Queries: 04/02

Navcomm back-ups, KXWX56 radar support, aircraft payload questions

Im a new aircraft owner (1979 Grumman Tiger) and I would appreciate some feedback on an avionics upgrade. I have a Narco Nav122 with glideslope and marker beacons and I want to replace this with a used Bendix/King KX155 with glideslope with the KI 209A as my primary IFR approach equipment. Your recent article on used avionics mentioned the KX170 as an alternative back-up but you suggested KX155 as being a better deal. Are you saying that aused KX155 would only be good for a back-up and not a primary navcomm? My other idea is to buy a used KLN89B GPS and then (eventually) install the UPSAT MX20 to use for the moving map. This way I can be legal /G and shoot GPS approaches using my Garmin 295. Am I on the right track?

-Ken Finley
Via e-mail

The KX155 is certainly acceptable for a primary system, while the KX170B is better for a back-up. The Narco NAV122 could be trouble and a 170B, in our view, would prove to be a more reliable and serviceable secondary. The KLN89B and KX155 connected to a KI209Avia a high quality switching unit-the Mid-Continent MD41 series, for example-is the way to go.

The KLN89B is legal /G and approach-approved if interfaced correctly. The Garmin GPS295 is a good source of nav to the final approach fix, if needed, but we don’t think its wise to use it for approaches in real weather.


KWX56 Radar?
Who bought the Bendix/King/Narco KWX56 radar? I spoke to Narco and they will only say we sold the radar system and no longer manufacture it. What a cop-out.

-Scott Cameron
Via e-mail

Garmin bought the KWX56 radar to round out its product line. It doesnt yet know if it will manufacture the line but it wont support older units.


Payload Variation?
I notice from time to time that the payload figures you give for airplanes varies both from what the POH says and specs found in the Bluebook. What gives?

-Larry Green
Bethel, Connecticut

For aircraft payload, we use a combination of Bluebook, POH and weights provided by owners from actual aircraft documentation. Also, don’t forget that even for the same model, payloads can vary year to year, sometimes substantially. We try to describe this variation in our charts but sometimes omit it due to the model years selected.