On Wed, 03 Dec 2003 20:16:47 -0500, vincent p. norris
wrote:

I actually heard a guy on a GCA once, in near zero zero conditions...I
forget just exactly how bad it was...but it was approach marginal at any
rate. This guy was on a GCA final in weather up to his armpits. I know
because I was right behind him holding.

Dudley, It's a good story, but I'm afraid I find it
a bit hard to believe.

1. In my experience, admittedly years ago, we were instructed not to
roger for further transmissions and to break off the approach if we
failed to hear the controller for about three seconds. Actually, it
sounded like the controller never took his (her) finger off the mike
button, which would block any calls from the pilot.

2. If you were holding, you would be on a different frequency. The
final controller has a channel all his (her) own, for obvious reasons.


As a former military GCA controller, I can say that the lost comm
instructions we transmitted had a time interval based upon the type of
radar approach being made, i.e. if on a vector to the final approach,
the time interval prior to lost comm being assumed was not to exceed
one minute, on a surveillance (ASR) approach the time interval was 15
seconds, and on a precision (PAR) approach the interval was 5 seconds.

Lost comm procedures may be different for the pattern/approach to
final and the final approach itself.

The "do not acknowledge further transmissions" was not done until
after aircraft contact with the final controller.

GCA controllers don't routinely keep the mike keyed during the entire
final approach - each sequence of instructions is a separate
transmission, unless there are a number of instructions being relayed
very closely together.

Been there, done that, thousands of times.

John Hairell )