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Why do I need a THIRD radio if I want GNS430w + GNS530w (dual GNS certification issue)

Peter wrote:

It is actually a very interesting Q whether this EASA “fear” of a dual GNS failure killing both boxes is still applicable to one GNS and one non-GNS box.

It just shows how clueless are people involved in defining such regulation.

Pirho wrote:

I would never have thought having two boxes from the same family would be an issue.

And it’s not an issue – just take G1000 as an example.

LDZA LDVA, Croatia

I haven’t read the whole thread, but our current aircraft relies on two GNS430 units. I can also think of about 5 aircraft I previously flew both privately and commerically that had various combinations of 430 and 530 boxes. I would never have thought having two boxes from the same family would be an issue.

United Kingdom

I’m afraid I have no further information. I ended up replacing my 430 with a 530W, and then adding a Trig radio as backup, so two radios in total, and not three.

Howard

Flying a TB20 out of EGTR
Elstree (EGTR), United Kingdom

The initial post references a 3rd COM requirement. One could ask @Howard for more info…

But perhaps no longer applicable to newer (non-GNS/GNSW) boxes? I might ask Socata about the other questions.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

So the dual-GNS STC which required a separate (third) radio was done by somebody else. Who was that?

There are quite a few dual GNS STCs listed by EASA – no AML versions, and nothing in the descriptions to suggest they had to have the third Comm fitted. I had heard that some German companies were pushed down that road by the LBA but were doing the dual GNS as a Minor change and had to do the third Comm to avoid an STC.

We achieved dual GNS certification in quite a few Part 23 aircraft under Minor changes (both as direct UK CA-approved Minor mods prior to EASA and later also under our Part 21J). The hassle one for me was on a Citation 500 when a particular UK CAA expert pushed the third Comm issue and we spent a long time arguing about it. I won in the end!

Last Edited by wigglyamp at 25 Feb 17:08
Avionics geek.
Somewhere remote in Devon, UK.

I then misread your post above.

So the dual-GNS STC which required a separate (third) radio was done by somebody else. Who was that?

And has this issue gone away for

  • a combination of GNS and non-GNS boxes
  • Avidyne products

I also wonder how exactly Socata got their 2×GNS430 option (which sadly I didn’t choose in 2002 ) approved, presumably by the DGAC? IIRC, they also had a 430+530 option available.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

@wigglyamp did the original “extra radio” STC.

Wigglyamp certainly did not do the ‘Extra radio STC’. As I said in an earlier post on this subject, my STCs claimed credit for other existing systems (transponder, DME) to mitigate a potential dual GNS failure and these arguments were accepted by EASA..

Avionics geek.
Somewhere remote in Devon, UK.

It is actually a very interesting Q whether this EASA “fear” of a dual GNS failure killing both boxes is still applicable to one GNS and one non-GNS box. In the past, before Avidyne came along with the IFDs, if you wanted two modern navigators they had to both be GNS.

Thinking about my last Q, I vaguely recall Avidyne have an STC for two, but I am not sure. @steveavidyne will know.

@wigglyamp did the original “extra radio” STC.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Is this dual GPS installation issue still current under present EASA regime?

FWIW, I know about one SE-reg which was equipped with a used GNS430 and a new GPS175 (Garmin’s simplest SBAS navigator) last year, both hooked up to dual G5. At least the avionics shop had no problems with that.

ESKC (Uppsala/Sundbro), Sweden

Is this dual GPS installation issue still current under present EASA regime?

Is it also applicable to Avidyne?

Administrator
Shoreham EGKA, United Kingdom
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