Section 61.53 - Prohibition on operations during medical deficiency(a)Operations that require a medical certificate. Except as provided for in paragraph (b) of this section, no person who holds a medical certificate issued under part 67 of this chapter may act as pilot in command, or in any other capacity as a required pilot flight crewmember, while that person:(1) Knows or has reason to know of any medical condition that would make the person unable to meet the requirements for the medical certificate necessary for the pilot operation; or(2) Is taking medication or receiving other treatment for a medical condition that results in the person being unable to meet the requirements for the medical certificate necessary for the pilot operation.(b)Operations that do not require a medical certificate. For operations provided for in § 61.23(b) of this part, a person shall not act as pilot in command, or in any other capacity as a required pilot flight crewmember, while that person knows or has reason to know of any medical condition that would make the person unable to operate the aircraft in a safe manner.(c)Operations requiring a medical certificate or a U.S. driver's license. For operations provided for in § 61.23(c) , a person must meet the provisions of-(1) Paragraph (a) of this section if that person holds a medical certificate issued under part 67 of this chapter and does not hold a U.S. driver's license.(2) Paragraph (b) of this section if that person holds a U.S. driver's license.Doc. No. 25910, 62 FR 16298, Apr. 4, 1997, as amended by Amdt. 61-110, 69 FR 44866 , July 27, 2004; Amdt. 61-124, 74 FR 42550 , Aug. 21, 2009