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Replacing GNS430/530 with 430W/530W in an EASA-reg, and LPV etc

I met up with a possible new aircraft buyer today and this came up.

What is the situation given that PRNAV approval is highly desirable if spending any real money?

AIUI, the GTNs have EASA AML STCs with an AFMS which gives you PRNAV. And @bookworm’s post here appears to suggest that will be the job done.

But the GNS boxes never got an EASA AML STC, did they? There are various privately done (by avionics shops) STCs. I wonder how much these are sold for?

Also are “W” boxes direct plug-in replacement for the non-W?

I know that to be legal one also is supposed to fit the “W” antenna (though this was discussed here recently and it looks just a fake marketing / product differentiation job).

What about getting LPV? The non-W box would obviously have been wired to fly an ILS, with H+V guidance from the nav section. Would the same wiring also give you LPV?

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

There are various privately done (by avionics shops) STCs. I wonder how much these are sold for?

For EASA reg, check this and this.

Last Edited by Guillaume at 10 Mar 14:32

OK thank you; let me add this would be a TB20, S/N 2000+

So the cost is just £300?

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Also are “W” boxes direct plug-in replacement for the non-W?

I know that to be legal one also is supposed to fit the “W” antenna (though this was discussed here recently and it looks just a fake marketing / product differentiation job).

What about getting LPV? The non-W box would obviously have been wired to fly an ILS, with H+V guidance from the nav section. Would the same wiring also give you LPV?

The GNS430W/530W is plug compatible with the non WAAS version. There is an extra annunciator signal, and in many installations an external annunciator is required. The antenna needs to be updated to one compatible with WAAS, this is not marketing, it has a different gain and masking angle which are needed to meet the TSO requirements. The non WAAS antenna will function, but not at a satisfactory level. The antenna cable is also likely to need replacement. if it is not double shielded such as RG400.

If the non WAAS version was wired in accordance with the install manual, it will have used the GPS or ILS approach signal instead of ILS energize, in which case it will be compatible with most autopilots. Many avionics shops “don’t need to read no stinking manual”, so a rewire may be necessary for this pin. All in all, it is a relatively painless installation or upgrade.

KUZA, United States

Some good news on the EASA GNS-W AML STC for LPV.

Following several months of discussion with EASA, it was agreed that the need for a remote LPV annunciator could in some circumstances be removed, so aligning the EASA STC with Garmin’s FAA STC. Gama Aviation have now submitted the revised data package to EASA and are expecting the updated approval within the next month. This will open up use of the STC to a much wider range of aircraft where installing the required annunciator was physically difficult due to panel space issues and added significant extra cost.

Last Edited by wigglyamp at 13 Mar 10:40
Avionics geek.
Somewhere remote in Devon, UK.

wigglyamp wrote:

in some circumstances be removed

Great! But what circumstances?

ESKC (Uppsala/Sundbro), Sweden

The left edge of the GNS-W must be no more than 12.8 inches from the vertical centreline of the standard TEE attitude display (assuming it’s an aircraft flown from the left seat). This requirement should address most Part 23 light singles and Twins. There are still some exceptions where an annunciator will be needed, such as older Barons and Bonanzas with the throw-over style control and the angled radio stack well to the right of the pilot. The new STC documents have a dimensioned picture that the certifying staff must use to assess the location of the GNS in making the determination.

There’s also amended wording in the AFMS ‘Normal Procedures’ section requiring the pilot to ensure that the message display on the GNS-W is especially included in the normal scan, as this will now be the primary point of information for knowing the GPS approach status.

Avionics geek.
Somewhere remote in Devon, UK.
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