Do I need 1 or 2 FM Immune Nav for Airways Fit on G-Reg?

[irish seaplane]

Hi,

Just wanted to see who could shed light on this. Do I need 1 or 2 FM immune NAV radio's for a UK Airways fit on a Golf Reg aircraft?

Also has anybody installed any Overhauled King Avionics and been happy with them. I had looked at Narco but hear people have had a good deal of issues with them after installation.

Thanks

William

[Shunter]

I believe it's only 1 FM immune set required (but I'm sure someone will correct me if I'm wrong). Incidentily, having access to FM transmitters I tried to interfere with a non FM immune set a while back. Nothin' happened. Red herring if you ask me.

Got 2 FM immune Narcos in the Cardinal. Had no bother from them at all.

[IO540]

Most of the 1990s King avionics stuff is actually very good; arguably the best of the crowd of that era. E.g. KX165A.

A good source for overhauled avionics is Southeast Aerospace in Florida. Excellent service. Much of their overhauled stuff looks just like brand new.

[jxk]

Heard that Narco had been sold to repair only organisation. Can anyone confirm this?

[irish seaplane]

I see from AIC 87/2000 that you only need one FM immune Nav... In that case would I be better off getting a King KNS 80/81 as NAV2. My thinking is that it would make you RNAV compliant for the odd above high jaunt, give you a DME and a good backup to GPS?

Anybody had any luck with these units... Know they're old etc. Had'nt heard that Narco were sold....

W

[IO540]

In that case would I be better off getting a King KNS 80/81 as NAV2. My thinking is that it would make you RNAV compliant for the odd above high jaunt, give you a DME and a good backup to GPS?

A KNS80 will give you legal BRNAV only if the installation is thus certified, AIUI.

If you want the capability, not necessarily legal, get a used IFR GPS.

An IFR GPS is vastly better than a KNS80 because (airways context) ATC treat all waypoints as RNAV waypoints and will happily send you to XYZ where XYZ (which just happens to be a VOR) is 200nm away. A KNS80 is thus useless for RNAV. You could get a KNS80, get it BRNAV certified, and then you go up and ATC give you a 200nm DCT and then you are stuffed. And it's a lot of work, whereas doing a DCT with a GPS is as fast as setting up the waypoint name.

A KNS80 is also not FM immune unless you spend the £700 or so on an antenna filter.

An IFR GPS will also give you the OBS mode which is a really clever trick, dead handy for all kinds of stuff

[irish seaplane]

Sounds like your right IO-540.... I'll scrap that idea with the RNAV. Just looking at the quotes I got for 2xKX155's, 2 Indicators, DME and 2nd ALT makes me cringe.

I have 1xComm, 1xNav, 1xADF, 1xTXPR - so maybe I'll get quotes on the GNS430W and see if I can bear the pain. Would the Garmin "one box" fulfill the role of DME? An instructor once told me that GPS's read "Slant Range" too - but I wouldn't believe him......

W

[IO540]

The best way to do avionics is to get it new or refurb from the USA e.g. Southeast Aerospace and then find a friendly avionics man to install it on a daily charging rate.

The Q whether a GPS will do for a DME has never been settled. The normal wording in the equipment carriage regs is "distance measuring equipment" and it doesn't say it has to use the DME beacon. IMHO using a GPS instead of a DME is stretching the bounds of imagination but I am not a lawyer. I don't know of any prosecutions (UK or Europe) under the equipment carriage regs, but I don't think that is ever the problem in aviation - the real issue is insurance not paying out on a flight which was illegal to start with.

A more practical view is what kind of kit you want to backup a GPS. I would have a VOR/DME. ADF is not so good but it remains essential due to the large # of NDB approaches in Europe; again one actually flies them with GPS but checking the ADF at the FAF is a good idea.

[S-Works]

I am with IO on this, GPS is by far the best way to go. A good IFR GPS will beat hands down anything else you fit. The perfect solution is a Garmin 430/530 as you get IFR GPS and ILS and 8.33khz FM immune kit all in one box.

Couple it to a Garmin 340A Audio panel and you are quids in.

I have a 430, King DME, King ADF and an MX170B with a 340A audio panel connected to a NS360 HSI and the Garmin LOC/ILS indicator and a King indicator for the 170B.

Perfect interference free installation.