Buy a Navcomm?

Were kidding, right? Not at all. In some airplanes, a new conventional navcomm may be a better choice than a color GPS.

-by Larry Anglisano

In the world of avionics, the ever forward march of progress doesnt always make things easy for buyers. As new technology arrives, it takes awhile to displace the old stuff. The high rollers buy every new product under the sun but the vast middle of the market is more conservative.

And that, more than anything else, explains why the traditional navcomm-a radio and VOR/LOC receiver-are still standard equipment in most airplanes. But in an age where color mapcomms are the expectation, is it just nuts to even consider retaining or-gasp!-buying a new navcomm?

Not necessarily, in our view. For one thing, its a buyers market for used navcomms, even those of recent vintage. And for another, one color mapcomm is more than enough for most IFR cockpits. A decent KX155 or even a new UPSAT SL30 can play a reliable second fiddle.

As usual, it boils down to money. If you have tons, eat the lost value in the traditional navcomm, sell for what you can get and colorize the panel with multiple Garmins. For a fair-to-middling upgrade, keep or buy a navcomm. Itll do the job for the foreseeable future.

Fitting In
Two decades ago, everyone figured navcomms were forever but that turned out not to be true. If you have a 360-channel comm, its a museum piece. A 720-channel unit is better but itll leave you speechless in some airspace, thus a 760-channel comm is the practical minimum for anything being installed in an airplane now, new or used. (Were talking about the U.S. here; forget Europe.)

Speaking of the U.S., many buyers ask if (a) GPS is about to mandated for IFR and/or (b) is the VOR system shortly to be switched off. The answers are no and no. The most recent Federal Radionavigation Plan-a document written in rubber if there was one-calls for the start of the VOR phaseout to begin no sooner than 2010. ILS Cat I ILS is on a similar schedule.

In practical terms, this means that a new VOR receiver bought now has at least seven years worth of primary nav application but probably much more. Another way of looking at it is that youll be able to fly IFR with only VOR aboard for the foreseeable future.

Looked at another way, is there some date at which GPS will supplant VOR entirely? If there is, we cant see it from here. The GPS WAAS enhancement is expected to be officially available this summer for initial use. Whether GPS will ever graduate to sole means status is unknown, thus VOR remains the primary/sole means nav system for IFR.

Is One Enough?
While we wouldnt venture into serious weather with only one navcomm, its certainly legal. The tradition of having two stems from personal comfort and redundancy, not legality.

If you have two decent traditional navcomms now and contemplate an upgrade to something like a Garmin 430 or 530, one of those navcomms is sufficient. Theres no need to keep both.

If you have the choice, keep the one with glideslope. For enroute navigation, GPS will remain the system of choice but getting into an airport in skunky weather, ILS is still the main game. Having two glideslopes is a nice, cheap back-up.

On the other hand, retaining one navcomm from a dual stack during an upgrade depends on what vintage the navcomms are. The older the radio, the less attractive it is as a keeper. At some point, youll reach diminishing returns on function versus repair incidence.

In reality, an airplane equipped with a single Garmin GNS430 is well fitted out for IFR and most owners will use the second conventional radio as an ATIS listener. The second radios VOR may go months without being used, if its used at all. (It should always be turned on, however, to reduce liklihood of failure.)

The point is to make your upgrade decision based on how you really fly, not how you think you might fly. Nice-to-have back-ups rarely get used and add to clutter and maintenance load.

Low Budget Upgrade
As is always the case, budget determines what goes into the panel. But so do requirements. For basic VFR airplanes, one navcomm and a portable GPS is generous. For basic IFR, a pair of navcomms is sufficient. Does it make sense to put in a pair of color mapcomms, say Garmin GNS 430s?

If youre keeping the airplane for awhile and use it for serious IFR, the answer may be yes. But if the airplane is of modest hull value and/or flies only occasional IFR, why spend $20,000 on a panel that can get by with half that?

