weersch wrote:
Hi Eric
Very good overview article. Thanks for that.
I think you are maybe a bit too optimistic about the PCAS systems.
Please don't get me wrong.
I would still recommend everybody to get one.
But everyone needs to understand the limitations.
I don't have any pertinent data, but this is what I sense:
PCAS is not "watertight".

True. The threat aircraft has to have an operating transponder with a
working antenna, and it's transponder must be interrogated by ground
radar or an aircraft with a TCAS system.
I hear continuous stories about missed threats.
Last weekend my (transponder-on) threat did not show up on my friend's
PCAS.
You already indicate that it works "well", not perfect.
To stay with your phrasing and adjusting it a bit.
If you fly in Reno area and have 10 surpises a year, the PCAS will
probably indicate 8 out if those 10.
But not eliminate all 10 out of 10 surpises.

8 out 10 is definitely working "well" by my standards! I would still buy
one if it was only 50% surprise elimination.
My understanding is also that if a Mode C transponder does not get
interrogated (e.g. out of radar range), no threat will show up on your
PCAS.

It must be interrogated, but it doesn't require ground radar to be the
interrogator. It can be any aircraft (usually airliners, business jets,
some military) with a TCAS, too. If you are in an area with no ground
radar and no TCAS equipped aircraft, you probably don't have much
traffic to worry about, anyway.
For these remaining cases and all the other stuff without transponder,
you still very much need to keep your eyes out there.

Absolutely!

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Jan/2010" also ADS-B, PCAS, Flarm tinyurl.com/yg76qo9

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz