More damage to Aussie GA – ILS training
Thread Starter
Ftrplt
I have just checked with a friend of mine
He has a Garmin750 with the latest upgraded software. He recently did a GPS (RNAV16) approach into Wollongong. The approach was fully coupled to the autopilot both vertically and laterally with a full glideslope type indication.
On the Garmin screen it was named a “Lnav+V” approach. Ftrplt, you don’t mention such a nomenclature. What is the CASA description for this type of approach? Why is it different to the FAA/Garmin description?
I have just checked with a friend of mine
He has a Garmin750 with the latest upgraded software. He recently did a GPS (RNAV16) approach into Wollongong. The approach was fully coupled to the autopilot both vertically and laterally with a full glideslope type indication.
On the Garmin screen it was named a “Lnav+V” approach. Ftrplt, you don’t mention such a nomenclature. What is the CASA description for this type of approach? Why is it different to the FAA/Garmin description?
It depends what training/app endorsement CessnaPete holds as to whether it is actually a problem.
I have spoken to professional pilots who aren't confused. Again it depends on the training received by these professional pilots of yours and what approaches they are qualified to fly.
Doesn't really matter if some believe WAAS (which is actually one of a few SBAS service providers) is in Australia, we don't have charts published with LPV minima and the acft avionics wont work if they tried to fly LPV functionality in Oz anyway, so it is irrelevant.
If you started with a clean-sheet design for GPS approaches to today's capability would you design it they way it is now - probably not. However GPS approaches have evolved over 20 odd years so it has been constrained within the ability of exisiting avionics and autoflight systems to evolve with the increased capability.
I think of it differently - pre-GPS approach days you achieved your entry level instrument approach capability with NBD, and if it was real smick you had an RMI instead of fixed card. Some people could even fly VOR approaches! If you then wanted the really good capability you trained to fly ILS approaches. This certainly wasn't a transition without learning challenges.
I think of RNAV NPA as the entry level capability (like NDB/VOR app but better), LNAV/VNAV as the next level capability (note quite CAT I ILS), and LNAV LPV as ILS CAT I. Yes, the fact that you now effectively have 3 different capabilities within the same system does add initial understanding complexity - it just takes some effort to learn. You had similar learning challenges moving from NDB, to VOR, to ILS in the old days.
This evolution of GPS approach capability is not unique to Australia, in fact the evolving terminology is an effort to align terminology across the world. Short term disruption for longer term gain given the capability evolution over 20 years. The FAA is going through similar terminology/nomenclature changes.
You state ILS is simple - true if flying to CAT I only. Definitely not simple if you wish to extract the full ILS capability and fly to CAT II, or CAT IIIA / IIIB with AL and rollout.
I would equate your 'simple ILS' to flying RNAV NPA's only - pretty simple if you don't want to train and qualify to fly the enhanced GPS approach capability. Don't worry about anything other than the LNAV minima box, monitor the intermediate step heights, and don't bust the MDA.
(Dick - I will get back to you on the immediate post above, gotta step out - but its an LNAV NPA - with the avionics providing the internally generated GP, the approach is not designed with a 3 deg GP, its the acft's avionics effectively automating the DME/ALT scale. One of the documents I referred you to mentions Lnav+V, I will need to look again).
I have spoken to professional pilots who aren't confused. Again it depends on the training received by these professional pilots of yours and what approaches they are qualified to fly.
Doesn't really matter if some believe WAAS (which is actually one of a few SBAS service providers) is in Australia, we don't have charts published with LPV minima and the acft avionics wont work if they tried to fly LPV functionality in Oz anyway, so it is irrelevant.
If you started with a clean-sheet design for GPS approaches to today's capability would you design it they way it is now - probably not. However GPS approaches have evolved over 20 odd years so it has been constrained within the ability of exisiting avionics and autoflight systems to evolve with the increased capability.
I think of it differently - pre-GPS approach days you achieved your entry level instrument approach capability with NBD, and if it was real smick you had an RMI instead of fixed card. Some people could even fly VOR approaches! If you then wanted the really good capability you trained to fly ILS approaches. This certainly wasn't a transition without learning challenges.
I think of RNAV NPA as the entry level capability (like NDB/VOR app but better), LNAV/VNAV as the next level capability (note quite CAT I ILS), and LNAV LPV as ILS CAT I. Yes, the fact that you now effectively have 3 different capabilities within the same system does add initial understanding complexity - it just takes some effort to learn. You had similar learning challenges moving from NDB, to VOR, to ILS in the old days.
