Recently, Hartzell Engine Technologies announced the release of its new PowerUP S-1200 Series magnetos. This news came on the heels of Hartzell’s release of PowerUP versions of the classic Bendix S-20/S-200 Series magnetos, leading to the logical question, “Why would a leading firewall-forward component company be investing in new versions of old technology?” The answer is a combination of technology, regulation, reliability, and some basic business acumen.

Magnetos were eliminated from cars back in the 1930s, as soon as reliable automotive batteries became readily available. However, interrupt your car’s electrical power from the battery and it will stop running and leave you stranded in the breakdown lane. That’s not a risk aircraft designers (and the FAA) are willing to take with an airplane. So, aircraft engines have retained mechanical magnetos that can keep the engine running independent of the aircraft’s electrical system. These mechanical magnetos are both reliable and maintainable—and therefore remain the source of ignition for most aircraft in the general aviation fleet.

However, new electronic ignition solutions are beginning to gain some traction. SureFly and Electroair offer electronic ignition systems that replace traditional aircraft magnetos. These systems offer advantages in the form of reduced maintenance costs (due to fewer moving parts), as well as improved starting and performance and efficiency gains (due to their ability to vary ignition timing). However, both of these systems require a constant supply of electrical power from the aircraft battery in order to function. From a safety and reliability perspective, that leaves two options: Replace only one of the two mechanical magnetos or add a backup battery to the aircraft.

Neither of these solutions is ideal. If you replace only one magneto, then you only address half of the maintenance issues and performance opportunity. If you replace both magnetos (adding a backup battery to the aircraft), you add in the acquisition and maintenance cost of a second battery, and the “engine running countdown” kicks in should your primary electrical system fail. SureFly’s backup battery recommendation, for example, is the TCW 12-volt, 3-amp-hour battery, which retails for about $1,500 and must be capacity tested annually (just as the aircraft’s main battery should be). If it fails to meet the required endurance, it must be replaced. That cost should be factored into any anticipated cost savings over the maintenance of mechanical magnetos.

That said, the feedback has generally been quite positive from owners who have replaced even a single magneto with an electronic ignition system. Once any initial installation issues are resolved, most customers I have spoken with are happy with the systems. If they have timing advance features enabled, the performance gains at altitude allow them to choose between increased power or fuel savings. These gains aren’t entirely trouble free, though. Several owners report choosing to disable the timing advance feature in order to avoid the increased cylinder head temperatures that result from the advanced timing. Additionally, upgrading to electronic ignition systems doesn’t eliminate maintenance from the equation. SureFly units, for example, still have a 2,400-hour inspection interval. That’s much better than the 500-hour inspection interval for mechanical magnetos, but it does exist.

One exciting product on the horizon for certified aircraft is Hartzell’s E-MAG. This ignition system is internally powered by the rotation of the magneto drive on the engine, potentially allowing for replacement of both magnetos without the need for a backup battery (and without the dependence on any battery to keep the engine running). It’s something I’m keeping a close eye on.

Until a true “drop-in” magneto replacement solution is available for both mags, mechanical magnetos remain a cost-effective and predictable ignition solution. However, understanding that predictability is critical to their reliability. Mechanical magnetos have key wear items that require attention on a routine basis. This is what drives the need for 500-hour inspections. By the time a magneto reaches 500 hours in service, the points that open and close to initiate the spark have likely worn to the extent that they need to be replaced, and the distributor will be worn as well. Additionally, the condenser can lose effectiveness due to age and heat exposure, and the elements also take their toll on the coil, bearings, and plastic gears.

Against this backdrop, Hartzell has chosen to invest in improving mechanical magnetos at the same time as it pushes forward with E-MAG. Under the PowerUP brand, Hartzell continues to secure parts manufacturer approvals for new versions of existing magneto designs. These updated designs address traditional weak points of the older designs. They reinforce physical weak points that have been shown to crack over time, remove failure-prone rivets from impulse coupling designs, and add more powerful coils, among other improvements. Most of all, they add another competitive product and supplier to the market, increasing availability and (hopefully) lowering overall prices due to healthy competition.

The electronic ignition systems available today reduce maintenance and improve performance (for those able to take advantage of advanced timing features). They will achieve their full potential and become drop-in electronic mag replacements once they no longer rely on external power to generate ignition spark. Until then, there is a reasonable case to be made for sticking with mechanical magnetos, as long as you give them the proper inspection, adjustment, and maintenance that they require. Until next time, I hope you and your families remain safe and healthy, and I wish you blue skies.