KLN 90B RNAV Approaches

[falcon71]

Hello, I'm interested in the KLN 90B. As the KLN 90B is an older device, I wonder if it supports RNAV approaches? Or does it only support VOR/NDB approaches? I assume that ILS/LOC approaches are not in the database?

[IO540]

The KLN90B can be installed with an AFMS (approved flight manual supplement) which authorises full IFR i.e. enroute BRNAV, SIDs/STARs, and approaches.

Same as the KLN94 which I have.

I assume you are EASA-reg. Getting the AFMS for an N-reg is almost impossible in Europe because the NY IFU has washed its hands of avionics 337s. There are some back door routes but most avionics shops haven't got them organised.

One issue in Europe is that the database does not contain any SIDs/STARs although it does contain the waypoints which make them up. Honeywell have washed their hands of this - as they have with all GA avionics in recent years.

These units cannot be certified for PRNAV.

However, don't install the KLN90B now. It's way obsolete. I hate to say this, and I hate feeding Garmin as they already own the world, but a GNS430W is the way to go in Europe, with all the Eurocontrol crap. You can get PRNAV with that too, one day when avionics shops work out how to do the paperwork. But if you must install a GPS of that form factor, put in a KLN94.

[falcon71]

Thank you for your answer.
Yes I'm aware that the KLN 90B is outdated, but I've seen it in action once and I liked it much more than the GNS430. And it's so much cheaper!

Do you know how the situation in the USA is? Is the KLN 90B approved for RNAV approaches there?

[IO540]

Yes, that is what my earlier reply related to.

If you install an IFR approved GPS in the USA, the avionics shop does a flight and ground avionics test, fills in some boxes (checking for e.g. interference between VHF transmissions and the GPS, on 11th and 13th subharmonics of the GPS 1575MHz carrier) and sends this off with a 337 and an AFMS (which comes straight out of the back of the GPS installation manual) to the FAA. It actually goes to an ACO (aircraft certification office) which stamps it, signs it, and it goes into the flight manual.

The EASA process is vaguely similar but there are no tests involved AFAIK; it is just a purchase of the papers and nobody looks at the aircraft.

The SID/STAR issue is that to fly an RNAV SID/STAR you should legally load the whole procedure out of the database. Most airports with RNAV ones also have some non-RNAV ones, however. Anyway, practically, you can load the individual waypoints... if you have time.

There are no real "overlay" approaches in these units, of the US style.You get some but it is a very stripped down representation and IMHO very confusing. GPS RNAV approaches are of course in there in full, but there are very few in Europe.

In general, conventional approaches are flown using a GPS in the OBS mode :) So you are not using the database at all.

[falcon71]

All right, that explains everything. Thank you very much!

[IFMU]

Here in the US my flying club has a KLN89B IFR legal GPS in our 1967 PA28R. It is old and archaic but is useable for IFR enroute navigation and GPS RNAV approaches. No ILS/Glideslope but we have radios for that. The ADF was removed from the airplane some time ago and the GPS is also handy to locate NDB final approach fixes on an ILS.

-- IFMU