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-   -   Why isn’t SELCAL used to contact us on 121,5? (https://www.pprune.org/atc-issues/577965-why-isn-t-selcal-used-contact-us-121-5-a.html)

sabenaboy 22nd Apr 2016 18:19

Why isn’t SELCAL used to contact us on 121,5?
 
As airline pilots, we're expected to listen out on 121,5 continuously, but frankly, over Europe that has become counterproductive.
There’s so much talking going on on that frequency, wrong dispatch calls, silly jokes, etc, that listening out on 121,5 makes crews miss calls more often than the other way around! When it’s really busy on the ATC frequency you’re using, monitoring 121,5 becomes very impractical.
So, why doesn’t atc use selcal to get our attention on 121,5 when there’s a loss of communication with a flight? The selcal-code is in the flightplan info! We just have to leave 121,5 tuned on VHF2 box, without the need to listen to all the bull****, elt’s and distortion on the frequency.
Don’t tell me the atc center doesn’t have the equipment! Any android smartphone or Iphone can do it with an app like this one! It works very well!

Not Long Now 22nd Apr 2016 20:42

Not sure about your specific point, sounds fine to me, but your presumption that a centre must have the capability because your smartphone does is way off. It's a bit like that moon landing computing analogy...

HEATHROW DIRECTOR 22nd Apr 2016 21:40

Does the aeroplane have SELCAL capability on VHF? Equipping all ATC sectors with SELCAL would cost a huge amount of money which I doubt the bean-counters would justify! At a place I worked 121.5 was removed from ATC positions.

kcockayne 23rd Apr 2016 00:33


Originally Posted by HEATHROW DIRECTOR (Post 9353265)
Does the aeroplane have SELCAL capability on VHF? Equipping all ATC sectors with SELCAL would cost a huge amount of money which I doubt the bean-counters would justify! At a place I worked 121.5 was removed from ATC positions.

Selcal can be used on VHF ( it is not exclusively used on HF), but ATC does not have selcal equipment available. If an ATC sector wanted to contact an a/c by selcal it would have to do it via Shanwick, & I don't think they would be too keen to offer this service on anything other than a "one off basis" ! The other alternatives would be a telephone/radio patch via Berne Radio, Portishead or Stockholm Radio - if they stil exist.

sabenaboy 23rd Apr 2016 05:54


Originally Posted by Not Long Now
Not sure about your specific point, sounds fine to me, but your presumption that a centre must have the capability because your smartphone does is way off.

What is a selcal signal? Basically, a selcal is just a (audible) audio tone of a certain frequency! To send one you need a) an encoder and b) a transmitter.
The encoder: any smartphone can do it with the app! The transmitter: you already have it! So how does it work? Simply tap the selcal code in the app (the selcal is or should be in the RMK section of the flightplan!), hold the microphone close to the smartphone loudspeaker, press the transmit button and the "generate now" button on the app and voilà, there is your Selcal signal! It really is that simple! It doesn't need to be material costing thousands of euro's. Any device able to create tones of the necessary frequency will do! And a selcal warning in our cockpit WILL get our attention!

Originally Posted by HEATHROW DIRECTOR
Does the aeroplane have SELCAL capability on VHF? Equipping all ATC sectors with SELCAL would cost a huge amount of money which I doubt the bean-counters would justify! At a place I worked 121.5 was removed from ATC positions.

a: Yes, selcal works fine on VHF in our Airbus! I'm not sure about Boeings, but I believe they're capable as well. b: No, it doesn't need to cost a lot: even any smartphone can do it; (even yours: try the app! It works!) c: now that's a shame! But you can use it on any frequency, also the one you're working on.
It really IS that simple: THE solution to get our attention on 121,5 without having us monitoring it all the time, which has become impossible!
Play store selcal encoder
Selcal encoder for iOS

flydive1 23rd Apr 2016 07:14

Monitoring 121.5 is not only for ATC to call you.

chevvron 23rd Apr 2016 07:18

I hardly think holding the microphone close to your smartphone is going to pass a 'safety case' for a function like this. In any case you've got to find someone who owns a smartphone with the app.
Sabenaboy, you don't seem to realise that anything ATC related has to be an approved system allowable under national aviation authority regulations.
As others have said, normal ATSUs do not have access to Selcal, just oceanic ones, so whilst laudable, your idea is a non-starter.

Not Long Now 23rd Apr 2016 07:32

Oh, and of course, not allowed your phone on in the ops room. For safety reasons...

sabenaboy 24th Apr 2016 10:52

@chevvron & Not Long Now:
The point I'm trying to make is that sending a selcal tone is not rocket science.
What ATCO's don't seem to realise is that monitoring 121,5 has become very impractical.
Very often when a pilot asks you to "say again" your instruction, the reason might well be because something or someone was transmitting on 121,5 at the same time. It's like listening to two songs at the same time! 121,5 is scrambled with pilots calling dispatch, false ELT warnings, ATC trying to reach lost com traffic several times, people telling jokes or playing music on it and static interference.
My point is that selcal works nicely on VHF and it should become mandatory for airliners to maintain selcal watch on 121,5 iso of having to monitor it which causes more problems then it solves.

I don't want to hear lame excuses like "It can't be approved unless is costs several hundreds of thousands of whatever currency" or "I'm not allowed to take my cellphone in the ops room"
The fact is: The technology is very simple and there's no reason why it should be expensive to implement! Instead of being negative towards this solution, ATCO's should be supporting this. The result would be "less flights with lost com and less scrambled fighters and improved safety". Who can be opposed to that?

