I just got round to looking this one up, and I have a question... 91.171(b)
is clear about "airport of intended departure". But 91.171(c) says that if
you have two VOR receivers (which I guess any serious IFR airplane does)
then you can check them against each other IN PLACE OF ... (b). It
doesn't say anything about airports of intended departure, or VOTs,
or complicated airborne procedures.

I would interpret this to read that if I have a decent VOR signal on the
ground at an airport (without a designated checkpoint) - which I do
at my home airport - then a simple cross-check is OK for 91.171.
(And for sanity's sake checked also against the GPS, although of course
this is neither necessary nor sufficient for 91.171).

Anyone have thoughts on this or know a FSDO that thinks differently?

John

"James L. Freeman" wrote in message
om...
What is the point of the phrase "at the airport of intended departure"
in FAR 91.171(b)(1)?

Interpreted literally, it would mean that while the VOR check done
with a VOT is good for 30 days, it is only valid for departures from
the airport where it was done. That makes no sense. Any other
interpretation that I can think of would be the same with or without
that phrase. What were "they" thinking?