach whilst being OCTA and whether it constitutes a clearance to clip CTA or not suggests there is a problem. Which should be cleared up with airspace users. There should be no confusion, especially when you're operating Single Pilot IFR, there is enough to do in the cockpit without confusion.

[tossbag]

Captain Bloggs, you'll note in my previous posts I was asking questions to understand what is being said by ATC. You obviously have someone sitting beside you to help clear up any confusion, sit in the cockpit by yourself in IMC and manage the workload of this procedure and see how you go. Personal problem? No, Dick is confused by whether he has a clearance to clip, the last thing you need when SP-IFRing in IMC is to be chipped by ATC for busting CTA.

I think you need to calm down a little, look at the broader implications of what is being discussed.

[Capn Bloggs]

I say again:
To go anywhere with this, we need to know exactly what ATC says.

[Big Pistons Forever]

Garmin navigators will provide vertical guidance on almost every approach in the database. On LNAV approaches it will give you LNAV+V where the the +V refers to a pseudo glide path that is a mathematically derived 3 deg slope. This is very handy but care must be taken because it will not account for any mandatory crossing altitudes.

One gotcha with GARMIN systems is that the system switches from terminal mode to approach mode (ie LPV, LNAV/VNAV or LNAV) when the active leg is the leg to the FAF. If there is a fix between the IAF and the FAF it will not sequence to approach mode until after that waypoint which means there will be no glide path until after you pass the waypoint at which point you will be above the glide path.

The work around is to activate vectors to final after you pass the IAF which will cause the FAF to be the active to waypoint.

[InSoMnIaC]

The work around is to activate vectors to final after you pass the IAF which will cause the FAF to be the active to waypoint.

This is a terrible idea. Never activate vectors unless you are actually “being vectored”. The work around to your dilemma is to use your 3 times tables

[tossbag]

I say again:

Well done.

So what it looks like

Is not a conclusion, rather, a summation.

[Big Pistons Forever]

InSoMNIac

There is no practical difference to the nav information you get if you activate vectors to final after the IAF. The only thing that changes is the box transitions from terminal to approach mode like it normally would inside the IAF, but does not in this case because of the waypoint inn between the IAF and the FAF

[WhisprSYD]

Captain Bloggs, you'll note in my previous posts I was asking questions to understand what is being said by ATC. You obviously have someone sitting beside you to help clear up any confusion, sit in the cockpit by yourself in IMC and manage the workload of this procedure and see how you go. Personal problem? No, Dick is confused by whether he has a clearance to clip, the last thing you need when SP-IFRing in IMC is to be chipped by ATC for busting CTA.

I think you need to calm down a little, look at the broader implications of what is being discussed.

As someone said above, when YSBK is IMC the only form of separation the tower have (being non radar) for IFR aircraft is 1 at a time until the arrival is Visual and within the circuit area. As a result the spacing between arrivals is large enough that #1 should be on short final for 11 or visual d/w for 29 before #2 is cleared for the approach.
The way it works is that when tower is able to separate the next arrival they’ll relay clearance for the approach to SY centre/deps who clear the aircraft for the approach. The intent of the clearance is for the segment into class D, BUT SY ATC are aware that without any VNAVS between RAKSO and WI that once the word ‘cleared’ has been uttered that they might clip C on descent, and therefore they’ll separate any other aircraft in C as necessary.
If an aircraft is conducting a practice RNP in VMC it’s a different story, the pilot will usually explicitly be told to remain OCTA until contacting 132.8 for clearance into D.

Hope that helps.

[tossbag]

The way it works is that when tower is able to separate the next arrival they’ll relay clearance for the approach to SY centre/deps who clear the aircraft for the approach. The intent of the clearance is for the segment into class D, BUT SY ATC are aware that without any VNAVS between RAKSO and WI that once the word ‘cleared’ has been uttered that they might clip C on descent, and therefore they’ll separate any other aircraft in C as necessary.
If an aircraft is conducting a practice RNP in VMC it’s a different story, the pilot will usually explicitly be told to remain OCTA until contacting 132.8 for clearance into D.

Hope that helps.

Excellent, thankyou. Very well communicated.

