Menu Sign In Contact FAQ
Welcome to our forums

KSN770 - opinions?

What I understood the KSN770 is TSO'd now but not yet STC'd. I think this will be on the market before Avydine is delivering....

I am counting down as jan 2014 is nearing and 8.33 Khz mandated for IFR is lurking close by as such my old KX155 will have to be decommissioned soon..

I may have to tackle the situation by replacing my KX155 NAV/COM 2 with a GNC255 and wait to see what will happen with the KSN770 approval..

The KSN770 may well be the answer to the Garmin monopoly in the field right now...lucky there is only the DME switch btw the NAV1/2 for compatibility if I choose that road..;)


Re the FAA holding things up at Avidyne, there may be a lot of truth in it. First, the FAA runs on a shoestring budget right now with much reduced capacity. I hear this from people working flr them that many departments have simply been halved or even closed down quite randomly. Avidyne are by far not the only ones to complain about this.

Secondly, Garmin seem to have preferential speed at everything they do plus nearlyunlimited finances..and human ressources. That is why their stuff sails through every certification and they have the means to pay add costs out of petty cash. King may have equal means financially with honeywell behind them to sort out issues fast and furious. Avidyne and Aspen are no match for them financially but seem to be a lot ahead in their thinking. So whenever certification authorities develop a new case of documentitis, it is a real issue for them whereas the competition simply can put the ressources forward to write up whatever satisfies the empires...

Personally my bet is on them on eventually deliver a system which will make Garmin cringe. That is ig garmin does not buy them first and subsequently close them down.

LSZH, Switzerland

Last year we found the KSN770 quite appealing when compared with the GTN. Our plane was "all King" with the KMD550, KLN94, KX155 et al. To replace this with another King product made us consider and request a quote for the installation. As you say Peter this box has been announced six years ago and was vaporware until now. We picked Garmin then.. We also considered the KMD840 PFD at the time - which is now removed from the market. We're saving for an Aspen...

At least Honeywell doesn't have one of these "give us $10,000 now and we may deliver a working product before 2020"-schemes Avidyne keep annoying us with. But as it was said above 8.33 is almost upon us and to be ready for the 2014 season the KSN should be available now. You will still have version 1.0 then and the GTN became only excellent from version 4..

just my two cents

..and btw flying behind the GTN750 won't make you look back once at a CGA resolution KMD... ;)


Re the FAA holding things up at Avidyne, there may be a lot of truth in it

There may be, but the years-long delays at Avidyne ran for years before this extremely useful latest excuse appeared.

What concerns me, with both Avidyne and Honeywell, but especially Honeywell because I have had a lot more contact with them, is that neither company seems to have any engineering expertise left in-house.

I have seen the "Avidyne blog" which seems to be very frank and open but really the content is just banal stuff which they could be making up on the spot, to stop even more people getting out of their IFD deposits.

Also who wants a beta 0.0 version of any firmware? In aviation? There is a word for that

I would also suggest taking a hard look at what expense is actually likely to be legally required.

8.33 is coming, no question. So look at how to meet that. You can get a KX165A/8.33. To replace a KX155 is about a day's work. To replace a KX155A is just a plug-in change. The cost of a 165A/8.33 is far less than installing a new big GPS box (770, GTN, IFD, whatever). There are also the new Garmin radios...

All the other legal requirements are some way off.

The only one I see is PRNAV in enroute airspace. This is being denied, but it is going to appear one day in TMAs, which for IFR GA is the same thing! So why not save your cash for when you need to rip out your perfectly working IFR kit to meet that stupid paperwork requirement. By then, the 770 and the IFDs will either be out and debugged, or will be long forgotten history.

The only other thing which would be "nice" is LPV, but the UK has still got just one LPV approach, after what seems like years... and most European airports that have the necessary (for us) Customs also have an ILS. And the cheapest and easiest way to get into Schengen is a €4.80 ILS+landing at Caen...

Shoreham EGKA, United Kingdom

I think a the new GNC255 is a good replacement radio to meet 8.33 Khz requirement and it's compatible with the king HSI & VOR/LOC/GS indicators. The KX165A is only 28V so no solution for a 14V airplane! It's outdated also I believe no ARINC outputs etc...

For GPS approaches they may come quicker as foreseen specially in France. I heard that the DGAC is not going to pay anymore for the ILS certification in Northern France (it's on the local Airport from 2014) and on airfields like Valenciennes these are going to be replaced by GPS RNAV approaches soon....

Anyway my old KLN90B is still approved for BRNAV...


Sure the KX radios don't output ARINC429 deviation data, but not a lot of gear can use ARINC429 anyway.

GPS/RNAV approaches are no problem; your KLN90B can do them. You just need the right AFMS to fly them, ahem, legally...

What is potentially pricey is GPS/LPV (synthetic glideslope). But the cost of sorting that out is likely to be way more than anything to do with 8.33 or Mode S. The only practical LPV option on the table right now is a GTN650 or 750.

Plus your autopilot needs to be capable of flying LPV. None of the old ones can do it officially so they have to be wired as for ILS, with a faked ILS ENERGISE signal.

Shoreham EGKA, United Kingdom

Plus your autopilot needs to be capable of flying LPV. None of the old ones can do it officially so they have to be wired as for ILS, with a faked ILS ENERGISE signal.

Eh why?

Operationally, I don't remember when I last used the autopilot on an ILS instead of hand flying it. I don't fly ILS all that often, I need all the training I can get.

Paperwork wise, the GTN AML STC includes all analog autopilots (via the "fake" ILS signals, which are needed for the HSI anyway and would be used for hand flying too).

Is there regulation that requires an autopilot for LPV? That wouldn't make sense IMO, as LPV approaches essentially fake everything an ILS would do, and typically terminate at higher than Cat I ILS DA.

LSZK, Switzerland

I agree with all you say Tom, but I would say that is the "purist" position for IFR

Shoreham EGKA, United Kingdom

Purist maybe, but at least I don't have to go around just because the AP decided not to capture the GS 8-)

LSZK, Switzerland

Proper installation of the GNS or GTN involves no extra stuff to fly a LPV or ILS on an autopilot that can track a GS. The exception to the rule is the KFC225/KAP140 autopilots that do require an extra wire, configuration setup, and operation. With the exception of adding the ARINC 429 inputs to the KFC225, there should be no extra work required on the autopilot side of the interconnect, it is all a change in pinning of the GNS/GTN connectors. I can't see this taking more than an extra hour of work, mainly for the addition of the ARINC 429 inputs.

The reason the KFC225 is different is that it recognizes a CDI source change going from GPS to ILS and disconnects navigation. Since the ILS signals are used for LPV and GPS source is still asserted, a fake GPS CDI source is controlled as a new discrete signal. Other autopilots don't use the GPS signal to detect a CDI source change and force a navigation disconnect. The way Garmin gets around this was to display a message to the pilot to assert the autopilot outputs for LPV before engaging APR mode, then no source change disconnect occurs. If you ignore the configuration setup but interconnect the KFC225 GTN/GNS properly, the autopilot will disconnect when the FAF becomes the active waypoint and requires one press APR a second time.

Sign in to add your message

Back to Top