Surely LNAV+V must be safer?
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In 2013 ICAO published the first PBN manual, which finally introduced a global standard to the myriad of terms used to describe the approaches formally known only as GPS approaches. It introduced the concept of approaches with vertical guidance or APV. Baro Vnav is one, LPV is another. Industry and all regulators are still trying to comply with the ICAO guidance, hence some non standard terms floating around. You need to check what your installation is set up to do, not what is written in the salesman’s glossy brochure. Read the AFM and the respective supplement, if unsure contact the owner if the STC. If if doesn’t say anything about Baro Vnav , don’t descend below the LNAV minima.
No Dick. I'm not answering your question because the answer is in the manual for your equipment, that you clearly haven't read.
It is a combination of your equipment and how it interprets the coding of the approach, which then gets wrapped around live data at the time of flying.
Its not a hard coded, fixed point. It is interpolated. And because different nav systems all do it with different logic the result will be slightly different each time.
No one is saying you cant use it, and no one is saying its not safer. The only thing we are trying point out is its advisory, not guidance and that is why the CAAP makes no mention of it.
Your welcome
It is a combination of your equipment and how it interprets the coding of the approach, which then gets wrapped around live data at the time of flying.
Its not a hard coded, fixed point. It is interpolated. And because different nav systems all do it with different logic the result will be slightly different each time.
No one is saying you cant use it, and no one is saying its not safer. The only thing we are trying point out is its advisory, not guidance and that is why the CAAP makes no mention of it.
Your welcome
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Dick,
I found a CASA document which explains some of the questions you are asking. It is titled ‘CASA’s methodology for validation of Baro-VNAV instrument approaches’ August 2016.
My reading of your first post implies that you want a seperate RNAV approach called the LNAV + V. There is either LNAV/VNAV (Baro-VNAV) or LNAV. LNAV + V is an additional feature of your avionics which provides vertical flight path advisory in the form of glide slope indications to the LNAV approach. Therefore; if you’re lucky enough to have this feature fitted, then by all means use it. As you noted, nobody is saying you can’t do this.
But at the end of the day, you are flying an LNAV approach and need to abide by all the requirements (step heights).
The problem with adding LNAV/VNAV approaches everywhere is that the requirements are more onerous, and thus more expensive. Specifically, 3.4.3 Obstacle monitoring and aerodrome operators (of the above article) notes the additional ground surveys or aerodrome management training required.
In addition I believe (reference not handy) LNAV/VNAV requires a local source of QNH - therefore an AWIS/ATIS etc fitted at the aerodrome.
Also noted in the above document is paragraph 6.2 Flyability and navigation database coding. Paragraph ‘LNAV coding of VNAV path angle’ indicates how coders (Garmin) design the advisory vertical guidance.
If you wouldn’t fly your LNAV/VNAV off your glideslope, then how do you fly your ILS approaches? Somewhat a rhetorical question as I think the hang up is on the use of the word ‘solely’.
I found a CASA document which explains some of the questions you are asking. It is titled ‘CASA’s methodology for validation of Baro-VNAV instrument approaches’ August 2016.
My reading of your first post implies that you want a seperate RNAV approach called the LNAV + V. There is either LNAV/VNAV (Baro-VNAV) or LNAV. LNAV + V is an additional feature of your avionics which provides vertical flight path advisory in the form of glide slope indications to the LNAV approach. Therefore; if you’re lucky enough to have this feature fitted, then by all means use it. As you noted, nobody is saying you can’t do this.
But at the end of the day, you are flying an LNAV approach and need to abide by all the requirements (step heights).
The problem with adding LNAV/VNAV approaches everywhere is that the requirements are more onerous, and thus more expensive. Specifically, 3.4.3 Obstacle monitoring and aerodrome operators (of the above article) notes the additional ground surveys or aerodrome management training required.
In addition I believe (reference not handy) LNAV/VNAV requires a local source of QNH - therefore an AWIS/ATIS etc fitted at the aerodrome.
Also noted in the above document is paragraph 6.2 Flyability and navigation database coding. Paragraph ‘LNAV coding of VNAV path angle’ indicates how coders (Garmin) design the advisory vertical guidance.
