"Teacherjh" wrote in message
...

Rather than explain, let me ask how a search is begun for an
aircraft that does not land when it is expected to. Say you
hand off to the tower, and the aircraft does not contact the
tower. The plane is below radar.


There are no handoffs without radar.



A few minutes go by, then a few more, and still no contact.
Perhaps the airplane has been abudcted by aliens, or has crashed
in the forest, or has had an electrical failure, or the nut behind the
yoke came off. So, what happens?


The tower calls the facility providing IFR services.



When?


A few minutes after the time that was passed to the tower.



Triggered by what?


Non-contact with the aircraft.



Why?


Because there should have been contact by that time.



Same question, nontowered.


Usually the first step is to call the FBO.