SOUTH PRAIRIE, Washington -- A Maple Valley couple were slightly injured when a small helicopter crashed at an airstrip east of Tacoma.

The two-seat chopper, known as a gyrocopter, crashed shortly before 2 p.m. Saturday near South Prarie.

Randy Rogers, the pilot, told KIRO 7 that he was just taking off in his gyrocopter when he heard a plane coming in his direction.

Rogers said that he made a quick turn, and then another turn, just before the gyrocopter crashed.

KIRO 7 reported that the gyrocopter crashed into the grass landing strip at South Prairie Airport when a nearby aircraft apparently spooked the pilot into a downward dive. An air show reportedly was being performed at or near the airstrip.

Pierce County sheriff's spokesman Ed Troyer said the husband and wife in the gyrocopter were taken to Good Samaritan Hospital in Puyallup, where the woman was treated for nonlife-threatening injuries.

Federal officials will investigate the cause of the crash.