Mode S Transponders
Thread Starter
Joined: Nov 2001
Posts: 355
Likes: 0
From: united kingdom
Mode S Transponders
I’d be interested to hear the ATC view of mode S transponders.
I’m a PPL and my flying is a mixture of VFR and IFR in a single engine Cessna. My transponder has mode A and C, in common with most other light aircraft. It never seems to be any sort of a problem to ATC, whether inside or outside of controlled airspace.
From 2003, as I understand it, all aircraft flying IFR inside controlled airspace will need Mode S. This will cost me around £5000 or so and I wonder what benefit it will bring. As you can imagine, light aircraft owners are feeling a bit sensitive, after having to shell out for 8.33kHz spacing radios, and nav sets with FM immunity.
Will you guys use the extra Mode S information? Will you even be able to display it on your screens? Will it help, for example, to get direct routings (thus saving time and money), or indeed to get an ad hoc transit clearance through the class D CTAs? Will it help reduce unnecessary TCAS alerts?
It is planned to get even worse in 2008, when all aircraft (actually including gliders, parascenders and so on) will need Mode S, outside as well as inside CAS, VFR as well as IFR. Won’t there be so many returns on your screens that you won’t see the wood for the trees. Especially for ATCOs working the TMAs, where many light aircraft fly underneath CAS, many not squawking at all. Does this mean you will have to filter out returns you are not interested in? (The French civilian ATC system filters out military transponder returns, I believe). If so, where is the benefit?
By the way, I’ve no axe to grind, or political point to make. I don’t even want to stand in the way of progress if there is a benefit.
Regards.
I’m a PPL and my flying is a mixture of VFR and IFR in a single engine Cessna. My transponder has mode A and C, in common with most other light aircraft. It never seems to be any sort of a problem to ATC, whether inside or outside of controlled airspace.
From 2003, as I understand it, all aircraft flying IFR inside controlled airspace will need Mode S. This will cost me around £5000 or so and I wonder what benefit it will bring. As you can imagine, light aircraft owners are feeling a bit sensitive, after having to shell out for 8.33kHz spacing radios, and nav sets with FM immunity.
Will you guys use the extra Mode S information? Will you even be able to display it on your screens? Will it help, for example, to get direct routings (thus saving time and money), or indeed to get an ad hoc transit clearance through the class D CTAs? Will it help reduce unnecessary TCAS alerts?
It is planned to get even worse in 2008, when all aircraft (actually including gliders, parascenders and so on) will need Mode S, outside as well as inside CAS, VFR as well as IFR. Won’t there be so many returns on your screens that you won’t see the wood for the trees. Especially for ATCOs working the TMAs, where many light aircraft fly underneath CAS, many not squawking at all. Does this mean you will have to filter out returns you are not interested in? (The French civilian ATC system filters out military transponder returns, I believe). If so, where is the benefit?
By the way, I’ve no axe to grind, or political point to make. I don’t even want to stand in the way of progress if there is a benefit.
Regards.
Joined: Apr 2000
Posts: 608
Likes: 0
From: UK
There is ongoing trials at the ATMDC in Bournemouth (Air Traffic Management and Development Centre).
I was not part of the trials but a briefing said that they would be used extensively, as it can also display what the pilot has selected on the autopilot (just level and roc info I beleive).
As you know, all aircraft will have an indivisual ID so there will be no need for individual squawks.
As you say, in terms of displaying this info there could be an information overload problem! I think that they are trialling the use of electronic strips with all the data on, but it is still at an early stage.
[ 22 January 2002: Message edited by: Bright-Ling ]</p>
I was not part of the trials but a briefing said that they would be used extensively, as it can also display what the pilot has selected on the autopilot (just level and roc info I beleive).
As you know, all aircraft will have an indivisual ID so there will be no need for individual squawks.
As you say, in terms of displaying this info there could be an information overload problem! I think that they are trialling the use of electronic strips with all the data on, but it is still at an early stage.
[ 22 January 2002: Message edited by: Bright-Ling ]</p>
Joined: Oct 1998
Posts: 24
Likes: 0
From: UK
I think it will clutter up radar displays with SO much stuff outside CAS that any RAS/RIS services will be severely limited and downgraded. How many spurious TCAS alerts will it generate ? How many radar processors will start 'dropping' tracks as they will hit overload ?
