63.6. The chairman of a committee shall direct its activities and preside over its sittings.
The vice-chairman shall replace the chairman where the latter is absent or incapacitated or refuses to act, or where the office of chairman is vacant and the chairman is unable or unwilling to remain in office until his successor is appointed.
Where both the vice-chairman and the chairman are absent or incapacitated or refuse to act, or where the offices of chairman and vice-chairman are vacant and they are unable or unwilling to remain in office until their successors are appointed, the members present at a sitting of the committee shall designate one of their number to preside over the sitting.