D.C. Mun. Regs. tit. 7, r. 7-253
In the event the Chief Administrative Appeals Judge is temporarily disabled or unavailable to perform his or her duties, the Chief Administrative Appeals Judge shall designate a member of the Board to serve as Acting Chief Administrative Appeals Judge until such time as the Director designates an Acting Chief Administrative Appeals Judge.
In the event that the Chief Administrative Appeals Judge is physically unable to make such designation, the next senior member of the Board shall serve as Acting Chief Administrative Appeals Judge until such time as the Director designates an Acting Chief Administrative Appeals Judge.
In the event that an Administrative Appeals Judge is temporarily unable to carry out his or her responsibilities because of disqualification, illness, or for any other reason, the Chief Administrative Appeals Judge, with the concurrence of the Director, may appoint a qualified individual to serve in the place of such member for the duration of that member's inability to serve.
D.C. Mun. Regs. tit. 7, r. 7-253