I don't think that too many SP-IFR pilots are aware of the intent? In my opinion this needs to be communicated to industry somehow. Not just in words but in something like the privately produced IFG (but an ASA document)

(Thanks Captain Bloggs, you're welcome :ok:)

[Lead Balloon]

Lead Balloon,

To clarify, the airspace data and approach data are in separate parts of the database. They are unknown to each other, and so there are no smarts to compare approach path and airspace data…..

Thats kind of the point of the prediction arc in large fms systems. It allows the pilot to know if an altitude is going to be reached by a certain point and adjust if required.Roger.

Thanks again, alpha.

[Dick Smith]

In the USA, where Garmin comes from, all IFR approaches are in a minimum of class E controlled airspace so there is no such thing as going in and out of controlled airspace when on an IFR approach.

It's clear that Garmin or other manufacturers are not going to do a special design just for Australia.

That's why we decided to go to the US NAS airspace system many years ago!

Now after Mangalore it just may happen.

[Lead Balloon]

Just goes to show: There's no fool like an old fool. Even a rich one.

I'm a big fan, Dick. But seriously: Do you not remember what's happened many times before?

[Dick Smith]

Yes. Remember well.

In those days many said that our self separation when IFR was perfectly safe.

After Mangalore there is a changing view.

Remember. They were all professional pilots.

[tossbag]

Now after Mangalore it just may happen.

Not...A...Chance...In...Hell...

[alphacentauri]

In those days many said that our self separation when IFR was perfectly safe

I have some questions......

What, exactly do you (or they) mean by "perfectly safe"?
Does it mean no accidents, ever?
Does it mean 1 x 10-7 (1 accident 10 million movements)
Does it mean 1 x 10-8 (1 accident 100 million movements)
What if the Mangalore incident was the 1 accident for 10 million movements? ( or even the 100 million). Just because you have an accident, does not mean that the desired risk level has not been achieved.

The missing link in Australia is that we don't have established risk classifications for different operations in different airspace that are published and accepted by industry. So we don't know what target level of safety we are trying to achieve....but I will give you a hint........it cant be zero.......its statistically impossible.

That also means of the options I give you above....you also cannot pick zero......which means you must pick one of the other 2.......which means you must ponder the answer to the last question.

Don't get me wrong, I am not against considering changes to the airspace system. I am against assuming changes to the airspace system will fix the assumed problems. If it can be determined that Mangalore statistically fits the risk model for that operation in that airspace class, then do we actually need to change anything at all?

Alpha

[43Inches]

Listened to a close situation in class E only a few weeks ago, where a VFR blasted straight through the approach path of an IFR doing an RNP approach at Avalon. VFR was listening to the wrong frequency so had no idea what was going on, was just aware they didn't need a clearance to transit the E area. The IFR had to discontinue the approach and try to visually identify the VFR traffic, none of it sounded very 'safe'. I think some of the ATS distance were as close as 2nm.

[Lead Balloon]

Happens in 'G' quite frequently, too, 43. And I'd be interested to know how the pilots of VFR aircraft in the vicinity of any aerodrome avoid flying through instrument approaches to the aerodrome.The missing link in Australia is that we don't have established risk classifications for different operations in different airspace that are published and accepted by industry. So we don't know what target level of safety we are trying to achieve....but I will give you a hint........it can’t be zero.......its statistically impossible.But we do know what the political target level of safety in aviation is:

Zero deaths that scare the hell out of punters.

It’s about perception, not reality.

The death of four indulgees in a mid-air at Mangalore doesn’t scare the hell out of punters. Class ‘G’ and the ongoing obligation to maintain vigilance so as to see and avoid neatly justifies the status quo. Had the accident instead involved the same PICs but e.g. two ‘Angel Flight’ passengers, more effort would be needed to justify the status quo.

Every day in Australia, passenger-carrying RPT aircraft fly in uncontrolled airspace and mix it with aircraft that are not certified by CASA and not under the command of pilots licensed by CASA or certified as medically fit by CASA. The level of mid-air collision risk to which those RPT passengers are exposed is not zero. But it is evidently ‘acceptable’ to CASA and, given the number of incidents involving RPT aircraft in proximity to aerodromes in ‘G’ and ATSB’s ‘dare not speak its name’ attitude to mentioning the potential for higher classifications of airspace to reduce the extent of these risks, the ATSB and the operators of the RPT aircraft are untroubled as well.

