Economical Traffic Detection -ZAON MRXa

by Wally Moran on February 24, 2012

Zaon MRXIn January of this year, I set out to buy an airplane that was reasonably fast and equipped for limited IFR flight. Given my budget, I did not expect to get a lot of fancy electronics.

What I ultimately purchased was a 1966 Mooney M-20C with a low time engine, Garmin 430W a second nav/com and no autopilot.

As my budget has recovered from the purchase expenses, I began to think about some upgrades to improve safety and my first choice was to get a ZAON portable collision avoidance system (PCAS) model MRXa. This is a little box about the size of a package of cigarettes, powered by two AA batteries and sits on the top of your instrument panel with Velcro. Nothing to hook up, it is totally self contained. The cost is just under $500. You can learn more at

This device detects other transponder equipped aircraft and presents the distance and relative altitude. The presentation is on a brightly lit screen which presents a digital display of the information. For example, the range screen may say 2.0 and the altitude screen +500. This means that there is traffic within 2 miles that is 500 above you. It does not give a direction for the traffic but, if you see the distance or altitude numbers getting smaller, that means you better start looking around. If they are getting bigger, no sweat. The unit has a set of menus that allow the operator to make the detection bubble larger or smaller as desired. It also has aural alerts that warn you as the traffic gets closer. Because of the small size, it can be easily carried in your flight bag and used in rental or club aircraft.

I first purchased one of these several years ago to use in a glider. Since fiberglass gliders do not show up well on radar and we fly near a class C airport, it seemed like a good investment to avoid getting run over by a jet. It has been working as advertised for about 5 years and has a few saves to its credit. The one I just purchased has a few more bells and whistles that make it even better.

Even though I get traffic advisories or am on IFR most of the time, having the PCAS makes life better. When ATC advises traffic, even though I can’t see it, I can watch it on the PCAS and ensure that we do have altitude separation and as the distance begins to increase, I know we are clear. I would also know quickly if the threat aircraft began a climb or descent as the PCAS gives you that information. All this without ever spotting the traffic.

When out of radar service, having a device in the cockpit that lets you know there is traffic in the vicinity, reminds you to keep your head outside the cockpit rather that to get distracted with an inside issue.

In my view adding the Zaon portable collision avoidance system was a great first step in making my Mooney flying as safe as I can. I intend to make my next safety upgrade a set of shoulder harness. In 1966 they did not come standard on aircraft.

Does anyone have any experience with other portable collision systems or any other good suggestions for reasonable cost, safety upgrades for these old airplanes?

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