If you wouldn’t fly your LNAV/VNAV off your glideslope, then how do you fly your ILS approaches? Somewhat a rhetorical question as I think the hang up is on the use of the word ‘solely’.
I don't understand the issue here? Use the VNAV guidance but compare it to the plate steps for accuracy and safety with the relevant minima...
Where is the argument or point here? Even your favourite operator of all time Dick does it that way ^
Where is the argument or point here? Even your favourite operator of all time Dick does it that way ^
Thread Starter
The point is that CASA has not once recommended that pilots perform the almost zero cost upgrade of Garmin 650/750 units to allow +V operations.
Whenever I have suggested this they rave on about how other systems are better!
Try and show me one CASA statement that recommends upgrading to +v. You won’t find one Why?
Whenever I have suggested this they rave on about how other systems are better!
Try and show me one CASA statement that recommends upgrading to +v. You won’t find one Why?
Dick, I'm not sure it's CASA's role to monitor every gadget known to aviation and suggest to pilots that they get it modified.
If the pilots are so detached from the equipment they are using that they aren't seeking improvements (especially if they are doing LNAVs for real) and the manufacturers are too lazy to advise pilots when this stuff is available, why should CASA do it?
I would become mildly annoyed pretty quickly if my inbox starts getting emails from CASA with "You should update your Garmin XXX because of this!".
That's why.
Take ownership of your operation and equipment. It is your responsibility to know.
If the pilots are so detached from the equipment they are using that they aren't seeking improvements (especially if they are doing LNAVs for real) and the manufacturers are too lazy to advise pilots when this stuff is available, why should CASA do it?
I would become mildly annoyed pretty quickly if my inbox starts getting emails from CASA with "You should update your Garmin XXX because of this!".
That's why.
Take ownership of your operation and equipment. It is your responsibility to know.
Thread Starter
Bloggs. I am clearly mistaken.
I understood that with CASA the “most important consideration should be safety”
Why not a simple mention in the Directors newsletter that CASA recommends +V as a safety improvement instead of being completely obsessed with pushing for $150 million SBAS that is many years away?
I understood that with CASA the “most important consideration should be safety”
Why not a simple mention in the Directors newsletter that CASA recommends +V as a safety improvement instead of being completely obsessed with pushing for $150 million SBAS that is many years away?
Bloggs. I am clearly mistaken.
I understood that with CASA the “most important consideration should be safety”
Why not a simple mention in the Directors newsletter that CASA recommends +V as a safety improvement instead of being completely obsessed with pushing for $150 million SBAS that is many years away?
I understood that with CASA the “most important consideration should be safety”
Why not a simple mention in the Directors newsletter that CASA recommends +V as a safety improvement instead of being completely obsessed with pushing for $150 million SBAS that is many years away?
WAAS for Australia – you heard it here first!
Thread Starter
Yep. That was I.
Since then the price appears to have gone from $50 to $150 m and Baro VNAV does almost the same job at hardly any cost..
A post on the previous thread said. “ airlines don’t need WAAS so will not willingly pay for it”
Sounds logical to me.
But I would like to see a proper cost benefit study that also
looks at the non aviation users.
Since then the price appears to have gone from $50 to $150 m and Baro VNAV does almost the same job at hardly any cost..
A post on the previous thread said. “ airlines don’t need WAAS so will not willingly pay for it”
Sounds logical to me.
But I would like to see a proper cost benefit study that also
looks at the non aviation users.
Baro VNAV does almost the same job at hardly any cost
However, please do not get me wrong, I am not saying that the LNAV+V is not somewhat beneficial in being an aid to situational awareness, just as long as it is not followed on blind faith that it will meet the requirements of keeping you above the steps of an approach.
Thread Starter
I wasn’t referring to LNAV +V. I was referring to Baro VNAV. Which I understand are very similar to an ILS.
