When a vessel arrives at a port of entry it is boarded by an immigration officer. The crew list is furnished to the officer and the entire crew is gathered so that the officer can examine each crewmember to determine admissibility to the United States. Very often this examination, usually called the inspection, is quite summary, particularly for large passenger vessels and for crewmembers who have been coming regularly with their vessels or planes. Each crewmember is also examined by a medical officer of the Public Health Service. The purpose of this scrutiny is to determine whether the aliens are admissible under the general immigration laws and whether they are bona fide crewmembers who intend in good faith to leave the United States when the period of their shore leave expires. At the conclusion of the examination the immigration officer decides, in his or her discretion, whether shore leave shall be granted. If the officer's decision is favorable the crewmember is admitted.
The immigration officer can authorize one of two types of shore leave. The first is for alien crewmembers who intend to depart with their vessel or aircraft. Such persons are known as D-1 crewmembers and are permitted shore privileges only while their vessel or aircraft is in the port of arrival or other ports of the United States, but in no event for more than 29 days, provided their passports are surrendered for safe keeping to the master of their vessel. D-1 crewmembers are required to depart with their vessel in the port of arrival and other ports in the United States, but may rejoin their vessel at another United States port, before the vessel touches at a foreign port or place, if they have advance written permission from the master or agent to do so. The second type of admission is for crewmembers who intend to reship or depart on another vessel or plane. Such persons are known as D-2 crewmembers and are allowed temporary admission for a period not in excess of 29 days, to reship, or to depart as passengers if satisfactory arrangements for such departure have been made, and the immigration officer has consented to the crewmembers' pay off or discharge by the vessel on which they arrived.
An alien crewmember ordinarily is ineligible to apply for extension of stay beyond the allotted 29-day period or for change to other nonimmigrant status. However, in the event of illness or injury, the alien crewmember may change from D-1 to D-2 status to allow them to depart on another vessel or plane.