This accident occurred when the driver of a dump truck was carrying out repair work for clutch failure under the cargo bed. The driver was caught between the arm that lifts the cargo bed and the truck body.

On the way back to the company after the completion of transportation work on the day of the accident, the clutch of the dump truck failed and the driver conducted repair work with the help of two fellow drivers who were contacted via radio.

Although the driver first replenished oil in the empty crankcase, the clutch still failed to operate.

The driver then lifted the cargo bed and entered between the cargo bed and the truck body to release air by following the advice of a colleague, and loosened the screw of a clutch booster by a monkey wrench to release the air. The colleague pressed the clutch some dozen times from the driver's seat to release the air. Despite these efforts, the clutch could not be restored.

At this time the cargo bed descended, and the driver was killed by being caught between the arm lifting the cargo bed and the truck body. 

The following can be considered as the causes of this accident.

1. Because of the fear of touching an electric line above the dump truck, the driver stopped lifting the cargo bed at an angle of elevation of about 25 degrees.
   
   
2. Although a colleague advised lifting of the cargo bed further as there was still room before the cargo bed touched the electric line and the driver operated the lever to do so, the cargo bed failed to ascend because of operating trouble.
   
   
3. Safety measures such as using a safety block were not taken.
   
   
4. The time frame when the accident occurred was not suitable for the inspection of a vehicle as it was after sunset and there wasn't enough light.