This evolution of GPS approach capability is not unique to Australia, in fact the evolving terminology is an effort to align terminology across the world. Short term disruption for longer term gain given the capability evolution over 20 years. The FAA is going through similar terminology/nomenclature changes.
You state ILS is simple - true if flying to CAT I only. Definitely not simple if you wish to extract the full ILS capability and fly to CAT II, or CAT IIIA / IIIB with AL and rollout.
I would equate your 'simple ILS' to flying RNAV NPA's only - pretty simple if you don't want to train and qualify to fly the enhanced GPS approach capability. Don't worry about anything other than the LNAV minima box, monitor the intermediate step heights, and don't bust the MDA.
(Dick - I will get back to you on the immediate post above, gotta step out - but its an LNAV NPA - with the avionics providing the internally generated GP, the approach is not designed with a 3 deg GP, its the acft's avionics effectively automating the DME/ALT scale. One of the documents I referred you to mentions Lnav+V, I will need to look again).
I'm going to do my best to close some loops in the discussion. I acknowledge that many aircraft navigation suites are cutting edge and provide functionality beyond what the approaches currently allow.
So we need to make 2 distinctions, there is such a thing as a '3d approach' and there is such a thing as a '3d approach operation'. Your mate flying the YWOL RNAV16 with LNAV +V is using capabilities of his avionics as vertical advisory and is effectively flying a 2d approach as a 3d approach operation. There is nothing wrong with this provided, the integrity of the underlying 2d approach is not compromised. This means that the minimum segment altitudes must also be monitored and adhered to. For the purposes of IR currency this example also ticks the box for 3d approach currency.
In the example above it needs to be clearly stated that this is NOT vertical guidance. This is vertical advisory. Understand that LNAV +V is purely a GARMIN term......you would need to read the GARMIN manuals to determine its limitation.
Now for SBAS approaches, apart from the extra line of minima, there are a few other things that are required for it to be coded appropriately. (I refer your attention to any of the GLS approach charts for YSSY and YMML). There will be on the chart an SBAS channel number and an approach identifier. These form part of the SBAS data block that is provided to the data houses for coding onto the approach. Without it, you do not have an LPV.
Cessnapete, I am not sure what you have been flying but it has not been LPV. This comment
scares the crap out of me if that is in fact what you have been doing.
Since there is no WAAS in Australia then the height element for your nav system can only have been derived from barometric data.
Dick mentioned coding in a previous post....you have to be careful with your assumptions made on coding. Yes the heights are coded for the approach and either your system can read/understand or it cannot. But ask a question, in order for your system to give you vertical deviation corrections it needs to be comparing the coded height against some other height source. If there is no WAAS, then only other thing it can be using is a barometric altimeter, and I would argue that in cessna pete's 182 this source would not be temp compensating..........there is reason minimum temps are published on baro charts and at YWOL if it gets cold enough you may be to low on the approach path to the clear the escarpment. Have a think about that.
So we need to make 2 distinctions, there is such a thing as a '3d approach' and there is such a thing as a '3d approach operation'. Your mate flying the YWOL RNAV16 with LNAV +V is using capabilities of his avionics as vertical advisory and is effectively flying a 2d approach as a 3d approach operation. There is nothing wrong with this provided, the integrity of the underlying 2d approach is not compromised. This means that the minimum segment altitudes must also be monitored and adhered to. For the purposes of IR currency this example also ticks the box for 3d approach currency.
In the example above it needs to be clearly stated that this is NOT vertical guidance. This is vertical advisory. Understand that LNAV +V is purely a GARMIN term......you would need to read the GARMIN manuals to determine its limitation.
Now for SBAS approaches, apart from the extra line of minima, there are a few other things that are required for it to be coded appropriately. (I refer your attention to any of the GLS approach charts for YSSY and YMML). There will be on the chart an SBAS channel number and an approach identifier. These form part of the SBAS data block that is provided to the data houses for coding onto the approach. Without it, you do not have an LPV.
Cessnapete, I am not sure what you have been flying but it has not been LPV. This comment
flies LPV to CAT I limits.
An GNSS LPV approach does not use barometric data. The height element for the G/S is satellite derived with WAAS augmentation
Dick mentioned coding in a previous post....you have to be careful with your assumptions made on coding. Yes the heights are coded for the approach and either your system can read/understand or it cannot. But ask a question, in order for your system to give you vertical deviation corrections it needs to be comparing the coded height against some other height source. If there is no WAAS, then only other thing it can be using is a barometric altimeter, and I would argue that in cessna pete's 182 this source would not be temp compensating..........there is reason minimum temps are published on baro charts and at YWOL if it gets cold enough you may be to low on the approach path to the clear the escarpment. Have a think about that.
