Definition
A flight instructor's signature is the formal endorsement, written and signed by a certificated flight instructor (CFI) in a student's logbook or on a lesson plan, that confirms a specific training requirement has been met or that the student has been authorized to perform a particular activity, such as solo flight, a stage check, or a checkride.
Plain English
A signed note from your instructor that officially shows you've completed a required step in training, or that you're cleared to do something on your own.
Context Anchor
Seen on lesson plans, training records, logbooks, and endorsements where an instructor must show responsibility for a training action or approval.
Derivation
Signature comes from the Latin idea of making a sign or mark. That helps here because the signature is not just a name; it is the instructor’s identifying mark that attaches responsibility to the document.
Why Pilots Care
A valid flight instructor signature is legally required before a student may solo, apply for a certificate, or exercise certain privileges; missing or improper signatures invalidate training time and can prevent progression.
Intuition Check
Do not treat a flight instructor’s signature as just a formality or decoration. In aviation records, it usually means the instructor is confirming something specific and accepting responsibility for that confirmation.
Example Sentence 1
Before her first solo, the student needed her flight instructor's signature in her logbook endorsing her to operate the aircraft alone.
Example Sentence 2
Without the flight instructor’s signature on the pre-solo endorsement, the student could not legally fly solo.