Multicom vs area frequency
)
Join Date: Jun 2008
Location: Perth
Posts: 133
Likes: 0
Received 0 Likes
on
0 Posts
Surely we have enough frequencies left over for each aerodrome to have its own discrete frequency rather than a big multicom?
And for places where multiple strips are in proximity just give them an area multicom.
At 5000 feet, VHF is about 60NM.
So let's say any given place has 20 discrete frequencies dedicated to high level comms and you can't reallocate them within 400NM, this leaves
At 25Khz spacing, we have 760 channels to choose from.
At 50Khz spacing, we have 360 channels to choose from.
How many strips exist?
Country airstrip guide has a total of about 1900 airstrips.
NSW about 310
NT has 182
QLD has 595
SA has 178
TAS has 64
VIC has 143
WA has 382
"AOPA Airfield directory" says about 2000 (ERSA plus unlicensed).
At 25Khz spacing I really think we have enough for every airstrip to have a discrete frequency including "farmer joe's paddock".
I'd be happy with mandatory radio calls required for operations at an aerodrome plus ops 0-2500ft AGL within X NM of aerodrome are required to tune into said aerodrome.
Really we need avionics to come into the 21st century where you just press a button for GPS-linked "choose suitable frequency button".
Or, better yet, a transmit-and-store mechanism built into avionics that lets multiple people speak simultaneously and transmissions "keyed" by various items such as callsign (eg. adsb ID). Aircraft have two transmit buttons - one for ATC direct comms and the other for broadcast. Let's also have a "replay" button in case you want to re-hear that again.
But I digress!
And for places where multiple strips are in proximity just give them an area multicom.
At 5000 feet, VHF is about 60NM.
So let's say any given place has 20 discrete frequencies dedicated to high level comms and you can't reallocate them within 400NM, this leaves
At 25Khz spacing, we have 760 channels to choose from.
At 50Khz spacing, we have 360 channels to choose from.
How many strips exist?
Country airstrip guide has a total of about 1900 airstrips.
NSW about 310
NT has 182
QLD has 595
SA has 178
TAS has 64
VIC has 143
WA has 382
"AOPA Airfield directory" says about 2000 (ERSA plus unlicensed).
At 25Khz spacing I really think we have enough for every airstrip to have a discrete frequency including "farmer joe's paddock".
I'd be happy with mandatory radio calls required for operations at an aerodrome plus ops 0-2500ft AGL within X NM of aerodrome are required to tune into said aerodrome.
Really we need avionics to come into the 21st century where you just press a button for GPS-linked "choose suitable frequency button".
Or, better yet, a transmit-and-store mechanism built into avionics that lets multiple people speak simultaneously and transmissions "keyed" by various items such as callsign (eg. adsb ID). Aircraft have two transmit buttons - one for ATC direct comms and the other for broadcast. Let's also have a "replay" button in case you want to re-hear that again.
But I digress!
Join Date: Apr 2008
Location: Australia
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
In light of various claims of folklore and nothing having changed, I figured I would dig out an old AIP and compare. I had one from 2010, which is probably a good age - not prehistoric, but old enough to be prior to the current set of changes.
There are 2 sections dealing with the CTAF frequency - Climb and Cruise Procedures, and Procedures at Non-Towered Aerodromes.
2010 AIP
OPERATIONS IN CLASS G AIRSPACE - CLIMB AND CRUISE PROCEDURES
A pilot of a flight intending to operate in the vicinity of a non-towered aerodrome at altitudes used by arriving and departing aircraft should:
a) monitor the appropriate CTAF, and broadcast by 10NM or earlier
It does not specify the appropriate CTAF but it is obviously the aerodrome CTAF
CLASS G AIRSPACE - The Common Traffic Advisory Frequency (CTAF) and procedures at non-towered aerodromes
The CTAF is the frequency on which pilots operating at a non-towered aerodrome should make positional radio broadcasts. If a discrete frequency is not listed use Multicom 126.7MHZ.
