I have been only loosly following this thread. *I'm pretty confused at
this point, but now have specific questions.

We have a ZAON PCAS in our club glider. * We are now installing a
transponder too. *I understand that the PCAS will know that the
glider's own transponder is not a threat so it will filter it out.

If we tow behind a towplane which also has a transponder, what will
happen? *Will the PCAS see the tow plane as a threat, and display
that? *But another airplane might be on a collision course... * but
the PCAS will not see that because it sees the towplane as the closest
threat?

OR..........will the PCAS think that the towplane transponder is
actually the glider's transponder since it stays at the same relative
altitiude and position? *Will it filter out both the glider's
transponder and the tow planes' transponder?

Should we put the glider's transponder to "stand by" during tow? *If
we do, will the PCAS then think the tow plane's transponder is really
the glider's transponder and filter it out, allowing the PCAS to see
other targets?

Should we just say "screw it" and ignore the PCAS entirely during tow?

Cookie

Probably yes to all the above, with a big does of "it depends" like it
depends on the exact pressure altitude the Zaon reads, the relative
power it sees from the different transponders as to which of the
transponders it locks onto (or if it sees synchronous garbling).

If the Zaon thinks the tow plane is a threat it will not display other
threats. Until they become more of a threat in which case you see the
"NEW" message. It is also possible it thinks your own transponder is a
threat at times. Remember the threat algorithm is biased towards
threats at a similar altitude.

What do people who tow behind a tow plane with a Zaon MRX see (with or
without their own local transponder?) I often self launch my ASH-26E
(with Zaon MRX and transponder) so am not the right person to answer
the question.

One thing I am pretty sure on is you should not be turning on and off
transponders unless in touch with ATC. And if ATC does prefer that
talk to them about the radio and other procedures they want followed.

Darryl- Hide quoted text -

- Show quoted text -

Thanks Darryl,

I guess in a practical sense we should just leave the transponder on
altitude and squawk 1200 during tow and the entire flight too.

Whatever the PCAS says....it says.........probably no useful PCAS
during tow........we should just ignore.

Perhaps in the future there may be some procecure agreed upon by ATC.

Cookie