Pilots are selected twice a year for a three-year tour of duty.

In 1934 she completed a three-year, 90-port tour of the nation.

That assignment took him to Germany for a three-year tour.

His three-year tour is scheduled to end this year.

Even given these conditions, the men were expected to serve three-year tours of duty.

The exhibition comes to Westchester at the end of a three-year national tour.

She expects to leave for a three-year tour of duty on Sept. 15.

But he made clear that his three-year tour of diplomatic duty had marked him.

Men signed up for a three-year tour of duty with the cavalry.

The show runs though April 30, when it begins a three-year international tour.