14 CFR § 61.215

A person who holds a basic ground instructor rating is authorized to provide—

Ground training in the aeronautical knowledge areas required for the issuance of a sport pilot certificate, recreational pilot certificate, private pilot certificate, or associated ratings under this part;

Ground training required for a sport pilot, recreational pilot, and private pilot flight review; and

A recommendation for a knowledge test required for the issuance of a sport pilot certificate, recreational pilot certificate, or private pilot certificate under this part.

A person who holds an advanced ground instructor rating is authorized to provide:

Ground training on the aeronautical knowledge areas required for the issuance of any certificate or rating under this part except for the aeronautical knowledge areas required for an instrument rating.

The ground training required for any flight review except for the training required for an instrument rating.

A recommendation for a knowledge test required for the issuance of any certificate or rating under this part except for an instrument rating.

A person who holds an instrument ground instructor rating is authorized to provide:

Ground training in the aeronautical knowledge areas required for the issuance of an instrument rating under this part;

Ground training required for an instrument proficiency check; and

A recommendation for a knowledge test required for the issuance of an instrument rating under this part.

A person who holds a ground instructor certificate is authorized, within the limitations of the ratings on the ground instructor certificate, to endorse the logbook or other training record of a person to whom the holder has provided the training or recommendation specified in paragraphs (a) through (c) of this section.

Ground training provided to an initial applicant for a flight instructor certificate may only be provided by an authorized instructor in accordance with § 61.195(h)(1).