Is There Any Current Move Underway To Switch Away From AM On Aviation Frequencies?

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JASII

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As posted above, has there been any recent attempts to switch away from AM modulation on aviation frequencies? I was at an FBO recently and listened to the aviation communications for a while when I was there. I will say that they sounded better on their aviation radios than me listening on a scanner or amateur radio. However, they are still AM modulation, which seems pretty archaic in this day and age.

I get how it would be a major undertaking to switch from AM to a different mode, but it just seems like it might have to happen at some point in the future. What, if any, other modes have been discussed for aviation radios? At this point in time, I really doubt that plain old FM would even be considered.
 

kayn1n32008

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As posted above, has there been any recent attempts to switch away from AM modulation on aviation frequencies? I was at an FBO recently and listened to the aviation communications for a while when I was there. I will say that they sounded better on their aviation radios than me listening on a scanner or amateur radio. However, they are still AM modulation, which seems pretty archaic in this day and age.

I get how it would be a major undertaking to switch from AM to a different mode, but it just seems like it might have to happen at some point in the future. What, if any, other modes have been discussed for aviation radios? At this point in time, I really doubt that plain old FM would even be considered.
I doubt they will switch from AM.

It works, why change it? besides, the standard would need to change world wide. good luck with that
 

ATCTech

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From a VHF radio perspective it's not likely going to change any time soon, however already in-place SATCOM data link systems do have (digital of course) voice capability in addition to CPDLC that's been deployed for many years now in oceanic control. The first thing to fade away would be HF voice communication as this technology takes hold. As SATCOM capacity increases there will no doubt be a push to move domestic en route voice traffic away from conventional terrestrial radio, leaving analog voice for low level, VFR, tower and terminal control operations. Once an aircraft logs on to the SATCOM system there are no frequency changes required and hand-offs from one ATC sector or facility to another would be essentially invisible to the crew, lightening the workload on the flight deck by removing another distracting task.

Cheers!
 

Weaksignal

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At this point in time, I really doubt that plain old FM would even be considered.
AM does not exhibit the capture effect that FM does. If there is a stuck mic on frequency, AM transmissions can generally still be heard. Not so with FM mode.
 

SteveEJ

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Some time ago there was a push to move away from conventional AM and go to digital with controller override capabilities. This proved very effective in use but the airborne side of the equation, i.e.: airlines, cargo haulers, private owners in the USA said that it costs too much. That seems to be a pretty common theme when it comes to upgrading the NAS. Even with ADS-B the FAA has been providing rebates and other incentives in order for US Registered aircraft to get equipped. Bottom dollar is the bottom line for the users of the system. When they (airlines) say we have an outdated system is it partially because of them and their bottom line.
 

JStemann

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Yes, in the United States there is a strong FAA program to move away from AM phone to, essentially, text messaging between controller and pilot.

https://www.faa.gov/nextgen/update/progress_and_plans/data_comm/
Keep in mind, this "text messaging" isn't moving away from AM voice communication, just a supplement to it. Primarily to be used for an aircraft sitting on the ground, awaiting departure instructions & clearances. The taxi instructions and "cleared to takeoff/land" along with most instructions for the aircraft while airborne will still be done using AM voice.

Jeff.
 

majoco

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One of the demands on the pilot of any aircraft is "situation awareness". The information required by the pilot to maintain this 'awareness' is not just by looking out the window and seeing the other aircraft, but by listening to the radio, hearing other aircraft and noting where they might be or where they might appear from. Admittedly ADSB and TCAS avoids unpleasant surprises, but having this mental picture of what's going on around you is vital. Now data comms is fine, but you only get the stuff that's intended for you, you don't get to see everybody elses stuff and so lose that info that you would have got from listening. Sorry, AM will never die - not even replaced by FM. Range has nothing to do with it, not often are you required to talk over much more than 50nm and from a few thousand feet that's a doddle. Data comms is fine if you have the time, but if the bloke in the tower wants flight NZ1234 to do an immediate turn right on to heading 270 he's not going to type out a message now is he?
 

WA8ZTZ

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One of the demands on the pilot of any aircraft is "situation awareness". The information required by the pilot to maintain this 'awareness' is not just by looking out the window and seeing the other aircraft, but by listening to the radio, hearing other aircraft and noting where they might be... Data comms is fine if you have the time, but if the bloke in the tower wants flight NZ1234 to do an immediate turn right on to heading 270 he's not going to type out a message now is he?
Exactly, there already exists ACARS, been around for a long time but used for routine stuff, not for second by second comm in a high traffic environment.

Also, the part about the situational awareness is right on, the pilot needs to have a clear mental picture of where he is and his surroundings.
 

SteveEJ

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One of the demands on the pilot of any aircraft is "situation awareness". The information required by the pilot to maintain this 'awareness' is not just by looking out the window and seeing the other aircraft, but by listening to the radio, hearing other aircraft and noting where they might be or where they might appear from. Admittedly ADSB and TCAS avoids unpleasant surprises, but having this mental picture of what's going on around you is vital. Now data comms is fine, but you only get the stuff that's intended for you, you don't get to see everybody elses stuff and so lose that info that you would have got from listening. Sorry, AM will never die - not even replaced by FM. Range has nothing to do with it, not often are you required to talk over much more than 50nm and from a few thousand feet that's a doddle. Data comms is fine if you have the time, but if the bloke in the tower wants flight NZ1234 to do an immediate turn right on to heading 270 he's not going to type out a message now is he?
So true. Being on the other side of the situation for a very long time I have learned that overloading eye and underusing ear is not a good thing. Their needs to be a effective balance maintained. That is one reason I did not understand the abandonment of the digital com system with override capabilities. It worked just like AM but there was no 'stepping on' other transmissions which had the bad effect of hurting ears.
 

