Definition
A federal aviation regulation that prohibits any person from operating a civil aircraft unless it is in an airworthy condition. It places the legal duty of ensuring airworthiness before flight on the operator of the aircraft.
Plain English
It is against federal rules to fly a civil aircraft that is not safe and legal to fly. Someone has to make sure the aircraft is fit for flight before it leaves the ground.
Context Anchor
You will see this cited during preflight discussions, especially when deciding whether an aircraft may legally be flown after an inspection issue, maintenance concern, or equipment problem.
Derivation
CFR stands for Code of Federal Regulations, the official collection of U.S. federal rules. 'Part 91' is the section of those rules covering general operating and flight rules for civil aircraft. '91.7(a)' points to a specific paragraph within that part. Knowing the citation format helps a pilot find and quote the rule directly.
Why Pilots Care
It places direct legal responsibility on the pilot to confirm the aircraft is safe, affecting both regulatory compliance and flight safety decisions.
Intuition Check
Do not read this as a handbook tip or a checklist note. It is a specific federal rule, and the “(a)” means one particular subsection of that rule.
Example Sentence 1
Under 14 CFR part 91, section 91.7(a), the pilot refused to depart until a cracked landing light lens was evaluated for airworthiness.
Example Sentence 2
The pilot refuses to fly until any discrepancies are resolved to satisfy 14 CFR part 91, section 91.7(a).