Reporting Distance as DME/GNSS

[Brakerider]

Hi All

What is the general consensus on reporting distance as GNSS/DME on CTAFs? I've always found it peculiar someone would bother reporting distance as 30 GNSS to Doomadgee, considering I don't ever recall a DME being installed there. 30 miles would suffice for me, I will make the assumption you're using a GPS to get that distance.

[gettin' there]

Hi All

What is the general consensus on reporting distance as GNSS/DME on CTAFs? I've always found it peculiar someone would bother reporting distance as 30 GNSS to Doomadgee, considering I don't ever recall a DME being installed there. 30 miles would suffice for me, I will make the assumption you're using a GPS to get that distance.

It's like you're reading my mind. I love "approximately 31 nautical miles GN double S".

[mcgrath50]

Have you determined you are 31nm from your GNSS or because you just flew over farmer bob's dam which is 3 thumb widths and a hair from the airport on the WAC? :ok:

Plus I was under the impression the AIP said to do it, but I'll that to someone who is annoyed by the use of "31 GNSS" to look that up.

[Lead Balloon]

The bigger question is: What is the source of the direction information?

I think the report should be: "Springfield traffic, ABC is three one miles, by gee enn ess ess (or e.g. Deduced reckoning), to the north west, by magnetic compass (or e.g. Directional Gyro) inbound, estimating circuit area two three, Springfield."

That results in substantially different decisions in my cockpit than if the report was merely: "Springfield traffic, ABC is three one miles to the north west inbound, estimating circuit area two three, Springfield." How can I possibly plan around that, if I can't figure out how you figured out where you are with reference to Springfield?

[travelator]

GNSS is Global Navigation Satellite System (GPS). Nothing to do with DME.

[The Green Goblin]

Provided the information references the ARP, and the pilot has an approval for the use of the GPS, it is endorsed in his/her logbook and the unit is certified for aviation use, then it is perfectly acceptable.

Personally I always said nm in CTAFs. Even in a jet. But that's just me.

You learn in this game your way isn't the only way, and there are many ways to get the job done within the rules safely.

[Capn Bloggs]

30 miles would suffice for me, I will make the assumption you're using a GPS to get that distance.
Agree! It doesn't matter where it comes from; if it's possibly not accurate (3 thumb widths+hair), then say "approximately".

That results in substantially different decisions in my cockpit than if the report was merely
?? Give us an example of where the distances could be so different at a location that would result in a "substantially different decision".

Unless it is a report to ATC IAW ENR 1.1 21.3.3, keep the R/T verbal-diarrhoea-free and use "miles".

[Cloud Cutter]

Wow, Bloggs, really?

Lead Balloon sums the whole thing up perfectly (USING SARCASM by the way) - it doesn't matter to the receiving station how you got the info - as long as it's accurate!!! :ok:

[Lead Balloon]

?? Give us an example of where the distances could be so different at a location that would result in a "substantially different decision".If the broadcast says the position is by reference to GNSS and DG, I will scratch my left arse cheek. If the report says the position is by reference to DR and magnetic compass, I will scratch my right arse cheek. :}

[Cloud Cutter]

Something really needs to be done about getting a 'like' button on this forum.

[Capn Bloggs]

Lapstrap undone, LB? :} :eek:

[Brakerider]

My understanding was it was only required to clarify the distance as DME/GNSS if there was a DME at the station you were reporting to, i.e. Tamworth for example. That was what I meant by the DME reference.

But great to know to know I'm not the only one!

[FoolCoarsePitch]

I always treat position broadcasts from randoms with great skepticism. When I hear GNSS I drop the skepticism. Actually, no, wait, I'm still skeptical AF.

[Squawk7700]

You learn in this game your way isn't the only way, and there are many ways to get the job done within the rules safely.

This is exceptionally good advice and many out there should take note :ok:

[Tinstaafl]

Oh, FFS, Leady! How could you get it so wrong? It should be your *right* arse cheek if by GNSS, and *left* arse cheek if by DR/compass/whatever.

Y'know, I used to respect your posts...until now.

[josephfeatherweight]

"Oztraya, mate!" - at its best! Never, ever, will you hear this ridiculous distinction overseas...

[Arm out the window]

estimating circuit area two three, Springfield."


You forgot about "by wristwatch."

