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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{ 7 comments… read them below or add one }

Claudio Guajardo September 17, 2015 at 10:23 am

I need information the connection output RS232 or ARINC 429 for installations GPS Garmin 695.

Thanks a lot.

havacılık haberleri May 1, 2013 at 3:51 pm

The Zaon Company is selling a product like this. I dont remember the fee but it was cheaper. The Traffic advisory systems are inevitable for VFR pilots. I hope everyone buy one if still do not have it on board.

Larry Olson August 24, 2012 at 4:15 pm

Agree with Tom on the engine monitor… that’s a MUST for me. However, I’m shopping traffic and nice to hear of options. The ADS-B looked like it might be the ticket, but still too many issues.

I had a Monroy… POS. Now looking at the Zaon, but with the azmuth info. And FWIW, none of these are close to perfect, but sure a nice help. Even the expensive TCAS doesn’t always show traffic correctly, so one needs to keep looking, too.

tom July 5, 2012 at 3:37 pm

While $500 is chump change to an aircraft owner, traffic boxes are probably not the first thing to get unless you fly in incredibly dense traffic. Midairs are not all that prevalent, but fuel exhaustion, oil exhaustion and engine failures are. Throw in electrical failures for added excitement.

So why not an engine monitor with aural alerts tied into the audio panel? I think it’s more important to know that you just flew into the last ten gallons of gas or a cylinder has just self-ignited into pre-ignition or oil pressure and temp just exceeded a pre-defined limit. Or that the alternator quietly died and the ancient battery is also dying? Not cheap, but probably covers the more common stupid pilot tricks. And take the Advance Pilot seminar to learn how to use it wisely. It isn’t only about flying lean of peak, it’s about good engine management of temperatures and pressures.

Speaking of pilot tricks, terrain and towers take their toll, so a GPS that offers visual and aural warnings to avoid CFIT.

Density altitude is also a contributing factor in many takeoff accidents. Yes, you can do it with a pencil. Or an E6B. Most don’t. Why not get a widget that automatically calculates and displays density altitude in the cockpit? Davtron sells them, and DA is also part of many other displays like the Dynon D10 or D100, which is happens to be a dandy backup for other stuff. Certification problems? Plug it into the cigar lighter, Velcro the display somewere safe and put the temp probe in a vent. TaDa! Portable equipment or at worse, a minor mod.

There are also free density altitude apps for iphones, ipads, droid and other devices that do that easier than the E6B. Even a passenger can do it.

Get a few of the free attitude indicator apps while you are at it and find a place to put the device in an emergency, and practice with it. They use the gyros in the device for pitch, rattle and roll data and seem to be pretty good.

An angle of attack/reserve lift indicator is also a worthy option – The big boys use them, why not GA? Some are a minor mod to install.

AOA display and software is built into the Dynon D10/D100. Put the probe in an inspection plate under the wing and do not connect to the instrument static pressure system to placate the feds. They don’t like stuff attached to the certified hose. It could be a minor mod if you FSDO shop.

Carl April 5, 2012 at 1:49 pm

I will have to check it out. This product maybe a great addition to our pilot shop

Sunny Sethi April 5, 2012 at 11:10 am

Great write up. Exactly what I did after I got my Arrow II a few months ago.

Tim Drubbel March 18, 2012 at 12:28 pm

In europe lots of gliders are equipped with FLARM. A device that shows other flarm equipped gliders. It gets its position and height from gps signal. The catch is that giders with flarm will only be “seen” by other flarm equipped planes. Nowadays gliders in europe are also equipped with transponders (mandatory). So you need to have zaon and flarm to be in the loop? Nope. The developers of flarm have combined the two! So now you can “see” both flarm and transponder equipped (sail) planes for around 1400 euro.

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