Medical Deficiency

FAR 61.53 Medical Deficiency

FAR 61.53 prohibits acting as PIC or required crew with a disqualifying medical condition or medication. Learn the rule for Class 1-3, BasicMed, and sport pilots.

In Plain English

FAR 61.53 is the FAA's "don't fly sick" rule. It applies anytime you act as pilot in command or as a required flight crewmember, and it covers three groups of pilots differently:

  • Pilots flying on a Part 67 medical certificate (Class 1, 2, or 3): You may not fly if you know — or have reason to know — of any medical condition that would prevent you from meeting the standards of the medical you need, or if you're taking medication or treatment that would disqualify you.
  • Pilots operating under § 61.23(b) (operations not requiring a medical, like glider or balloon ops): You may not fly if you know or have reason to know of a condition that would make you unable to operate the aircraft safely.
  • Sport pilots flying under § 61.23(c) on a U.S. driver's license: Same "safe to operate" standard as paragraph (b). If you're a sport pilot using a Part 67 medical instead, the stricter paragraph (a) standard applies.

Why it matters: even with a valid medical in your wallet, you are responsible for grounding yourself when something changes — a new diagnosis, a new prescription, or even a temporary illness. Flying anyway is a regulatory violation and a safety hazard.

Regulation Text
14 CFR § 61.53
§ 61.53 Prohibition on operations during medical deficiency. (a)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)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)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. [Docket 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]
Oral Exam Questions a DPE Might Ask
Q1You have a valid third-class medical but woke up with a bad head cold and started taking a prescription decongestant. Can you fly today?
No. Under FAR 61.53(a), I can't act as PIC or required crew if I know of a medical condition — or am taking medication for one — that would prevent me from meeting the standards for my medical certificate.
Q2How does FAR 61.53 apply differently to a sport pilot operating on a driver's license versus a private pilot on a third-class medical?
Per FAR 61.53(c), a sport pilot using a U.S. driver's license is held to the paragraph (b) standard — don't fly if you can't operate safely. A private pilot on a Part 67 medical must meet paragraph (a)'s stricter standard of being able to meet the medical certificate requirements.
Q3Does FAR 61.53 apply only to the pilot in command?
No. FAR 61.53 applies to anyone acting as pilot in command or in any other capacity as a required pilot flight crewmember, such as a required SIC.
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FAR 61.53 — Flying With a Medical Deficiency