14 CFR § 121.429

No certificate holder may use a pilot as pilot in command in an operation under this part unless the pilot has completed the following ground training in accordance with the certificate holder's approved training program:

Leadership and command training in § 121.419(c)(1) and mentoring training in § 121.419(c)(2); or

Leadership and command training in § 121.420(b)(1) and mentoring training in § 121.420(b)(2).

Credit for training provided by the certificate holder:

The Administrator may credit leadership and command training and mentoring training completed by the pilot, with that certificate holder, after April 27, 2017, and prior to April 27, 2020, toward all or part of the training required by paragraph (a) of this section.

In granting credit for the training required by paragraph (a) of this section, the Administrator may consider training aids, devices, methods, and procedures used by the certificate holder in voluntary leadership and command and mentoring instruction.