What do you reckon the response is when I explain this reality to the average punter? Give it a go yourself sometime, and watch their face: “You know that there’s no control tower at (enter name of the place to which the punter's flying).” [Here their eyes usually widen and their brows usually furrow.] “And there’ll be other aircraft flying near you that aren't under air traffic control and aren’t necessarily certified airworthy by CASA.” [Here their head usually pulls back.] “And the pilots of those aircraft won’t necessarily be licensed by CASA or certified as medically fit by CASA.” [And here they usually shake their head and accuse me of making it up.]

The first mid-air involving an RPT aircraft in ‘G’ in Australia will test the comfy CASA/Air Services/ATSB/Operator status quo against the political target level of safety. It will scare the hell out of a lot of punters. My guess is that CASA won’t get away with saying: “It’s the one-in-1XX million movement accident that is a risk that we’re always taking.”

[tossbag]

The first mid-air involving an RPT aircraft in ‘G’ in Australia will test the comfy CASA/Air Services/ATSB/Operator status quo against the political target level of safety. It will scare the hell out of a lot of punters. My guess is that CASA won’t get away with saying: “It’s the one-in-1XX million movement accident that is a risk that we’re always taking.”

I still don't think an occurrence like this will change anything. Australia will go to extraordinary lengths to avoid building 'permanent' infrastructure, like towers. ASA doesn't want to cop the bills for their construction or staffing costs and they have allies in government who know that it's their budget allocations that fund it in the end. What happens are ridiculous airspace concepts (see Ballina) that can be dropped once the traffic 'normalises.' (if that will ever happen).

When a politicians job is genuinely on the line, if they're ever accountable, thats when things will change i.e. things will never change.

[Lead Balloon]

"Ridiculous airspace concepts" like Ballina are themselves changes, but I agree with your underlying point. The usual response is to put more lumps on the camel, rather than to question whether a camel is now the most efficient animal in the circumstances.

Dick gets criticised for using the term "affordable safety", but that is the inescapable reality of the world in which we live. And the answer to a mid-air involving a passenger-carrying RPT aircraft in 'G' will be: That's the level of safety for which you paid.

[43Inches]

When a politicians job is genuinely on the line, if they're ever accountable, thats when things will change i.e. things will never change.

Sadly this is not the case, accountability just leads to higher levels of corruption, look at CEOs and the golden parachute phenomenon. All that happens is when some force wants something wrong to happen, you pay someone enough to take the fall, while the main perps remain behind the scenes pulling the strings. The shenanigans over the last 20 years of knifing PMs should have shown us all the leader is not the leader, they are the puppet for those on an agenda, when the PM starts wandering from the script they get axed. Yet the average voter is more and more led to believe the name they vote for is in control.

I think reality is the more we can push for systems that give the pilot more awareness and 'smart' aircraft warnings for proximity are far better than any controlled 'airspace system' will afford. By that I mean systems like TCAS displays, so pilots can see everything squawking around them, I use this a lot for situational awareness and it makes a huge difference. OZ runways and similar traffic displays, although some integration with TCAS would be perfect so it comes from transponder feed for local traffic. I personally think Class E is an abomination waiting for a mid air when someone is not paying attention. Letting the lowest trained and least reliable just fly through with the other traffic believing they are being monitored and safe. At least in Class G you know it's the wild west and anyone can come at you from any angle, so you keep the eyes peeled.

[Lead Balloon]

Please: No more gadgets.

Focussing on what the gadgets tell you is the traffic is itself a problem. Gadgets have delays, margins of error and sometimes fail.

E is an "abomination" but 'G''s OK, because you know you have to keep your eyes peeled in 'G'? I've some (very old) news for you: You have to keep your eyes peeled in every class of airspace. At least in E there is a 3rd party who has the job of assisting IFR not to collide with whomever. That's what you heard when that VFR "blasted through" Class E airspace while on the "wrong frequency", isn't it?