Pretty clear - if no other frequency is listed, use Multicom 126.7. No mention of whether or not the aerodrome is marked on charts, or the area frequency.
6 MAR 2014 AIP
OPERATIONS IN CLASS G AIRSPACE - CLIMB AND CRUISE PROCEDURES
Pilots of radio-equipped VFR aircraft must listen out on the appropriate VHF frequency and announce if in potential conflict.
The appropriate VHF frequency is:
a) in the vicinity of an aerodrome depicted on aeronautical charts, with a discrete frequency, the discrete CTAF shown.
b) in the vicinity of an aerodrome depicted on aeronautical charts, with no discrete frequency, the CTAF 126.7
c) in all other cases the FIA frequency
OK, here we have the aeronautical charts and area frequency appearing.
CLASS G AIRSPACE - The Common Traffic Advisory Frequency (CTAF) and procedures at non-towered aerodromes
The CTAF is the frequency on which pilots operating at a non-towered aerodrome should make positional radio broadcasts. If a discrete frequency is not listed use Multicom 126.7MHZ.
No change to procedures at non-towered aerodromes - still use 126.7!
21 AUG 14 AIP
OPERATIONS IN CLASS G AIRSPACE - CLIMB AND CRUISE PROCEDURES
Pilots of radio-equipped VFR aircraft must listen out on the appropriate VHF frequency and announce if in potential conflict.
The appropriate VHF frequency is:
a) in the vicinity of an aerodrome depicted on aeronautical charts, with a discrete frequency, the discrete CTAF shown.
b) in the vicinity of an aerodrome depicted on aeronautical charts, with no discrete frequency, the CTAF 126.7
c) in all other cases Area VHF
No significant difference from 6 MAR 2014.
CLASS G AIRSPACE - The Common Traffic Advisory Frequency (CTAF) and procedures at non-towered aerodromes
Entire section is deleted!
My observations:
It definitely has changed - even 6 March 2014 clearly says that 126.7 should be used if no frequency is listed. The distinction between marked an unmarked strips is only in the climb and cruise procedures, not operations at the airfield.
There are 2 sections dealing with the CTAF frequency - Climb and Cruise Procedures, and Procedures at Non-Towered Aerodromes.
2010 AIP
OPERATIONS IN CLASS G AIRSPACE - CLIMB AND CRUISE PROCEDURES
A pilot of a flight intending to operate in the vicinity of a non-towered aerodrome at altitudes used by arriving and departing aircraft should:
a) monitor the appropriate CTAF, and broadcast by 10NM or earlier
It does not specify the appropriate CTAF but it is obviously the aerodrome CTAF
CLASS G AIRSPACE - The Common Traffic Advisory Frequency (CTAF) and procedures at non-towered aerodromes
The CTAF is the frequency on which pilots operating at a non-towered aerodrome should make positional radio broadcasts. If a discrete frequency is not listed use Multicom 126.7MHZ.
Pretty clear - if no other frequency is listed, use Multicom 126.7. No mention of whether or not the aerodrome is marked on charts, or the area frequency.
6 MAR 2014 AIP
OPERATIONS IN CLASS G AIRSPACE - CLIMB AND CRUISE PROCEDURES
Pilots of radio-equipped VFR aircraft must listen out on the appropriate VHF frequency and announce if in potential conflict.
The appropriate VHF frequency is:
a) in the vicinity of an aerodrome depicted on aeronautical charts, with a discrete frequency, the discrete CTAF shown.
b) in the vicinity of an aerodrome depicted on aeronautical charts, with no discrete frequency, the CTAF 126.7
c) in all other cases the FIA frequency
OK, here we have the aeronautical charts and area frequency appearing.
CLASS G AIRSPACE - The Common Traffic Advisory Frequency (CTAF) and procedures at non-towered aerodromes
The CTAF is the frequency on which pilots operating at a non-towered aerodrome should make positional radio broadcasts. If a discrete frequency is not listed use Multicom 126.7MHZ.
