On January 28, 1996, at 1146 hours Hawaiian standard time, a Piper PA-30, N7358Y, veered off runway 26 during landing at Hilo International Airport, Hilo, Hawaii, and struck a runway distance remaining marker with the right wing. The aircraft was substantially damaged; however, the ATP-licensed flight instructor and his commercial-licensed student were not injured. The flight departed from Hilo at 0950 hours for the local area instructional flight. Visual meteorological conditions prevailed and multiple practice instrument approaches had been conducted prior to the accident. The pilot/flight instructor told inspectors from the FAA Honolulu Flight Standards District Office that the student pilot was in the left seat operating the controls as they approached Hilo for landing with the left engine idled to simulate zero thrust. The student flared the aircraft for landing 10 feet above the runway and the flight instructor, believing they were too high, called for a go-around. The student advanced power on the right engine and the aircraft yawed about 30 degrees to the left. The flight instructor took control of the aircraft and reduced power to idle on both engines as the aircraft veered off the runway to the left about 5,000 feet from the landing threshold. The aircraft landed in a grass area off the runway, and the right wing struck the distance remaining marker about 3 feet inboard from the wing tip. The flight instructor regained control, stopping the aircraft in the grass area.