[43Inches]

Problem is those lil private craft are getting faster and harder to see, not long before they climb higher as well with better emerging technologies. That has made it so far that class E is mostly clear of smaller VFR craft, as the airspace populates with more and more and airservices seems to provide less and less, who is really able to be watching. En-route ATS seems overwhelmed with 5 aircraft floating around, let alone monitoring IFR approaches into every field in their area, automation is the only way it can be done safely. So far ATS seems to accurately pass on about half the traffic to me, I've seen RAs due to multiple traffic and ATS only passing on one and the IFR aircraft thinking they are clear after that, then "SUPRISE, I wasn't talking and my transponder is now telling yours to fly up... and you have paperwork to do now"

Then there's the myriad of shonks that don't follow the rules to any particular method, just do their own thing. I'd be happy if they just turn on their transponder so I can see where they are and give em a wide berth.

The other issue in class E is that an IFR aircraft requires a clearance to deviate from cleared track in order to avoid a potential conflict, which in some cases the act of requesting such manuvre would be too long. In class G I could see a potential conflict or be alerted by TCAS TA and change course to avoid immediately, avoiding the possibility of an RA or worse. In class E you can only alter course for an RA, in which case you then need to waste time on paperwork.

[Lead Balloon]

If your loved ones are sitting as passengers in an RPT jet descending to land at an aerodrome, would you prefer them to be descending through E all the way to and including circuit height, or in G? In E, those transponder gizmos are compulsory.

Only in Australian aviation could there be any debate about the answer. Only in Australian aviation can there be a weight of opinion to the effect that if we can't have C or D we'll have G, thank you very much.

Lucky the diameter of the roulette wheel involved is very, very large.

[43Inches]

The debate is because I've seen a lot of incidents recently around this airspace, in theory it might work, however the recent one I mentioned highlighted when it goes wrong, 2nm separation is not ideal. Once the training factories return to full strength post covid and the city class E areas start to get swamped with solo VFR navigators we will see ATS completely overwhelmed with radar dots, with no control over what the VFRs do in class E. Anyone who has flown in the areas around these facilities would be familiar with the ATS phrase "multiple VFRs" with no possibility of really passing on the information to the IFR except for, "there's too many of them, good luck soldier you're on your own...". Also all this debate over mid airs, we have to remember over the last 20-30 years an equal amount of collisions have happened in controlled airspace and most in radar environments. Mid air collisions are a result of traffic density more than third parties watching, while a 3rd party might be able to intervene all you have to look at is the Benalla Cheyenne crash where ATS didn't even notice the aircraft wasn't on track, let alone prevent a mid air. Or should I even mention Mildura or heavens forbid mention the ditching, where ATS failed to pass on critical information.

As for class D in Australia is a complete joke, install ADSB, radar scopes, train them and make it class C. One IFR aircraft doing an approach blocking out 6000ft x 30nm of airspace is just silly.

BTW ATS do a great job on most occasions, but relying on humans to be infallible while watching multiple dots over hundreds of miles especially when two or more close contacts start to occur and things get out of hand fast.

[Dick Smith]

It looks as if it is time to quote Voices of Reason and Class E airspace again. Here it is, from 22 April 2004:

“Class E airspace Is Safe

Class E Airspace and United States Practice

We have watched with incredulity at the dangerously naive statements being made on threads in the Australian PPRuNe sites, concerning the operation of Class E airspace. Class E airspace is NOT an unsafe categorization of airspace, and is in fact used safely and effectively in substantial portions of the globe.

EACH AND EVERY transport and passenger carrying aircraft operating in the United States is required to operate for some portion of their flight in designated Class E airspace – effectively between 18,000 feet and the upper limit of Class B, C or D airspace – or the surface for non controlled aerodromes. This equates to over 10,000 passenger-carrying flights per day, every day of the year. The Class E airspace within which they operate is in the so-called most dangerous phase of flight – climb or descent. Your national carrier is no exception.

There are in excess of 150,000 general aviation aircraft operating in the United States, to either the visual or instrument flight rules – many many thousands per day.

There are CONSTANT interactions between IFR passenger carrying aircraft and VFR aircraft on a daily basis – with no hint that this practice is unsafe.

There are countless examples where aircraft provided with routine terminal area instructions whilst still in Class E airspace are routinely provided sequencing descending turn instructions by controllers in one breath, and VFR traffic information in the other.

We agree that Class E airspace is mostly within radar cover in the United States – probably the greater part of 95%. In that airspace, air traffic controllers positively separate IFR flights from other IFR flights – and where they can, provide traffic information on VFR flights.

