I must say that I've found the responses to be quite interesting: the
majority see a problem with "blocked". I plan to reverse a
long-standing procedure that I've always used (effectively, I might
add) and stop using it.

My experience is (from my perspective) that using "blocked" works very
well. I hear it most often with LA or Oakland Center where there are
as many airliners and commuters as bug smashers. There is a key
requirement that *before responding "blocked" a sufficient amount of
time must has elapsed to make it clear that neither intended message
went through*. It seems to work so well because when a true blocking
occurs, there are 2 entities that probably don't know that their
transmissions were not received. A single short transmission
("blocked") *often* replaces 2 or more (since the second attempt is
also blocked) longer transmissions (e.g. "Continental 760, cross XYZ
at and maintain 123, expect ABCD, do not exceed 999 knots, altimeter
30.00, over"). I have *never* heard any confusion on Center
frequencies, when this happens. Transmitting "blocked" almost never
causes total blocking itself since it is so short.

The bottom line: whatever works best.


"SeeAndAvoid" wrote in message link.net...
Been a controller for 18 years and I wish "blocked" would
go away.
Once I was in a jumpseat, and this one pilot kept a
firm grip on his mic just waiting to say "blocked" even when
it was obvious the call wasn't for him. I finally told him
to knock it off, free ride or not, I had to finally say something.
I let him know just because it sounded blocked to him, or
that the call may have been for another frequency (controller
working more than one freq at a time) and he may have only
heard half of the communication, etc etc.
It's just bad form, and more often than not the call wasnt really
"blocked" at all as the person the call was intended for shortly
thereafter answers and at least HE was paying attention and
listening. I love it when I hear "blocked" with one aircraft on
frequency. I'll reply with "let me guess, blocked by Guard?"
No, usually blocked by someone not paying attention or blocked
by flight attendant. Usually something can be picked out of the
most blocked, heterodyned call. If you think your callsign was
part of that call, ask "was that for N12345?".
Chris

"Lee Elson" wrote in message
m...
I'd like some input from those of you who are familiar with the
working ATC environment.

In a situation where a transmission to/from ATC is "interfered with"
by a second transmission I've always believed that it is useful to let
all parties know that the tranmission was blocked, even if I suspect
that I'm not the intended receiver. In order to make sure that the
transmission did not go through despite the interference, I usually
wait a few seconds to see if there is an answer. Often there is and I
just keep quiet.

On Sunday I was flying (VFR) in the Ontario, CA Class C, talking to
ATC in the northeast sector. Things were not as zoo-ey (a technical
term, sorry) as they can be in Socal space, in fact there was not alot
of congestion on the freq. However there were 2 transmissions that
occured at the same time making the first part unintelligable. From
the last few words (from ATC) I strongly suspected the transmission
was intended for me. After waiting a few seconds, I transmitted
"Blocked". The angry response from ATC was "who said 'blocked'?". I
repled that I did and he said "don't do that". He later had time to
explain that this often blocks another of his transmissions and that
it can interfere with a second frequency that he may be using or that
the transmission is not "blocked" at all. He said it is his preference
for pilots not to do this but if they do, they should also give their
N number (e.g. "blocked, N12345").

So here's my question: it's my impression that such a short
transmission almost never causes confusion or interference. Rather it
quickly clears up the situation enabling other aircraft to talk,
freeing up the frequency. So you controllers out the which is it?
Does this help or hurt the situation?