At places like Mildura you can already get a 300’ minima. Incredible
At places like Mildura you can already get a 300’ minima. Incredible
Dick,
Baro VNAV is very onerous for both the pilot and owner of the aircraft. Here is an extract from a recent CASA Flight Safety article:
Crew training
As well as having a suitably equipped aircraft, each member of the flight crew must have a current instrument approach procedure endorsement. This includes approved training in how to safely conduct a baro-VNAV operation, including:
use of baro-VNAV instrument approach charts, including LNAV/VNAV minimums, temperature limitations, and vertical flight path angle
principles of baro-VNAV vertical guidance, including path display and depiction and the effect of temperature
use of MDA and DA for LNAV and LNAV/VNAV minimums respectively
approach procedure selection from the relevant onboard navigation database
barometric pressure (QNH) selection (altimeter subscale setting), and cross checking and verification procedures, including effect of incorrect setting
VNAV mode selection and monitoring
VNAV failure modes and mode reversions
VNAV flight tolerances.
Other requirements
the GNSS navigation database must be valid, and the entire approach procedure capable of being loaded into the system
the pilot must verify that the approach in the system is in accordance with the approach chart
for two-pilot operations, the same barometric altitude from two independent sources must be displayed, and one must be in each pilot’s primary field of view
the aerodrome must have a promulgated ICAO PANS-OPS design-compliant baro-VNAV approach procedure
the aerodrome needs to have accurate aerodrome QNH and temperature available through either an aerodrome air traffic service, an aerodrome weather information services (AWIS) or automatic terminal information services (ATIS).
Approved approaches:
The Airservices Australia website lists aerodromes at which baro-VNAV approaches have been approved, validated or are planned. It also shows locations at which baro-VNAV approaches cannot be made, because the aerodrome has an unsuitable approach alignment, has been deregistered or has no local QNH or temperature available.
Where a baro-VNAV approach is available, the RNAV GNSS chart will specify that the aerodrome QNH and temperature are required, and the temperature range under which the procedure can be flown. For the RNAV GNSS RWY 32L approach at Launceston, for example, the temperature range is minus 5 to plus 61 degrees Celsius.
The actual path flown by the aircraft will depend on the ambient air density. A temperature higher than ISA will result in a steeper approach path; conversely temperatures lower than ISA will result in a lower descent profile. Where temperature and aerodrome QNH are temporarily unavailable, the LNAV-only approach must be used.
So when it comes to GNSS approaches—don’t ‘push your own baro’. If you want vertical guidance, make sure you are properly equipped, trained and that the approach is approved for where you’re going.
Airservices will also have a vested interest in this:
The implementation of Baro-VNAV approaches is to be funded through normal industry cost recovery arrangements administered by Airservices using the same mechanism as that used to fund procedures maintenance.
Baro VNAV will not be permitted at aerodromes without an AWIS and those that do will not necessarily have much lower minimums than LNAV. The aircraft barometric system will also have to be compliant.
SBAS will not require any of this b******t. Modern navigators have this capability already, most if not all minima are 200' and all the pilot needs is a 3D endorsement.
WAAS is the US version of SBAS and is far superior to Baro VNAV. It is possibly an option over there, but I do not read of anyone using it.
As I type the Government is requesting submissions from aviation interests for the 2019 budget. GeoScience wants it and if we are blasé about this then SBAS will be available for other industries, but not for aviation due to further certification requirements. Just because the airlines have their collective heads up their a**e over this does not make it right.
If you would like the appropriate person to contact regarding this then please PM me. You probably know him already.
Please put your efforts toward SBAS.
Baro VNAV is very onerous for both the pilot and owner of the aircraft. Here is an extract from a recent CASA Flight Safety article:
Crew training
As well as having a suitably equipped aircraft, each member of the flight crew must have a current instrument approach procedure endorsement. This includes approved training in how to safely conduct a baro-VNAV operation, including:
use of baro-VNAV instrument approach charts, including LNAV/VNAV minimums, temperature limitations, and vertical flight path angle
principles of baro-VNAV vertical guidance, including path display and depiction and the effect of temperature
use of MDA and DA for LNAV and LNAV/VNAV minimums respectively
approach procedure selection from the relevant onboard navigation database
barometric pressure (QNH) selection (altimeter subscale setting), and cross checking and verification procedures, including effect of incorrect setting
VNAV mode selection and monitoring
VNAV failure modes and mode reversions
VNAV flight tolerances.
