Title: Why Do Aircraft Engines Have Two Spark Plugs Per Cylinder? | Boldmethod
Headings: Why Do Aircraft Engines Have Two Spark Plugs Per Cylinder?
Why Do Aircraft Engines Have Two Spark Plugs Per Cylinder?
1) Reliability
2) More Power
3) Even Combustion
https://www.flickr.com/photos/scsibug/
Spark Plug Fouling
AA1Car.com
Two Really Is Better Than One
Colin Cutler
Images Courtesy:

Content: 1) Reliability
First off, reliability plays a major role as to why your aircraft's engine has two spark plugs per cylinder. Picture this: you're flying along in cruise, and your magneto fails. If you had a single ignition system with only one spark plug per cylinder, your engine would stop running. And your prop? Depending on your airspeed, it would either slowly windmill as you started descending toward Earth, or it would stop completely. Remember the saying that a propeller is a big fan that keeps pilots cool, and when it stops, pilots start to sweat? There could be some major sweating from that kind of failure. But that's not the only problem. Let's say you had a spark plug stop working in-flight.