Thread Starter
Problem is that the RNAV NPA is potentially dangerous as the descent requires a human not making a simple error and stepping down to early.
Look at many professional pilot CFIT accidents.
The LNAV plus V is a staggering safety improvement because you monitor what the aircraft is doing. And in the case of Garmin 650/750 owners it is zero or minimum cost to upgrade The software
So it’s quite different to what you say.
Alpha. With the Garmin LNAV plus V I am referring to there is no barometric input. It takes the height from the GPS. Yes. Garmin also has Baro Vnav equipment but that’s not what I am referring to.
The GPS in my phone gives altitude with great accuracy. Why not a far more expensive aircraft certified unit!
Look at many professional pilot CFIT accidents.
The LNAV plus V is a staggering safety improvement because you monitor what the aircraft is doing. And in the case of Garmin 650/750 owners it is zero or minimum cost to upgrade The software
So it’s quite different to what you say.
Alpha. With the Garmin LNAV plus V I am referring to there is no barometric input. It takes the height from the GPS. Yes. Garmin also has Baro Vnav equipment but that’s not what I am referring to.
The GPS in my phone gives altitude with great accuracy. Why not a far more expensive aircraft certified unit!
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Dick, a lot of the answers you are after is explained in an article by flight safety Australia: ‘when advice is not the same as guidance’.
These LNAV/VNAV approaches are somewhat ballpark (albeit slightly higher) to ILS approaches. But importantly are considered 3D as mentioned above. New instrument rating requirements have a 2D and 3D currency. The LNAV/VNAV ticks this 3Dbox.
Given the proliferation of the LNAV/VNAV approaches - essentially everywhere with an ATIS or AWIS for now, and more soon, it seems like primacy for 3D approaches will become the LNAV/VNAV.
If we say that most GA requirements for ILS training is for initial instrument rating endorsement. Then why not train first for LNAV/VNAV and then the requirement for ILS slots becomes a ‘differences’ flight for button pushing the ILS/symbology.
I think this will result in less need for GA ILS slots. Thereby returning to you original question.
Of note Nowra will have 15 HATS ec135 helicopters training all the navy and army pilots onto helicopters and conducting IFR training. All the conversions onto NRH90 and MH60R. Plus all the local training/currency for the NRH90/MH60R. All IFR aircraft. I would hazard a guess that given ILS takes aircraft into the circuit area, aircraft will need to be separated from other IFR aircraft for the ILS plus circuit traffic - this might be why it’s getting harder to book.
These LNAV/VNAV approaches are somewhat ballpark (albeit slightly higher) to ILS approaches. But importantly are considered 3D as mentioned above. New instrument rating requirements have a 2D and 3D currency. The LNAV/VNAV ticks this 3Dbox.
Given the proliferation of the LNAV/VNAV approaches - essentially everywhere with an ATIS or AWIS for now, and more soon, it seems like primacy for 3D approaches will become the LNAV/VNAV.
If we say that most GA requirements for ILS training is for initial instrument rating endorsement. Then why not train first for LNAV/VNAV and then the requirement for ILS slots becomes a ‘differences’ flight for button pushing the ILS/symbology.
I think this will result in less need for GA ILS slots. Thereby returning to you original question.
Of note Nowra will have 15 HATS ec135 helicopters training all the navy and army pilots onto helicopters and conducting IFR training. All the conversions onto NRH90 and MH60R. Plus all the local training/currency for the NRH90/MH60R. All IFR aircraft. I would hazard a guess that given ILS takes aircraft into the circuit area, aircraft will need to be separated from other IFR aircraft for the ILS plus circuit traffic - this might be why it’s getting harder to book.
The LNAV plus V is a staggering safety improvement because you monitor what the aircraft is doing.
With the Garmin LNAV plus V I am referring to there is no barometric input. It takes the height from the GPS.
Your iphone is currently using signals from SBAS as part of the trial currently ongoing. These signals cannot be used by aircraft avionics, yet.
How do you know the altitudes are accurate?
How do you know the altitudes are accurate?
At the moment, yes
Again, how do you know? You don't what signal it is using, you don't know the source of elevation. How can you possibly make assertions about accuracy?
