Operation of Transponders

[John Brady]

With the help of other LAA members I am analysing aircraft and radio licensing data to assess what proportion of what class of aircraft are fitted with transponders. I often hear it said that transponders would have saved an airspace incursion or a collision or near miss but nobody seems to know how many and which aircraft actually do carry them so nobody is in a position to confirm or refute that proposition. So we are trying to find out. When we do I will tell you

But there is a view that some pilots who have transponders do not switch them on or that they only turn them on sometimes.

In Switzerland it is the law that if an aircraft has a transponder it must be switched on at all times in flight.

Should the UK have a similar law?

John Brady

[Ian Melville]

Though I am very much in favour of everyone who does have a transponder making full use of it, I cannot see how a 'law' would work in practice.

What if there was an issue with the transponder or it was away for servicing? Would the aircraft be grounded, or would there be an application for exemption?

The easiest way to find out which aircraft have transponders fitted and working is to make it a mandatory question at C of A or permit renewal. Take a few years though.

[dmcnicholl]

Making the use of a transponder (where fitted) mandatory makes no sense to me when making use of a radio (where fitted) is not mandatory. OK, in certain classes of airspace radio contact is equired but you get my point.

And what happens when we get L.A.S.T. or L.P.S.T. devices which will be the only ones possible for lighter, simpler types of aircraft? As they are discussed just now such devices will be movable between aircraft so a C of A or Permit renewal question would be easily circumvented and the poll rendered meaningless.

[Brian Hope]

Hi John. Education and trust are better than a law that would be difficult, if not impossible, to police. I think most of us who have been flying for a while have a distrust of the authorities and are wary of using our transponders all the time because they 'may be used in evidence against us'. This comes from a time when the CAA was seen as somewhat less accommodating of GA than I'd like to think it is now but old habits die hard. Trust has to be won and only when pilots are convinced that CAA isn't going to reap the benefit of us all using our transponders only to hang us out to dry when we err, will they become more universally used. These 'on the spot' fines aren't exactly going to encourage anybody either, are they? Start handing those out like confetti and my guess everybody will be switching off.
How big an issue is it? On our strip there are ten aeroplanes; seven have transponders and maybe one pilot use his as a matter of course; they are generally used for helping to get clearances through airspace or, as we are close to Southend, warding off the biggies who are invading the Class G airspace. We may not be typical of course but, discounting the twelve fingers and webbed feet, I'd be surprised if we were that far off normal.

[Nigel Hitchman]

I agree with Brian.
I fitted a transponder to my RV as I thought it would make it easier to get thru certain controlled airspace and so I could go in transponder mandatory zones or certain countries Class C/D airspace where they demand a transponder to go through. I don't want to be forced to switch is on all the time and especially to have some sort of check that I am complying with this rule. sounds like lots more unnecessary bureaucracy. And as I paid for the transponder, I should be able to use it when I like and not when someone else tells me.
I tend to turn on the transponder if Im going thru some airspace where its going to help me and then tend to leave it on for the rest of the flight, otherwise I conserve it for future use by leaving it turned off.
What also needs to be taken into account is fitted transponders that are unserviceable. Mine stopped working 4 or 5 years ago, but was still fitted for a couple more years, but inoperative, until I got around to getting it fixed.
Now if the airlines who want to grab our airspace and make us all have transponders and 8.33 KHz radios were to pay for those transponders and radios, then I might think again.