Jurisdiction: United States United States

This is an noncitizen serving in a capacity required for normal operations and service on board a vessel or aircraft. Crewmen are admitted for 29 days with no extensions. The INA defines two categories of crewmen: D-1, departing from the United States with the vessel or aircraft on which they arrived, or some other vessel or aircraft; and D-2, departing from Guam with the vessel on which they arrived.

Source: USCIS Glossary, U.S. Citizenship and Immigration Services