No change to procedures at non-towered aerodromes - still use 126.7!
21 AUG 14 AIP
OPERATIONS IN CLASS G AIRSPACE - CLIMB AND CRUISE PROCEDURES
Pilots of radio-equipped VFR aircraft must listen out on the appropriate VHF frequency and announce if in potential conflict.
The appropriate VHF frequency is:
a) in the vicinity of an aerodrome depicted on aeronautical charts, with a discrete frequency, the discrete CTAF shown.
b) in the vicinity of an aerodrome depicted on aeronautical charts, with no discrete frequency, the CTAF 126.7
c) in all other cases Area VHF
No significant difference from 6 MAR 2014.
CLASS G AIRSPACE - The Common Traffic Advisory Frequency (CTAF) and procedures at non-towered aerodromes
Entire section is deleted!
My observations:
- Each Climb and Cruise procedures section specifies the frequency that the pilot should be listening to, not broadcasting on.
- The initial change appears to be trying to say that, in climb and cruise, if the aerodrome is not marked on charts you should be listening to area not 126.7 - which seems reasonable as these would normally be low traffic airfields.
- This seems to have created some confusion because of a perceived requirement to that aircraft in climb or cruise should be receiving broadcasts from aircraft operating at unmarked strips. In practice this is debatable - the likelihood of conflict appears to be much lower than with other aircraft in cruise, yet no broadcast is required there.
- It is slightly bizarre that the whole Common Traffic Advisory Frequency (CTAF) and procedures at non-towered aerodromes section has been deleted. They seem to have seen a conflict with the cruise and climb procedures and decided it was redundant, without realizing that it applies to a different phase of flight.
It definitely has changed - even 6 March 2014 clearly says that 126.7 should be used if no frequency is listed. The distinction between marked an unmarked strips is only in the climb and cruise procedures, not operations at the airfield.
Last edited by andrewr; 18th Aug 2014 at 08:18. Reason: missing word
Depending on where that strip is, and depending on whether it’s marked on a chart and you want to avoid clogging up the area frequency if it isn’t marked on a chart: YES. OF COURSE. PUBLISH A NOTAM. I’ve read NOTAMS about kite flying and kid’s balloon releases FFS. It ain’t hard. (I will make my point another way: What is the risk in arranging for a NOTAM about the fly-in to be published?)
Join Date: Apr 2008
Location: Australia
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
And what was the definition of 'non-towered aerodrome' for the purposes of the 2010 AIP you quoted?
Non-towered Aerodrome: An aerodrome at which air traffic control is not operating
Aerodrome: A defined area of land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and movement of aircraft.
It would be difficult to argue that an area is either not defined or not intended to be used by aircraft unless it appears on a chart. Charts generally show the location of an airfield, rather than defining an area.
My unqualified opinion: Marking a runway (white tyres etc.) is sufficient to define an area of land intended to be used by aircraft. Probably, erecting a windsock and saying I am going to use the back paddock to takeoff and land also defines an area of land intended to be used by aircraft.
If the argument is that it isn't an aerodrome if it's not on a chart, does that have implications for every other rule about operations at non-towered aerodromes?
2. The "area frequencies" are primarily for aircraft in class A/C airspace.
AIP:
Flight Information Area (FIA): An airspace of defined dimensions, excluding controlled airspace, within which flight information and SAR alerting services are provided by an ATS unit.
In fact in the event of having strife, a broadcast by you on an FIA is more likely to be heard by ATC and/or other aircraft, than relying on other aircraft hearing and understanding you on 126.7 (and them then being put in the position of trying to figure out who to notify and on what frequency …….).
The fact is though that Airservices will only publish NOTAMs for certified and registered aerodromes.
*sigh*
**bigger sigh**
Random pick from today's NOTAMS:
Fly-ins don't happen every day at Farmer Brown's Farm. Why would anyone need to promulgate a NOTAM every day for a fly-in BBQ at Farmer Brown's Farm?
