gasax

Full info was on the LAA site a few months ago (not checked since). The situation was stated at the last mode s meeting at LAA HQ and the CAA were advised that some offices were not accepting new aircraft with mode c, by the LAA.

Rod1

The CAA policy on Mode S transponder fit is best summarised as follows:

When operating in airpsace or under any air traffic service where transponder equippage is required, then Mode S SHALL be the means of compliance.

These are my words rather than a direct quote, but are clearer than the AIC and I assure you that this is precisley the emphasis that the CAA intend with their current mandate.

What this does not preclude is the fitting or continued use of Mode A/C purely for purposes of conspicuity (both to ATC and TCAS). Whether you can continue to buy non-Mode S kit is another matter.

This is a copy of the CAA stuff;

Phase 1 of the CAA’s phased approach for the further carriage of Mode S requires that Mode S transponders replace the use of Mode A/C in all circumstances where transponders are currently mandatory. This proposal was considered to be the minimum next step that should be taken towards the phasing out the use of conventional Mode A/C SSR in UK airspace. This proposal was submitted to and subsequently accepted by the Secretary of State for Transport, and thus enters into force in the Air Navigation Order (ANO) from 31 March 2008.

This measure does NOT affect the voluntary carriage of transponders.

A transition period until 31 March 2012 is being provided to permit time for owners of affected aircraft currently equipped with Mode A/C transponders to have them upgraded to Mode S.

Owners and operators of Mode A/C transponder equipped aircraft are exempted from the ANO until 31 March 2012 by the General Exemption, Official Record Series 4 No. 670.

The exemption only applies if:

the aircraft is equipped with SSR equipment, installed on or before 31 March 2008, which includes pressure altitude reporting capable of operating in Mode A & Mode C and capable of being operated in accordance with such instructions as may be given to the aircraft by the ATC unit;
the aircraft is not operating under IFR within EHS airspace; and
written notice of the aircraft registration and aircraft serial number has been given to the CAA.

Ahhh!

This set of statements does not apply to the VOLUNTARY carriage of transponders - so if there is not a compulsory requirement to carry Mode S then none of the above is applicable.... because it applies to the transition arrangements of compulsory transponder carriage!

As usual with this whole debacle the CAa being less than straight forward (or even honest and transparent!).

Rod I've had a browse through the LAA site and not been able to find the applicable guidance. I'll drop John Brady a note to see if he can post something suitable.

Many thanks for the help!

I suspect you are right. I was hopeful this unit would be on sale last year but the last news from Kinetic said it was going through the certification stage. Since then there's been no update and I doubt it would take over a year for this process.

I understand that Mode C is now prohibited in Dutch airspace?

There are some threads on the Flyer site re Mode S applicability over the channel. My understanding is that above 1200 ' Mode S is required and in the designated TMZ areas, which do cover quite an area. The Dutch seem to be further along with the process than any of the other Europeans.

gasax

Your statement;

Ahhh!

This set of statements does not apply to the VOLUNTARY carriage of transponders - so if there is not a compulsory requirement to carry Mode S then none of the above is applicable.... because it applies to the transition arrangements of compulsory transponder carriage!

Is correct. However remember most transponders on VFR aircraft fall into the voluntary bracket now the CAA has backtracked on the compulsory mode s for all nonsense. Mode C is also very useful in France and as second hand units are very inexpensive, with no fitting costs on LAA aircraft this is a solution which is quite popular.

Rod1

So it seems I can legally fit a second hand mode C unit to my Emeraude that doesn't have one at all & never has for it's 50 yrs. But no body is building new mode C units anymore?

I believe all of the US manufacturers will still supply new Mode a/c sets and there is still a stock of mode a/c sets from even the european manufacturers.

And as Rod says thanks to the various regulatory authorities there are a lot of secondhand sets available (I fitted a mode c unit I bought from the RSA website last year - 400 Euro complete).

You can still buy a B/K KT76A Mode A/C unit from HM for 1051 inc vat. You would be mad to do it with second hand units around for £2 – 300.

I have Mode C, and will put off mode s for as long as possible. The regulator has a three phase plan. Phase Three is ADS-B, and I may save big money by fitting a second hand mode s, or going straight for an integrated, approved ADS-B with GPS unit (which will probably also be mode s compatible).

Rod1

Rod, see your pm's. Regards - Chris N.

I have been told that it is impossible to purchase a Mode S transponder!!

All that are available are combined Mode A/C/S. A solely Mode S would sit under the panel or in some obscure place in the aircraft as it would not be necessary to touch it and would presumably be cheaper. The sqawk codes are obsolete with Mode S.

Is this correct?

Mode S includes Modes A and C
 

Jodelman - I think you are confused. All Mode S transponders are required to reply to legacy Mode A/C interrogations, so obviously any "Mode S" transponder is really Mode A/C/S. Hence, to put Mode S into an aircraft that has a Mode A/C transponder, you remove the Mode A/C transponder and replace it with a Mode A/C/S unit.

Also, the squawk code is alive and well with Mode S. It still forms a primary part of the identification of the aircraft, along with the callsign (Flight ID), and is required anyway for interworking with Mode A/C interrogators.

The CAA says yes!
 

I've revived this thread as I have an answer from John Brady of the LAA on CAA 'policy' on voluntary fitment of transponders

"the CAA have confirmed you can fit an A/C transponder without restriction as long as you don't try to fly in airspace where mode S is mandatory (Airways and IFR in the London TMA). "

So much of the official output is almost misleading. Given the present low cost of Mode C units it would be well worth getting hold of one and fitting it!