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Removal of DGA approaches

Old 11th May 2016, 12:28
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Removal of DGA approaches

I'll admit I was a bit shocked when I got the May amendment to DAPS to see the removal of several DGA approaches, in conjunction with the decommissioning of NAVAIDS.

I understand a DGA requires a NAVAID as a reference point, however I'd assumed an alternative, even the aerodrome itself as a GPS waypoint would suffice (I understand navaids can be offset by some distance but in the majority of instances, they aren't and could be resurveyed)

Did I miss something in the briefs from Airservices that these approaches would be removed in addition to the actual approaches associated directly with the Navaid?

Shannon
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Old 11th May 2016, 13:59
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Didn't know they were supposed to go, but a good idea still! Creating DGA approaches without a ground based aid would be an anachronism.
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Old 11th May 2016, 14:37
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Why would that be anachronistic. I actually think it would be forward thinking and flexible. DGAs are often a great help in IMC. Getting onto the 25 approaches in Albury is a real pain if just using LSALTs or MSAs. You either need to hold to get down or get high RODs. The DGA provides the flex to get down.


GPS can be used for stand alone approaches = why not for GPS arrivals?
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Old 11th May 2016, 14:38
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The concept of DGA where you have a you beaut GPS accurate to 0.3 nm for your distance and then rely on a wandering ADF needle pointing to a station that may not be within the confines of the airport boundary always had me wondering "why?".
Wouldn't it be possible to create an "approach" that would take you to a cloudbreak altitude ..below the 10 mile MSA and close to the circling minima ...based on a GPS track. Sectorised DGA's were ok with an NDB ...what's so bad about the lateral tracking of a GPS?
I know circling approaches are fast becoming persona non grata amongst the heavy metal but a circuit sometimes can be the most efficient way to effect a landing
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Old 11th May 2016, 15:08
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Originally Posted by rodney rude View Post
Why would that be anachronistic. I actually think it would be forward thinking and flexible. DGAs are often a great help in IMC. Getting onto the 25 approaches in Albury is a real pain if just using LSALTs or MSAs. You either need to hold to get down or get high RODs. The DGA provides the flex to get down.


GPS can be used for stand alone approaches = why not for GPS arrivals?
They already are, they may have made sense when CSIRO invented the Australian DME, and maybe made some sense until appropriate RNAV approaches could be developed, and the technology matured.

In the case of albury they clearly need some more RNAV approaches.
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Old 11th May 2016, 15:11
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Time to keep up with the times.

An RNAV approach is cheaper and more accurate, lining you up on finals at a lower minima. Surely this is more desirable than breaking visual in the 'vicinity' of the airport and visually manoeuvring to get on finals.
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Old 11th May 2016, 15:59
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Originally Posted by kumul1 View Post
Time to keep up with the times.

An RNAV approach is cheaper and more accurate, lining you up on finals at a lower minima. Surely this is more desirable than breaking visual in the 'vicinity' of the airport and visually manoeuvring to get on finals.
Cheaper??? Cheaper for who?

Flying into devonport from Hobart for example, with a east / west runway and inbound from the south - is going to add a lot of unnecessary track miles by doing a RNAV approach if it's say BKN at 2400'.

I have no issue in breaking visual in the vacinity of an Aerodrome and conducting a visual approach, a visual approach is cheaper to fly than a procedural approach
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Old 11th May 2016, 17:07
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In a C172 it may add an extra 2.5 mins in your example, approaching from the east or west and landing the opposite direction is more of an issue. That would add in the order of 30 + track miles.
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Old 11th May 2016, 23:19
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Many of the AUS RNP procedures used navaids as waypoints. Doesnt matter if it is operational or not, it is a waypoint defined with GPS coordinates.

https://www.airservicesaustralia.com...MLGN04-140.pdf
https://www.airservicesaustralia.com...SYGN05-142.pdf
https://www.airservicesaustralia.com...SYGL01-142.pdf

An RNAV approach is cheaper and more accurate,
That just depends on the constraints placed on the design. Due to environmental issues (ie, the screaming public) many are forced to be overlays, not allowing for short finals.
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Old 12th May 2016, 00:52
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RENURPP,

Couldn't you just do the RNAV for the opposite runway and then circle off the bottom as you would for a DGA?
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Old 12th May 2016, 01:44
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http://www.airservicesaustralia.com/...LIGN01-146.pdf

flying a cat c aircraft now has a minima of 1370 if you're going to land on the longest runway, with a requirement to stay to the west of the aerodrome ... that's going to be fun today with the wind

SPECI YFLI 120030Z AUTO 26033G44KT 9999 // SCT023 BKN030 OVC036 16/12 Q1003
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Old 12th May 2016, 02:06
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Dont let the truth get in the way of a good story.

The current DGA's at YFLI all come in from westerly directions. With todays weather most available options are not that good. Removal of the DGA's does make this situation worse.

I fail to see the point you are making..
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Old 12th May 2016, 02:25
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Don't you guys have Distance Steps your airways?

If I understand the DGA it's really just a step down procedure based on a track MSA. Distance steps on an airway achieve the same thing.

There's also TAA's which can be used in a similar fashion.
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Old 12th May 2016, 03:01
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yeah Apart from the 14 mile descent to 2100 feet allowed on the dga on the LT-FLI approach, meaning you'd be breaking visual, with less of a tailwind and less tracking than doing a RNAV

Likewise the 1400 descent at 20 miles on the DPO track
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Old 12th May 2016, 04:04
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I know circling approaches are fast becoming persona non grata amongst the heavy metal but a circuit sometimes can be the most efficient way to effect a landing
Just like to point out that they are not the same thing. Jets will always be doing visual circuits because as you point out they are the most efficient way of arriving and usually via the DME arrival.

'Circling approaches' are a whole different matter entirely.
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Old 12th May 2016, 04:35
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Couldn't you just do the RNAV for the opposite runway and then circle off the bottom as you would for a DGA
Yes, assuming there is no conflicting traffic and then only to circuit altitude in VMC. As discussed above we are not permitted to fly a circling approach.
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Old 12th May 2016, 08:09
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Just like to point out that they are not the same thing. Jets will always be doing visual circuits because as you point out they are the most efficient way of arriving and usually via the DME arrival.
What is the technical difference between the two?

ie what is stopping someone from conducting the RNAV approach down to the Straight in MDA and then conducting a "visual circuit".

Seems to be a bit of a grey area where you can call anything a "visual circuit" to circumvent the no circling area and circling approach MDA.

Or am I missing something?
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Old 12th May 2016, 09:28
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straight in mda is typically a lot lower than you'd comfortably circle at for a start.
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Old 12th May 2016, 09:46
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straight in mda is typically a lot lower than you'd comfortably circle at for a start
Clearly you'd climb if required to an altitude at which you are comfortable to fly a standard visual circuit.
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Old 12th May 2016, 10:06
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mike, whats your ifr background so that others may be able to help you with your understanding?
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