You must have the validity of the foreign license and medical certificate or endorsement you hold verified by the Civil Aviation Authority that issued those certificates.
The FAA has devised a form entitled Verification of Authenticity of Foreign License, Rating, and Medical Certification (PDF). You must submit this information, along with a copy of the license you wish to have verified, to:
Airmen Certification Branch
PO Box 25082
Oklahoma City, OK 73125-0082
You may fax the form to (405) 954-9922.
For more detailed information you should review the information available at the following links:
Page Last Modified: 04/16/13 07:57 EDT
This page can be viewed online at: http://www.faa.gov/licenses_certificates/medical_certification/faq/response16/