2 sheds 24th Apr 2016 11:33

sabenaboy

You seem to have received only a very negative reaction for some reason that I cannot fathom, with pointless comment about cost (totally unknown) and practicality of using a mobile phone in an Ops Room (it would hardly be engineered or approved thus!).

Surely this perfectly practical and useful suggestion could be implemented, in the UK via D&D, for the few isolated occasions when it might be required. It's not as if every unit and ACC sector would require it.

Why not take up the suggestion through your national Authority? Mind you, some of your current reported problems do seem to be within your (pilots') court!


121,5 is scrambled with pilots calling dispatch, ..., ..., people telling jokes or playing music on it
2 s

le Pingouin 24th Apr 2016 11:42

It comes down to why you're monitoring 121.5. Yes, we get others to call you on it because we know you're monitoring but surely the primary reason is in case of an aircraft emergency. SELCAL rather defeats that.

obwan 24th Apr 2016 22:26

[B]121,5 is scrambled with pilots calling dispatch, false ELT warnings, ATC trying to reach lost com traffic several times, people telling jokes or playing music on it and static interference.

I thought it was a distress frequency

Cough 25th Apr 2016 15:23

I think what SabenaBoy is saying.

Listening to 121.5 over Europe is distracting to the primary job because of all the rubbish that people say on it. Leaving Europe it gets a lot quieter and you are more able to listen.

With modern ATC suites, surely it wouldn't be that technologically difficult to add an option to the screen to bring up a SELCAL option to call an aircraft. After all, if a geek can program a smartphone app in a few hours, surely a function could be dropped on to your systems? I can however see the future of this in CPDLC instead.

HEATHROW DIRECTOR 25th Apr 2016 16:59

I worked in ATC for most of my life and only recall a couple of occasions when contact was lost with an aircraft; maybe it's worse nowadays? Point is, when accountants are asked for money they ask how much the service will be used. In my experience, not a lot!

chevvron 25th Apr 2016 19:46


Originally Posted by HEATHROW DIRECTOR (Post 9356040)
I worked in ATC for most of my life and only recall a couple of occasions when contact was lost with an aircraft; maybe it's worse nowadays? Point is, when accountants are asked for money they ask how much the service will be used. In my experience, not a lot!

Seems to happen more since they introduced 8.33 khz frequency spacing. It's far too easy to misdial one digit and on the early ones, you had to remember to switch between 25 and 8.33 spacing on your own radio.

GlobalJourney 26th Apr 2016 08:14


Originally Posted by HEATHROW DIRECTOR (Post 9356040)
I worked in ATC for most of my life and only recall a couple of occasions when contact was lost with an aircraft; maybe it's worse nowadays? Point is, when accountants are asked for money they ask how much the service will be used. In my experience, not a lot!

It's pretty common, usually have to round up someone on guard a couple of times a week. It's normally only a matter of a few minutes rather than full on prolonged loss of communication (PLOC).

Denti 26th Apr 2016 16:00

Especially central europe has often very small atc sectors and therefore an incredible number of frequency changes. It is very easy to get loss comm there and passing through two or more sectors until you realize it. With all the crap on 121.5, mentioned above plus other legit but distracting stuff like practice pans (which can be heard well outside UK airspace), frequency tests from every atc unit and so on, it is usually set to a very low volume, otherwise it will lead to problems listening on the primary frequency. Listening and talking on the radio is after all just a part of our job, flying and managing our aircraft and crew has to be done as well. And SOPs with a lot unnecessary callouts, like for example the airbus standard SOPs, can interfere with radio calls as well.

Pizza Express 27th Apr 2016 20:11

Heathrow Director

I am guessing you spent your time working in the London TMA? When you are in that phase of flight climbing and descending everyone is switched on and tuned in because things are happening and it's also my companies policy not to monitor 121.5 at those times as it can be distracting. I can promise you that after 13 years of short haul flying over Europe that 121.5 has now become one hell of a pain in the arse. During the cruise anywhere over Europe you now have a constant chatter of practice Pans, Acidental handling calls, lost coms relays and there has been a recent trend of silly sound effects probably played via IPhone App. You still have to monitor it and every day you will miss a call because someone is chatting on 121.5. It's not something that happens in the London TMA because people are generally not listening to it it's really a cruise thing. I think something g has to be done because it's now counter productive IMHO!

HEATHROW DIRECTOR 27th Apr 2016 21:47

PE.. yes, mostly LTMA but also in Africa! Having read about these problems both in this thread and previously I'm drawn to the conclusion that R/T discipline doesn't exist in some places. Is this a training problem or do some people just enjoy messing about with radio? Heaven forbid but one day their lives may depend on good comms.... Happy landings.

Pizza Express 28th Apr 2016 03:32

It's actually unbelievable but there are guys flying for well known European airlines making silly noises on 121.5 all the time, generally over Spain/ Brest area. The main issue is the number of lost com calls happening, I would estimate once every 15 mins over Central Europe you will Sudanly have chatter or aircraft relaying a new frequency or an accidental handling call. It's always been like that but the volume has increased with the number of aircraft in the sky. Of Course you have to monitor 121.5 because it might be you that has lost Coms!! flying over Germany in the cruise where you have a frequency change every 3 -5 mins combined with trying to brief an approach and cabin crew calling you up, sometimes I have 4 voices at once to listen to, it's no wonder there are lost coms all the time and then more chatter on 121.5 to get them back.


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