FAA Powerplant Written Practice Test

What advantage do iridium and platinum fine wire electrode spark plugs have over massive electrode spark plugs?

1. They are cheaper and more available

2. They provide a more intense spark

3. They have a longer lifespan but produce less heat

4. They require less maintenance

The correct answer is: They provide a more intense spark

Iridium and platinum fine wire electrode spark plugs provide a more intense spark due to their design and the materials used. The fine wire construction allows for a smaller spark gap compared to massive electrode spark plugs, which leads to a concentrated and more efficient ignition of the air-fuel mixture in the combustion chamber. This more intense spark can improve engine performance, enhance starting, and result in better fuel efficiency. Using advanced materials like iridium or platinum also contributes to a more stable and reliable electrode performance, which further enhances the intensity of the spark over different operating conditions. This makes these spark plugs particularly advantageous for applications where high performance and reliability are crucial. The other options focus on cost, lifespan, and maintenance, which while relevant, do not directly address the specific benefit of spark intensity that is characteristic of iridium and platinum fine wire electrodes.