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SteveEJ

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Don't be confused by the phrase 'Tower'. There are several different positions in the 'Tower'. The one mentioned that is using the 'Text' type of transfer of data is 'Clearance Delivery' which formulates and issues flight plan clearances to aircraft before they start to taxi. 'Ground' control (taxi) and 'Tower' control (Takeoff/Landing clearances) are on AM radios. Not all ATCT's (Air Traffic Control Towers) have digital clearance delivery, usually just the larger ones.
 

bharvey2

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Yes, in the United States there is a strong FAA program to move away from AM phone to, essentially, text messaging between controller and pilot.

https://www.faa.gov/nextgen/update/progress_and_plans/data_comm/
That seems strange. While not a pilot, I've spent some time in the cockpit of small aircraft. It seems that being able to hear radio traffic would be a better fit than reading a text message.

To be honest, the first thing that came to mind when I read this is the proliferation of distracted driver laws that have come to pass in the last several years. Suffice it to say that there will be no flying over California! :)
 
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JStemann

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That seems strange. While not a pilot, I've spent some time in the cockpit of small aircraft. It seems that being able to hear radio traffic would be a better fit that reading a text message.

To be honest, the first thing that came to mind when I read this is the proliferation of distracted driver laws that have come to pass in the last several years. Suffice it to say that there will be no flying over California! :)
Generally, I believe, this would be used for an aircraft on the ground getting ready to position for departure. The message would include "directions" to the destination airport possibly other info, too. The directions would basically be landmarks along the approved route. As far as I know, the pilot really wouldn't be able to text a response back to air traffic, just acknowledge receipt of it. I'm sure the pilots can give a lot better explanation than I can. I hear the instructions being read off all the time, but haven't had any reason to "listen" to them.

Jeff.
 

bharvey2

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That makes sense. If they had the RF infrastructure to implement long range, two way texting capabilities then they be most of the way toward a digital voice mode.
 

majoco

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As far as I know, the pilot really wouldn't be able to text a response back to air traffic, just acknowledge receipt of it.
Acknowledging receipt of a message does not insure that you have fully understood it. Another 'must do' is to read back the features of an ATC 'command' off your clipboard back to the controller such as a standard departure procedure, assigned altitudes, rates of climb, what to do at the next reporting point and to make sure that the pilot has the local QNH and maybe an area QNH. The pilot or the 'non-flying' pilot will have his hands full at this time and can't risk having his head down below the glareshield typing away on the tiny keyboard to get his acknowledgement back to the controller.

The system as it stands at the moment worldwide is not broken - there is no need to fix it.

The directions would basically be landmarks along the approved route.
30 minutes before the flight the pilot has to file a flight plan unless he's going to go VFR, (but even then it's still better to put in a plan) all the controller has to do is confirm that he has the plan in front of him. He will say "NZ1234 is cleared as per flight planned route...blah blah...". The only time he will change the route is if there may be a conflict, but even then he is more likely to change an altitude rather than the route. The pilot may request a deviation "five miles east of track due weather" and the controller will accept or decline the request, or even say "'cleared to deviate ten miles left of track and proceed direct to GUPTI " if the next reporting point is over that way. The flight plan will have been passed to all the other controlling stations along the route and so will say "At GUPTI contact Ohakea Control on 123.40, g'day".
 
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ATCTech

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Guys, I'm not going to argue with you but the technology I mentioned at the top of this thread already exists and is in use in some very busy airspace in this world.

Reading clearances over the air at an airport handling 30-50 departures an hour is not the "all a controller has to do" model of efficiency. PDC (pre-departure clearance) via ACARS/VDL has existed for well over a decade. To only have to contact ATC with a 4 digit validation code is a vast improvement over reading back every word. It absolutely confirms the crew has an exact copy of the flight plan. I won't even get into how efficient it is when a flight plan needs to be modified pre-departure or once airborne.

Second, CPDLC has been in use in the most heavily traveled trans-oceanic airspace in the world for many years, and of course it's primarily satellite-delivered. It cuts down voice traffic by at least 70% for equipped aircraft and allows contant communication versus SELCAL and noisy, difficult to monitor HF radio. More important to this conversation, for oceanic service it's now used globally to relay route changes, altitude change requests, and other instructions to and from the cockpit, and it's in use in high level, en route *domestic* airspace across Canada and in Europe. It isn't the way of the future, it's already here. And believe me, I've seen first-hand both controllers and commercial pilots that don't already fly oceanic routes dip their toes into the CPDLC water with great skepticism only to come away with "that's pretty impressive" comments after a few cycles. And for those that do, being able to stay on CPDLC once into domestic airspace has been widely applauded here.

I get your argument that small aircraft don't need that service and that's true if you're operating in an area covered by conventional voice and radar service, but these types of technology are not initially developed specifically for those operations. Commercial flights using densely packed routes are the bread and butter of the ATC system and providing the safest, most efficient service to airlines is the global goal of ATC providers.

And remember, I did say this system is in use in EN ROUTE high level sectors, leaving terminal and tower services to use conventional voice communications.

I'm not trying to start a war here, I'm simply pointing out that what I said initially is already in use, it's not hear-say or speculation. Get used to it, it's here to stay and will only become more widespread and of course less expensive as it does. As my tagline says, I spent 34 years in this, going from tube-type radios to where we are today first-hand.

Cheers!
 
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