FAA Powerplant Written Practice Test

What must be done if a spark plug is dropped during removal from an engine?

1. It can be reused if cleaned

2. It must be carefully inspected without replacement

3. A replacement plug must be used

4. It should be placed back without concerns

The correct answer is: A replacement plug must be used

When a spark plug is dropped during removal from an engine, a replacement plug must be used because dropping can cause internal damage that is not visible. The integrity of a spark plug is critical to proper engine function, as it needs to withstand high temperatures and pressures while also providing a reliable ignition source. Even if the spark plug appears undamaged on the outside, internal components could be compromised, potentially leading to failure during operation. Safety and reliability are the top priorities in aviation maintenance, and using a spark plug that has been dropped could lead to engine performance issues, misfires, or even engine failure. Therefore, it is essential to replace any dropped spark plugs rather than attempt to reuse them or inspect them, as the potential risk outweighs any perceived benefit of reusing an item that could be faulty.