The SureFly Electronic Ignition, the Solid-State Box That Retires One of Your Magnetos and Advances Your Timing on Its Own

The SureFly Ignition Module (SIM) is an FAA-certified, solid-state electronic ignition designed to replace one of your two magnetos on many Lycoming and Continental engines. Unlike a magneto’s fixed spark timing, it uses a computer to advance the ignition automatically based on manifold pressure, delivering easier starts, a modest fuel-efficiency gain, and less recurring maintenance - while a traditional magneto stays on the other side as an independent backup.

What Is a Magneto, and Why Is It Still in Your Airplane?

To understand why the SureFly box matters, you have to understand the strange survivor it replaces. The two devices lighting the fire in your engine were designed before the First World War - before jets, before glass panels.

Your car abandoned the magneto long ago. It runs a battery, a coil, and a computer that decides exactly when each plug fires, adjusting timing dozens of times a second based on load, speed, and temperature. Your airplane engine does none of that.

A magneto is a self-contained spark generator: a spinning magnet, a coil of wire, a set of breaker points, and a distributor. Spin it, and it makes its own electricity and fires the plugs by itself. It needs nothing from the battery - and that is precisely the point.

Here is the stubborn logic that kept it alive for a century. If your electrical system dies completely in flight - alternator out, battery drained - your engine keeps running. The magnetos make their own spark and do not care. That independence is why certification authorities loved them, and why we still fly behind them today.

Why Replace a Magneto at All?

That independence comes at a real cost. A magneto fires at fixed timing - on a typical Lycoming, roughly 20 to 25 degrees before top dead center - and it never changes. Not at sea level on a hot day at full power. Not at 11,000 feet, where the thin, lean air burns more slowly. It is a compromise timing, chosen once and frozen forever.

The mechanical parts also wear. Breaker points erode, internal timing drifts, and bearings age. That is why your mechanic pulls the magnetos and services them on a schedule, and why you sometimes get a rough mag on the run-up. Points, springs, and a distributor gear spinning at engine speed for thousands of hours in a hot, vibrating environment eventually wear out.

The magneto isn’t just old - it’s old technology doing a job modern electronics can do dramatically better. The only reason we accepted the compromise so long is that nobody wanted to fight the certification battle. That is the fight SureFly picked.

How the SureFly Ignition Module Works

The SureFly Ignition Module is a bolt-on, drop-in electronic ignition that replaces one magneto. It mounts to the same accessory pad, uses the same drive, and connects to the same spark plug leads. From the outside, it swaps right in where a magneto came out.

Inside, everything is different. There are no breaker points and no distributor cap. It is solid state. A Hall-effect sensor reads engine position, a small internal computer decides when to fire, and a coil delivers the spark.

Critically, that computer can vary the timing. The module advances the ignition based on manifold pressure. At low power settings and at altitude, where the mixture is thinner and burns more slowly, it lights the fire a little earlier so the burn completes at the right moment in the cylinder - exactly what cars have done for forty years, now in certified form.

What Does Variable Timing Actually Buy You?

There are four real benefits, and it’s worth being honest about the size of each.

Easier starting. Electronic ignition delivers a hotter, better-timed spark at cranking speed, and many units include a built-in start retard so the engine doesn’t kick back against the starter. Pilots consistently report easier starts, especially on cold mornings and on hot-start-prone fuel-injected engines. This benefit is real and noticeable.

Lower fuel burn. Because timing is optimized at cruise instead of frozen at a sea-level compromise, you can pick up a small efficiency gain. SureFly cites savings in the neighborhood of about one gallon per hour in the right conditions - lean of peak, up high. Be skeptical of best-case numbers; your real result depends on your engine, operation, and leaning. Call it a modest gain, not a miracle - but over hundreds of hours, it adds up.

Less maintenance. No points to erode, no internal magneto timing to drift, and no 500-hour internal inspection the way many magnetos require. There is far less inside to wear out of spec.