I think it is an unecessary burden to place on GA, but when did the CAA ever take that into account ? Witness the FM Immunity additional costs. Bad for GA, and potentially cluttersome for ATC.
I think it is an unecessary burden to place on GA, but when did the CAA ever take that into account ? Witness the FM Immunity additional costs. Bad for GA, and potentially cluttersome for ATC.
Joined: Oct 2000
Posts: 155
Likes: 0
Modr 'S' will be a big benefit to ATC for aircraft in CAS. From about 2005 we will be able to see some FMS info from the auto pilot (enhanced mode'S'). Mode S altitude will come down to the ground in 25ft increments. All this can be used to help safety in CAS. I am not an expert, but I cannot see what benefit Mode S can be to GA outside CAS, unless it will be used for TCAS.
Joined: Jun 2001
Posts: 70
Likes: 0
From: Somewhere on the warm side!
I believe that the current plan is for the UK to skip introducing Mode S Elementary Surveillance in 2003, but to progress straight to Enhanced Mode S.
Terminal Control is the first likely candidate for Enhanced Mode S, with a date of 2005 being discussed. Enhanced Mode S will enable a host of Aircraft Derived Data to be downlinked to the ATC system. Only selected items will be displayed to the controller - some items could be used by existing ATC systems, such as STCA, and be transparent to the controller.
One significant Enhanced parameter is Selected Altitude. This will enable controllers to see what altitude the flight crew have inserted in the Selected Altitude window on the Autoflight system, and thus give controllers an early warning of a potential level bust. This feature is seen as being a technical solution to the rising number of Level Busts that are occurring within the UK, despite several awareness campaigns. <img src="frown.gif" border="0">
Terminal Control is the first likely candidate for Enhanced Mode S, with a date of 2005 being discussed. Enhanced Mode S will enable a host of Aircraft Derived Data to be downlinked to the ATC system. Only selected items will be displayed to the controller - some items could be used by existing ATC systems, such as STCA, and be transparent to the controller.
One significant Enhanced parameter is Selected Altitude. This will enable controllers to see what altitude the flight crew have inserted in the Selected Altitude window on the Autoflight system, and thus give controllers an early warning of a potential level bust. This feature is seen as being a technical solution to the rising number of Level Busts that are occurring within the UK, despite several awareness campaigns. <img src="frown.gif" border="0">
Joined: Nov 2000
Posts: 1,086
Likes: 0
From: Greystation
If it comes in to force, does that mean we need new equipment ourselves, or possibly even a new centre to house it <img src="confused.gif" border="0"> <img src="confused.gif" border="0"> <img src="confused.gif" border="0"> <img src="confused.gif" border="0">
Sorry, must have been having a nightmare or something <img src="redface.gif" border="0"> <img src="redface.gif" border="0">
Sorry, must have been having a nightmare or something <img src="redface.gif" border="0"> <img src="redface.gif" border="0">
Thread Starter
Joined: Nov 2001
Posts: 355
Likes: 0
From: united kingdom
Thanks for the input. It seems there is support from ATCOs for the problems Mode S will cause GA generally and light aircraft specifically. I hope this view comes out of the consultation process. I know AOPA and other organisations are lobbying hard.
It also seems there will be plenty of new problems for ATC, both equipment and procedures, so the implementation dates proposed my be optimistic.
The most up to date official information I have found seems to be the AIC 88/2001 (Yellow 65), which follows on from AIC 100/1997. Anybody interested without access to a paper copy can read these AICs on the ais.org.uk website – they are part of the AIP.
AIC 88/2001 says that France and Germany are implementing IFR from 31 March 2003 and VFR (in airspace where carriage of transponders is mandatory) from 31st March 2005. However, these dates refer to Mode S with only basic functionality (i.e unique address, identity, capability [what is this??] altitude, and status [flying or on ground], not including download of heading, IAS, ROC/ROD, roll, track angle, ground speed and selected altitude, which are enhanced functions).
The UK game plan seems to be to go straight to enhanced functionality for IFR in TMA and en-route airspace and implement from from 31st March 2005. VFR will be basic functionality only from 31st March 2008. The AIC makes reference to temporary exemptions to be proposed lated.
