Monday, 26 May 2014

2.24 explain the potential dangers of electrostatic charges, eg when fuelling aircraft and tankers

Lightning

As the rain drops and water vapour bumps together static electricity is created. This leaves the top of the cloud positively charged and the bottom of the cloud negatively charged. This creates a huge voltage (charge difference) and a big spark to earth.

Fuelling

If you're fueling an aircraft or a car the fuel rushing out of the pipe can cause static to be created. This can easily lead to a spark which can ignite the fuel. To prevent this make the nozzle out of metal so that the charge is conducted away. Also earthing strips are necessary to discharge the static safely.

3 comments:

  1. The charge is on the aircraft, not the pipe.

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    Replies
    1. A difference in charge is created between the nozzle and the aircraft as the fuel rushes out of the nozzle. This means a voltage is created which can cause a spark etc.

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    2. I get that. But what about the charge on the aircraft, due to the friction between it and air molecules, created during flight? This increase in charge causes an increased potential difference between the aircraft and the Earth. With high potential differences, it's possible for the charge on the airplane to escape to earth as a spark during refuelling. <This can cause an explosion.
      You're not wrong, but you missed out a few points.

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