Sector DME arrivals
Primarily because folks in other countries don't understand them and don't understand what we are trying to achieve with them. It's more fear of what you don't know.
DGA's really only work in Oz because our country is flat as a pancake. DGA's wouldn't really work in terrain challenging environments. LT, HB, CS and TL are about as difficult as it gets here.
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DGA's really only work in Oz because our country is flat as a pancake. DGA's wouldn't really work in terrain challenging environments. LT, HB, CS and TL are about as difficult as it gets here.
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Dr "Time was, many (most?) an IR renewal concluded with an asymmetric, limited panel, DME homing and let down!"
Great in GA but useless in a jet...my company doesn't permit its use...
"Alpha" –"DGA's really only work in Oz because our country is flat as a pancake. DGA's wouldn't really work in terrain challenging environments. LT, HB, CS and TL are about as difficult as it gets here.
I've used them to great effect in a jet plenty of times. Additionally, you effectively do one on most arrivals into D class airspace when you're cleared to XXXX' "not below the DME steps..." Admittedly not normally to a minima, but if you're doing it efficiently you still need to be aware of the limiting step.
I know that when I arrived in Australia from spending a good amount of time flying internationally based overseas, it took me a good while to get my head around DME arrivals. The main reason was that I wasn't used to an 'approach' that didn't end up with you runway aligned (or very close to it). I remember my first approach into Launceston in a jet and trying to figure out why if you flew the DME arrival as published it would take you out of OCTA, It seemed madness to me that you had to position yourself in a high position and then do a 'dirty' dive to try and get visual so you could then break off and self position for the opposite runway when the is a perfectly good procedural arrival to the ILS. The training Captain told me it saved time and therefore money to get visual for the circuit, I am still not sure this is the case when you have to slow so much to take into account the CTA steps. There is a major difference between flying in Australia and the rest of the world and it seems to be that Australian RPT jet operations still have a good amount of GA mentality attached. The rest of the world has moved on, due to airspace congestion / safety etc. every time this is mentioned in OZ you get all the incredulous comments about 'not wanting to handfly ECT' when in reality a mature and safe system doesn't want you flinging a heavy jet around at low altitude WHEN THERE IS AN ALTERNATIVE. DME arrivals are great tools for the GA piston crowd but shouldn't be a first choice approach for RPT jets.
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I remember my first approach into Launceston in a jet and trying to figure out why if you flew the DME arrival as published it would take you out of OCTA, It seemed madness to me that you had to position yourself in a high position and then do a 'dirty' dive to try and get visual so you could then break off and self position for the opposite runway when the is a perfectly good procedural arrival to the ILS.
I do plenty of DGA's and ILS's into Launy (admittedly in a Dash-8) via overhead Devonport and I'd be hesitant to call the ILS approach "perfectly good".
From my POV, a DGA that gets me visual above circuit height to break right for a left circuit into Launy is around 5 min quicker than the ILS. The final limiting step is 2300' at 5Nm, which is only 200' above circuit height so not much dirty diving involved to join downwind for 32L.
Having said all that I agree with your comments wrt GA mentality in Oz.
DIVOSH!
DIVOSH!
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Many parts of the world use something similar to the Australian DGA. Minimum vectoring altitude charts, manoeuvring charts, "MRA" charts in NZ, and so on.
The difference is that Australia wants them treated as an approach, implying speed limits and FAFs and missed approach procedures.
I think they're a fantastic tool to get visual below cloud, in the circuit vicinity. Be at whatever speed and configuration you like, ready to convert to a visual approach when ready.
What I don't like is using them as a pseudo-approach, down to well below circuit height and needing to be configured and slow (but not runway aligned) before getting visual.
Not irrelevantly, there's also the cost of an extra "approach" type to be kept current...
Happy DGA-ing, anyway!
O8
The difference is that Australia wants them treated as an approach, implying speed limits and FAFs and missed approach procedures.
I think they're a fantastic tool to get visual below cloud, in the circuit vicinity. Be at whatever speed and configuration you like, ready to convert to a visual approach when ready.
What I don't like is using them as a pseudo-approach, down to well below circuit height and needing to be configured and slow (but not runway aligned) before getting visual.
Not irrelevantly, there's also the cost of an extra "approach" type to be kept current...
Happy DGA-ing, anyway!
O8
'08' i hear where ya coming from but I can see why they are classified as an App.
Don't 4get most here are ref to the dist side of this procedure but as we all know there are lateral req's also be that Sat based Nav or Grnd based Nav to be taking into consideration hence it comes under the heading of an App especially after FF5 Nm (no maouvering).ALL App's have a Lat Nav req so this proc is no diff.
The speed side of it is often due the type of drome yr coming into (if that be the case) so 'any speed you like' wouldn't apply at some places hence a std has been developed for all DGA's.
The fact that you are allowed below normal circuit height off a DGA is to do what ALL Approaches where designed for in the first place, to effect a Ldg that's the whole idea of any App. Also you can obviously go down to the Cat circling height at any time in day VMC after a DGA to the Min where you where initially Viz. The thought of flying a Cat C machine at 400ft in the circuit would be real fun
Anyway I think the concept is great for a cloud break proc.
