FAA Powerplant Written Practice Test

What advantage do iridium and platinum fine wire electrode spark plugs offer?

1. They are less expensive

2. They provide a more intense spark compared to massive electrode spark plugs

3. They last longer but provide less performance

4. They work better at colder temperatures

The correct answer is: They provide a more intense spark compared to massive electrode spark plugs

Iridium and platinum fine wire electrode spark plugs provide a more intense spark compared to massive electrode spark plugs due to several factors related to their design and materials. The fine wire electrodes reduce the voltage requirement to create a spark, leading to better ignitability of the air-fuel mixture in the combustion chamber. Additionally, the noble metals used, such as iridium and platinum, have excellent conductivity and require less energy to produce a spark. This more intense spark can improve combustion efficiency and performance, leading to better throttle response, increased power output, and potentially improved fuel economy. While they also tend to have longer lifespans compared to traditional plugs and can perform well in various temperature ranges, the primary advantage lies in the intensity and efficiency of the spark they produce.