Exactly the same argument can be used for those people using LNAV +V, or 'other'. You don't actually know the altitude source, and you cannot determine the accuracy of this source. Yet for some reason people seem to think that flying IFR to CAT I minima, when no provision for this minima has been provided, is perfectly acceptable.
Again, how do you know? You don't what signal it is using, you don't know the source of elevation. How can you possibly make assertions about accuracy?
Exactly the same argument can be used for those people using LNAV +V, or 'other'. You don't actually know the altitude source, and you cannot determine the accuracy of this source. Yet for some reason people seem to think that flying IFR to CAT I minima, when no provision for this minima has been provided, is perfectly acceptable.
Thread Starter
If I am standing at my hangar at bk and my iPhone says 60’ I know it is accurate.
Is using Lnav plus V I check the altitude from the altimeter with the distance on the Gps to the next waypoint and check with the instrument plate.
But I let the autopilot fly the approach. Less workload. Less errors.
Are you suggesting that Garmin and Cessna have not thought out the +V approaches?
Can you tell me more about the iPhone SBAS Australian trials? Or is it a furphy ?
Is using Lnav plus V I check the altitude from the altimeter with the distance on the Gps to the next waypoint and check with the instrument plate.
But I let the autopilot fly the approach. Less workload. Less errors.
Are you suggesting that Garmin and Cessna have not thought out the +V approaches?
Can you tell me more about the iPhone SBAS Australian trials? Or is it a furphy ?
Dick, I say again - no one is saying you cannot couple the AP to the vertical profile generated within the Garmin (LNAV+V) when flying an RNAV NPA (i.e LNAV minima). It makes sense to maximise safety and that is why it was provided by Garmin (and others). Note that this capability of internal V profile generation came about before LNAV/VNAV and LPV came into being, its history was to make the early LNAV only GPS approaches safer.
However, the pilot is solely responsible for ensuring any intermediate altitudes between the FAF and the MDA are not busted. In the case of the RNAV 16 at YWOL - make sure you do not intercept your +V glidepath below 2700ft prior to the FAF, and then dont go below 2200 on your barometric altimeter (regardless of whether the +V on the Garmin is GPS derived altitude) until passing 4.4nm to run to WOLNM, and then don't bust the MDA for your category and approach (SI or Circling). How you use your avionics and autoflight system to achieve this is up to you and the rules you fly under. If there aren't any intermediate steps its even easier, just dont bust MDA.
If you are able to fly to an LNAV/VNAV minima instead - i.e the approach has an LNAV/VNAV minima block, and your acft is certified, and you are in the temp range with an accurate QNH - you can still fly to a coupled GP, you aren't responsible for intermediate heights as there are none. It is also a DH vice an MDA.
Have a look at Hotham (YHOT) RNAV 29 - it has both minima blocks.
The bottom of page 14 of the document I originally referred you to (which you said you have read) provides background to the +V capability.
However, the pilot is solely responsible for ensuring any intermediate altitudes between the FAF and the MDA are not busted. In the case of the RNAV 16 at YWOL - make sure you do not intercept your +V glidepath below 2700ft prior to the FAF, and then dont go below 2200 on your barometric altimeter (regardless of whether the +V on the Garmin is GPS derived altitude) until passing 4.4nm to run to WOLNM, and then don't bust the MDA for your category and approach (SI or Circling). How you use your avionics and autoflight system to achieve this is up to you and the rules you fly under. If there aren't any intermediate steps its even easier, just dont bust MDA.
If you are able to fly to an LNAV/VNAV minima instead - i.e the approach has an LNAV/VNAV minima block, and your acft is certified, and you are in the temp range with an accurate QNH - you can still fly to a coupled GP, you aren't responsible for intermediate heights as there are none. It is also a DH vice an MDA.
Have a look at Hotham (YHOT) RNAV 29 - it has both minima blocks.
The bottom of page 14 of the document I originally referred you to (which you said you have read) provides background to the +V capability.
Last edited by ftrplt; 18th Mar 2018 at 01:36.
So, to bring back to the original argument,
There are very few ground based ILS to practice on. Currency can be maintained , as always, by flying approaches on approved synthetic devices.
LNAV+V is a 2D app flown as a 3D operation and ticks the box for 3D currency..(you learn something new every day
)
We are in the middle of a WAAS trial in Australia...it would be opportune if CASA would approve design of full LPV apps to even one aerodrome to ascertain valididty (...why, I do not know. Thousands of LPVs flown already in the US negates argument)
WAAS benefits all of Australia, not just aviation. WAAS saves lives!
