"Steven P. McNicoll" wrote in message
ink.net...
http://www.faa.gov/atpubs/ATC/Chp10/atc1002.html#10-2-5

See subparagraph b.

He didn't get it quite right. ATC must initiate a search when there is an
UNEXPECTED loss of radar contact AND radio communications. If the losses
occur in an area where it's normal to lose them ATC isn't required to do
anything.

Thanks. Interesting. I assume that somewhere buried in the chain of
"inform the/alert the..." there's someone who actually starts the search and
rescue proceedings?

Given that both radar contact and radio communications must be lost, and
given that losing both unexpectedly is sufficient to cause an emergency to
be assumed, what is the maximum amount of time between the two events that
can happen while still defining an emergency?

That is, suppose radio communications are ceased but radar contact is still
present. Suppose further that the pilot eventually lands somewhere, at some
point descending low enough to no longer be on radar. It seems obvious to
me that if the pilot flies out of the controller's sector, or some lengthy
period of time goes by (30 minutes? 60 minutes?), that the controller might
be able to assume there's no emergency, while near-simultaneous loss of
radio and radar would constitute an emergency.

Somewhere in between there must be a point where the assumed emergency is no
longer an assumed emergency. Is that point well-defined, or does the
controller make a judgment call?

Finally, what constitutes radar contact? Is a primary return sufficient?
What about a 1200 transponder return? If a 1200 transponder return is
sufficient, what happens if THAT radar contact is lost within the time limit
I asked about above? Can the controller assume that the pilot switching
from his assigned code to 1200 has terminated flight following? Does the
switch to 1200 make any loss of radio communications and radar contact
"expected", or could the controller be obligated to declare an emergency
even if the transponder has been set to 1200 unexpectedly and then radar
contact is lost altogether?

Pete