Cleaner plugs. The hotter, fine-wire-style spark can help keep plugs clean and smooth out the lean-of-peak operation many owners chase for efficiency.

Does It Sacrifice the Magneto’s Independence?

This is the honest catch. The SureFly module needs electrical power to run - it does not generate its own like a magneto. So the engineers built in a backup: an internal power supply that keeps the module firing for a period of time if the ship’s electrical system fails. You don’t instantly lose ignition when the alternator quits.

But read that carefully - it’s a backup, not infinite independence. That is exactly why SureFly is designed to replace only one of your two magnetos, not both.

That single-side design is the right call. You keep one traditional magneto that is still fully independent and makes its own spark regardless of your battery. In the worst case - total electrical failure with the electronic unit eventually running down - you still have a genuine, self-powered magneto keeping the engine alive. Old reliability on one side, new capability on the other.

What Are the Downsides for Your Wallet and Logbook?

Cost. A single module runs in the low four figures - roughly $1,100 to $1,300 for the unit, plus installation. Overhauling or replacing a magneto is cheaper up front, so the payback isn’t instant. You’re buying easier starts, better timing, and lower long-term maintenance, and you have to decide whether that math fits how much you fly.

Coverage. It is approved for a specific and growing list of Lycoming and Continental four- and six-cylinder engines under FAA approval, with matching approvals in several other countries. This is not a universal part - confirm your exact engine and airframe are on the approved list before you buy.

Track record. Magnetos have a century of field history, and every mechanic knows them cold. The electronic module now has a strong record with thousands of units flying, but it’s younger. Some mechanics love it; some remain cautious. That’s normal and healthy - new technology earns trust one flight hour at a time.

Who Builds SureFly, and Where Is Electronic Ignition Headed?

SureFly brought the module to market in the last several years, earned FAA approval, and steadily expanded its engine coverage. Then something telling happened: the company was folded into the larger world of certified engine-accessory manufacturers - the same ecosystem that builds props and ignition components for the general aviation fleet.

That absorption is the point. This wasn’t a science-fair project that flamed out; it was a startup with a genuinely good idea that got pulled into the mainstream supply chain because the idea worked. That’s how real innovation enters certified aviation - not with a splashy demo, but with an approval document and a growing eligibility list.

The bigger picture: electronic ignition is no longer a question of if, but how fast. Experimental builders have run full electronic ignition on both sides for years. The certified world moves slower on purpose, and the single-side replacement is the bridge that lets a legacy airplane get most of the benefit without giving up the magneto’s fundamental safety architecture.

Should You Install One? Why This Matters for Pilots

If you’re facing a magneto overhaul anyway, that’s when the math gets interesting. Instead of rebuilding century-old technology, you can replace one side with the electronic module and rebuild or replace the other magneto as your independent backup - coming out with easier starts, self-adjusting timing, a small efficiency gain, and less recurring maintenance.

If your magnetos are healthy and recently serviced, there’s no urgency. This is not a safety recall - it’s an upgrade you can plan for at your next natural service point.

Either way, this is a conversation to have with a mechanic who knows your specific engine and has installed one before. The value is real, but it’s engine- and operation-specific, and a good A&P will tell you straight whether it pays off for the way you fly.

Key Takeaways

• The SureFly Ignition Module is an FAA-certified, solid-state replacement for one of two magnetos, keeping a traditional magneto as an independent backup.
• Unlike a magneto’s fixed 20–25° BTDC timing, it advances the spark automatically based on manifold pressure, using a Hall-effect sensor and internal computer.
• Real-world benefits include easier starts, roughly 1 gallon per hour best-case fuel savings, cleaner plugs, and no 500-hour internal inspection.
• It requires electrical power but includes an internal backup supply; the single-side design preserves magneto independence.
• A unit costs about $1,100–$1,300 plus installation and fits a growing list of Lycoming and Continental four- and six-cylinder engines - verify your engine is approved before buying.