5 CFR 831.903: Conditions for coverage in primary positions.

(a) An employee's service in a position that has been determined by the employing agency head to be a primary law enforcement officer or firefighter position is covered under the provisions of 5 U.S.C. 8336(c).

(b) An employee who is not in a primary position, nor covered while in a secondary position, and who is detailed or temporarily promoted to a primary position is not covered under the provisions of 5 U.S.C. 8336(C)