Every Farmer Brown's Farm out there is some distance and direction from something identified on some chart that Airservices cares about.
Couldn't you just do what every other sentient being on the planet seems to be able to do, and tell Airservices that some 'intense aviation activity' is going to happen at a specified latitude and longitude and direction and bearing from a 'real' aviation thing, between specified times on specified dates?
EDIT: My post was posted before I saw Capt M's. Ignore mine: Read Capt M's.
**bigger sigh**
Random pick from today's NOTAMS:
C4532/14 REVIEW C2206/14
METEOROLOGICAL BALLOON RELEASE FROM KAHNCOBAN, NSW
PSN S36 13.3 E148 06.5 (BRG 098 MAG 12.8NM FM 'CRG' CORRYONG NDB)
SINGLE BALLOONS WILL RELEASED AT 3-HOURLY INTERVALS
OPR SNOWY HYDRO LIMITED CTC TEL 0438 370 828
SFC TO UNL
FROM 07 020328 TO 10 010300 EST
METEOROLOGICAL BALLOON RELEASE FROM KAHNCOBAN, NSW
PSN S36 13.3 E148 06.5 (BRG 098 MAG 12.8NM FM 'CRG' CORRYONG NDB)
SINGLE BALLOONS WILL RELEASED AT 3-HOURLY INTERVALS
OPR SNOWY HYDRO LIMITED CTC TEL 0438 370 828
SFC TO UNL
FROM 07 020328 TO 10 010300 EST
Every Farmer Brown's Farm out there is some distance and direction from something identified on some chart that Airservices cares about.
Couldn't you just do what every other sentient being on the planet seems to be able to do, and tell Airservices that some 'intense aviation activity' is going to happen at a specified latitude and longitude and direction and bearing from a 'real' aviation thing, between specified times on specified dates?
EDIT: My post was posted before I saw Capt M's. Ignore mine: Read Capt M's.
[I]n the event of having strife, a broadcast by you on an FIA is more likely to be heard by ATC and/or other aircraft, than relying on other aircraft hearing and understanding you on 126.7.
(Jack: Please take your medicine in accordance with the psychiatrist's directions!)
Join Date: Jul 2010
Location: rangaville
Posts: 2,280
Likes: 0
Received 0 Likes
on
0 Posts
Nothing worse than when lawyers are involved in aviation Creampuff 
make that when they're involved in anything they created all this garbage in the first place not aviators
make that when they're involved in anything they created all this garbage in the first place not aviators
Geezus JR.....
"Nursie Nursie, pain's gettin' worsie....wotcha gonna do..??
IT USED TO BE ALL SO 'SIMPLES'.......
And WHO changed it..???
(P.S. Tks again for the redundo.......)
"Nursie Nursie, pain's gettin' worsie....wotcha gonna do..??
IT USED TO BE ALL SO 'SIMPLES'.......
And WHO changed it..???
(P.S. Tks again for the redundo.......)
Nothing worse than when lawyers are involved in aviation Creampuff
Avmed zealots on a medical crusade to rid the skies of commercial pilots with CVD? The lawyers did it!
DJ to blame for the ditching of NGA? The lawyers did it!
Airspace management a political plaything? The lawyers did it!
CASA and ATSB tell the Senate Committee to shove it? The lawyers did it!
Only lawyers would be prepared to separate pathetically weak aviators from their rights and money. Because it's fun!
Ex FSO. The reason it is not simple now is that the NAS airspace change was not completed .
I believe we should either go back to the airspace pre 1991AMATS ( yes. And recruit another 700 FSOs ) or complete the introduction of NAS which was based on the North American system.
Try giving circuit or other announcements on ATC frequencies in the USA or Canada and you would be jumped on pretty smartly. It just not allowed!
It looks to me that there is no one in CASA who understands the approved NAS plan.
For example the current airspace has class C in the lower collision risk link airspace to non radar towers but then lower category class D in the higher collision risk tower airspace. Only dopes could justify that- no wonder the morale at CASA is so low!
