5 CFR § 315.806 - Appeal rights to the Merit Systems Protection Board.
(a) Right of appeal. An employee may appeal to the Merit Systems Protection Board in writing an agency's decision to terminate him under § 315.804 or § 315.805 only as provided in paragraphs (b) and (c) of this section. The Merit Systems Protection Board review is confined to the issues stated in paragraphs (b) and (c) of this section.
(b) On discrimination. An employee may appeal under this paragraph a termination not required by statute which he or she alleges was based on partisan political reasons or marital status.
(c) On improper procedure. A probationer whose termination is subject to § 315.805 may appeal on the ground that his termination was not effected in accordance with the procedural requirements of that section.
(d) An employee may appeal to the Board under this section a termination that the employee alleges was based on discrimination because of race, color, religion, sex (including pregnancy and gender identity), national origin, age (as defined by the Age Discrimination in Employment Act of 1967, as amended), or disability. An appeal alleging a discriminatory termination may be filed under this subsection only if such discrimination is raised in addition to one of the issues stated in paragraph (b) or (c) of this section.