Passive Collision Avoidance Systems

[Bruce Hughes]

Zaon Flight Systems in now selling 3 types of PCAS,
the XRX, the PCAS, and the Bubble of Awareness.   The
XRX was "affordable" to me so I bought one at OSH last
summer.

It has an 8 character red LED display that shows the distance
to aircraft within a 5 nm radius AND the altitude DIFFERENCE
from you to them.   Also it shows whether the other guy is
below or above you and whether he is climbing or descending.

If there are 2 or more aircraft, the XRX shows the most
important threat.  It will beep twice for new aircraft in the
area and 4 times for aircraft that are getting really close.

If there are no aircraft around, the unit shows YOUR altitude
and squawk code.    Thus it is a backup for your altimeter
(but it is set at 29.92 in.)

There are many areas in the US that are not covered by ground
radar BUT the unit can also be activated by airliners which use
active transponder signals.

There are some aircraft that lack a transponder so you will not
be able to detect them.

You can run the unit on 2 AA batteries which are supplied but I
plan to run mine off the 12 VDC battery (they furnish an adapter)

I have not flown N199BH yet and have not had time to mount
the unit.   I think I will mount the XRX where the copilot can see it.
 However it is very small so I can move it up front when flying solo.

For information see www.zaonflight.com or call 800-496-9430
They have information on the MUCH more expensive PCAS unit
which shows the direction to the other aircraft.

Bruce Hughes  

[Dave in Eugene]

I'd love to hear actual reports from folks using any of this new stuff.

Thanks,

Dave

[Hmanvel]

Dave, I use the Surecheck VRX (former Xaon) and really like it.  It seems to be very accurate, and really gives me more piece of mind when travelling.  Actually the real appeal for me is when it shows "no" traffic.  I can relax just a little.  The VRX will track up to, I think, 5 targets.  I have it piped into the intercom so a nice lady talks to me when a target starts getting close.  Only problem I have with it is space.  I have run out on the panel so had to bracket it off to the side.  I mounted an antenna under the pilots seat.

[Chairboy]

When I heard "Passive", I immediately began to imagine what "active" would entail.  After a moment of contemplation, I decided that active would be similar to Mode S or primary radar, and not the swarm of protective missiles I had originally imagined.

I'd like to see a serial output on some of these inexpensive PCAS devices.  I imagine something like the Blue Mountain EFIS or equivalent could do wonderful things with that data considering all the screen real-estate and CPU power.

[JonC]

When I heard "Passive", I immediately began to imagine what "active" would entail.  After a moment of contemplation, I decided that active would be similar to Mode S or primary radar, and not the swarm of protective missiles I had originally imagined.

Correct. Active surveillance broadcasts a query for transponders to respond to, exactally like a ground based radar station would. It will also listen for responces from aircraft that have been queried by an actual ground based radar.

Mode S on the other hand does not listen for other aircraft. It depends on ground based repeaters at the radar station to rebroadcast the traffic information to it. If you fly into an area with no re-transmit coverage you get "Traffic Not Available" with a Mode S system.

Passive surveillance sits and listens for transponder responces that are started by a ground based radar station... if you are in an area without a radar around then you will not see the other traffic. This is normally not an issue as where you really need this service is in busy terminal areas which  normally all have a ground radar on site or near by.

[eric r]

Did you know tthat the ground based transponder/radar can be formatted to NOT SHOW 1200 returns? I wonder if this means that is does not query them or it just doesn't show them on the controllers screen? If it doesn't query them the passive detectors won't see them either! I wonder if Los Angeles ever turned on the 1200's? Don't believe for a minute that the controllers are looking out for you in a VFR environment ... or if they even care to "see" you.

[Bruce Hughes]

Eric, you said "I wonder if this means that it does not query them"

I believe it would be a physically/electronically impossible to not query
them.

The software just does not show the locations of "1200" aircraft to
avoid confusion.

Bruce Hughes.

[Bruce Hughes]

Ryan sells Active systems.   The unit sends out a signal which
causes transponders to reply.   Even if you are not near an airport,
your passive system will show any replies to the active.

I don't know the cost of the active systems but it is significantly more
than passives.   6000?  8000?

Many military aircraft also have radar which triggers the passives.

Bruce Hughes

[Juan Rivera]

I have a Garmin 420 that uses the info from a garmin mode s transponder.  It displays the traffic info on the color moving map and switches to a traffic only display when traffic is closer than 2 miles.  Sixteen years ago when I first flew my longez I installed the best nav I could find at the time (Northstar) now I have upgraded to something much better and I think it is worth the money and peace of mind to have the best nav and com (especially when it is combined with mode S info) that you can get.

[Dave in Eugene]

Juan,,,, If you don't mind me asking...what is the $ amount of that total set-up?

Thanks,

Dave

[Juan Rivera]

I think it was somewhere around 7K for both the 420 and transponder.