I believe we should either go back to the airspace pre 1991AMATS ( yes. And recruit another 700 FSOs ) or complete the introduction of NAS which was based on the North American system.
Try giving circuit or other announcements on ATC frequencies in the USA or Canada and you would be jumped on pretty smartly. It just not allowed!
It looks to me that there is no one in CASA who understands the approved NAS plan.
For example the current airspace has class C in the lower collision risk link airspace to non radar towers but then lower category class D in the higher collision risk tower airspace. Only dopes could justify that- no wonder the morale at CASA is so low!
Join Date: Jan 1999
Location: Abeam Alice Springs
Posts: 1,109
Likes: 0
Received 0 Likes
on
0 Posts
Firstly there is obviously some confusion on what MULTICOM was designed to do and there is obviously a lack of corporate history and knowledge within CASA on the background and purpose of the MULTICOM, hence the misguided changes that they have pushed thru over the past year.
It was o so simple and what’s more it worked, but as I said earlier, the education at the time (10+years ago) was for some reason poor and as a result, I suspect that many did not even know it existed (and this thread seems to prove that!).
As Dick says, (and he is correct on this one) it was only ever designed for locations where there was no published CTAF and back then there was no mention of if it was on the charts or not! The en-route area frequency in Class G is now operated by the respective Centres and the procedures were never designed to cater for a/a chat - as in other countries all calls should be made thru Centre. The MULTICOM was only there to take the chat off the area Class G frequency as specific CTAF frequencies do - not to just cruise along and listen to it, tho' I believe many pilots do as they don't wish to listen to the Jets above! Call MAYDAY on 126.7 and see how many will answer…. you might be surprised?
Back in the days of FS, many aero clubs at rural locations used 119.1 as a local frequency, which might have been the MULTICOM of the ‘60’s and ‘70’s(??) – for exactly the same reason as it was introduced more than a decade ago – to get the LOCAL chat off the area frequency! Particularly when the area frequency is now operated by ATC.
The discussion above on having a NOTAM for farmer Joe's fly-in is not something that is practical as NOTAMs are only issued against promulgated locations and navaids and such NOTAMs will only be published in the FIR list (not against any nearby locations), which is, I suggest, not something that the average GA flyer would check very often as there is usually a bucket load in the list and it is very difficult to find something on the list that might be relevant. A subject of much discussion at the RAPACs over the years, but NOTAMs have very strict guidelines in accordance with ICAO recommended standards etc.
Actually we don't! The frequency spectrum is one of the most polluted part of our environment and there are often technical reasons why some air band frequencies cannot be used in some locations.
How come we have a never ending list of CTAF frequencies in Oz when in North America there is perhaps less than half a dozen?? The reason here, I suggest, is that our procedures encourage us to talk far too much! Again, something that the folk at CASA don’t appear to understand.
One can live in hope that those in CASA that pushed this change thru so poorly might see the light (!!) and review this mess. I would be also interested to know how they got ASA to agree to this change? Or were they just bullied in the name of safety?? CASA know best... actually they don't!
I suspect that our Controller friends might have something to say on this in due course.
It was o so simple and what’s more it worked, but as I said earlier, the education at the time (10+years ago) was for some reason poor and as a result, I suspect that many did not even know it existed (and this thread seems to prove that!).
As Dick says, (and he is correct on this one) it was only ever designed for locations where there was no published CTAF and back then there was no mention of if it was on the charts or not! The en-route area frequency in Class G is now operated by the respective Centres and the procedures were never designed to cater for a/a chat - as in other countries all calls should be made thru Centre. The MULTICOM was only there to take the chat off the area Class G frequency as specific CTAF frequencies do - not to just cruise along and listen to it, tho' I believe many pilots do as they don't wish to listen to the Jets above! Call MAYDAY on 126.7 and see how many will answer…. you might be surprised?