So we have two problems:
If we want to fly in French and German airspace, will we need basic Mode S from 2003?
If we fit basic Mode S for this reason, will we have to upgrade in 2005 to fly in the UK? I f we did upgrade, where would all the extra information come from in a light aircraft?
All this has given me a headache, I guess I have to hope for successful lobbying, common sense and exemptions for GA, or for lighter aircraft.
However, I think it is also a real headache for ATC services too.
Re the glider comments from ‘No Speed Restriction’ and turn ‘RIGHT’: the AIC refers to ‘aircraft.’ If my memory of air law is correct, aircraft is a class comprising all flying things (no jokes about ducks, please) and airplanes, helicopters, balloons, gliders, microlights etc are sub-classes and will thesefore have to comply, if no exemptions are agreed. Again, I hope common sense prevails. There was an article in December ‘Pilot’ magazine which suggested that gliders etc could be caught by Mode S.
Regards
It also seems there will be plenty of new problems for ATC, both equipment and procedures, so the implementation dates proposed my be optimistic.
The most up to date official information I have found seems to be the AIC 88/2001 (Yellow 65), which follows on from AIC 100/1997. Anybody interested without access to a paper copy can read these AICs on the ais.org.uk website – they are part of the AIP.
AIC 88/2001 says that France and Germany are implementing IFR from 31 March 2003 and VFR (in airspace where carriage of transponders is mandatory) from 31st March 2005. However, these dates refer to Mode S with only basic functionality (i.e unique address, identity, capability [what is this??] altitude, and status [flying or on ground], not including download of heading, IAS, ROC/ROD, roll, track angle, ground speed and selected altitude, which are enhanced functions).
The UK game plan seems to be to go straight to enhanced functionality for IFR in TMA and en-route airspace and implement from from 31st March 2005. VFR will be basic functionality only from 31st March 2008. The AIC makes reference to temporary exemptions to be proposed lated.
So we have two problems:
If we want to fly in French and German airspace, will we need basic Mode S from 2003?
If we fit basic Mode S for this reason, will we have to upgrade in 2005 to fly in the UK? I f we did upgrade, where would all the extra information come from in a light aircraft?
All this has given me a headache, I guess I have to hope for successful lobbying, common sense and exemptions for GA, or for lighter aircraft.
However, I think it is also a real headache for ATC services too.
Re the glider comments from ‘No Speed Restriction’ and turn ‘RIGHT’: the AIC refers to ‘aircraft.’ If my memory of air law is correct, aircraft is a class comprising all flying things (no jokes about ducks, please) and airplanes, helicopters, balloons, gliders, microlights etc are sub-classes and will thesefore have to comply, if no exemptions are agreed. Again, I hope common sense prevails. There was an article in December ‘Pilot’ magazine which suggested that gliders etc could be caught by Mode S.
Regards
Joined: Feb 2000
Posts: 446
Likes: 3
From: solent-on-sea
F o F, if ATCO s are going to receive data on what the pilot has just set in the autopilot (flight level for example), I fear it wont be long before we will be responsible if they get that wrong having read it back correctly. OK great theoretically for safety, but to be quite honest I've got enough things to be getting on with, without having to check that sort of thing as well!
Joined: Apr 2000
Posts: 608
Likes: 0
From: UK
It has already been highlighted as a potential problem.
Also, on some glass cockpits, we were told that it was not uncommon for crew to put a lower than cleared level in to help get the height off. Is this true?!?!
Also, on some glass cockpits, we were told that it was not uncommon for crew to put a lower than cleared level in to help get the height off. Is this true?!?!
Joined: Jun 2001
Posts: 70
Likes: 0
From: Somewhere on the warm side!
Not Long Now,
Yes, the issue about legal / moral responsibilities in the event of an incident occurring when additional data is available to controllers has been raised. No answer has been provided to date as far as I am aware. An interesting issue - and one that needs to be discussed.
Yes, the issue about legal / moral responsibilities in the event of an incident occurring when additional data is available to controllers has been raised. No answer has been provided to date as far as I am aware. An interesting issue - and one that needs to be discussed.
