Out with the old

SPOF is an abbreviation for “single point of failure.” The formal definition is “A flaw in the design, configuration, or implementation of a system, circuit, or component that poses a potential risk because it could lead to a situation in which just one malfunction or fault causes the whole system to stop working.”

Bendix created the so-called D mag more than 45 years ago to free up accessory pad space on Lycoming engines. Engineers fit both magnetos in a single housing by having them share a single shaft and drive gear. If either component fails—and they have more than once—the engine quits. It’s a SPOF. With at least eight airworthiness directives on those mags, the idea of flying behind that Frankenstein mashup wasn’t comforting.

Fast forward to 2020 when I decided it would be nice having two doors on my airplane. In a “right place, right time” moment, I secured a magnificent 1983 Cessna TR182 from a Canadian airline captain. It was perfect except for one thing: its Lycoming O-540 had a D mag.

According to Kelly Aerospace—the sole manufacturer of replacement parts since new D mags haven’t been made since 2010—more than 25,000 airplanes have the Bendix D/2000 or D/3000 magneto. Among them are assorted Pipers, Cessnas, and Mooneys.

Based on some reporting I’d done years prior, I knew Michigan-based Electroair was developing a solid state, dual electronic ignition system that could replace Bendix’s orphan product. Unlike Electroair’s well-regarded, single unit system that has eliminated one of the magnetos in more than 5,500 airplanes, back-up power was required with the dual ignition system for redundancy. In April 2022, back-up alternators were approved.

I preferred a cheaper, lighter, lithium-iron-phosphate battery that could attach to the firewall and last roughly seven years. However, that required a supplemental type certificate, which the FAA finally issued in January. A panel mount gauge that comes with the battery should alleviate any concerns about its health.

Since my airplane is undergoing an extensive interior upgrade, it will be months before I can ditch its D mag. In the meantime, here’s what I learned from other pilots who made the switch in 2022 after getting back-up alternators.

Climb higher, go faster, burn less fuel

Minnesota resident Jay Schmidt has been flying 45 years, including 30 with a commercial airline and a private jet company. Twenty-three years ago, he bought a Mooney M20J with 2,400 hours total time. It needed a top overhaul but has since flown 2,000 more hours.

“We fought that D mag for years,” he said. “I had two airborne turnarounds because of ignition issues. Plus, we could never get it timed right. Instead of the standard 500 hours overhaul schedule, we rebuilt it at least three times in the last five years. At $2,200 a pop, that added up. I hated that mag. The sooner we could get rid of it, the better.”

According to Jed-Aire Aviation’s A&P Jason Doscher, a complete D mag overhaul currently runs around $3,000. Doscher has maintained Schmidt’s airplane from the outset and said he’s a stickler for maintenance, knowing his airplane inside and out. When the installation was completed after more than 50 shop hours, they were both surprised by the performance improvements.

Among other things, the engine started almost instantly and was able to easily idle at 440 rpm when they were setting the mixture. It was “super smooth, like an electric motor,” said Schmidt.

On initial departure, it got airborne 200 feet sooner and was climbing much better: 1,200 to 1,300 feet per minute versus its usual 1,000 fpm rate. Schmidt thought something must be wrong, but a 90-minute test flight convinced him otherwise.

After numerous flights, he said it’s capable of flying much higher while burning at least five percent less fuel going three to four knots faster. That’s doubtless because the Electroair system generates a 70,000-volt spark which is at least six times greater than traditional or electronic magnetos. It can also automatically change engine timing based on manifold pressure. The result is a more complete fuel burn. Cylinder head temperatures thus tend to be 15 to 20 degrees higher while exhaust gas temperatures are considerably lower.

“I used to feel my engine was weak. Not anymore,” said Schmidt, who had considered replacing the engine with a new one that had separate magnetos. “I’d spend the money on this again in a heartbeat. It puts a smile on my face every time I fly.”

In Austin, Texas, Mario Zambrano was having a similar experience with a 1979 Cessna TR182 he’s owned since 2010. With a Robertson STOL kit, it easily gets in and out of ranches, but the D mag had timing issues and there was an inflight emergency when it started filling with oil.

“Since we installed the Electroair system last summer, it’s changed the way we approach everything on our carbureted engine, from startup to shutdown. There’s so much energy in the spark that I haven’t found a way of flooding it. I could prime it 100 times and it just ignites. That’s changed my mindset since I don’t have to worry about hot starts or over priming.”

He also noted that during runup, there’s hardly any rpm drop because the spark is so robust.

As a subscriber to Mike Busch’s Savvy Aviation program, Zambrano is religious about logging data on his multiprobe engine monitor. He said EGTs are now 200 degrees lower, the turbonormalizer inlet temperature is 150 degrees lower, and CHTs are around 40 degrees higher.

His CHTs are roughly 20 degrees higher than the usual increase, said Electroair CEO Mike Kobylik, a pilot with an aerospace engineering degree. Baffling and induction leaks are usually the cause. Zambrano is having those checked. Regardless, all temperatures are well within the safe zone for cylinder longevity, according to Savvy Aviation.

“You feel the extra power in the engine,” said Zambrano, who has logged 40 hours since the installation. “Because you’re generating more power, you have more control and options. We’re loving it.”

In terms of fuel burn, at 14,000 feet running 25 inches of manifold pressure and 2,100 rpm, he’s burning 11.5 gallons per hour with a true airspeed of 160 knots. That’s 14 percent less fuel than Cessna book performance at identical settings. Electroair estimates most pilots will enjoy 10 to 15 percent fuel savings.

Since many Pipers have Lycomings with D mags, I spoke with Ken Jordan in The Villages, Florida. A 35-year flight veteran with more than 3,000 hours, he owns and flies a 1976 Piper Lance.

“I’m still amazed the FAA approved the Bendix D magneto,” he said. “I was always looking for a better way. Installing this electronic ignition system is the best thing you’ll ever do. My confidence level is much higher now.”

It’s worth noting this new ignition system dramatically reduces carbon and lead deposits because they’re thoroughly vaporized into exhaust gas. That was evident to Park Rapids Aviation Maintenance Director Brian Lee in Minnesota after installing a dual Electroair system in a carbureted Cessna TR182 last spring. He borescoped it immediately before the installation and two hours after the test flight.

“Before the test flight, the cylinders looked like those in a standard midtime engine, with heavy lead and carbon deposits. After a few hours of flying, they looked like car cylinders that were tuned to avoid buildup. I didn’t expect the cylinders to shed all that gunk. We had to clean the bottom plugs once, but they stayed clean.”

He added that lead and carbon deposits are usually worse in carbureted engines than fuel injected ones.

Although Electroair’s dual system was designed as a D mag replacement, pilots with pressurized magnetos might consider this upgrade. The design is based on advanced automotive technology and eliminates any risk of arcing inside the distributor chamber since that can lead to backfiring, preignition, or detonation.

Systems cost $5,000 to $7,000 depending on the number of cylinders and airplane voltage, plus whatever power backup is chosen. Rather than a standby alternator, my preference is the small, TCW Technologies lithium-iron-phosphate battery that attaches to the firewall. The company has thousands of batteries flying in airplanes, and its battery chemistry is renowned for safety and performance.

For details, including referrals to experienced installers, visit electroair.net. Whoever you work with, it will save time and money if you agree on a plan and budget beforehand.

Kevin Knight is an instrument-rated owner of a Cessna TR182 who splits time between Texas and the Pacific Northwest.