[Code of Federal Regulations] [Title 14, Volume 2] [Revised as of January 1, 2007] From the U.S. Government Printing Office via GPO Access [CITE: 14CFR63.19] [Page 425] TITLE 14--AERONAUTICS AND SPACE CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PART 63_CERTIFICATION: FLIGHT CREWMEMBERS OTHER THAN PILOTS--Table of Contents Subpart A_General Sec. 63.19 Operations during physical deficiency. No person may serve as a flight engineer or flight navigator during a period of known physical deficiency, or increase in physical deficiency, that would make him unable to meet the physical requirements for his current medical certificate.