[Ex FSO GRIFFO]

At the speed at which some of youse guys travel, by the time you said all of that, I would bet London to a brick, that you're now a whole lot closer to around 25 'miles' inbound....
And, 'we' all know that 'we' navigate in NM, don't we?

Like, in the ole AFIZ days, a jet reporting at '30miles' would generally take about 7 mins 'exactly' to reach circuit area.....

Give or take ten seconds or so.....

Cheers:}

[Lead Balloon]

Oh, FFS, Leady! How could you get it so wrong? It should be your *right* arse cheek if by GNSS, and *left* arse cheek if by DR/compass/whatever.I'm embarrassed to realise I'd mixed up the northern and southern hemispheres. In the southern hemisphere the rule is, of course: "Scratchy lefty turning north and scratchy righty turning south."

Another important point made by AOTW. As you know, AOTW, the timing references are increasingly diverse and so it is increasingly important to include the reference in the broadcast. "By wristwatch/iPhone/iPad [with statement of IOS version] /Android [with statement of device and operating system version] / etc." That will determine which nostril I pick.

[gerry111]

I've heard that Lead Balloon's primary time base, when flying is an elderly analogue clock radio. Apparently he listens to the AM radio "Shock Jocks" when in the cruise. It's a back up just in case the ADF goes bung.. :O

[Radix]

.............

[Capn Bloggs]

- GNSS is assumed these days
Unless I have set up the Fix page (and which I can't be stuffed doing when I have a nice DME showing me my MILES to the field), I don't have a "GNSS" distance direct to the field. :cool:

Use Nothing.
Sprouting radials or bearings and miles all with no names is not a smart idea.

If you insist on not saying "miles" then at least say "Thirty One"...:rolleyes:

[Radix]

.............

[AerocatS2A]

Doesn't matter. Same distance.


Technically it is not, but normally, for the purposes of CTAF calls, it doesn't matter. To illustrate the difference, in case you really don't know, at 6000' AGL and directly above the DME, a DME will display 1NM while the GNSS with the DME as the reference waypoint will display 0NM.

[GlenQuagmire]

yes but at a gps distance of 31nm you are 31.016D and nobody cares about the difference...

[gettin' there]

yes but at a gps distance of 31nm you are 31.016D and nobody cares about the difference...

What they said.

If it's an IFR aircraft they now have to have a GPS so it's use in a radio call at a bush CTAF with no DME is superfluous. Keep the call only as long as it needs to be.

[Car RAMROD]

And for the love of god please let us all know that it's nautical miles that you are reporting to stop any confusion with statute miles!

:}

[Lead Balloon]

And whether the estimated times are in local or zulu!

Safety, people.

Safety.

[Lead Balloon]

I think we can simplify the CTAF inbound broadcast requirement to:

Traffic [aerodrome] ABC is [state number] [nautical miles / statute miles / kilometres / other distance units], measured by [GNSS / DME / DR / WAG], [state direction referenced to aerodrome] measured by [DG / Mag Compass / DR / WAG], inbound on descent from [cruising altitude] with altimeter set to [QNH setting] and calibrated to [VFR / IFR] standards, estimating circuit area, by which I mean [overflying / joining crosswind / joining downwind / joining base / joining straight in approach] [nominate runway], at [nominate time] [local / UTC] by [wristwatch / GPS / WAG].

Simple. :ok:

[Bluemeaway]

I wonder about this sometimes,






Is it possible that in OCTA "gnss" is just a hangover from Reporting "GNSS" in CTA so that ATC can provide DME based Separation??


that and It sounds really cool :D

[+TSRA]

Just a stranger from another land poking his head in, but up here in Canada we have the same feeling - who cares. By the time I finish the transmission I'll be 5 miles closer.

However, we are told by Ottawa that there is indeed specific phraseology. Should we be reporting distance based on DME we shall use the phrase "30 DME from Sumspot VOR." If, however, the distance is based from GNSS we shall use the phrase "30 miles from Sumspot VOR" (Ref TC AIM COM 3.14.8).

That clears it up without having to say GNSS. I've not ever come across a pilot who uses statue in radio transmissions, so I'm sorry to hear some of you down under may have to deal with that.

Not sure if a bit of different perspective helps.

[AerocatS2A]

yes but at a gps distance of 31nm you are 31.016D and nobody cares about the difference...

As I said, normally it doesn't matter.

[Lead Balloon]

What are the abnormal circumstances in which it matters? :confused:

[Arm out the window]

It seems the advent of GNSS as the acronym for satellite nav rather than GPS has made it seem a bit sillier than usual.

