Gov. Code, § 21154

The application shall be made only (a) while the member is in state service, or (b) while the member for whom contributions will be made under Section 20997, is absent on military service, or (c) within four months after the discontinuance of the state service of the member, or while on an approved leave of absence, or (d) while the member is physically or mentally incapacitated to perform duties from the date of discontinuance of state service to the time of application or motion. On receipt of an application for disability retirement of a member, other than a local safety member with the exception of a school safety member, the board shall, or of its own motion it may, order a medical examination of a member who is otherwise eligible to retire for disability to determine whether the member is incapacitated for the performance of duty. On receipt of the application with respect to a local safety member other than a school safety member, the board shall request the governing body of the contracting agency employing the member to make the determination.