(Portland, OR)  --  Two men are seriously injured following a small plane crash near Hillsboro.  Police say the 73-year-old and 88-year-old men were flying a single-engine Yakovlev Yak-52 to the Hillsboro Airport yesterday afternoon when the plane began experiencing engine trouble.  The plane crashed down in a filbert orchard at Duyck Family Farms Produce, and both men were rushed to a hospital in serious condition.  Police say no one on the ground was injured.