Definition
A specific federal regulation within Title 14 of the Code of Federal Regulations, Part 61 (Certification: Pilots, Flight Instructors, and Ground Instructors), Section 61.405, paragraph (a), which requires an applicant for a flight instructor certificate to pass a knowledge test on the aeronautical knowledge areas listed in that paragraph before being eligible for the practical test.
Plain English
This is the rule that says anyone applying to become a flight instructor must first pass a written knowledge test covering specific subject areas before they can move on to the flight test.
Context Anchor
Seen in FAA handbooks, knowledge-test eligibility guidance, instructor endorsements, and certification checklists.
Derivation
CFR stands for Code of Federal Regulations -- the official compilation of U.S. federal rules. Title 14 covers Aeronautics and Space. 'Part 61' is the chapter on pilot and instructor certification. The number after the decimal (.405) identifies the specific section, and (a) marks the first paragraph within that section. This numbering system lets pilots and examiners pinpoint a single rule out of thousands.
Why Pilots Care
Instructors and applicants must meet this regulation to legally teach and to ensure the knowledge test covers the required subjects for safe instruction.
Analogy
Think of the citation like an address in a large rulebook: Title 14 is the state, Part 61 is the city, Section 61.405 is the street, and paragraph (a) is the exact house.
Intuition Check
Do not read this as a page number in a handbook. It is a regulation address that points to a specific FAA rule.
Example Sentence 1
Before scheduling her flight instructor practical test, she reviewed 14 CFR part 61 section 61.405(a) to confirm she had passed all the required knowledge tests.
Example Sentence 2
During ground training the instructor pointed to 14 CFR part 61 section 61.405(a) to explain why certain topics were emphasized before the written exam.