Other requirements
the GNSS navigation database must be valid, and the entire approach procedure capable of being loaded into the system
the pilot must verify that the approach in the system is in accordance with the approach chart
for two-pilot operations, the same barometric altitude from two independent sources must be displayed, and one must be in each pilot’s primary field of view
the aerodrome must have a promulgated ICAO PANS-OPS design-compliant baro-VNAV approach procedure
the aerodrome needs to have accurate aerodrome QNH and temperature available through either an aerodrome air traffic service, an aerodrome weather information services (AWIS) or automatic terminal information services (ATIS).
Approved approaches:
The Airservices Australia website lists aerodromes at which baro-VNAV approaches have been approved, validated or are planned. It also shows locations at which baro-VNAV approaches cannot be made, because the aerodrome has an unsuitable approach alignment, has been deregistered or has no local QNH or temperature available.
Where a baro-VNAV approach is available, the RNAV GNSS chart will specify that the aerodrome QNH and temperature are required, and the temperature range under which the procedure can be flown. For the RNAV GNSS RWY 32L approach at Launceston, for example, the temperature range is minus 5 to plus 61 degrees Celsius.
The actual path flown by the aircraft will depend on the ambient air density. A temperature higher than ISA will result in a steeper approach path; conversely temperatures lower than ISA will result in a lower descent profile. Where temperature and aerodrome QNH are temporarily unavailable, the LNAV-only approach must be used.
So when it comes to GNSS approaches—don’t ‘push your own baro’. If you want vertical guidance, make sure you are properly equipped, trained and that the approach is approved for where you’re going.
Airservices will also have a vested interest in this:
The implementation of Baro-VNAV approaches is to be funded through normal industry cost recovery arrangements administered by Airservices using the same mechanism as that used to fund procedures maintenance.
Baro VNAV will not be permitted at aerodromes without an AWIS and those that do will not necessarily have much lower minimums than LNAV. The aircraft barometric system will also have to be compliant.
SBAS will not require any of this b******t. Modern navigators have this capability already, most if not all minima are 200' and all the pilot needs is a 3D endorsement.
WAAS is the US version of SBAS and is far superior to Baro VNAV. It is possibly an option over there, but I do not read of anyone using it.
As I type the Government is requesting submissions from aviation interests for the 2019 budget. GeoScience wants it and if we are blasé about this then SBAS will be available for other industries, but not for aviation due to further certification requirements. Just because the airlines have their collective heads up their a**e over this does not make it right.
If you would like the appropriate person to contact regarding this then please PM me. You probably know him already.
Please put your efforts toward SBAS.
Last edited by Jenna Talia; 14th Apr 2018 at 12:10.
Thread Starter
You are correct. I should have kept my ndb approach rating current!
I am sure you agree that it will depend on a proper and honest cost benefit study.
But I wonder if the $150 million was spent on subsidising the flying and LAME training industry if we would get greater long term safety results?
The best expert I know is Ian Mallet. I talk to him regularly and respect his advice.
He hasn’t yet got the cost benefit figures for the whole of our country. Do you?
I am sure you agree that it will depend on a proper and honest cost benefit study.
But I wonder if the $150 million was spent on subsidising the flying and LAME training industry if we would get greater long term safety results?
The best expert I know is Ian Mallet. I talk to him regularly and respect his advice.
He hasn’t yet got the cost benefit figures for the whole of our country. Do you?
The best expert I know is Ian Mallet. I talk to him regularly and respect his advice.
He hasn’t yet got the cost benefit figures for the whole of our country. Do you?
He hasn’t yet got the cost benefit figures for the whole of our country. Do you?
Sorry but I don't have any such figures. All aviation interests need to get going with this, as Ian will tell you, this is our last chance to have SBAS. Ben at AOPA is now onto this as well.
20 years ago Australia was a world leader in GNSS, now we are so far behind due to past governments who did not give a rat's.
Are you accessing a GPS RAIM availability brief for the appropriate time period, prior to flying the approach ?
Thread Starter
Yes. In the last few years RAIM has always been available for the approach’s I have done.
Could that be because there are so many satellites these days?
Could that be because there are so many satellites these days?
Originally Posted by Dick Smith
Is there any reason why the chart does not use the words “ Baro VNAV “ so it is clear that’s what it is?