Back in the days of FS, many aero clubs at rural locations used 119.1 as a local frequency, which might have been the MULTICOM of the ‘60’s and ‘70’s(??) – for exactly the same reason as it was introduced more than a decade ago – to get the LOCAL chat off the area frequency! Particularly when the area frequency is now operated by ATC.
The discussion above on having a NOTAM for farmer Joe's fly-in is not something that is practical as NOTAMs are only issued against promulgated locations and navaids and such NOTAMs will only be published in the FIR list (not against any nearby locations), which is, I suggest, not something that the average GA flyer would check very often as there is usually a bucket load in the list and it is very difficult to find something on the list that might be relevant. A subject of much discussion at the RAPACs over the years, but NOTAMs have very strict guidelines in accordance with ICAO recommended standards etc.
Surely we have enough frequencies left over for each aerodrome to have its own discrete frequency rather than a big multicom?
How come we have a never ending list of CTAF frequencies in Oz when in North America there is perhaps less than half a dozen?? The reason here, I suggest, is that our procedures encourage us to talk far too much! Again, something that the folk at CASA don’t appear to understand.
One can live in hope that those in CASA that pushed this change thru so poorly might see the light (!!) and review this mess. I would be also interested to know how they got ASA to agree to this change? Or were they just bullied in the name of safety?? CASA know best... actually they don't!
I suspect that our Controller friends might have something to say on this in due course.
The discussion above on having a NOTAM for farmer Joe's fly-in is not something that is practical as NOTAMs are only issued against promulgated locations and navaids and such NOTAMs will only be published in the FIR list (not against any nearby locations), which is, I suggest, not something that the average GA flyer would check very often as there is usually a bucket load in the list and it is very difficult to find something on the list that might be relevant. A subject of much discussion at the RAPACs over the years, but NOTAMs have very strict guidelines in accordance with ICAO recommended standards etc.
If you’re saying it’s not possible to get a NOTAM promulgated to say that a fly-in is going to happen at a specified distance and bearing from an aerodrome or Navaid with a code that’s on a chart, I call ‘bullsh*t’.
The suggestion that there’s all this ‘chat’ going on at hundreds of unmarked airstrips across the country, that’s going to clog up the area frequencies when it ‘moves’ from 126.7, is laughable. I listen to three frequencies when I fly: Area frequency, 126.7 and the nearest CTAF that’s not 126.7 (or sometimes 123.45 if there are friends around and we do want to ‘chat’). I can count on the fingers of one hand the number of calls I’ve heard on any of those frequencies from an airstrip that isn’t marked on a chart.
There is a NOTAM in force, today, that says the area VHF frequency must be used for operations at and in the vicinity of strips that aren’t marked on charts. Have the area frequencies been flooded with broadcasts from all those people operating in and out of unmarked strips who were previously broadcasting on 126.7? Have 747s collided because of the ‘chat’ and confusion? (That’s right – I forgot: The people that operate in and out of these places are too lazy or incompetent to read NOTAMS.
)
Issued by CASA today......
http://casa.grapevine.com.au/lists/l...YBWR9VAQsETA4A
Page 21 refers......
Calls on 'the area VHF' get a mention - Yep! - That's the one ATC use to sort out their lot & issue clearances etc etc.....
p.s. Hi Dick, you wouldn't need anywhere near 700 FSO's these days.
But a few with 'strategically placed' AREA VHF outlets would be more than just 'good'.....OVAH.....
Cheers
http://casa.grapevine.com.au/lists/l...YBWR9VAQsETA4A
Page 21 refers......
Calls on 'the area VHF' get a mention - Yep! - That's the one ATC use to sort out their lot & issue clearances etc etc.....
p.s. Hi Dick, you wouldn't need anywhere near 700 FSO's these days.
But a few with 'strategically placed' AREA VHF outlets would be more than just 'good'.....OVAH.....
Cheers
Last edited by Ex FSO GRIFFO; 19th Aug 2014 at 05:54. Reason: punctuation....agin.....