Traffic in close vicinity
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I'd be interested to hear how many piots leave mode 'C' turned off even if they have it fitted? I know for a fact that it's not that uncommon, quite often asking the pilot 'G-xx, do you have mode C?' will lead to it magically appearing.
What I don't know if these pilots appreciate is that if they are in class G and not talking to anyone, (no problems with that, btw, it's up to you), with 7000 set and no mode 'C', they are effectively wiping out a 10 (ten) mile diameter cylinder of airspace around them from the surface to FL245 for anyone who is in receipt of a radar advisory service.
The radar controller providing the service must achieve - if the subject of the RAS cannot see the unknown traffic - either lateral separation of 5 miles or 3000 feet vertically based on mode 'C' returns from the unknown aircraft (our non-talking 7000 squawker). The easiest of these is nearly always the 3000 feet, and this is not an option if there is no mode 'C'.
The most frustrating thing is when the unknown aircraft is showing on secondary radar only since it is too low for primary contact. As a controller you know that it is down in the weeds, but the rules say that you must take a 10 mile detour with your departing passenger jet which is passing FL100.
So does anyone leave their mode 'C' off as a matter of course? I'm genuinely interested.
What I don't know if these pilots appreciate is that if they are in class G and not talking to anyone, (no problems with that, btw, it's up to you), with 7000 set and no mode 'C', they are effectively wiping out a 10 (ten) mile diameter cylinder of airspace around them from the surface to FL245 for anyone who is in receipt of a radar advisory service.
The radar controller providing the service must achieve - if the subject of the RAS cannot see the unknown traffic - either lateral separation of 5 miles or 3000 feet vertically based on mode 'C' returns from the unknown aircraft (our non-talking 7000 squawker). The easiest of these is nearly always the 3000 feet, and this is not an option if there is no mode 'C'.
The most frustrating thing is when the unknown aircraft is showing on secondary radar only since it is too low for primary contact. As a controller you know that it is down in the weeds, but the rules say that you must take a 10 mile detour with your departing passenger jet which is passing FL100.
So does anyone leave their mode 'C' off as a matter of course? I'm genuinely interested.
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Rodan
You appear to be saying that if you see an unverified (e.g. no radio) 7000 return without Mode C, flying "across" an airway whose base is say FL55 and which has traffic in it at say FL65, you have to reroute that airway traffic??
There are many such situations!
I think a lot of people knowingly don't switch Mode C on. In my PPL training it was never switched on. Bizzare...
You appear to be saying that if you see an unverified (e.g. no radio) 7000 return without Mode C, flying "across" an airway whose base is say FL55 and which has traffic in it at say FL65, you have to reroute that airway traffic??
There are many such situations!
I think a lot of people knowingly don't switch Mode C on. In my PPL training it was never switched on. Bizzare...
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I get the impression that some aircraft commanders are of the opinion that leaving "Mode C" off is a good way to avoid detection if they infringe CAS by accidently departing their cruise altitude i.e. the are VFR at 2400' under the London TMA and they "drift" up to say 2600'
For myself, I switch on to Mode C and leave it on. I have had the fortunate benefit of visiting Farnborough LARS and Thames Radar ATSUs and so have been able to see the benefit to the ATCOs and therefore other aircraft.
I like the idea of using all methods available both visual and by means of RF to enable me to see and be seen with all available information to anyone whom it concerns.
For myself, I switch on to Mode C and leave it on. I have had the fortunate benefit of visiting Farnborough LARS and Thames Radar ATSUs and so have been able to see the benefit to the ATCOs and therefore other aircraft.
I like the idea of using all methods available both visual and by means of RF to enable me to see and be seen with all available information to anyone whom it concerns.
Last edited by Andrew Sinclair; 25th Jul 2003 at 19:27.
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The use of Mode C is also for your benefit. Although the "C" may be unverified the likelihood is that is it a reasonable indication of your altitude. We see traffic not working us with "C" on we pass the traffic and say "indicating ****ft unverified" the other aircraft is able to look above or below it to find said aircraft also they sometimes decide to climb or descend to help with their separation.
As an aside but with reference to Andy's post when we verify Mode C if the figure indicated on our radar screen is with 200ft of that stated by the pilot we consider the "C" to be verified
I have said it before and will say it again , we are not there to Police the skys we are there to help pilots out, so why do they think we are in some way Big Brother
As an aside but with reference to Andy's post when we verify Mode C if the figure indicated on our radar screen is with 200ft of that stated by the pilot we consider the "C" to be verified
I have said it before and will say it again , we are not there to Police the skys we are there to help pilots out, so why do they think we are in some way Big Brother
Last edited by flower; 25th Jul 2003 at 19:26.
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IO540
traffic not transponding, or not transponding "C" are deemed to be flying beneath Controlled Air Space , we do not take avoiding action unless we have reasonable knowledge that the aircraft is in side CAS, or we have a an aircraft with radio failure which may possibly have entered CAS.