There are very few ground based ILS to practice on. Currency can be maintained , as always, by flying approaches on approved synthetic devices.
LNAV+V is a 2D app flown as a 3D operation and ticks the box for 3D currency..(you learn something new every day
)We are in the middle of a WAAS trial in Australia...it would be opportune if CASA would approve design of full LPV apps to even one aerodrome to ascertain valididty (...why, I do not know. Thousands of LPVs flown already in the US negates argument)
WAAS benefits all of Australia, not just aviation. WAAS saves lives!
If I am standing at my hangar at bk and my iPhone says 60’ I know it is accurate.
But I let the autopilot fly the approach. Less workload. Less errors.
Are you suggesting that Garmin and Cessna have not thought out the +V approaches?
Can you tell me more about the iPhone SBAS Australian trials? Or is it a furphy ?
OZBUSDRIVER
This is happening later this year. 4 approaches with data have been provided for an operational trial and demo of what is possible. They're on it
This is a good point. SBAS is already a proven technology in aviation, so in theory there is little to do except implement them. Unfortunately the bean counters do not understand the technology and so it is in our best interest to demonstrate it to them.
.it would be opportune if CASA would approve design of full LPV apps to even one aerodrome to ascertain valididty
(...why, I do not know. Thousands of LPVs flown already in the US negates argument)
Thread Starter
Isn’t the cost of SBAS for Australia estimated at over $100m?
With Baro Vnav providing minimums only 100’ higher at near nil cost to the government I can see the way we will go.
With Baro Vnav providing minimums only 100’ higher at near nil cost to the government I can see the way we will go.
With Baro Vnav providing minimums only 100’ higher at near nil cost to the government I can see the way we will go.
Folks,
A little bit of history.
Almost twenty years ago, there was satellite coverage of Australia that was suitable for providing SBAS service. I forget which satellite operator it was, but PanAmSat comes to mind.
When Australia did not take up the offer, the satellite was moved in orbit further east to reinforce coverage of the west of the Americas and the eastern Pacific.
I equally well remember, at the time, being in a group discussion at a conference in Canberra on the subject, including the capital and running costs of the necessary two ground stations.
At the time the DoTaRS view was:
(1) Advances in GPS systems (as in the US system, not other mooted systems like Galileo) would largely negate the need for SBAS accuracy in terrestrial applications.
(2) Aviation was the only wide-scale use of SBAS which would still need SBAS with the advent of GPS 3 etc.
(3) As there was no possible cost recovery option to charge aviation, the Commonwealth would not support SBAS, just for aviation.
As far as I can see, nothing has changed, there are other options for centimeter accuracy for GPS in surveying etc, or high accuracy plowing of paddocks, or the many other uses of hi-precision position information.
Where it make commercial sense for major airlines, they have GBAS -- and the savings to airlines have nothing to do with more efficient and lower noise terminal area operations, but they should.
Tootle pip!!
PS: A junior officer of "The Department" present at the meeting above is now a very senior bureaucrat in "The Department", I wonder do they recall the meeting??
A little bit of history.
Almost twenty years ago, there was satellite coverage of Australia that was suitable for providing SBAS service. I forget which satellite operator it was, but PanAmSat comes to mind.
When Australia did not take up the offer, the satellite was moved in orbit further east to reinforce coverage of the west of the Americas and the eastern Pacific.
I equally well remember, at the time, being in a group discussion at a conference in Canberra on the subject, including the capital and running costs of the necessary two ground stations.
At the time the DoTaRS view was:
(1) Advances in GPS systems (as in the US system, not other mooted systems like Galileo) would largely negate the need for SBAS accuracy in terrestrial applications.
(2) Aviation was the only wide-scale use of SBAS which would still need SBAS with the advent of GPS 3 etc.
(3) As there was no possible cost recovery option to charge aviation, the Commonwealth would not support SBAS, just for aviation.
As far as I can see, nothing has changed, there are other options for centimeter accuracy for GPS in surveying etc, or high accuracy plowing of paddocks, or the many other uses of hi-precision position information.
Where it make commercial sense for major airlines, they have GBAS -- and the savings to airlines have nothing to do with more efficient and lower noise terminal area operations, but they should.
Tootle pip!!
PS: A junior officer of "The Department" present at the meeting above is now a very senior bureaucrat in "The Department", I wonder do they recall the meeting??