3.2 - Aircraft Systems and Flight

The ignition system plays a vital role in the operations of an aircraft powered by a reciprocating engine. At the heart of the ignition system is the magneto.   The magneto has been used successfully since early machines, and the first patent for one was issued in 1914 (Wild & Kroes, 2013).  Although modern engines on automobiles do not use a magneto due to being seen as outdated technology, they are still the preferred ignition system in aircraft due to the extreme reliability, general ruggedness, and proven technology (Crane, 2018).

As the magneto is the ignition system’s heart, without a functioning magneto, an aircraft would fail.   Without the magneto producing a spark, fuel would not be able to ignite; without fuel igniting, no power would be created; without power, the aircraft is not going anywhere (except down if it’s in the air).  A failure of the magneto can be catastrophic for the airplane (Crane, 2018).

Luckily straight failure of a magneto is improbable. A benefit of utilizing the same technology for 107 years is that we have had time to perfect it. What is much more likely is for magnetos to fall out of timing (Savy Aviation, 10).   While a magneto that is not time correctly may not cause immediate failure, it can cause a general deterioration of the engine and premature wear on other parts of the engine (Crane, 2018).  If left unchecked, a magnetos timing can cause hot stops to form within the engine, causing misfires and backfires, leading to the engine’s failure (Quality Aircraft Accessories, n.d.).

There are two types of timings performed on magnetos; internal timing and external timing.  These are done at regular intervals to avoid issues with the aircraft (Wild & Kroes, 2013).  An external timing, timing the magneto to generate a spark at the correct time for the engine, is done every annual inspection and every 100-hour check at a minimum (Savy Aviation, 10).  This type of timing is also commonly done for troubleshooting power loss (Quality Aircraft Accessories, n.d.). An internal timing, which involves overhauling the magneto and timing internal components to each other, is done every 500-hours, or after around 50 hours on a new aircraft or installation of a replacement magneto (Savy Aviation, 10).

References

Crane, D. (2018). Aviation Maintenance Technician Series: Powerplant (4th ed.). (T. D. Scroggins, Ed.) Newcastle, Washington: Aviation Supplies & Academics, Inc.

Flight Mechanic. (n.d.). Checking the Internal Timing of a Magneto. Retrieved from https://www.flight-mechanic.com/checking-the-internal-timing-of-a-magneto/

Quality Aircraft Accessories. (n.d.). Ultimate Magneto Troubleshooting Guide. Retrieved from https://www.qaa.com/magneto-troubleshooting-guide

Savy Aviation. (10, December 2016). All About Magnetos. Retrieved from Youtube.com: https://www.youtube.com/watch?v=cOr3b10zmrQ

Wild, T., & Kroes, M. (2013). Aircraft powerplants (8th ed.). New York: McGraw Hill Education.