john smith wrote in news:hPMWc.34135$cT6.21347
@fe2.columbus.rr.com:

John Ross wrote:
As I understand it, in order to fly (legally) above 17,500 feet, the
pilot must be instrument-rated and file an IFR flight plan.

In sunny, cloudless conditions can you file an IFR flight plan and go
over 17,500 if your plane (like my Pitts 12) is not equipped to fly at
night or in bad weather, i.e. no lights or gyros?

IIRC, flight above FL180 also requires dual transponders.

Only in airspace controlled by a country that requires such. One of the
trivia questions I ask pilot friends once in a while is what two points in
the US can you fly to over FL180 without having to file an instrument
flight plan or even have an instrument rating. One of the possible answers
is Miami to San Juan, Puerto Rico, because class A stops 12 miles off the
shoreline. Once you pass that you can fly as high as you want over
international waters.

Juan