14 CFR § 141.63

A pilot school must meet the following prerequisites to receive initial approval for examining authority:

The school must complete the application for examining authority on a form and in a manner prescribed by the Administrator;

The school must hold a pilot school certificate and rating issued under this part;

The school must have held the rating in which examining authority is sought for at least 24 consecutive calendar months preceding the month of application for examining authority;

The training course for which examining authority is requested may not be a course that is approved without meeting the minimum ground and flight training time requirements of this part; and

Within 24 calendar months before the date of application for examining authority, that school must meet the following requirements—

The school must have trained at least 10 students in the training course for which examining authority is sought and recommended those students for a pilot, flight instructor, or ground instructor certificate or rating; and

At least 90 percent of those students passed the required practical or knowledge test, or any combination thereof, for the pilot, flight instructor, or ground instructor certificate or rating on the first attempt, and that test was given by—

An FAA inspector; or

An examiner who is not an employee of the school.

A pilot school must meet the following requirements to retain approval of its examining authority:

The school must complete the application for renewal of its examining authority on a form and in a manner prescribed by the Administrator;

The school must hold a pilot school certificate and rating issued under this part;

The school must have held the rating for which continued examining authority is sought for at least 24 calendar months preceding the month of application for renewal of its examining authority; and

The training course for which continued examining authority is requested may not be a course that is approved without meeting the minimum ground and flight training time requirements of this part.