Safer Flying - Understanding the Aircraft Ignition System

The aircraft ignition system, responsible for creating and supplying the electrical spark that ignites the fuel air mixture in the aircraft engine's cylinders, has been a key part of aircraft engines since the very beginning. The Wright Brother's original engine that powered the 1903 Wright Flyer during their groundbreaking flights used a “make-and-break” style ignition system, powered by a low-tension magneto. Though today's piston engine aircraft still use magnetos, they have added many other parts to the mix, such as spark plugs and ignition leads, that are necessary for proper functioning. And, unlike those early aircraft engines, modern engines are required to have a dual ignition system (14 CFR 1.C Part 33 Subpart C 33.37). This dual ignition system provides two main advantages: increased safety, in the case of one magneto system failing, the engine can still be operated on the other system until the aircraft can be safely landed; and improved burning and combustion of the fuel/air mixture, which leads to improved performance.

In general, understanding how an aircraft works benefits the pilot. So in an effort to help private pilots become familiar with a key part of the engine, the aircraft ignition system, Disciples of Flight decided to put together a detailed ignition system video course. In this course, we cover such topics as how the ignition system works; how you service the ignition system; what you would look for to know if there's a problem; how to determine if the problem is solvable or would keep you from flying; and how to use the engine related flight instruments and determine what the readings obtained from them mean. We believe that taking the time to understand how an aircraft ignition system works will make you a better and safer pilot, by allowing you to make more informed decisions.

To start, here is the introduction to the course, hosted by A&P IA mechanic Jim Hoddenbach, who has over 30 years experience as a mechanic:

For this course, we chose to look under the hood of a Beechcraft Bonanza. For those not familiar with this much loved airplane, this segment provides a brief overview:

Performing an ignition check, also called a mag check, is a key part of the run-up process before every flight. In this segment, we discuss the ignition check process; how to read and understand the information the tachometer is telling you; and the graphic engine monitor, a popular aftermarket addition for high-performance airplanes:

So, how does an ignition system work? In this next segment, we go under the hood and cover the basic functioning of the ignition system; the components that make up the ignition system; the benefit of a dual ignition system; and why the ignition system uses magnetos:

There is a lot that goes into the ignition system of an airplane, and a lot to consider when it comes to keeping it functioning properly. These videos are just the first four out of sixteen segments in our ignition system course. The remaining segments cover such things as the process of removing, checking and installing spark plugs; how the magneto works, the process of timing a magneto, and why properly timing a magneto is so important; and what kind of ignition system care and maintenance can be performed by owner / operators under the rules.

To see the full course, please visit the airplane ignition system course page on the Disciples of Flight website. Our hope is that the information provided in this course will prove useful to private pilots, and aid in making your flying both safer and more enjoyable.

Guest writer: Disciples of Flight