Problems with static electricity
4 marks · NormalAircraft are always earthed after landing. Explain why this is necessary.
Suggest and describe a method by which the aircraft can be safely earthed after landing.
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(a) To allow any static charge that built up during flight to escape safely, preventing sparks that could cause an explosion, especially during refuelling.
(b) Attach a thick metal cable from the plane to the ground (earth) as soon as it lands, providing a path for charges to flow safely.
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Marking points
B1 (a) · 1 mark · Recognises build-up of static charge during flight.
B2 (a) · 1 mark · Explains that earthing prevents sparks that could ignite fuel.
B3 (b) · 2 marks · Correctly describes using a conductor/metal cable to earth the plane.
Worked solution
(a) Planes become charged due to friction with air during flight. If the charge is not removed, it could discharge as a dangerous spark during refuelling.
(b) A thick metal cable is attached between the plane and the ground after landing, before refuelling. This provides a safe path for the charge to flow to earth, removing static build-up.