Radar coverage is NOT a prerequisite for Class E airspace, and in fact in several cases the Class E airspace linking certain aerodromes to upper airspace is not covered by radar. In that airspace, air traffic controllers positively separate IFR flights from other IFR flights – and as they cannot observe VFR, do not pass traffic unless they know by some other means. That positive IFR-to-IFR separation may, in many cases, be applied on a “one in at a time” basis. The airlines accept that mode of operation.

NOT ONE SINGLE AIRLINE in the United States is lobbying for a higher level of service in current Class E areas.

Our observation in relation to the Australian experience has been one of giving proper effect not just to training and education, but also to the cultural change requirements. Pilots need to understand that operating in Class E airspace IS FUNDAMENTALLY DIFFERENT to the service that they have received in the past – but need to accept that this is a normal way of doing business.

Australian controllers need to STOP being negative, embrace the concept of Class E airspace and to be blunt, get on with it. Controllers in the United States provide services in Class E, without questioning its “safety”, day in and day out, and have done so [either as Class E, or its predecessor], for over 50 years.

NOT ONE SINGLE CONTROLLER in the United States is lobbying for a higher level of service in current Class E areas.

We are concerned that this constant questioning and second-guessing by your pilot and controller fraternity will in fact generate a safety deficiency larger that the problem you are trying to solve. By our estimation, there is NO JUSTIFICATION for the large amount of Class C airspace presently designated in Australia, and subject to the appropriate change management processes we have previously described, you should introduce Class E airspace wherever possible.”

[43Inches]

To be fair what I see is an understanding of airspace issue, the VFRs just think class E is uncontrolled airspace and treat it as such. Which it is for them, but there is also a requirement to be more vigilant of IFR operations. WRT to some of the comments in that note, of course Airlines don't want higher ATS levels, why, because it's user pays system now. It's quite easy to see in GA whereRPT/Charter below 5700kg opt to go VFR to avoid airservices costs sometimes in what I would call marginal conditions. The age old cost vs safety always errs to cost reduction. WRT controllers, Australia has so many issues with airservices at the moment, no one is going to stick their neck out to complain about it. Luckily in most situations so far our traffic levels are low enough that the spread thin controllers can monitor both class E and G to some amount. Will class E stop a A320 from getting too close to light aircraft in Ballina, nope, but the automated TCAS and such will stop it from hitting it.

Anyway moving away from the point that class E airspace does not offer any real tangible improvement in safety over what aircraft based situational awareness tools do. Looking at the last few that happened in the USA, one was at a controlled airport in the circuit, another was two floatplanes where both had the equipment to have warned each other however one had its transponder output turned off, so neutralised the automatic warning it should have received, which would have prevented the event. Basically everything flying should have a working operating transponder if it flies above 1000ft agl.

[le Pingouin]

"As for class D in Australia is a complete joke, install ADSB, radar scopes, train them and make it class C. One IFR aircraft doing an approach blocking out 6000ft x 30nm of airspace is just silly."

Except that's incorrect. The procedure is used in "D" associated with aeordromes such as Bankstown and Moorabbin which are far smaller in dimension than that - 2500ft x 3NM for YMMB.

[43Inches]

I'm more referring to class D like Albury. However Moorabbin and Bankstown are no different where a class G airport would handle more IFR movements in IMC and safely. I'm pretty sure the powers at be have no idea what happens OCTA these days, the restrictiveness of some CTA especially when unidentified is just silly. And the controllers seem to sound completely aghast when we choose to go OCTA to self separate because it's easier than trying to deal with their rules.

[Lead Balloon]

If you believe that the ‘close call’ risk for an A320 in E is the same as it would be in G, 43, you’re in the just the right country to practise your religion. Ditto your prayer beads gadgets.

Bless your heart.

[43Inches]

I actually don't see any difference between class E and G when it comes to separating VFR and IFR, like I said, what I've seen in practice gives me this concept, not what is written on paper. I just see more flexibility for an IFR aircraft to deal with the issue in class G than in class E, where it's restricted to it's clearance limits. If you believe that some guy 1000 miles away watching you on a 2d flat panel, with maybe 20 other things going on telling you what to do is making you safer, yes ,maybe it is religious, sounds like faith to me.