And therein lies the argument for a conventional navcomm; you want redundancy but not sophisticated redundancy, just a reliable back-up. Remember, too, that most money you invest in the panel gets relayed to the next owner. Even premium avionics upgrades return only a fraction of their value at resale. Lets look at some for instances. Lets say you bought a decent Cherokee Six with a pair of Bendix/King KX170Bs. Great radios but also dated. Keep one or remove both in favor of something newer?

A marginal choice. Obviously, such an airplane is a good candidate for a color mapcomm. But what about the number 2 slot? If the budget allows, we would favor replacement with a newer used navcomm or even a new model navcomm.

The market for used KX170Bs is virtually non-existent so theres no trade-in value. Under no circumstances would we install a used KX170B in any airplane, unless its a pin-for-pin freebie to replace one that has fried.

A more difficult example is the mid-1980s panel with a couple of KX155s and maybe digital ADF and DME. Again, assuming one color mapcomm, whats the back-up strategy? Considering that theres still a lukewarm market for KX155s, you could keep one and sell one towards trade-in on the color map. Where possible, keep the KX155 with glideslope, so youll have redundancy, perhaps without spending much money. (Read on to see why this isnt always a cheap solution.)

The other equipment-ADF and DME-are toss ups. Believe it or not, some owners are still installing ADF for reasons that baffle us. We can see the attraction of DME for the belt-and-suspenders crowd, but you can get by handily without it, too.

Watch the Bucks
What we mention above relates to the installation of a navcomm- going to the expense and time of wiring and physically installing the equipment. But what if your airplane already has an older navcomm thats still acceptable within the criteria we stated about available and legal comm channels but your plans include upgrade to a modern, one-box integrated system?

The money could add up when retaining a once primary system for use as the secondary for a few simple reasons: First, youll want the older system (Collins, KX155, or whatever you decide to keep) interfaced as the true secondary system, not just a panel-hole filler.

That means the audio wiring needs to be accessed and reconfigured. Second, if your airplane has an HSI, chances are the navcomm that you retain was interfaced with the HSI and now, as a secondary system, it needs a compatible nav indicator. Youll spend close to $1000 on average for a reliable secondary indicator.

Next comes the issue of autopilot interface. Do you want the flexibility of switching the secondary nav through the autopilot for nav tracking? Its gilding the lily but if you want it, it can get time consuming and pricey, depending on the current interface.

Think all of these issues through because after doing the math, it might be more cost effective to remove and replace what you have rather than retaining what is already there. Ask the shop to run an estimate on both keeping some of what youve got and upgrading to new, be it a conventional navcomm, a second comm or a second mapcomm.

Winners and Losers
Obviously, not all navcomms are suitable as keepers, even for second fiddles. Were ignoring aesthetics but acknowledge that some owners do care about how the radio stack looks. By far the best choice from a reliability and serviceability view is the Bendix/King KX155 series.

Weve reported over the years that this system, still in production, is perhaps the most desired stand alone navcomm. Unfortunately, for those selling, the used market doesnt reflect this.

Garmin has all but assured that the market is flooded with used KX155s so prices have declined on what is still a premium radio.

If your airplane and KX155 are of the 28-volt variety, resale is even grimmer. Hundreds of these models are collecting dust on the used radio shop shelves. Keep that in mind if you need a 28-volt replacement and dont want to upgrade what you have; buy used and slip it into the tray.

The KX155 series requires relatively small panel space, has a nice gas discharge digital (LED) display and is as common in the GA world as Cessna and Piper. Most shops can work on these radios and if they cant, youre in the wrong place.

Similar comments can be made of the Narco MK12D series but the avionics world has been demoralized by Narcos factory-only service policies. We give them credit for shrugging off these complaints and still providing the service but we still dont recommend buying these radios new or used. If youve got one in good condition, its certainly worth keeping.

