eine gute Zusammenfassung dazu gab's in diesem Forum unter folgendem Beitrag https://www.pilotundflugzeug.de/forum/2015,09,23,23,4449324 24.09.2015 von Tobias Schnell

Hier noch eine schöne Übersicht der US-AOPA, Auszug hieraus:

Flight Review:

Applicant Completes a Flight Review. A flight review, required by 14 CFR 61.56, must be administered by the holder of an FAA flight instructor (also: Fluglehrer, kein Examiner/Prüfer) certificate with the appropriate ratings before the foreign pilot may exercise the privileges of his or her U.S. pilot certificate. Proficiency checks administered by a foreign flight instructor do not count as meeting the flight review requirements of 14 CFR 61.56.

Medical:

In cases when a medical endorsement is not used, a current medical license from the person's foreign medical examiner or a current FAA airman medical certificate issued under 14 CFR Part 67 will satisfy the requirement.

14 CFR 61.56 sagt dazu:

§61.56 Flight review.

[...]

(c) Except as provided in paragraphs (d), (e), and (g) *) of this section, no person may act as pilot in command of an aircraft unless, since the beginning of the 24th calendar month before the month in which that pilot acts as pilot in command, that person has—

(1) Accomplished a flight review given in an aircraft for which that pilot is rated by an authorized instructor and

(2) A logbook endorsed from an authorized instructor who gave the review certifying that the person has satisfactorily completed the review.

[...]

*) Ausgenommen hiervon sind (d) Prüfungsflüge innerhalb der 24 Monate (e) spezielle FAA-Programme (g) Flugschüler in der Ausbildung