Hope that helps
traffic not transponding, or not transponding "C" are deemed to be flying beneath Controlled Air Space , we do not take avoiding action unless we have reasonable knowledge that the aircraft is in side CAS, or we have a an aircraft with radio failure which may possibly have entered CAS.
Hope that helps
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Flower
That's what I expected. What I didn't get was Rodan's statement
What I don't know if these pilots appreciate is that if they are in class G and not talking to anyone, (no problems with that, btw, it's up to you), with 7000 set and no mode 'C', they are effectively wiping out a 10 (ten) mile diameter cylinder of airspace around them from the surface to FL245 for anyone who is in receipt of a radar advisory service.
ATC would direct traffic receiving a RAS around suspected conflicts. Would you advise an a/c receiving a RAS, in any airspace, around a radar return without Mode C, or would this happen only if the a/c receiving RAS was outside CAS? I suspect the latter might be the case. I flew under RAS only once (outside CAS) as I normally prefer RIS, and got directed in doglegs all over the place.
That's what I expected. What I didn't get was Rodan's statement
What I don't know if these pilots appreciate is that if they are in class G and not talking to anyone, (no problems with that, btw, it's up to you), with 7000 set and no mode 'C', they are effectively wiping out a 10 (ten) mile diameter cylinder of airspace around them from the surface to FL245 for anyone who is in receipt of a radar advisory service.
ATC would direct traffic receiving a RAS around suspected conflicts. Would you advise an a/c receiving a RAS, in any airspace, around a radar return without Mode C, or would this happen only if the a/c receiving RAS was outside CAS? I suspect the latter might be the case. I flew under RAS only once (outside CAS) as I normally prefer RIS, and got directed in doglegs all over the place.
Why do it if it's not fun?
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IO540 - you can't get a RAS inside controlled airspace, only outside! If you receive radar vectors inside controlled airspace, it would be a Radar Control Service. 
FFF
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FFF
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I try to fly as high as possible and leave let others bimble around at 1500-2000', that way you tend to get cleaner air and stay clear of other traffic. Trouble is, high as possible often aint that high in the UK [though we did get to FL210 the other day outside CAS 
]
I can't believe someone with mode C would leave it off, thats insane in my view.
EA
]I can't believe someone with mode C would leave it off, thats insane in my view.
EA
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I was always taught to squawk 7000 Mode C as soon as I had switched the landing light off on after take off checks (unless in the circuit) and switch it to STBY when I had the airfield in sight and switched my landing light on. This seems sensible, and is easy to remember:
Landing Light On: Transponder STBY
Landing Light Off: Transponder ON
F-Wyg
Landing Light On: Transponder STBY
Landing Light Off: Transponder ON
F-Wyg
Fly Stimulator
If you are buying a transponder for your new CT, I assume that since it's the cheapest and lightest on the market you're probably looking at the Microair T2000. Do be aware that the importer has never actually bothered to get CAA approval on it and therefore you can't fit it until they do (rumoured to happen sometime in the hopefully-not-too-distant-future on the back of a German JTSO that doesnt exist yet).
My opinion on people selling avionics in the UK that can't legally be fitted you can probably guess.
G
If you are buying a transponder for your new CT, I assume that since it's the cheapest and lightest on the market you're probably looking at the Microair T2000. Do be aware that the importer has never actually bothered to get CAA approval on it and therefore you can't fit it until they do (rumoured to happen sometime in the hopefully-not-too-distant-future on the back of a German JTSO that doesnt exist yet).
My opinion on people selling avionics in the UK that can't legally be fitted you can probably guess.
G
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IO540:
I was referring to the situation where an aircraft outside controlled airspace receiving a RAS comes into conflict with a no-mode-C unknown aircraft - happened to me again this morning, and a passenger carrying flight had to be vectored all over the sky to avoid a 7000 squawk that was probably no threat whatsoever
.
With aircraft inside controlled airspace, like airways, it is assumed that any unknown traffic is outside controlled airspace unless the controller has reason (eg., mode 'C' returns) to believe it is inside controlled airspace - lost etc. This brings up another situation which has been mentioned - if you inadvertantly strayed into an airway or control zone without mode C selected. The controller would assume you were beneath the airway or above the control zone unless they had any other reason to suggest you weren't, and would ignore you. In these circumstances, quite apart from the ramifications of the airspace infringement, leaving mode C on is a good way to avoid an airprox or worse
.