Many mid-1980s or older Bonanzas still have the Collins MicroLine VHF/VIR series of navcomms. One nice thing about these radios is that the nav and comm side are discrete boxes so each can be removed separately for repair. If youre trying to stretch your upgrade dollar, we think the Collins line is a keeper. Although theyre physically on the large side, the radios work well and are still well supported by S-TEC. They probably have another decade of life in them.

How about the Sperry/ARC line found in older Cessnas? The 28-volt variety of this line-RT385/RT485-are, depending on condition, reasonable to keep as back-up. While many shops will snicker when you try to slip one across the repair bench due to their age, stretching their service at least into the short-term as back-up gear isnt unreasonable, in our view. These units are common in later model Cessna Centurions and light twins. We wouldnt, however, go out of our way to install one fresh in any airplane. We also advise against the 14-volt version of the ARC stuff (RT328 series). These are not confidence builders, in our view.

Buying New
So much for the used gear. Does it ever make sense to buy a new navcomm in a world dominated by Garmins color map products? We think it does, depending on some unique factors. One is lack of space in the panel, a second is budget and a third is personal taste and preference.

The space issue is a problem in many airplanes. Many panels can accommodate a single moving map or mapcomm but theres no room for anything else except a conventional navcomm.

In severely space-challenged panels, UPSAT/Apollos SL30 slimline navcomm is an excellent choice. We think this radio has been underrated in the market because it has been overshadowed by glitzier map products from Garmin, Bendix/King and UPSAT.

Yet its a very capable, state-of-the-art radio with digital circuitry, lots of practical features and easy-to-learn logic. At 1.3 inches high and standard rack width, it will often fit where nothing else will.

Weve found that in some panels, its the only navcomm option for the center stack. Dont expect to get out of the SL30 installation under $5000 on average, if you need the MD200 nav head, however. You get a lot for the money but we see a lot of owners question this kind of money in standalone navcomms. Subtract the cost of the indicator if you already have an HSI and the SL30 could be the number one choice for a modern navcomm.

The two other contenders for new conventional navcomms are the Bendix/King KX155 and the newer variant of this, the KX155A. Both sell for close to the same price but the KX155A has features the 155 lacks, such as 32 programmable comm channels, stuck mic alert, internal CDI and a built-in timer.

List price for the 155A is $3430 while the older 155 sells for $3600, if both have glideslope. Figure on $4500 to $5500 installed.

Since the newer model is actually cheaper, isnt it a no-brainer to go with it over the KX155? You may not have a choice; KX155As are available only in 28-volt versions while the older 155 is available new in 14-volt and 28-volt versions.

For whatever reason, Bendix/King decided not to offer a combined GPS/comm, even as Garmin swept the world with its GNS430/530 series. But that hasnt stopped owners who want a single-brand panel from pushing ahead with Bendix/King.

We recently installed a KLN94 color GPS with a pair of existing KX155s in a 12-volt airplane. It provides plenty of IFR capability and a nice color map, all without breaking the bank or requiring a shoehorn to get it into the panel.

Total cost was about $10,000 less than the owner would have paid for dual Garmin GNS430s. One thing the owner is missing: the older 155s dont integrate as with KLN94 as the 155As do. The integration is not quite so sophisticated as are the Garmin units but its still nice to have.

Assuming youre not keeping a navcomm you already own but for space or budget reasons, you want to add one to your panel. What are the best values?

In the current market, 28-volt Bendix/King KX155s bought on the used market are a great buy, if you have the volts to run them. If not, a used KX155 in 14-volts is also a good choice.

For new boxes, our top choices are the Bendix/King KX155 series and the UPSAT SL30, which is pretty much all there is, anyway. The field has shrunk to a mere shadow of what it used to be but navcomms still have a place in the panel and will have for some years to come, in our view.

Also With This Article
Click here to view “Brand Integration.”
Click here to view “Checklist.”

-Larry Anglisano is Aviation Consumers avionics editor. He works at Exxel Avionics in Hartford, Connecticut.