Incident Description
The airplane surged forward and impacted a tug when the number 2 engine went to full power during engine start. According to the flight crew's written statements, the captain had written up the number 2 thrust reverser following the previous flight because it required extra effort and movement to reach normal reverse thrust. Maintenance personnel adjusted the rigging and released the aircraft for service. The flight crew informed maintenance that they would verify the rigging after engine start.
Sequence of Events
The airplane was pushed back and the flight crew started the number 1 and 2 engines with no anomalies noted. They were in the process of starting the number 3 engine when they heard a loud roar of an engine and felt the airplane lunge forward. The flight engineer announced the number 2 throttle was open and pulled the throttle lever to idle. The captain applied brake pressure and called for engine shutdown.
Crew Observations
According to the captain, he did not notice the number 2 throttle move forward because he was looking at the ground crew for a brake signal. The copilot did not observe the number 2 throttle move forward because he was concentrating on starting the number 3 engine and examining the oil pressure gauges for the number 1 and 2 engines. The flight engineer indicated that he had not noticed the number 2 throttle movement because he was looking at his panel to confirm that the number 2 start valve had closed and the number 3 start valve had opened. He then monitored the oil pressure when he heard the engine spooling up to high power followed by the movement of the airplane.
CVR and Post-Accident Examination
A cockpit voice recorder was installed on the accident airplane, but review of the recording revealed that the engine start and accident had been recorded over. Mechanics examined the engine and throttle control rigging after the accident under the supervision of a Federal Aviation Administration airworthiness inspector. According to the mechanics and the airworthiness inspector, no anomalies were noted with the throttle's rigging. Subsequent engine runs were unsuccessful in duplicating the engine surge. The airplane was not equipped with an autothrottle system.