A flight instructor is a person who teaches others to fly aircraft. Specific privileges granted to holders of a flight instructor qualification vary from country to country, but very generally, a flight instructor serves to enhance or evaluate the knowledge and skill level of an aviator in pursuit of a higher pilot’s license, certificate or rating.
A person who holds a flight instructor certificate (called a “certificated flight instructor” or CFI) is authorized to give training and endorsements required for and relating to:
a student, private, commercial or other pilot certificate;
the three hours of training with reference only to instruments in preparation for a private pilot certificate, note that this does not need to be a CFII.
an instrument rating, only if the CFI has an instrument instructor rating (CFII); This cannot be given by a “safety pilot”. A safety pilot can only be used to help maintain instrument proficiency with an instrument-rated pilot by flying the required six instrument approaches-holding-intercepting and tracking courses, within the preceding six calendar months.
a flight instructor certificate is only given if the experience requirements have been met (detailed below);
a flight review, endorsement (previously called BFR) (currently referred to as flight review see 14 CFR part 61.56), or recency of experience requirement;
preparation for a practical test (typically three hours within the preceding 60 days in preparation for a certificate or rating); or endorsement for a knowledge test (written examination)
Certain limitations are placed on the instruction a flight instructor may give. For example, flight instructors wishing to train applicants for a flight instructor certificate must have held their own flight instructor certificate for at least 24 months and must have given at least 200 hours of instruction (and approved by the local FSDO). Specific training programs have additional requirements or limitations.