Wmk2
Don't 4get most here are ref to the dist side of this procedure but as we all know there are lateral req's also be that Sat based Nav or Grnd based Nav to be taking into consideration hence it comes under the heading of an App especially after FF5 Nm (no maouvering).ALL App's have a Lat Nav req so this proc is no diff.
The speed side of it is often due the type of drome yr coming into (if that be the case) so 'any speed you like' wouldn't apply at some places hence a std has been developed for all DGA's.
The fact that you are allowed below normal circuit height off a DGA is to do what ALL Approaches where designed for in the first place, to effect a Ldg that's the whole idea of any App. Also you can obviously go down to the Cat circling height at any time in day VMC after a DGA to the Min where you where initially Viz. The thought of flying a Cat C machine at 400ft in the circuit would be real fun
Anyway I think the concept is great for a cloud break proc.
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Wally, the lateral navigation and speed requirements are strict because the procedure is designed to get down to 500' agl or so, terrain permitting. For that, you need FAFs, MDAs, "PANS-Ops" speeds, the whole nine yards.
Lose the idea of 500', think 1500' to 2000' agl (in other words, lose the part between FAF and MAPt).
Then you'd not need all the other niceties that go with an approach; it would just be a manoeuvring chart like any other, with lateral and vertical navigation appropriate to an Arrival (which is not the same as an Approach).
Of course, many people in the regions would be inconvenienced by being unable to descend in IMC below ~1500' agl on a DGA!
But that is the key difference between an Arrival via manoeuvring chart (anywhere in the world) and an Approach via a somewhat mis-named DME/GNSS Arrival (which is actually an Approach).
The OP, Inboard Flap, might be better thinking of a DGA as a sector arrival up until 5nm or so, then it becomes a non-precision approach like any other. Not quite true, but almost so!
Lose the idea of 500', think 1500' to 2000' agl (in other words, lose the part between FAF and MAPt).
Then you'd not need all the other niceties that go with an approach; it would just be a manoeuvring chart like any other, with lateral and vertical navigation appropriate to an Arrival (which is not the same as an Approach).
Of course, many people in the regions would be inconvenienced by being unable to descend in IMC below ~1500' agl on a DGA!
But that is the key difference between an Arrival via manoeuvring chart (anywhere in the world) and an Approach via a somewhat mis-named DME/GNSS Arrival (which is actually an Approach).
The OP, Inboard Flap, might be better thinking of a DGA as a sector arrival up until 5nm or so, then it becomes a non-precision approach like any other. Not quite true, but almost so!
DME was an Australian invention from the 1950s with application in the terminal area and as an enroute nav aid. In its heyday (long before GPS) enroute nav aids were fairly sparse - being VARs at capital city airfields and a scattering of NDBs. IFR enroute fix requirements could be met with an NDB at each end of track or an NDB at one end and a DME at the other.... if you could track on the DME. This is why the DME homing procedure was used and a logical extention of tracking in on a DME was to develop a cloud break procedure, which became the "DME descent".
So enroute Nav requirements could be met on the leg DN-MGD with dual ADFs (and two lots of ADF errors) or an ADF and a DME (which gave you track & distance and you could calculate ground speed). If you wanted to get visual, then do an ADF approach. But if your ADF or the NDB failed then you could use the published DME descent procedure (not to be confused with the DME arrival procedure).
Halas you probably were the last one, if you did homings in the 90s. We were still doing DME descents at Darwin for renewals late 80s-early 90s, but I never did one in anger.
All this is explained here DME Operational Notes
So enroute Nav requirements could be met on the leg DN-MGD with dual ADFs (and two lots of ADF errors) or an ADF and a DME (which gave you track & distance and you could calculate ground speed). If you wanted to get visual, then do an ADF approach. But if your ADF or the NDB failed then you could use the published DME descent procedure (not to be confused with the DME arrival procedure).
Halas you probably were the last one, if you did homings in the 90s. We were still doing DME descents at Darwin for renewals late 80s-early 90s, but I never did one in anger.
All this is explained here DME Operational Notes
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Strahan was a typical use of DME homing. The NDB had a range of 30 miles, was difficult to track in weather. We could pickup the DME at about 75 miles and conduct the homing to overhead, and, if not visual conduct the DME approach.
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I was going to say my understanding of DME Homing was to provide another approach alternative in case of NDB failure, however pithblot's link seems to have slightly better reasoning under Homing and Descent Procedures. Meets the requirement of two independent nav aids.
Don't get the issue towards DME ARR for jet ops, a 'long' gone domestic jet operator used that quite a bit throughout WA and if you knew what you were doing (meaning trained) it worked quite well.
Don't get the issue towards DME ARR for jet ops, a 'long' gone domestic jet operator used that quite a bit throughout WA and if you knew what you were doing (meaning trained) it worked quite well.
