Two men walked away uninjured after their small plane made a controlled emergency landing in a field near the H-2 Freeway in Waipio Tuesday night. The Federal Aviation Administration said the Cessna 172 touched down in a field near the Ka Uka Boulevard off-ramp at 7:10 p.m. A flight instructor was flying the plane with a student, when they experienced engine trouble at 2,000 feet. The reason for the engine trouble will be investigated. The plane was not damaged.