Sorry, vA..not [too] clear
The pilot {Commander of the a/c]
may nominate a "Responsible Person" to pass an ATD to the Parent ATSU,
or the Commander may elect to contact an en-route ATSU to pass details to the Parent ATSU.
At "most" uncontrolled airfields, either the pilot closes his FPL,
or "someone in the clubhouse/other environs of the a/f ring us [resposible person? perhaps]
Being brutally honest, only about 30% tell us that they have "arrived", and 40-50%
do NOT pass an airborne time
watp,iktch