We used to say '35 DME' or '35 GPS' (which I guess could make a bit of a difference if you're talking to centre who are then giving IFR traffic on you to someone, if the GPS reference point is the ARP and the DME is, well, the DME). In reality though, as has been aptly pointed out, it makes bugger all difference in the grand scheme of things.

[Lead Balloon]

In case anyone's interested in reality...

If someone makes a position report relative to an aerodrome, I'll assume:

- the position information is probably accurate, irrespective of what reference is being used,

- the position information might be 180 degrees wrong, and

- there is other traffic that's either not fitted with VHF, not using it, or on the wrong frequency.

[Pinky the pilot]

Reading the posts on this thread really makes me wonder.....

Fellow Aussie Ppruners; Just what is the problem here that takes so many posts on what is a simple procedure?:confused:

When you are inbound to wherever; If it has a DME, you are 'Three zero miles (or three zero DME) DME inbound from..."direction and intentions".'

If you are using a GPS; You are ....'Three zero miles GPS inbound from..etc.'

If it is an airfield with no navaid and you are not using a GPS you are

'Three zero miles inbound from...etc.'

Someone on this forum once posted, I thought at the time somewhat unkindly, that only Aussies could get 'so anal' over trivial bits of procedure. I now can see just what that poster was alluding to.:=

If my post offends anyone....Tough!:=

[wishiwasupthere]

If you are using a GPS; You are ....'Three zero miles GPS inbound from..etc.'

To be pedantic, it's actually 'three zero miles GNSS'.

[Derfred]

What do I say if I'm referencing an FMC position derived from triple IRS's with GNSS updating? :E

[AerocatS2A]

What are the abnormal circumstances in which it matters? :confused:

I don't know. If I said it never mattered, some schlub would come along and find some fringe case where it actually mattered.

[R755]

So what do all you experts do, when approaching a CTAF 'drome in South Australia?

"wun seven miles North, four thousand, on descent, estimate circuit LOCAL time zero three"

OR

"wun seven miles North, four thousand, on descent, estimate circuit ZULU time three three

[ShyTorque]

If you're getting your bottom chewing up the seat cushion over giving a position report to decimal places, I hope you're synchronising your watch and passing the data exactly to the second....

ATC will probably react like this..... :rolleyes:

[gerry111]

Those South Australians on CST may certainly put a cat amongst the pigeons if not on Zulu.


Pinky, This thread has been all about good Australian humour almost from the start.. :ok:


(The OP perhaps asked a rather inane question?)

[Car RAMROD]

What do I say if I'm referencing an FMC position derived from triple IRS's with GNSS updating?

You say exactly that! :ok:


Honestly I don't care where you are deriving your distance from and I won't broadcast where I'm getting mine from unless asked. If I though we are that close and it mattered, I'll ask.

AOTW I'm with you, "GPS" was so much easier to say than "GNSS". Hell even "RNAV" was easier than "GNSS"!!


Leadie, we have had some good banter but in this instance what you say below I couldn't agree more with!

If someone makes a position report relative to an aerodrome, I'll assume:

- the position information is probably accurate, irrespective of what reference is being used,

- the position information might be 180 degrees wrong, and

- there is other traffic that's either not fitted with VHF, not using it, or on the wrong frequency.

Can we all please start up the "left" or "leaving" a cruise level or the "turns" or "turning" base/final etc debate again after this? :E

[Hempy]

You of course are all aware that GPS (Global Positioning System - the American system of satellites) was superceded in nomenclature terms by GNSS (Global Navigation Satellite System) several years ago, right? Nothing changed, except GPS=GNSS. GPS/GNSS is used in lieu of DME....

[Tinstaafl]

"Cessna, Navajo, Space Shuttle, 15 south (or north or whatever), FL200 (shuttle example) descending, inbound". Accurate enough...

[Ex FSO GRIFFO]

Aw C'mon Pinky,

At the speeds at which you and I travel these days, it matters not whether you add a reference after the 'magic numbers', COZ, by the time you've finished it all, you are going to be a bit closer, and if I am the one in your way lookin' for ya, I won't care much if you're not 'xactly' 31.16 recurring, as long as I see you 'somewhere' at around the 30 nm mark OR SO, I'm happy...!!:8

Couldn't resist the 'tough'......:p

Cheers, LOTS of 'em....:ok: