Teacherjh wrote:


The tower is sent an "expect arrival at 5:34".

It will be printed on a flight progress strip.


At 5:36 the plane arrives.
What is different about the two minutes after 5:34 compared to the two minutes
before 5:34?

None. Make it 20 minutes, still no difference.


Just that at 5:34, 5:34 happened, and that is special because it
is an expected arrival time that was not consummated.

But if you landed at 5:36, where were you at 5:34? Say about 3 miles
out? Think the tower might know that? Think the approach controller
might know that?



So, at least in somebody's mind, an alarm went off at 5:34. No?

No, no alarm went off because we knew exactly where you were.


Otherwise
there is nothing special about the two minutes afterwards, and no search would
be initiated.

Right.

That is, unless what you mean is that a search begins any time a handoff fails
under IFR.

Handoffs fail for any number of reasons. Like your cheap ass
transponder isn't sending a signal right now so I can't take the handoff
from the center because my computer won't take handoffs like that.
Modem failure. Other telephone line failure. You're too low for my
radar coverage. If the you are still in radio contact with ATC then we
don't need to go look for you. If all the electrics fail we'll do a
manual handoff. And when you land we will do exactly nothing, except
file the strip. Because nothing needs to be done. You're here and ATC
knows that.


This is another reasonable interpretation, when "handoff" is
expanded to include "expected position report".

That's not a handoff.


But then, each ETA (EPRT)
would function as the "alarm" I am talking about... getting reset every time.

If center has no radar with you they will ask for position reports.
When you fail to report he will call you on the radio. If you don't
answer he will start a search.