Why Following Correct Torque Procedures is Critical

Torque tools play a key role in ensuring safety and quality in a variety of industries. But these torque tools can only provide this quality when the correct torque procedures are followed. Click on the case studies below to read about what can go wrong when torque procedures aren't followed correctly in a variety of industries.

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China Airlines Flight 120

Industry: Aviation

Impacts:
- Wrote off a Boeing 737-800
- 3 Injuries

On the 20th of August 2007, China Airlines Flight 120 caught fire and exploded after landing at Naha Airport in Japan. As a result, the Boeing 737-800 hull was written off due to the extensive damage. Thankfully, everyone was evacuated safely with only minor injuries reported.

After an investigation, it was discovered that an incorrectly installed bolt within the right wing structure was the cause of the fire. Six weeks before the incident during scheduled maintenance, the bolt was fitted without a washer in place which had fallen loose during the installation. This led to the bolt working itself loose, and eventually led to the down-stop assembly detaching.

It was whilst taxiing the Boeing 737-800 after the flight that the detached down-stop assembly then pierced the fuel tank, after being pushed through the fuel tank wall by the slat track which was returning to its fully retracted position. Fuel started leaking out of the punctured tank as the result of a hole measuring 2-3 centimetres in diameter. High temperatures coming from the right engine then caused this fuel to ignite, starting the fire which would write off the aircraft.

Source:
Federal Aviation Administration