IO540 makes some good points but thay are minority cases.
Most of the recreational flying community fly at weekends when VFR traffic, certainly in my area, are most unlikely to get granted a RIS outside controlled airspace. Result, this is of very little value in the real world.
“Carrying a Mode C/S transponder also makes you visible to commercial traffic's” true, but how many commercial movements are there a less than 1000 ft in class g airspace? For that mater how many at less than 2000 ft. Again, this is a very small advantage in the real world.
“Carrying a Mode C/S transponder also makes it easier to get CAS transits in many areas, especially abroad.”
Completely true, and the reason I have mode c, but most recreational flying stay in the uk and fly most of the time if not exclusively in class g. Again this is a minority advantage.
“And finally carrying a Mode C/S transponder makes you visible to GA traffic carrying some kind of traffic warning device, either one of the cheapo transponder receivers, or the full £20k system.”
Again completely true, but most flying machines do not have such a device. I did an estimate of the traffic in my local area following the recent collision (which was at 1400ft agl by the way) and came to the conclusion that 80 – 90% of the local flying machines did not have transponders. With this in mind I have modified my operating procedures and increased my lookout as much as possible.
“It is obvious from the pattern of UK GA that pilots who fly without a transponder are statistically much more likely to be flying low down, and it is low down where they are much more likely to get hit. So the "only bimbling" anti-transponder argument is”
I have nothing against transponders, I have a fully serviceable mode c unit and I use it. However we must face the fact that most uk flying machines cannot fit one, and unless the LASP finally arrives (which is very unlikely) they never will.
Please feel free to use traffic alert systems, but still work on the lookout. I recently had a ride in a top end IFR single doing 140kn with all the kit, and the owner made no attempt to keep a good lookout, he just engaged the autopilot and monitored the systems. When I asked him he was of the opinion that his equipment would warn him if there was an issue. This is a very bad idea, please do not do this.
The only option in town for spotting most of the traffic which is flying around at the weekend is lookout. We all need to give it more effort.
Rod1