I was referring to the situation where an aircraft outside controlled airspace receiving a RAS comes into conflict with a no-mode-C unknown aircraft - happened to me again this morning, and a passenger carrying flight had to be vectored all over the sky to avoid a 7000 squawk that was probably no threat whatsoever
.With aircraft inside controlled airspace, like airways, it is assumed that any unknown traffic is outside controlled airspace unless the controller has reason (eg., mode 'C' returns) to believe it is inside controlled airspace - lost etc. This brings up another situation which has been mentioned - if you inadvertantly strayed into an airway or control zone without mode C selected. The controller would assume you were beneath the airway or above the control zone unless they had any other reason to suggest you weren't, and would ignore you. In these circumstances, quite apart from the ramifications of the airspace infringement, leaving mode C on is a good way to avoid an airprox or worse
.
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It's not just ATC who have a problem if Mode C isn't used.
The pilot of any aircraft with TCAS, (which detects aircraft with an operating transponder), will not know the altitude of the other aircraft without C.
This means that his TCAS will give a loud "TRAFFIC! TRAFFIC!" voice warning (20 seconds to a collision, impossible to ignore) even when the aircraft may be well separated in altitude. I can't stress how difficult it is to locate an aircraft visually if you don't know whether it is above, below, or at the same level as yourself.
This causes a major problem to passenger carrying aircraft. The last thing I want to do is to start any unnecessary hard manoeuvring, it puts the $hit$ up the pax, that's what TCAS is supposed to prevent. It also greatly reduces the number of heartbeats left over for my retirement, if you get my drift.
If you've got it, please use it whenever you use the transponder. It's for your safety as well as mine.
I do my best to avoid you, so please help us both out.
Thanks.
The pilot of any aircraft with TCAS, (which detects aircraft with an operating transponder), will not know the altitude of the other aircraft without C.
This means that his TCAS will give a loud "TRAFFIC! TRAFFIC!" voice warning (20 seconds to a collision, impossible to ignore) even when the aircraft may be well separated in altitude. I can't stress how difficult it is to locate an aircraft visually if you don't know whether it is above, below, or at the same level as yourself.
This causes a major problem to passenger carrying aircraft. The last thing I want to do is to start any unnecessary hard manoeuvring, it puts the $hit$ up the pax, that's what TCAS is supposed to prevent. It also greatly reduces the number of heartbeats left over for my retirement, if you get my drift.
If you've got it, please use it whenever you use the transponder. It's for your safety as well as mine.
I do my best to avoid you, so please help us both out.
Thanks.
I was always taught to squawk 7000 Mode C as soon as I had switched the landing light off on after take off checks (unless in the circuit) and switch it to STBY when I had the airfield in sight and switched my landing light on.
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hello all!
in Germany it is required to have your transponder on 0022 above 5000 ft MSL or 3500 GND for motorized aircraft (gliders exempt), below that 0021 is only recommended. I remember a student telling me that another instrutor told him "leave the transponder off, they (i.e. ATC) don't need to see what we're doing".
not a good example for a student IMHO!
I flew with another student on a XC... we stayed below 5000 ft but had the transponder on 0021 C as recommended and listened into FIS, not announcing ourselves, but listening in gave us any info we needed (we were outside any type of restricted areas, of course). There was quite a bit of military traffic around. At one point we heard ATC tell a military jet about "unidentified traffic at about suchandsuch altitude flying, flying NW at suchandsuch o'clock position"... the jet replied "in sight"... my student looked at me with a big eyed look and asked "did they mean us?" I calmly affirmed. That is one student that will always turn on his transponder I'm sure!
Westy
in Germany it is required to have your transponder on 0022 above 5000 ft MSL or 3500 GND for motorized aircraft (gliders exempt), below that 0021 is only recommended. I remember a student telling me that another instrutor told him "leave the transponder off, they (i.e. ATC) don't need to see what we're doing".
not a good example for a student IMHO!I flew with another student on a XC... we stayed below 5000 ft but had the transponder on 0021 C as recommended and listened into FIS, not announcing ourselves, but listening in gave us any info we needed (we were outside any type of restricted areas, of course). There was quite a bit of military traffic around. At one point we heard ATC tell a military jet about "unidentified traffic at about suchandsuch altitude flying, flying NW at suchandsuch o'clock position"... the jet replied "in sight"... my student looked at me with a big eyed look and asked "did they mean us?" I calmly affirmed. That is one student that will always turn on his transponder I'm sure!
Westy
Last edited by WestWind1950; 27th Jul 2003 at 16:14.
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Current thinking is that you turn your transponder on before take-off and turn it off after landing. It doesn't get much simpler than that.
I stand to be corrected.
FWyg
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People flying below CA with only mode A is a pain for those above them in CA. mode A will set of a Traffic Advisory on the TCAS, because it doesnt know exactly how far below it is.... If mode C was switched on then the TA may not have happened in the first place.
Why do it if it's not fun?
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I was told that this was not encouraged on return to the airfield once it was within visual range as aircraft in the circuit just create screen clutter for ATC and can potentially cause TCAS alerts for other aircraft on approach?
FFF
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