(a) Except as provided in paragraph (b) of this section:

(1) Each United States Registered Pilot upon completing an assignment at a change point designated in § 401.450, and

(2) Each United States Registered Pilot upon completing a series of assignments totaling more than 10 hours with no more than 2 hours rest between assignments, must not perform pilotage services for at least 10 hours.

(b) In the event of an emergency or other compelling circumstances a pilotage pool may assign a United States Registered Pilot for service before their 10-hour rest period required under paragraph (a) of this section is completed. Pilotage pools must advise the Director of each assignment made under this paragraph.