“A horse, a horse! My kingdom for a horse,” cried Shakespeare’s grounded Richard III at the bloody Battle of Bosworth.

In later centuries, author James Baldwin tells us that an entire mythical kingdom was lost through a chain of events that began “for want of a nail” to hold a horseshoe.

But no horsing around, although it’s a horse of a different color, we lost our horsepower, and—like King Richard the Third, we were grounded. And like Baldwin’s lost kingdom, it was from the lack of the simplest implement. Not a nail, in our case; our flight was lost for the want of a wrench.

Naturally, like it always happens when these things occur, it was the loveliest day to fly you can imagine. The sky was clear. It was chilly, but not cold. The wind gods must have overslept, as the long grasses beyond the taxiway stood tall and still like sentinel soldiers.

Breakdowns never happen when the weather sucks and you don’t want to fly anyway.

It all started out when my plane friend Lisa was planning on some last-minute landing practice, with me along as her safety pilot, before her burst of intensive training with a real flight instructor, which was set for pretty much every day of her college’s winter break. With a stereo screeches we pulled her south-facing hangar doors back to let in the pale white winter sunlight.

We pre-flighted Warbler: Carefully checking the pitot tube, static ports, alerions, rudders, elevator, landing gear, exhaust, and prop. We sumped the fuel tanks and double-checked the oil level. Getting a plane ready to fly takes time. Airplanes aren’t like cars. You can’t just drive to the airport and jump into your plane and fly. Well, you can, but such carelessness often ends badly. As they say, if your car breaks down, you can pull to the side of the road. If your plane breaks down, you can’t pull to the side of the sky.

All in readiness, we pulled Warbler out, buttoned up Lisa’s hangar, and climbed aboard,

Lisa ran through the short and simple engine start checklist: Opening the fuel cut off, reaching behind me to turn on the master switch (like with many Ercoupes, Warbler’s master is in the original odd-ball location in the baggage compartment behind the pilots), turning the ignition key to “both,” giving the engine two slow shots of prime, then reaching over practically into my lap to pull the starter handle—which is arguably located on the wrong side of the plane.

The prop swung in a lazy arc. The engine coughed once, then took hold. Unlike Tess, who’s sometimes a hard plane to start, Warbler is always eager to go.

But this morning something didn’t sound quite right. Or maybe it didn’t feel quite right. The vibrations through the airframe were different. The symphony of noise not quite in tune. Still, the oil pressure gauge lazily came off the mark and sauntered into the green. Slowly the vibrations settled down. The symphony got their act together, except perhaps for one rogue violin.

But the oil temperature needle lay firmly against the peg. Warm up was going to take a while. Winter flying in Warbler takes patience.

We busied ourselves with getting our headsets plugged in and making small talk. When at long last the temperature of the oil was at least detectable, Lisa taxied from her little patch of crumbling asphalt in front of her hangar, across the gravel, and onto the smooth surface of Taxiway Foxtrot; which you’d only know was Taxiway Foxtrot if you were based at SXU. For years, the taxiway was labeled with a proper yellow and black sign with a large capital F, but for whatever reason the sign was taken down and not replaced during the most recent remodeling in 2014. We still call it Foxtrot, but for the benefit of visitors, add “by the hangars” to all our radio calls.

Once safely onto the smooth, gravel-free taxiway, Lisa pulled the parking brake, a long handle on the floor between the pilots, and locked it by pulling a knob on the panel. Then she slowly pushed the throttle forward and Warbler’s engine spooled up, the propwash back off the propeller making him jerk, sway, and buck. First, she checked the carb heat, then she reached over to the ignition switch. Although this switch has a key, that’s where the similarity to your car’s ignition switch ends. Well, that assumes that your car still uses a key. Mine doesn’t. It uses a magic wireless box the size of a Zippo lighter. But I digress.

Cars traditionally have ignition switches with two positions: On and Off. Airplanes have four positions: On and Off, plus a position called Right, and a position called Left. This is because of one of the unique safety features of airplane engines: Each cylinder has not one, but two sparkplugs. And each of these sparkplugs is run by a separate and independent magneto. In Warbler’s engine, the top sparkplugs in each cylinder are run by one mag and the bottom plugs in each cylinder are run by another mag, the idea being that if one mag fails, the engine will keep running. In fact, you may recall that not too long ago, Lisa had some adventures with one of her magnetos, so it was damn lucky for her that our aviation forefathers had the good foresight to provide her with two.

Anyway, before flight, pilots test these dual systems to ensure that both are working properly. This is done by increasing the power to a high level and shutting off first one, then the other, set of plugs. Typically, a small RPM drop is seen. If one of the mag systems faileds, when you isolate it, the engine stops. Which is why we test the system while we are still on the ground.

Lisa checked the first mag and all was well. Then she checked the second. Suddenly, the orchestra rioted. The RPM dropped a ton and the plane shook like a wet dog.

We knew at once what was wrong. We had a fouled plug. Only three of Warbler’s four cylinders were firing. We knew it was a plug, not a mag problem, because the engine was still running, even if badly. We didn’t know about the plug before the mag check, because the second plug in the cylinder was firing when both the mags were on.

And we also knew it was a fouled plug because, frankly, this wasn’t our first rodeo. In fact, we’d been riding in this very rodeo not two weeks before in Santa Fe, when we picked Warbler up following the installation of his new tail. One of the plugs was fouled with oil then, but the plane had only flown two hours since.

Lisa uttered a few choice words about airplanes, airplane mechanics, and the nature of the universe.

I whipped out my iPhone and Googled the instructions for trying to clear a fouled plug by burning off whatever is fouling it. Basically, this involves throttle and mixture combinations to increase the heat in the engine, but I knew it was a lost cause. Ercoupe engines aren’t really powerful enough to generate the kind of heat needed to clear a fouled plug. It failed when we tried this two weeks ago, and it failed when Lisa’s mechanic repeated the experiment, but we tried anyway on the theory that there couldn’t be too much crap on a sparkplug so recently cleaned. At least, assuming it was the same plug giving us trouble. Once we tried. Twice we tried. Thrice we tried. Just like Uncle Goggle recommended.

And as before, we failed. There was nothing left to do but to taxi back to the hangar and call Lisa’s mechanic.

He allowed as how it sounded like a plug again. And he suspected a particular one, the plug in the bottom of the right-aft cylinder, which had been oil-fouled, although he admitted that it might be one of the others that he didn’t check, as he stopped checking them once he found a problem. He offered to come over the following week, unless in the meantime we wanted to pull the plug and see if it was dirty. Always handy with a wrench, Lisa opted for that, and her mechanic talked her though the process.

And this is where we get back to horses.

We disconnected the electrode lead and, using a socket wrench, tried to remove the sparkplug. But there was a problem. The socket of the socket wrench wasn’t long enough. It didn’t reach the nut on the sparkplug.

Over the next 48 hours, I would learn more about sparkplugs than I had previously learned in my entire lifetime, but here’s the only thing you need to know for the moment: Aviation sparkplugs come in two common brands, Champion and Tempest. Champion plugs have a nut in the middle of the plug. Any garden variety socket wrench will easily reach the nut to remove the plug. Tempest plugs, however, have the nut all the way at the base of the plug, beyond the reach of standard sockets, and as we’d learn the hard way, also beyond the reach of “deep” sockets, as well.

But I’ve been long winded today, so the hunt for the nail to shoe the horse, to send the rider into battle, to save the kingdom, will have to wait until next week…