If you implement class E in ballina it would not make a shred of difference to the IFR vs VFR situation, why, because the VFR will do the exact same thing it does currently, because that's what class E allows. The controller can not tell the VFR what to do, it's uncontrolled, and being a CTAF, it wont be listening to class E frequencies most likely.

[le Pingouin]

The class of the controlled airspace has nothing to do with the "one in, one out" processing, it's the lack of surveillance facilities available to the controllers meaning they use procedural separation. Don't conflate the two.

[43Inches]

That's what class D is, procedural separation, is it not? Or do we have a radar controlled class D in operation somewhere?

[le Pingouin]

Airspace rules and separation rules are two entirely separate things - the airspace rules tell you who to separate and the separation rules tell you how. Procedural separation is used where no surveillance coverage or it's not assured - it is used in all controlled airspace classifications.

[Dick Smith]

I have spoken to the people at Airservices and they are going to look at changing the coding and the plate so a coupled approach will descend early enough so the aircraft does not enter the class C 2500' step.

In the meantime I suggest any pilot wanting to do a fully A/P coupled approach using Garmin equipment specifically requests a clearance to enter the class C step.

[le Pingouin]

That should be the principle applied anywhere, if you think you might need a clearance, ask! And the controllers should be proactive and offer one if they can if there's a chance you'll clip a step on the way down.

[Lead Balloon]

I think Dick's point is that it's counter-intuitive that a clearance would be required on that approach in the first place. Counter-intuitive = room for confusion = risk.

[tossbag]

It should not be up to the pilot to 'request' a clearance on this type of approach. In fact, this approach should be either in CTA or OCTA, no ambiguity. SP-IFR in IMC, you have got enough to do without managing a sub standard airspace system.

[le Pingouin]

LB, then why doesn't he come out and say that at the start?

TB, be that as it may, that's what the situation is. Why wouldn't you plan for it and ask early while you aren't busy?

[tossbag]

LP, yes, that is the situation. In my experience ATC push aircraft OCTA, particularly in the Sydney basin. It's a case of easing the controllers workload over what is best for the aircraft. I'm more commenting on the way it should be rather than the way it is.

[Lead Balloon]

LB, then why doesn't he come out and say that at the start?Dicks move in mysterious ways.

[BronteExperimental]

Did this approach in IMC a few days back.
Dogs breakfast.
Got “cleared” for the approach at RAKSO and dialed in VS to hit WI at 2500.
I was half expecting it so wasn’t surprised 2 minutes later to get a terse remain OCTA.
ceilings were about 2000 so the SY CEN controller spent the next 3-4 minutes giving me multiple VFR (probably only just) traffic which I couldn’t see anyway!
would have been infinitely simpler to just be in the C for a few miles of descent prior to WI. There’s obviously no traffic inside CTA at 3000’ within 20miles of that route.
So between being relatively unstable/dive and drive/button pushing and loads of unnecessary radio chat it was quite a painful procedure. Unnecessary.

[Dick Smith]

Good point. It's clearly safer to stay higher and in controlled airspace for as long as possible.

[Atlas Shrugged]

Well, well, well...............

[tossbag]

Did this approach in IMC a few days back.
Dogs breakfast.
Got “cleared” for the approach at RAKSO and dialed in VS to hit WI at 2500.
I was half expecting it so wasn’t surprised 2 minutes later to get a terse remain OCTA.
ceilings were about 2000 so the SY CEN controller spent the next 3-4 minutes giving me multiple VFR (probably only just) traffic which I couldn’t see anyway!
would have been infinitely simpler to just be in the C for a few miles of descent prior to WI. There’s obviously no traffic inside CTA at 3000’ within 20miles of that route.
So between being relatively unstable/dive and drive/button pushing and loads of unnecessary radio chat it was quite a painful procedure. Unnecessary.

Airspace management at its best, where else in the world do you get forced OCTA on an instrument approach?

[BronteExperimental]

Airspace management at its best, where else in the world do you get forced OCTA on an instrument approach?
got the bill in the mail today too. Awesome 👏

[tossbag]

got the bill in the mail today too. Awesome

Oh, they've got front. Half the country's airspace is closed or half capacity and they'll charge you full price.