The YO-3A airplanes returned to CONUS from Vietnam in September 1971. YO-3A 69-18006 and 69-18007 were acquired by the Louisiana Dept. of Wildlife and Fisheries (LDWF) for the discovery of poachers and illegal shrimpers.
Subsequently, in the mid-late 70s, the FBI used these two airplanes in kidnapping and extortion cases. Notable cases: Patty Hearst and Wounded Knee.
YO-3A 69-18010 was acquired by NASA for rotorcraft research. This airplane still flies and belongs to Vietnam Helicopter Museum, Concord California.